Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) are required to create an Endangered Species Recovery Plan outlining the goals, tasks required, likely costs, and estimated timeline to recover endangered species (i.e., increase their numbers and improve their management to the point where they can be removed from the endangered list). The ESA does not specify when a recovery plan must be completed. The FWS has a policy specifying completion within three years of the species being listed, but the average time to completion is approximately six years. The annual rate of recovery plan completion increased steadily from the Ford administration (4) through Carter (9), Reagan (30), Bush I (44), and Clinton (72), but declined under Bush II (16 per year as of 9/1/06).

What four topics are required in an Endangered Species Recovery Plan?

goals, tasks required, likely costs, and estimated timeline to recover endangered species

What is the time limit for completing an Endangered Species Recovery Plan?

The ESA does not specify when a recovery plan must be completed.

What Recovery Plan duration the does Fish and Wildlife Service plan for in their policies?

completion within three years

What is the average time of completion of an Endangered Species Recovery Plan?

approximately six years

Which president had the most completed Recovery Plans during their administration?

Clinton (72)

What does FWS require NMFS to create?

I'm not sure.

What length of time does the NMFS policy say plans must be completed by?

I'm not sure.

What was the average completion time for an FWS plan?

I'm not sure.

Who requires the FWS to have a completion policy?

I'm not sure.

What organizations are not required to have a recovery plan?

I'm not sure.


The question to be answered is whether a listed species will be harmed by the action and, if so, how the harm can be minimized. If harm cannot be avoided, the project agency can seek an exemption from the Endangered Species Committee, an ad hoc panel composed of members from the executive branch and at least one appointee from the state where the project is to occur. Five of the seven committee members must vote for the exemption to allow taking (to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or significant habitat modification, or to attempt to engage in any such conduct) of listed species.

What is the primary consideration for determining if projects may be carried out in areas with endangered species?

whether a listed species will be harmed by the action and, if so, how the harm can be minimized

If a species may be harmed, who holds final say on whether the project may proceed?

the Endangered Species Committee

How many members are on the ad hoc panel that allows project exemptions for cases where a species may harmed?

seven

How many votes must be in favor of the exemption in order to award the exemption?

Five

What is one specific requirement regarding the make-up of the exmeption panel?

at least one appointee from the state where the project is to occur

Who does the Endangered Species Committee get an exemption from?

I'm not sure.

How many members must vote against the exemption?

I'm not sure.

How many members must a project agency have?

I'm not sure.

What do project agencies vote on?

I'm not sure.

What happens if the harm can be minimized?

I'm not sure.


Long before the exemption is considered by the Endangered Species Committee, the Forest Service, and either the FWS or the NMFS will have consulted on the biological implications of the timber harvest. The consultation can be informal, to determine if harm may occur; and then formal if the harm is believed to be likely. The questions to be answered in these consultations are whether the species will be harmed, whether the habitat will be harmed and if the action will aid or hinder the recovery of the listed species.

Who reviews exemption considerations before the Endangered Species committee?

the Forest Service, and either the FWS or the NMFS

During informal consultation, what is the goal?

to determine if harm may occur

What prompts the need for formal consultation?

if the harm is believed to be likely

What considerations are weighed during the consultations?

whether the species will be harmed, whether the habitat will be harmed and if the action will aid or hinder the recovery

Who is consulted after the Endangered Species Committee?

I'm not sure.

What implications does the Endangered Species Committee consider?

I'm not sure.

What type of consultation is used if harm is not going to occur?

I'm not sure.

What kind of consultation does the Endangered Species use when harm is likely?

I'm not sure.

Who is consulted before going to the FWS and Forest Service?

I'm not sure.


There have been six instances as of 2009 in which the exemption process was initiated. Of these six, one was granted, one was partially granted, one was denied and three were withdrawn. Donald Baur, in The Endangered Species Act: law, policy, and perspectives, concluded," ... the exemption provision is basically a nonfactor in the administration of the ESA. A major reason, of course, is that so few consultations result in jeopardy opinions, and those that do almost always result in the identification of reasonable and prudent alternatives to avoid jeopardy."

How many times has the exemption process been used, as of 2009?

six

What were the results of those exemption petitions?

one was granted, one was partially granted, one was denied and three were withdrawn

Why is this exemption provision often considered a nonfactor?

few consultations result in jeopardy opinions

How can jeopardy opinions be dissuaded?

in the identification of reasonable and prudent alternatives to avoid jeopardy.

How many exemptions were granted in 2009?

I'm not sure.

What is a key factor for the ESA?

I'm not sure.

What did Donald Baur write in 2009?

I'm not sure.

How many exemptions were withdrawn in 2009?

I'm not sure.

How many exemptions has Donald Baur ruled on?

I'm not sure.


More than half of habitat for listed species is on non-federal property, owned by citizens, states, local governments, tribal governments and private organizations. Before the law was amended in 1982, a listed species could be taken only for scientific or research purposes. The amendment created a permit process to circumvent the take prohibition called a Habitat Conservation Plan or HCP to give incentives to non-federal land managers and private landowners to help protect listed and unlisted species, while allowing economic development that may harm ("take") the species.

Who owns the majority of critical habitat?

non-federal property, owned by citizens, states, local governments, tribal governments and private organizations

What program gives incentives to private landowners to protect species on their land?

Habitat Conservation Plan

Before the amendment in 1982, under what situations could a listed species be displaced?

only for scientific or research purposes

What fraction of habitat for listed species is owned by citizens?

I'm not sure.

Who created the 1982 amendment?

I'm not sure.

When was it decided species could be taken for scientific purposes?

I'm not sure.

What purpose does the HCP state listed species cannot be taken for?

I'm not sure.

What can economic development not do under HCP?

I'm not sure.


The person or organization submits a HCP and if approved by the agency (FWS or NMFS), will be issued an Incidental Take Permit (ITP) which allows a certain number of "takes" of the listed species. The permit may be revoked at any time and can allow incidental takes for varying amounts of time. For instance, the San Bruno Habitat Conservation Plan/ Incidental Take Permit is good for 30 years and the Wal-Mart store (in Florida) permit expires after one year. Because the permit is issued by a federal agency to a private party, it is a federal action-which means other federal laws can apply, such as the National Environmental Policy Act or NEPA. A notice of the permit application action is published in the Federal Register and a public comment period of 30 to 90 days begins.

An approved HCP results in what being issued for the species?

an Incidental Take Permit (ITP)

How long do ITPs last?

allow incidental takes for varying amounts of time

How is the public made aware of ITP applications?

A notice of the permit application action is published in the Federal Register

How long does the public have to comment on ITP applications?

30 to 90 days

What is issued if an HCP is rejected?

I'm not sure.

How long does an HCP last for?

I'm not sure.

What state is San Bruno in?

I'm not sure.

What do not apply when a permit is issued?

I'm not sure.

What entity publishes the HCP for public comment?

I'm not sure.


The US Congress was urged to create the exemption by proponents of a conservation plan on San Bruno Mountain, California that was drafted in the early 1980s and is the first HCP in the nation. In the conference report on the 1982 amendments, Congress specified that it intended the San Bruno plan to act "as a model" for future conservation plans developed under the incidental take exemption provision and that "the adequacy of similar conservation plans should be measured against the San Bruno plan". Congress further noted that the San Bruno plan was based on "an independent exhaustive biological study" and protected at least 87% of the habitat of the listed butterflies that led to the development of the HCP.

What location held the first HCP?

San Bruno Mountain, California

What percentage of the critical habitat was protected for the area that received the first HCP?

What type of animal was being protected in the area that received the first HCP?

butterflies

Who did the US Congress ask to create an exemption?

I'm not sure.

When was the last permit given out?

I'm not sure.

What was the San Bruno plan compared to during its creation?

I'm not sure.

How many of the listed butterfly habitats were in San Bruno?

I'm not sure.

Who ran the biological study for the San Bruno plan?

I'm not sure.


Growing scientific recognition of the role of private lands for endangered species recovery and the landmark 1981 court decision in Palila v. Hawaii Department of Land and Natural Resources both contributed to making Habitat Conservation Plans/ Incidental Take Permits "a major force for wildlife conservation and a major headache to the development community", wrote Robert D.Thornton in the 1991 Environmental Law article, Searching for Consensus and Predictability: Habitat Conservation Planning under the Endangered Species Act of 1973.

What 1981 court decision added to the power of HCPs and ITPs for conservation?

Palila v. Hawaii Department of Land and Natural Resources

Who wrote the article "Searching for Consensus and Predictability: Habitat Conservation Planning under the Endangered Species Act of 1973."

Robert D.Thornton

What did Thornton compare the scientific and legal advances to, from the viewpoint of the development community?

a major headache

When did private lands start to have more recognition?

I'm not sure.

Who ruled on the Palila v. Hawaii Department of Land and Natural Resources?

I'm not sure.

What did Thornton say the role of private lands was like for the development community?

I'm not sure.

When was the Environmental Law magazine started?

I'm not sure.

What case limited ITP power?

I'm not sure.


The "No Surprises" rule is meant to protect the landowner if "unforeseen circumstances" occur which make the landowner's efforts to prevent or mitigate harm to the species fall short. The "No Surprises" policy may be the most controversial of the recent reforms of the law, because once an Incidental Take Permit is granted, the Fish and Wildlife Service (FWS) loses much ability to further protect a species if the mitigation measures by the landowner prove insufficient. The landowner or permittee would not be required to set aside additional land or pay more in conservation money. The federal government would have to pay for additional protection measures.

What is the name of the rule that protects the landowner if their conservation efforts fall short?

The "No Surprises" rule

Why is this particular rule so controversial?

the Fish and Wildlife Service (FWS) loses much ability to further protect a species if the mitigation measures by the landowner prove insufficient.

If the landowner fails to adequately protect the species, what penalties do they face with the "No Surprises" rule?

The landowner or permittee would not be required to set aside additional land or pay more in conservation money

Who covers the cost of additional efforts if the ITP holder's efforts fall short?

The federal government would have to pay for additional protection measures

Why is the ITP controversial?

I'm not sure.

What policy protects the species from unforeseen circumstances?

I'm not sure.

What is granted after the No Surprises rule comes into play?

I'm not sure.

What is the federal government is not required to pay for?

I'm not sure.

What does the No Surprises rule requires landowners to put aside?

I'm not sure.


The "Safe Harbor" agreement is a voluntary agreement between the private landowner and FWS. The landowner agrees to alter the property to benefit or even attract a listed or proposed species in exchange for assurances that the FWS will permit future "takes" above a pre-determined level. The policy relies on the "enhancement of survival" provision of Section §1539(a)(1)(A). A landowner can have either a "Safe Harbor" agreement or an Incidental Take Permit, or both. The policy was developed by the Clinton Administration in 1999.

What two groups are bound by a "Safe Harbor" agreement?

the private landowner and FWS

In exchange for altering the property to a more beneficial state, what does the landowner gain from the Safe Harbor agreement?

assurances that the FWS will permit future "takes" above a pre-determined level

Which presidential administration developed Safe Harbor policy?

the Clinton Administration

Are Safe Harbor agreements and ITPs mutually exclusive?

A landowner can have either a "Safe Harbor" agreement or an Incidental Take Permit, or both.

What provision is the ITP under?

I'm not sure.

When did FWS create the Safe Harbor agreement?

I'm not sure.

What form of agreement can a landowner no longer have if they acquire an ITP?

I'm not sure.

What provision relies on the Safe Harbor agreement?

I'm not sure.

What administration developed Section §1539(a)(1)(A)?

I'm not sure.


The Candidate Conservation Agreement is closely related to the "Safe Harbor" agreement, the main difference is that the Candidate Conservation Agreements With Assurances(CCA) are meant to protect unlisted species by providing incentives to private landowners and land managing agencies to restore, enhance or maintain habitat of unlisted species which are declining and have the potential to become threatened or endangered if critical habitat is not protected. The FWS will then assure that if, in the future the unlisted species becomes listed, the landowner will not be required to do more than already agreed upon in the CCA.

How do Candidate Conservation Agreements differ from Safe Harbor agreements?

Candidate Conservation Agreements With Assurances(CCA) are meant to protect unlisted species

How does a CCA help protect a private landowner?

if, in the future the unlisted species becomes listed, the landowner will not be required to do more than already agreed upon in the CCA.

How does a CCA impact unlisted species?

enhance or maintain habitat of unlisted species which are declining and have the potential to become threatened or endangered

What agreement is the Safe Harbor Agreement primarily different from?

I'm not sure.

How does the Safe Harbor agreement protect unlisted species?

I'm not sure.

What organization can make a landowner do activities beyond those agreed on in the CCA?

I'm not sure.

What does Safe Harbor protect?

I'm not sure.


Two examples of animal species recently delisted are: the Virginia northern flying squirrel (subspecies) on August, 2008, which had been listed since 1985, and the gray wolf (Northern Rocky Mountain DPS). On April 15, 2011, President Obama signed the Department of Defense and Full-Year Appropriations Act of 2011. A section of that Appropriations Act directed the Secretary of the Interior to reissue within 60 days of enactment the final rule published on April 2, 2009, that identified the Northern Rocky Mountain population of gray wolf (Canis lupus) as a distinct population segment (DPS) and to revise the List of Endangered and Threatened Wildlife by removing most of the gray wolves in the DPS.

What animal species was delisted in August 2008?

the Virginia northern flying squirrel

How long had the squirrel been listed as endangered?

listed since 1985

Which president signed an Act directing the delisting of the Northern Rocky Mountain population of gray wolf?

President Obama

What animal was added in 2008?

I'm not sure.

When was the gray wolf added to the list?

I'm not sure.

Who delisted the flying squirrel?

I'm not sure.

What did the Secretary of the Interior sign in 2011?

I'm not sure.

What is the latin name for the flying squirrel?

I'm not sure.


As of September 2012, fifty-six species have been delisted; twenty-eight due to recovery, ten due to extinction (seven of which are believed to have been extinct prior to being listed), ten due to changes in taxonomic classification practices, six due to discovery of new populations, one due to an error in the listing rule, and one due to an amendment to the Endangered Species Act specifically requiring the species delisting. Twenty-five others have been down listed from "endangered" to "threatened" status.

As of September 2012, how many species had been delisted due to recovery?

twenty-eight

Of the ten species removed due to extinction, how many are believe to have already been extinct when listed?

seven

How many species have been downgraded from endangered to threatened status?

Twenty-five

How many species were delisted due to discoveries of new populations?

six

How many species were delisted in September 2012?

I'm not sure.

How many species have gone from threatened to endangered?

I'm not sure.

How many new populations were lost?

I'm not sure.

How many species have recovered since 2012 due to changes?

I'm not sure.

When was the amendment to the ESA published?

I'm not sure.


Opponents of the Endangered Species Act argue that with over 2,000 endangered species listed, and only 28 delisted due to recovery, the success rate of 1% over nearly three decades proves that there needs to be serious reform in their methods to actually help the endangered animals and plants. Others argue that the ESA may encourage preemptive habitat destruction by landowners who fear losing the use of their land because of the presence of an endangered species; known colloquially as "Shoot, Shovel and Shut-Up." One example of such perverse incentives is the case of a forest owner who, in response to ESA listing of the red-cockaded woodpecker, increased harvesting and shortened the age at which he harvests his trees to ensure that they do not become old enough to become suitable habitat. While no studies have shown that the Act's negative effects, in total, exceed the positive effects, many economists believe that finding a way to reduce such perverse incentives would lead to more effective protection of endangered species.

How many species are currently listed?

over 2,000

What is the success rate of the list and the Endangered Species Act initiatives?

What is the name given to the act of pre-emptive habitat destruction by landowners fearing a protected species?

"Shoot, Shovel and Shut-Up."

How did a land owner impact the protected red-cockaded woodpecker species?

increased harvesting and shortened the age at which he harvests his trees to ensure that they do not become old enough to become suitable habitat

Less than how many species are still listed?

I'm not sure.

How long has the ESA been using the "Shoot, Shovel, and Shut-up" method?

I'm not sure.

What have studies shown the negative effects outweigh?

I'm not sure.

What is another name for the ESA's practices?

I'm not sure.

What is the success rate of Shoot, Shovel, and Shut-Up?

I'm not sure.


According to research published in 1999 by Alan Green and the Center for Public Integrity (CPI), loopholes in the ESA are commonly exploited in the exotic pet trade. Although the legislation prohibits interstate and foreign transactions for list species, no provisions are made for in-state commerce, allowing these animals to be sold to roadside zoos and private collectors. Additionally, the ESA allows listed species to be shipped across state lines as long as they are not sold. According to Green and the CPI, this allows dealers to "donate" listed species through supposed "breeding loans" to anyone, and in return they can legally receive a reciprocal monetary "donation" from the receiving party. Furthermore, an interview with an endangered species specialist at the US Fish and Wildlife Service revealed that the agency does not have sufficient staff to perform undercover investigations, which would catch these false "donations" and other mislabeled transactions.

What is one particular industry that exploits Endangered Species Act loopholes?

exotic pet trade

What is one particular loophole that aids roadside zoos and private collectors?

no provisions are made for in-state commerce

What allows exploitation of interstate commerce regulations?

the ESA allows listed species to be shipped across state lines as long as they are not sold

How can fake breeding loans be used to sell wildlife?

in return they can legally receive a reciprocal monetary "donation" from the receiving party.

Why are there not more arrests from undercover investigations of interstate wildlife commerce?

the US Fish and Wildlife Service revealed that the agency does not have sufficient staff to perform undercover investigations

When did people begin exploiting ESA loopholes?

I'm not sure.

What organization prevents animals from being sold to zoos or collectors?

I'm not sure.

What is the name of the endangered species specialist that was interviewed?

I'm not sure.

What agency is overstaffed?

I'm not sure.

What named organization has been exploiting loopholes?

I'm not sure.


Green and the CPI further noted another exploit of the ESA in their discussion of the critically endangered cotton-top tamarin (Saguinus oedipus). Not only had they found documentation that 151 of these primates had inadvertently made their way from the Harvard-affiliated New England Regional Primate Research Center into the exotic pet trade through the aforementioned loophole, but in October 1976, over 800 cotton-top tamarins were imported into the United States in order to beat the official listing of the species under the ESA.

The Center for Public Integrity found that 151 of what primate were moved from the New England Primate Research Center into exotic pet trade?

cotton-top tamarin

What happened in 1976 that impacted this primate's classification as Endanger?

over 800 cotton-top tamarins were imported into the United States

What school is affiliated with the New England Primate Research Center?

Harvard

What school was running the pet trade?

I'm not sure.

How many cotton-top tamarins were traded out of the US in 1976?

I'm not sure.

Who works for the New England Regional Primate Research Center?

I'm not sure.

What was the official number of the cotton-top tamarins species under the ESA?

I'm not sure.

How many primates did Harvard purchase?

I'm not sure.


Section 6 of the Endangered Species Act provided funding for development of programs for management of threatened and endangered species by state wildlife agencies. Subsequently, lists of endangered and threatened species within their boundaries have been prepared by each state. These state lists often include species which are considered endangered or threatened within a specific state but not within all states, and which therefore are not included on the national list of endangered and threatened species. Examples include Florida, Minnesota, Maine, and California.

Section 6 of the Endangered Species Act provided funding for what purpose?

development of programs for management of threatened and endangered species by state wildlife agencies

What is one notable drawback with state wildlife agencies creating their own lists?

These state lists often include species which are considered endangered or threatened within a specific state but not within all states

What states are listing species that are endangered in their own state, but that are not endangered in all other states?

Florida, Minnesota, Maine, and California

What states do not have their own lists?

I'm not sure.

What defunded the development of programs for managing endangered species?

I'm not sure.

What did Section 6 of the act separate boundaries by?

I'm not sure.

Who funded species within specific states?

I'm not sure.


A reward will be paid to any person who furnishes information which leads to an arrest, conviction, or revocation of a license, so long as they are not a local, state, or federal employee in the performance of official duties. The Secretary may also provide reasonable and necessary costs incurred for the care of fish, wildlife, and forest service or plant pending the violation caused by the criminal. If the balance ever exceeds $500,000 the Secretary of the Treasury is required to deposit an amount equal to the excess into the cooperative endangered species conservation fund.

Is the public given incentive to report Endangered Species Act violations?

A reward will be paid to any person who furnishes information which leads to an arrest, conviction, or revocation of a license

Given that a violator caused wildlife harm, who may provide financial assistance for the care of the harmed wildlife?

The Secretary

Costs over what balance lead to the Secretary of the Treasury depositing money into the cooperative endangered species conservation fund?

What do local employees get if they report information that leads to an arrest?

I'm not sure.

Up to how much is the reward worth?

I'm not sure.

What must the Secretary do if the budget is below $500,000?

I'm not sure.

What three types of employees are allowed to accept a reward?

I'm not sure.

What kind of cost does the Secretary not cover?

I'm not sure.


Vacuum is space void of matter. The word stems from the Latin adjective vacuus for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is lower than atmospheric pressure. The Latin term in vacuo is used to describe an object as being in what would otherwise be a vacuum.

The word Vacuum stems from what Latin adjective?

vacuus

What does the term used by Physicists, partial vacuum, refer to?

imperfect vacuum

What is a vacuum?

space void of matter

What type of pressure is less than atmospheric pressure in a vacuum?

gaseous

What Latin term is used to describe an object in a vacuum?

in vacuo

What Latin adjective does atmospheric pressure come from?

I'm not sure.

What is the definition of atmospheric pressure?

I'm not sure.

What do physicists often discuss will occur in a certain atmospheric pressure?

I'm not sure.

What does the term partial atmospheric pressure refer to?

I'm not sure.

What latin term is used to describe an object under atmospheric pressure?

I'm not sure.


The quality of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. Much higher-quality vacuums are possible. Ultra-high vacuum chambers, common in chemistry, physics, and engineering, operate below one trillionth (10−12) of atmospheric pressure (100 nPa), and can reach around 100 particles/cm3. Outer space is an even higher-quality vacuum, with the equivalent of just a few hydrogen atoms per cubic meter on average. According to modern understanding, even if all matter could be removed from a volume, it would still not be "empty" due to vacuum fluctuations, dark energy, transiting gamma rays, cosmic rays, neutrinos, and other phenomena in quantum physics. In the electromagnetism in the 19th century, vacuum was thought to be filled with a medium called aether. In modern particle physics, the vacuum state is considered the ground state of matter.

The Vacuum state is considered what?

the ground state of matter.

A typical vacuum cleaner produces enough suction to do what to air pressure?

reduce air pressure by around 20%

The quality of a partial vacuum refers to what?

how closely it approaches a perfect vacuum

Outer space has a high quality vacuum with what equivalent?

a few hydrogen atoms per cubic meter

If all matter is removed from a vacuum, would it be empty space?

it would still not be "empty"

What does a few hydrogen atoms per cubic meter reduce air pressure by?

I'm not sure.

What does the quality of dark energy refer to?

I'm not sure.

What does lower amounts of dark matter mean?

I'm not sure.

In what century was dark matter discovered?

I'm not sure.

What does dark matter usually operate below in space?

I'm not sure.


Historically, there has been much dispute over whether such a thing as a vacuum can exist. Ancient Greek philosophers debated the existence of a vacuum, or void, in the context of atomism, which posited void and atom as the fundamental explanatory elements of physics. Following Plato, even the abstract concept of a featureless void faced considerable skepticism: it could not be apprehended by the senses, it could not, itself, provide additional explanatory power beyond the physical volume with which it was commensurate and, by definition, it was quite literally nothing at all, which cannot rightly be said to exist. Aristotle believed that no void could occur naturally, because the denser surrounding material continuum would immediately fill any incipient rarity that might give rise to a void.

What did Aristotle believe about a void?

no void could occur naturally,

What was historically disputed about vacuums?

whether such a thing as a vacuum can exist.

What did something that was literally nothing at all,According to Plato, mean?

cannot rightly be said to exist

Aristotle thought what would fill any rarity that might give rise to a void?

denser surrounding material continuum

What did Greek philosophers believe could not occur naturally?

I'm not sure.

What language was spoken by Plato?

I'm not sure.

What did Aristotle believe were the fundamental elements of understanding physics?

I'm not sure.

What can an atom not be understood by according to Greek philosophers?

I'm not sure.

What did Ancient Greek philosophers believe atoms could not do?

I'm not sure.


In his Physics, book IV, Aristotle offered numerous arguments against the void: for example, that motion through a medium which offered no impediment could continue ad infinitum, there being no reason that something would come to rest anywhere in particular. Although Lucretius argued for the existence of vacuum in the first century BC and Hero of Alexandria tried unsuccessfully to create an artificial vacuum in the first century AD, it was European scholars such as Roger Bacon, Blasius of Parma and Walter Burley in the 13th and 14th century who focused considerable attention on these issues. Eventually following Stoic physics in this instance, scholars from the 14th century onward increasingly departed from the Aristotelian perspective in favor of a supernatural void beyond the confines of the cosmos itself, a conclusion widely acknowledged by the 17th century, which helped to segregate natural and theological concerns.

In what century did believes start to move away from Aristotle's idea regarding a void?

14th century

What thought process was used in the beginning belief of the existence of vacuums?

Stoic physics

What belief regarding a cosmic void was accepted by most in the 17th century?

a supernatural void beyond the confines of the cosmos itself

Roger Bacon,Walter Burley and Blasius of Parma were from what century?

13th and 14th

What book was written by Lucretius?

I'm not sure.

How many arguments against the void did Lucretius give in his Physics, book IV?

I'm not sure.

In what year did Aristotle first study physics?

I'm not sure.

What did Lucretuis try to unsuccessfully create in the 14th century?

I'm not sure.

What belief about a void was accepted by most in the first cenury AD?

I'm not sure.


Rapid decompression can be much more dangerous than vacuum exposure itself. Even if the victim does not hold his or her breath, venting through the windpipe may be too slow to prevent the fatal rupture of the delicate alveoli of the lungs. Eardrums and sinuses may be ruptured by rapid decompression, soft tissues may bruise and seep blood, and the stress of shock will accelerate oxygen consumption leading to hypoxia. Injuries caused by rapid decompression are called barotrauma. A pressure drop of 13 kPa (100 Torr), which produces no symptoms if it is gradual, may be fatal if it occurs suddenly.

What does Rapid decompression do to the lungs?

rupture of the delicate alveoli

What causes barotrauma?

rapid decompression

What amount of pressure drop can kill you if it occurs suddenly?

13 kPa (100 Torr),

What does acceleration of oxygen consumption do?

hypoxia

rapid decompression is more dangerous than what?

vacuum exposure

What can tissues seeping blood be more dangerous than?

I'm not sure.

What does increasing oxygen consumption do to the lungs?

I'm not sure.

Venting through the windpipe may end up rupturing eardrums and what?

I'm not sure.

What will seep out of the windpipe if you hold your breath?

I'm not sure.

What is venting through the windpipe also called?

I'm not sure.


Almost two thousand years after Plato, René Descartes also proposed a geometrically based alternative theory of atomism, without the problematic nothing–everything dichotomy of void and atom. Although Descartes agreed with the contemporary position, that a vacuum does not occur in nature, the success of his namesake coordinate system and more implicitly, the spatial–corporeal component of his metaphysics would come to define the philosophically modern notion of empty space as a quantified extension of volume. By the ancient definition however, directional information and magnitude were conceptually distinct. With the acquiescence of Cartesian mechanical philosophy to the "brute fact" of action at a distance, and at length, its successful reification by force fields and ever more sophisticated geometric structure, the anachronism of empty space widened until "a seething ferment" of quantum activity in the 20th century filled the vacuum with a virtual pleroma.

What did Descartes believe about vacuums in nature?

that a vacuum does not occur in nature

Whose work with metaphysics would come to define the notion of empty space?

Descartes

What philosophy combined with Descartes to push quantum activity in the 20th century?

Cartesian mechanical philosophy

What dichotomy did Descartes center his theory around?

I'm not sure.

What position did Plato agree with?

I'm not sure.

Where did Plato believe a vaccuum did not occur?

I'm not sure.

What philosophy was behind Plato's understanding of a vacuum?

I'm not sure.

What did Plato's discoveries about atomism come to define about empty space?

I'm not sure.


In 1930, Paul Dirac proposed a model of the vacuum as an infinite sea of particles possessing negative energy, called the Dirac sea. This theory helped refine the predictions of his earlier formulated Dirac equation, and successfully predicted the existence of the positron, confirmed two years later. Werner Heisenberg's uncertainty principle formulated in 1927, predict a fundamental limit within which instantaneous position and momentum, or energy and time can be measured. This has far reaching consequences on the "emptiness" of space between particles. In the late 20th century, so-called virtual particles that arise spontaneously from empty space were confirmed.

An infinite sea of particles with negative energy  was a model propesed by whom?

Paul Dirac

What year was the Dirac sea modeled?

When werer virtual particles confirmed?

late 20th century

What year was the uncertainty principle formed?

What theorized that time and energy can be measured?

Werner Heisenberg's uncertainty principle

What kind of energy did Werner Heisenberg believe a vacuum held?

I'm not sure.

What did Heisenberg call the particles with negative energy inside a vacuum?

I'm not sure.

What did Heisenberg predict the existence of in 1930?

I'm not sure.

How long did it take for the uncertainty principle by Dirac to be confirmed?

I'm not sure.

What in the late 20th century did Dirac theorize can be measured?

I'm not sure.


In general relativity, a vanishing stress-energy tensor implies, through Einstein field equations, the vanishing of all the components of the Ricci tensor. Vacuum does not mean that the curvature of space-time is necessarily flat: the gravitational field can still produce curvature in a vacuum in the form of tidal forces and gravitational waves (technically, these phenomena are the components of the Weyl tensor). The black hole (with zero electric charge) is an elegant example of a region completely "filled" with vacuum, but still showing a strong curvature.

what is a perfect example of a filled vacuum showing a curvature?

The black hole

Who's equations  helped to imply vanishing of the Ricci tensor?

Einstein

what produces curvature in a vacuum?

tidal forces and gravitational waves

What has no electric charge?

black hole

What kind of electric charge does a vanishing stress-energy tensor have?

I'm not sure.

What is a black hole a part of?

I'm not sure.

What field around the Earth was discovered by Einstein?

I'm not sure.

Tidal forces and gravitational waves can produce zero what?

I'm not sure.

What is the shape of a gravitational field?

I'm not sure.


But although it meets the definition of outer space, the atmospheric density within the first few hundred kilometers above the Kármán line is still sufficient to produce significant drag on satellites. Most artificial satellites operate in this region called low Earth orbit and must fire their engines every few days to maintain orbit.[citation needed] The drag here is low enough that it could theoretically be overcome by radiation pressure on solar sails, a proposed propulsion system for interplanetary travel.[citation needed] Planets are too massive for their trajectories to be significantly affected by these forces, although their atmospheres are eroded by the solar winds.

Where do most satellites operate?

low Earth orbit

What system could possibly be used for interplanetary travel?

solar sails

why do satellites need to fire engines every few day to keep orbit?

atmospheric density

above what line location in outer space to satellites orbit?

Kármán line

How often does Earth's orbit position change?

I'm not sure.

What are satellites eroded by?

I'm not sure.

What are satellites too large for their engines to be affected by?

I'm not sure.

How long is the Karman line?

I'm not sure.

What have satellite engines been suggested to be used for?

I'm not sure.


In the medieval Middle Eastern world, the physicist and Islamic scholar, Al-Farabi (Alpharabius, 872–950), conducted a small experiment concerning the existence of vacuum, in which he investigated handheld plungers in water.[unreliable source?] He concluded that air's volume can expand to fill available space, and he suggested that the concept of perfect vacuum was incoherent. However, according to Nader El-Bizri, the physicist Ibn al-Haytham (Alhazen, 965–1039) and the Mu'tazili theologians disagreed with Aristotle and Al-Farabi, and they supported the existence of a void. Using geometry, Ibn al-Haytham mathematically demonstrated that place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body. According to Ahmad Dallal, Abū Rayhān al-Bīrūnī also states that "there is no observable evidence that rules out the possibility of vacuum". The suction pump later appeared in Europe from the 15th century.

Al-Farabi concluded a perfect vacuum was incoherent using what?

handheld plungers in water.

Ibn al-Haytham used geometry to demonstrate  what?

place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body

who stated that there was no evidence to rule out a vacuum?

Abū Rayhān al-Bīrūnī

what did Al-Farabi say expanded to fill available space

air's volume

What type of pump appeared in the 15th century?

suction pump

What was Aristotle able to demonstrate about place?

I'm not sure.

In what century did Aristotle develop the suction pump?

I'm not sure.

What did Aristotle investigate to test the existence of a vacuum?

I'm not sure.

What did Aristotle suggest about the concept of a perfect vacuum after his experiment?

I'm not sure.

What did Aristotle state there was no evidence to rule out?

I'm not sure.


Medieval thought experiments into the idea of a vacuum considered whether a vacuum was present, if only for an instant, between two flat plates when they were rapidly separated. There was much discussion of whether the air moved in quickly enough as the plates were separated, or, as Walter Burley postulated, whether a 'celestial agent' prevented the vacuum arising. The commonly held view that nature abhorred a vacuum was called horror vacui. Speculation that even God could not create a vacuum if he wanted to was shut down[clarification needed] by the 1277 Paris condemnations of Bishop Etienne Tempier, which required there to be no restrictions on the powers of God, which led to the conclusion that God could create a vacuum if he so wished. Jean Buridan reported in the 14th century that teams of ten horses could not pull open bellows when the port was sealed.

Who required no restrictions regarding God's power?

Bishop Etienne Tempier

When did Buridan state that teams of ten horses could not open a bellow with a sealed port?

14th century

the 1277 Paris Condemnations led to what conclusion?

God could create a vacuum if he so wished.

What was a common belief about vacuums and nature?

nature abhorred a vacuum

what was the belief that nature abhorred a vaccuum called?

horror vacui

What did Bishop Etienne Tempier believe prevented a vacuum from forming?

I'm not sure.

What was the commonly held view in the medieval period that God could not create a vacuum called?

I'm not sure.

What point of view regarding God became popular in the 14th century?

I'm not sure.

According to Walter Burley in the 14th century, what could teams of ten horses not pull open?

I'm not sure.

What did Walter Burley require there be no restrictions on in the 14th century?

I'm not sure.


In 1654, Otto von Guericke invented the first vacuum pump and conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been partially evacuated. Robert Boyle improved Guericke's design and with the help of Robert Hooke further developed vacuum pump technology. Thereafter, research into the partial vacuum lapsed until 1850 when August Toepler invented the Toepler Pump and Heinrich Geissler invented the mercury displacement pump in 1855, achieving a partial vacuum of about 10 Pa (0.1 Torr). A number of electrical properties become observable at this vacuum level, which renewed interest in further research.

What was the vacuum created by the mercury displacement pump?

partial vacuum of about 10 Pa (0.1 Torr).

What year was the Toepler Pump invented?

What was first invented by Otto von Guericke ?

vacuum pump

Who conducted the Magdeburg experiment?

Otto von Guericke

What was made visible at a partial vacuum of 10 Pa?

A number of electrical properties

What was invented by Robert Boyle in 1654?

I'm not sure.

What was the famous experiment called that Robert Boyle conducted?

I'm not sure.

What type of vacuum did Robert Boyle achieve in 1855?

I'm not sure.

What did Heinrich Geissler help Otto von Guericke further develop?

I'm not sure.

In what year did Otto von Guericke invent the mercury displacement pump?

I'm not sure.


While outer space provides the most rarefied example of a naturally occurring partial vacuum, the heavens were originally thought to be seamlessly filled by a rigid indestructible material called aether. Borrowing somewhat from the pneuma of Stoic physics, aether came to be regarded as the rarefied air from which it took its name, (see Aether (mythology)). Early theories of light posited a ubiquitous terrestrial and celestial medium through which light propagated. Additionally, the concept informed Isaac Newton's explanations of both refraction and of radiant heat. 19th century experiments into this luminiferous aether attempted to detect a minute drag on the Earth's orbit. While the Earth does, in fact, move through a relatively dense medium in comparison to that of interstellar space, the drag is so minuscule that it could not be detected. In 1912, astronomer Henry Pickering commented: "While the interstellar absorbing medium may be simply the ether, [it] is characteristic of a gas, and free gaseous molecules are certainly there".

What was originally believed the heavens were filled with?

aether

Why were experiments done on luminiferous aether in the 19 Century?

"While the interstellar absorbing medium may be simply the ether, [it] is characteris

Who stated that the character of a gas and free molecule were in ether?

Henry Pickering

Where are the highest amounts of naturally occurring partial vacuums?

outer space

What was ether originally thought to be made of?

rigid indestructible material

What did Issac Newton believe existed in space in 1912?

I'm not sure.

What were molecules originally thought to be made of?

I'm not sure.

What is another name for mythology?

I'm not sure.

Where did the ideas about the properties of molecules come from?

I'm not sure.

What did experiments with molecules attempt to detect on the Earths orbit?

I'm not sure.


The quality of a vacuum is indicated by the amount of matter remaining in the system, so that a high quality vacuum is one with very little matter left in it. Vacuum is primarily measured by its absolute pressure, but a complete characterization requires further parameters, such as temperature and chemical composition. One of the most important parameters is the mean free path (MFP) of residual gases, which indicates the average distance that molecules will travel between collisions with each other. As the gas density decreases, the MFP increases, and when the MFP is longer than the chamber, pump, spacecraft, or other objects present, the continuum assumptions of fluid mechanics do not apply. This vacuum state is called high vacuum, and the study of fluid flows in this regime is called particle gas dynamics. The MFP of air at atmospheric pressure is very short, 70 nm, but at 100 mPa (~6997100000000000000♠1×10−3 Torr) the MFP of room temperature air is roughly 100 mm, which is on the order of everyday objects such as vacuum tubes. The Crookes radiometer turns when the MFP is larger than the size of the vanes.

What indicated the quality of a vacuum?

amount of matter remaining in the system

How is vacuum generally measured?

its absolute pressure

What does the MFP of residual gases show?

average distance that molecules will travel between collisions with each other.

What is particle gas dynamics?

study of fluid flows

What indicates the quality of residual gases?

I'm not sure.

How much matter is left in residual gases?

I'm not sure.

How are residual gases measured?

I'm not sure.

What other factors are necessary to measure residual gases?

I'm not sure.

What is the study of residual gases in a spacecraft called?

I'm not sure.


The SI unit of pressure is the pascal (symbol Pa), but vacuum is often measured in torrs, named for Torricelli, an early Italian physicist (1608–1647). A torr is equal to the displacement of a millimeter of mercury (mmHg) in a manometer with 1 torr equaling 133.3223684 pascals above absolute zero pressure. Vacuum is often also measured on the barometric scale or as a percentage of atmospheric pressure in bars or atmospheres. Low vacuum is often measured in millimeters of mercury (mmHg) or pascals (Pa) below standard atmospheric pressure. "Below atmospheric" means that the absolute pressure is equal to the current atmospheric pressure.

Absolute pressure  being equal to current atmospheric pressure means what?

"Below atmospheric"

What is a torr equal to?

displacement of a millimeter of mercury

What is another often used options to measure vacuum?

barometric scale

During what years was mercury commonly in use?

I'm not sure.

What is the barometric scale equal to?

I'm not sure.

What element did Torricelli discover in 1608?

I'm not sure.

How many pascals does the barometric scale equal?

I'm not sure.

What is another way to measure the state of being below atmospheric?

I'm not sure.


Hydrostatic gauges (such as the mercury column manometer) consist of a vertical column of liquid in a tube whose ends are exposed to different pressures. The column will rise or fall until its weight is in equilibrium with the pressure differential between the two ends of the tube. The simplest design is a closed-end U-shaped tube, one side of which is connected to the region of interest. Any fluid can be used, but mercury is preferred for its high density and low vapour pressure. Simple hydrostatic gauges can measure pressures ranging from 1 torr (100 Pa) to above atmospheric. An important variation is the McLeod gauge which isolates a known volume of vacuum and compresses it to multiply the height variation of the liquid column. The McLeod gauge can measure vacuums as high as 10−6 torr (0.1 mPa), which is the lowest direct measurement of pressure that is possible with current technology. Other vacuum gauges can measure lower pressures, but only indirectly by measurement of other pressure-controlled properties. These indirect measurements must be calibrated via a direct measurement, most commonly a McLeod gauge.

Why is mercury the better option for liquid used in a Hydrostatic gauge?

its high density and low vapour pressure

What is a vertical column of liquid in a tube which has different pressures at each end called?

Hydrostatic gauges

What is a hydrostatic gauge used for?

measure pressures ranging from 1 torr (100 Pa) to above atmospheric

Why is the McLeod gauge special?

can measure vacuums as high as 10−6 torr

An indirect measurement of pressure is most often calibrated by what?

McLeod gauge

What is the level of mercury in the air calibrated by?

I'm not sure.

What is the density level of mercury in the air?

I'm not sure.

What is used to measure mercury in the air?

I'm not sure.

What is the lowest amount of mercury that can be measured in the air?

I'm not sure.

What measurements are used to measure mercury in the air?

I'm not sure.


Thermal conductivity gauges rely on the fact that the ability of a gas to conduct heat decreases with pressure. In this type of gauge, a wire filament is heated by running current through it. A thermocouple or Resistance Temperature Detector (RTD) can then be used to measure the temperature of the filament. This temperature is dependent on the rate at which the filament loses heat to the surrounding gas, and therefore on the thermal conductivity. A common variant is the Pirani gauge which uses a single platinum filament as both the heated element and RTD. These gauges are accurate from 10 torr to 10−3 torr, but they are sensitive to the chemical composition of the gases being measured.

The fact that gases ability to conduct heat decreases with pressure is used by what form of measurement?

Thermal conductivity gauges

How is the wire filament in a Thermal conductivity gauge heated?

by running current through it

What is a Pirani gauge sensitive to?

chemical composition of the gases being measured

What is a RTD used for on a Thermal Conductivity gauge?

to measure the temperature of the filament

A Pirani gauge is accurate within what ranges?

10 torr to 10−3 torr

How does plantinums ability to conduct heat decrease?

I'm not sure.

What kind of filament does the RTD use?

I'm not sure.

How do thermal conductivity gauges use a single platinum filament as?

I'm not sure.

How quickly does a filament lose heat?

I'm not sure.

Pressure is sensitive to the heated element of what?

I'm not sure.


Ion gauges are used in ultrahigh vacuum. They come in two types: hot cathode and cold cathode. In the hot cathode version an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode gauges are accurate from 10−3 torr to 10−10 torr. The principle behind cold cathode version is the same, except that electrons are produced in a discharge created by a high voltage electrical discharge. Cold cathode gauges are accurate from 10−2 torr to 10−9 torr. Ionization gauge calibration is very sensitive to construction geometry, chemical composition of gases being measured, corrosion and surface deposits. Their calibration can be invalidated by activation at atmospheric pressure or low vacuum. The composition of gases at high vacuums will usually be unpredictable, so a mass spectrometer must be used in conjunction with the ionization gauge for accurate measurement.

What are the two types of Ion gauges?

hot cathode and cold cathode.

What affects the number of ions in a gauge?

the pressure in the gauge

What gauge is accurate from 10-2 torr to 10-9 torr?

Cold cathode gauges

What must be used for accurate measurement on the composition of gases at a high vacuums?

mass spectrometer must be used in conjunction with the ionization gauge

Why does a mass spectrometer need to be used with gauge to be accurate at high vacuum gas measurement?

composition of gases at high vacuums will usually be unpredictable

What are the two types of mass spectrometers?

I'm not sure.

In the hot cathode version what does corrosion produce?

I'm not sure.

What is ionized when electrodes travel through a mass spectrometer?

I'm not sure.

What is the accuracy of a mass spectrometer?

I'm not sure.

What is the nature of electrically heated filaments at high vacuums?

I'm not sure.


Cold or oxygen-rich atmospheres can sustain life at pressures much lower than atmospheric, as long as the density of oxygen is similar to that of standard sea-level atmosphere. The colder air temperatures found at altitudes of up to 3 km generally compensate for the lower pressures there. Above this altitude, oxygen enrichment is necessary to prevent altitude sickness in humans that did not undergo prior acclimatization, and spacesuits are necessary to prevent ebullism above 19 km. Most spacesuits use only 20 kPa (150 Torr) of pure oxygen. This pressure is high enough to prevent ebullism, but decompression sickness and gas embolisms can still occur if decompression rates are not managed.

density of oxygen like that of sea-level atmosphere is needed to do what?

sustain life at pressures much lower than atmospheric,

What is the lowest altitude where acclimatization or a suit is not needed to prevent sickness in humans?

of up to 3 km

What do colder air temperatures found at altitudes above 19km compensate for?

I'm not sure.

What is needed at altitudes of up to 3km to prevent altitiude sickness?

I'm not sure.

What do cold or oxygen-rich atmospheres usuall cause?

I'm not sure.

How much pure oxygen is in the atmosphere?

I'm not sure.

When people are acclimated to the altitude, gas embolisms and what can happen?

I'm not sure.


Humans and animals exposed to vacuum will lose consciousness after a few seconds and die of hypoxia within minutes, but the symptoms are not nearly as graphic as commonly depicted in media and popular culture. The reduction in pressure lowers the temperature at which blood and other body fluids boil, but the elastic pressure of blood vessels ensures that this boiling point remains above the internal body temperature of 37 °C. Although the blood will not boil, the formation of gas bubbles in bodily fluids at reduced pressures, known as ebullism, is still a concern. The gas may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Swelling and ebullism can be restrained by containment in a flight suit. Shuttle astronauts wore a fitted elastic garment called the Crew Altitude Protection Suit (CAPS) which prevents ebullism at pressures as low as 2 kPa (15 Torr). Rapid boiling will cool the skin and create frost, particularly in the mouth, but this is not a significant hazard.

When will a person or animal lose consciousness  when exposed to a vacuum?

after a few seconds

A shuttle astronauts prevents ebullism at 2 kPa with what item?

the Crew Altitude Protection Suit (CAPS)

What is the forming of gas bubbles in body fluids at a lowered pressure called?

ebullism

What prevents body rupture at low altitude when human body is bloated by gas bubbles?

tissues are elastic and porous

At what temperature does frost usually occur in space?

I'm not sure.

When exposed to frost who will die from ebullism within minutes?

I'm not sure.

What will frost cause in body fluids at reduced pressures?

I'm not sure.

What can a person wear to prevent frost on the skin?

I'm not sure.

What does a CAPS suit prevent frost at pressures as low as?

I'm not sure.


In ultra high vacuum systems, some very "odd" leakage paths and outgassing sources must be considered. The water absorption of aluminium and palladium becomes an unacceptable source of outgassing, and even the adsorptivity of hard metals such as stainless steel or titanium must be considered. Some oils and greases will boil off in extreme vacuums. The permeability of the metallic chamber walls may have to be considered, and the grain direction of the metallic flanges should be parallel to the flange face.

What can boil away in extreme vaccum exposure?

Some oils and greases

How should the grain direct of metallic flanges run to flange faces?

parallel

What are 2 metals that can be absorbed in an ultra high vacuum system?

stainless steel or titanium

What becomes a concern in an ultra high vacuum system regarding aluminum or palladium?

water absorption

What will boil off when aluminum absorbs water?

I'm not sure.

How should palladium be placed when it has oil on it?

I'm not sure.

What are two metals that can be absorbed in an metallic flange?

I'm not sure.

In what area will water boil off?

I'm not sure.

What will grease usually run parallel to?

I'm not sure.


In quantum mechanics and quantum field theory, the vacuum is defined as the state (that is, the solution to the equations of the theory) with the lowest possible energy (the ground state of the Hilbert space). In quantum electrodynamics this vacuum is referred to as 'QED vacuum' to distinguish it from the vacuum of quantum chromodynamics, denoted as QCD vacuum. QED vacuum is a state with no matter particles (hence the name), and also no photons. As described above, this state is impossible to achieve experimentally. (Even if every matter particle could somehow be removed from a volume, it would be impossible to eliminate all the blackbody photons.) Nonetheless, it provides a good model for realizable vacuum, and agrees with a number of experimental observations as described next.

The state with the lowest possible energy in quantum mechanics defines what ?

vacuum

A vacuum state with no matter particles or photons is called what?

QED

why is a QED vacuum impossible to achieve ?

impossible to eliminate all the blackbody photons

What is a QCD?

vacuum of quantum chromodynamics,

What are blackbody photons in quantum mechanics?

I'm not sure.

What do blackbody photons with no matter particles or photons form?

I'm not sure.

Why is a blackbody field impossible to achieve?

I'm not sure.

What would you need to remove to create a blackbody field?

I'm not sure.

What is a blackbody photon referred to in quantum mechanics?

I'm not sure.


QED vacuum has interesting and complex properties. In QED vacuum, the electric and magnetic fields have zero average values, but their variances are not zero. As a result, QED vacuum contains vacuum fluctuations (virtual particles that hop into and out of existence), and a finite energy called vacuum energy. Vacuum fluctuations are an essential and ubiquitous part of quantum field theory. Some experimentally verified effects of vacuum fluctuations include spontaneous emission and the Lamb shift. Coulomb's law and the electric potential in vacuum near an electric charge are modified.

When are electric and magnetic fields with zero average values, but their variances are not at zero?

In QED vacuum

What is a verified effect of vacuum fluctuation?

spontaneous emission

what is  vacuum fluctuation?

virtual particles that hop into and out of existence

Finite energy in a QED is called what?

vacuum energy

What modifies can Coulomb's Law in a vacuum?

vacuum near an electric charge

What part of quantum field theory are electric and magnetic fields?

I'm not sure.

What kind of properties does Coulomb's law have?

I'm not sure.

What values does vacuum energy have under Coulomb's law?

I'm not sure.

What are the variances of vacuum energy according to Coulomb's law?

I'm not sure.

What do particles defined in Colombo's law do?

I'm not sure.


Stars, planets, and moons keep their atmospheres by gravitational attraction, and as such, atmospheres have no clearly delineated boundary: the density of atmospheric gas simply decreases with distance from the object. The Earth's atmospheric pressure drops to about 6998320000000000000♠3.2×10−2 Pa at 100 kilometres (62 mi) of altitude, the Kármán line, which is a common definition of the boundary with outer space. Beyond this line, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar winds, so the definition of pressure becomes difficult to interpret. The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather. Astrophysicists prefer to use number density to describe these environments, in units of particles per cubic centimetre.

`Why does thermosphere past the Karman line vary so greatly?

due to space weather

What is commonly known as the boundary of outer space?

the Kármán line

What do Astrophysicists use to describe outer space beyond the karman line?

number density

What is more significant than isotropic gas pressure past the Karman line?

radiation pressure from the Sun and the dynamic pressure of the solar winds

What is commonly known as the boundary of the Sun?

I'm not sure.

What do astrophysicists use to describe sun radiation?

I'm not sure.

In what units do astrophysicists use to describe sun radiation?

I'm not sure.

What does the Sun's atmospheric pressure drop to at 100 km of altitude?

I'm not sure.

What becomes insidgnificant when it reaches the surface of the moon?

I'm not sure.


Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges.

What was the object to use first in widespread manner process of vacuum?

incandescent light bulb

What is produced by a vacuum and used in electron beam welding and vacuum frying?

chemical inertness

Hight to ultra-high vacuums removes what obstruction?

obstruction of air,

How does freeze drying, distillation and metallurgy benefit from a deep vacuum?

Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing

What are two things made possible by the electrical properties of vacuum?

electron microscopes and vacuum tubes

What three things are light bulbs useful for?

I'm not sure.

What are lightbulbs used to study?

I'm not sure.

What do lightbulbs allow particle beams to do without contamination?

I'm not sure.

What method of preserving food is dependant on using lightbulbs?

I'm not sure.

What are lightbulbs able to lower the boiling point of?

I'm not sure.


Manifold vacuum can be used to drive accessories on automobiles. The best-known application is the vacuum servo, used to provide power assistance for the brakes. Obsolete applications include vacuum-driven windscreen wipers and Autovac fuel pumps. Some aircraft instruments (Attitude Indicator (AI) and the Heading Indicator (HI)) are typically vacuum-powered, as protection against loss of all (electrically powered) instruments, since early aircraft often did not have electrical systems, and since there are two readily available sources of vacuum on a moving aircraft—the engine and an external venturi. Vacuum induction melting uses electromagnetic induction within a vacuum.

What provides power assistance for auto brakes?

vacuum servo

What are two available sources of vacuum on a moving airplane?

engine and an external venturi

Why are the Attitude indicator and heading indicator vacuum-powered?

protection against loss of all (electrically powered) instruments,

What does a manifold vacuum do on a car?

drive accessories

What no longer used accessories were powered by vacuum?

vacuum-driven windscreen wipers and Autovac fuel pumps

What do electrical systems use within a vacuum?

I'm not sure.

What can electrical systems be used to drive on automobiles?

I'm not sure.

What are electrical systems used to provide power assistance for on a car?

I'm not sure.

What two instruments do electrical systems usually power on some aircraft?

I'm not sure.

Why are the AI and the HI usually powered by autovac fuel pumps?

I'm not sure.


Evaporation and sublimation into a vacuum is called outgassing. All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. In man-made systems, outgassing has the same effect as a leak and can limit the achievable vacuum. Outgassing products may condense on nearby colder surfaces, which can be troublesome if they obscure optical instruments or react with other materials. This is of great concern to space missions, where an obscured telescope or solar cell can ruin an expensive mission.

what is evaporation and sublimation in a vacuum?

outgassing

When does outgassing become important in all solid or liquid materials?

vacuum pressure falls below this vapour pressure

Why can outgassing products ruin a space mission?

obscure optical instruments

What does liquid have the same effect as in a telescope?

I'm not sure.

What can solar cells limit the achievement of?

I'm not sure.

On what kind of surfaces can space missions happen?

I'm not sure.

What is the cost of a telescope for a space mission?

I'm not sure.

What is a solid touching a cold surface called?

I'm not sure.


To continue evacuating a chamber indefinitely without requiring infinite growth, a compartment of the vacuum can be repeatedly closed off, exhausted, and expanded again. This is the principle behind positive displacement pumps, like the manual water pump for example. Inside the pump, a mechanism expands a small sealed cavity to create a vacuum. Because of the pressure differential, some fluid from the chamber (or the well, in our example) is pushed into the pump's small cavity. The pump's cavity is then sealed from the chamber, opened to the atmosphere, and squeezed back to a minute size.

Repeatedly closing off a compartment of a vacuum allows what?

continue evacuating a chamber indefinitely without requiring infinite growth

How is a vacuum created inside of a manual water pump?

a mechanism expands a small sealed cavity

Why is fluid in a manual pump pushed into the pumps cavity when a small sealed cavity is expanded?

Because of the pressure differential

What are pumps based off principle of sealed compartment pulling,pushing and expanding called?

displacement pumps

What does repeatedly putting water into the atmosphere manually allow?

I'm not sure.

How is a vacuum created in the atmosphere?

I'm not sure.

What kind of growth happens when fluid enters the atmosphere?

I'm not sure.

What expands outside the pump?

I'm not sure.

What size is the vacuum in the pump?

I'm not sure.


The above explanation is merely a simple introduction to vacuum pumping, and is not representative of the entire range of pumps in use. Many variations of the positive displacement pump have been developed, and many other pump designs rely on fundamentally different principles. Momentum transfer pumps, which bear some similarities to dynamic pumps used at higher pressures, can achieve much higher quality vacuums than positive displacement pumps. Entrapment pumps can capture gases in a solid or absorbed state, often with no moving parts, no seals and no vibration. None of these pumps are universal; each type has important performance limitations. They all share a difficulty in pumping low molecular weight gases, especially hydrogen, helium, and neon.

What pump can capture gases in a solid or absorbed state?

Entrapment pumps

Entrapment pumps often work without seals, moving parts and what else?

no vibration.

What pump has a higher quality vacuum than a positive displacement pump?

Momentum transfer pumps

What can positive displacement pumps achieve more than entrapment pumps?

I'm not sure.

What can momentum transfer pumps capture?

I'm not sure.

Dynamic pumps often work without moving parts, seals and what?

I'm not sure.

What are entrapment pumps usually considered above all of the others?

I'm not sure.

What other pump do entrapment pumps have similarities to?

I'm not sure.


The lowest pressure that can be attained in a system is also dependent on many things other than the nature of the pumps. Multiple pumps may be connected in series, called stages, to achieve higher vacuums. The choice of seals, chamber geometry, materials, and pump-down procedures will all have an impact. Collectively, these are called vacuum technique. And sometimes, the final pressure is not the only relevant characteristic. Pumping systems differ in oil contamination, vibration, preferential pumping of certain gases, pump-down speeds, intermittent duty cycle, reliability, or tolerance to high leakage rates.

When multiple pumps are connected in series to produce higher vacuum it is called what?

stages

The choice of seals, or chamber geometry ,for example impact a pump. Together these are options are called what?

vacuum technique

What are two other relevant characteristics of a pumping system along with final pressure?

oil contamination, vibration

How can chamber geometry be connected?

I'm not sure.

What can oil contamination be dependent on instead of pump nature?

I'm not sure.

How do leakage rates usually happen?

I'm not sure.

What do certain gases usually help a pump achieve?

I'm not sure.

What are two other characteristics of a seal?

I'm not sure.


Fluids cannot generally be pulled, so a vacuum cannot be created by suction. Suction can spread and dilute a vacuum by letting a higher pressure push fluids into it, but the vacuum has to be created first before suction can occur. The easiest way to create an artificial vacuum is to expand the volume of a container. For example, the diaphragm muscle expands the chest cavity, which causes the volume of the lungs to increase. This expansion reduces the pressure and creates a partial vacuum, which is soon filled by air pushed in by atmospheric pressure.

What can be measured in the atmosphere?

I'm not sure.

What can a container spread and dilute?

I'm not sure.

What does fluid push into the lungs?

I'm not sure.

What moves high pressure in the atmosphere?

I'm not sure.

What can be used in a chest cavity during surgery?

I'm not sure.


The Han dynasty (Chinese: 漢朝; pinyin: Hàn cháo) was the second imperial dynasty of China, preceded by the Qin dynasty (221–207 BC) and succeeded by the Three Kingdoms period (220–280 AD). Spanning over four centuries, the Han period is considered a golden age in Chinese history. To this day, China's majority ethnic group refers to itself as the "Han people" and the Chinese script is referred to as "Han characters". It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han, and briefly interrupted by the Xin dynasty (9–23 AD) of the former regent Wang Mang. This interregnum separates the Han dynasty into two periods: the Western Han or Former Han (206 BC – 9 AD) and the Eastern Han or Later Han (25–220 AD).

What period followed the Han dynasty?

Three Kingdoms

What dynasty came before the Han dynasty?

Qin

Who founded the Han dynasty?

Liu Bang

When did the Former Han period begin?

206 BC

When did the Later Han period end?

220 AD


The emperor was at the pinnacle of Han society. He presided over the Han government but shared power with both the nobility and appointed ministers who came largely from the scholarly gentry class. The Han Empire was divided into areas directly controlled by the central government using an innovation inherited from the Qin known as commanderies, and a number of semi-autonomous kingdoms. These kingdoms gradually lost all vestiges of their independence, particularly following the Rebellion of the Seven States. From the reign of Emperor Wu onward, the Chinese court officially sponsored Confucianism in education and court politics, synthesized with the cosmology of later scholars such as Dong Zhongshu. This policy endured until the fall of the Qing dynasty in AD 1911.

When did the Qing dynasty fall?

AD 1911

What innovation was acquired from the Qin?

commanderies

What philosphy in education was sanctioned by the Chinese court?

Confucianism

What was an attributing factor that caused kingdoms to lose their Independence during the Han dynasty?

the Rebellion of the Seven States

What class did a majority of appointed ministers come from during the Han dynasty?

scholarly gentry


The Han dynasty was an age of economic prosperity and saw a significant growth of the money economy first established during the Zhou dynasty (c. 1050–256 BC). The coinage issued by the central government mint in 119 BC remained the standard coinage of China until the Tang dynasty (618–907 AD). The period saw a number of limited institutional innovations. To pay for its military campaigns and the settlement of newly conquered frontier territories, the government nationalized the private salt and iron industries in 117 BC, but these government monopolies were repealed during the Eastern Han period. Science and technology during the Han period saw significant advances, including papermaking, the nautical steering rudder, the use of negative numbers in mathematics, the raised-relief map, the hydraulic-powered armillary sphere for astronomy, and a seismometer employing an inverted pendulum.

In what year did the central government issue coins?

119 BC

What industry did the government use to help pay for its military campaigns?

iron

In what period did several government monopolies become repealed?

Eastern Han

A money based economy was first entrenched in what dynasty?

Zhou

A seismometer during the Han dynasty used what type of pendulum?

inverted


The Xiongnu, a nomadic steppe confederation, defeated the Han in 200 BC and forced the Han to submit as a de facto inferior partner, but continued their raids on the Han borders. Emperor Wu of Han (r. 141–87 BC) launched several military campaigns against them. The ultimate Han victory in these wars eventually forced the Xiongnu to accept vassal status as Han tributaries. These campaigns expanded Han sovereignty into the Tarim Basin of Central Asia, divided the Xiongnu into two separate confederations, and helped establish the vast trade network known as the Silk Road, which reached as far as the Mediterranean world. The territories north of Han's borders were quickly overrun by the nomadic Xianbei confederation. Emperor Wu also launched successful military expeditions in the south, annexing Nanyue in 111 BC and Dian in 109 BC, and in the Korean Peninsula where the Xuantu and Lelang Commanderies were established in 108 BC.

Which confederation defeated the Han in 200 BC?

The Xiongnu

What type of campaign helped establish the Silk Road?

military

In what year was Nanyue annexed?

111 BC

Which confederation conquered the territories north of the Han's border?

Xianbei

In what year did Emperor Wu of Han's reign end?

87 BC


After 92 AD, the palace eunuchs increasingly involved themselves in court politics, engaging in violent power struggles between the various consort clans of the empresses and empress dowagers, causing the Han's ultimate downfall. Imperial authority was also seriously challenged by large Daoist religious societies which instigated the Yellow Turban Rebellion and the Five Pecks of Rice Rebellion. Following the death of Emperor Ling (r. 168–189 AD), the palace eunuchs suffered wholesale massacre by military officers, allowing members of the aristocracy and military governors to become warlords and divide the empire. When Cao Pi, King of Wei, usurped the throne from Emperor Xian, the Han dynasty ceased to exist.

Which religious societies instigated the Yellow Turban Rebellion?

Daoist

Who killed the palace eunichs after the death of Emperor Ling?

military officers

Which King took the seat of power from Emperor Xian?

Cao Pi

Who was the last Emperor of the Han dynasty?

Xian

In what year did Emperor Ling die?

189 AD


China's first imperial dynasty was the Qin dynasty (221–206 BC). The Qin unified the Chinese Warring States by conquest, but their empire became unstable after the death of the first emperor Qin Shi Huangdi. Within four years, the dynasty's authority had collapsed in the face of rebellion. Two former rebel leaders, Xiang Yu (d. 202 BC) of Chu and Liu Bang (d. 195 BC) of Han, engaged in a war to decide who would become hegemon of China, which had fissured into 18 kingdoms, each claiming allegiance to either Xiang Yu or Liu Bang. Although Xiang Yu proved to be a capable commander, Liu Bang defeated him at Battle of Gaixia (202 BC), in modern-day Anhui. Liu Bang assumed the title "emperor" (huangdi) at the urging of his followers and is known posthumously as Emperor Gaozu (r. 202–195 BC). Chang'an was chosen as the new capital of the reunified empire under Han.

With what action did the Qin bring together the Chinese Warring States?

conquest

Which commander did Liu Bang defeat in the Battle of Gaixia?

Xiang Yu

Who was the first emperor during the Qin dynasty?

Qin Shi Huangdi

What ultimately caused the Qin dynasty's authority to be dissolved?

rebellion

Who urged Liu Bang to become emperor?

his followers


At the beginning of the Western Han dynasty, thirteen centrally controlled commanderies—including the capital region—existed in the western third of the empire, while the eastern two-thirds were divided into ten semi-autonomous kingdoms. To placate his prominent commanders from the war with Chu, Emperor Gaozu enfeoffed some of them as kings. By 157 BC, the Han court had replaced all of these kings with royal Liu family members, since the loyalty of non-relatives to the throne was questioned. After several insurrections by Han kings—the largest being the Rebellion of the Seven States in 154 BC—the imperial court enacted a series of reforms beginning in 145 BC limiting the size and power of these kingdoms and dividing their former territories into new centrally controlled commanderies. Kings were no longer able to appoint their own staff; this duty was assumed by the imperial court. Kings became nominal heads of their fiefs and collected a portion of tax revenues as their personal incomes. The kingdoms were never entirely abolished and existed throughout the remainder of Western and Eastern Han.

How many commanderies were in the western third of the empire?

thirteen

Who could appoint staff to the kings?

imperial court

When was the Rebellion of the Seven States?

154 BC

From what source did kings derive their personal income from?

tax revenues

The Han court replaced several kings with members of what royal family?

Liu


To the north of China proper, the nomadic Xiongnu chieftain Modu Chanyu (r. 209–174 BC) conquered various tribes inhabiting the eastern portion of the Eurasian Steppe. By the end of his reign, he controlled Manchuria, Mongolia, and the Tarim Basin, subjugating over twenty states east of Samarkand. Emperor Gaozu was troubled about the abundant Han-manufactured iron weapons traded to the Xiongnu along the northern borders, and he established a trade embargo against the group. Although the embargo was in place, the Xiongnu found traders willing to supply their needs. Chinese forces also mounted surprise attacks against Xiongnu who traded at the border markets. In retaliation, the Xiongnu invaded what is now Shanxi province, where they defeated the Han forces at Baideng in 200 BC. After negotiations, the heqin agreement in 198 BC nominally held the leaders of the Xiongnu and the Han as equal partners in a royal marriage alliance, but the Han were forced to send large amounts of tribute items such as silk clothes, food, and wine to the Xiongnu.

Who was the chieftain of the Xiongnu?

Modu Chanyu

What group had a trade embargo created against them?

the Xiongnu

In what year were Han forces defeated in Baideng?

200 BC

What agreement established equality between the Xiongnu and the Han?

heqin

What type of clothing were sent as a tribute to the Xiongnu?

silk clothes


Despite the tribute and a negotiation between Laoshang Chanyu (r. 174–160 BC) and Emperor Wen (r. 180–157 BC) to reopen border markets, many of the Chanyu's Xiongnu subordinates chose not to obey the treaty and periodically raided Han territories south of the Great Wall for additional goods. In a court conference assembled by Emperor Wu (r. 141–87 BC) in 135 BC, the majority consensus of the ministers was to retain the heqin agreement. Emperor Wu accepted this, despite continuing Xiongnu raids. However, a court conference the following year convinced the majority that a limited engagement at Mayi involving the assassination of the Chanyu would throw the Xiongnu realm into chaos and benefit the Han. When this plot failed in 133 BC, Emperor Wu launched a series of massive military invasions into Xiongnu territory. Chinese armies captured one stronghold after another and established agricultural colonies to strengthen their hold. The assault culminated in 119 BC at the Battle of Mobei, where the Han commanders Huo Qubing (d. 117 BC) and Wei Qing (d. 106 BC) forced the Xiongnu court to flee north of the Gobi Desert.

The heqin agreement was reaffirmed by a court conference in what year?

135 BC

In what year did Emperor Wu begin a series of attacks in Xiongnu territories?

133 BC

What type of colony did Chinese armies use to help firm their hold on the strongholds that they had taken over?

agricultural

In what year did the Battle of Mobei take place?

119 BC

Which Han commander died in the year 106 BC?

Wei Qing


In 121 BC, Han forces expelled the Xiongnu from a vast territory spanning the Hexi Corridor to Lop Nur. They repelled a joint Xiongnu-Qiang invasion of this northwestern territory in 111 BC. In that year, the Han court established four new frontier commanderies in this region: Jiuquan, Zhangyi, Dunhuang, and Wuwei. The majority of people on the frontier were soldiers. On occasion, the court forcibly moved peasant farmers to new frontier settlements, along with government-owned slaves and convicts who performed hard labor. The court also encouraged commoners, such as farmers, merchants, landowners, and hired laborers, to voluntarily migrate to the frontier.

Who made up a majority of the people on the frontier?

soldiers

Who forced peasant farmers to move to new settlements?

the court

In what year did Han forces stop a joint Xiongnu-Qiang invasion?

111 BC

Where were landowners encouraged to migrate willingly to?

the frontier

How many commanderies in the new frontier were created by the Han court in the year 111 BC?

four


Even before Han's expansion into Central Asia, diplomat Zhang Qian's travels from 139 to 125 BC had established Chinese contacts with many surrounding civilizations. Zhang encountered Dayuan (Fergana), Kangju (Sogdiana), and Daxia (Bactria, formerly the Greco-Bactrian Kingdom); he also gathered information on Shendu (Indus River valley of North India) and Anxi (the Parthian Empire). All of these countries eventually received Han embassies. These connections marked the beginning of the Silk Road trade network that extended to the Roman Empire, bringing Han items like silk to Rome and Roman goods such as glasswares to China.

What type of Roman item was traded on the Silk Road network?

glasswares

Which diplomat helped gather information on the country of Anxi?

Zhang Qian

When did Zhang Qian end his travels?

125 BC

Which network was used to exchange goods with Rome?

Silk Road

What empire had established an embassy in Anxi?

Han


From roughly 115 to 60 BC, Han forces fought the Xiongnu over control of the oasis city-states in the Tarim Basin. Han was eventually victorious and established the Protectorate of the Western Regions in 60 BC, which dealt with the region's defense and foreign affairs. The Han also expanded southward. The naval conquest of Nanyue in 111 BC expanded the Han realm into what are now modern Guangdong, Guangxi, and northern Vietnam. Yunnan was brought into the Han realm with the conquest of the Dian Kingdom in 109 BC, followed by parts of the Korean Peninsula with the colonial establishments of Xuantu Commandery and Lelang Commandery in 108 BC. In China's first known nationwide census taken in 2 AD, the population was registered as having 57,671,400 individuals in 12,366,470 households.

Which group did Han forces fight in the Tarm Basin?

the Xiongnu

When was the first national census taken in China?

2 AD

What was the population of China in 2 AD?

What year was the Protectorate of Western Regions created in?

60 BC

Which kingdom did the Han conquer in 109 BC?

Dian


To pay for his military campaigns and colonial expansion, Emperor Wu nationalized several private industries. He created central government monopolies administered largely by former merchants. These monopolies included salt, iron, and liquor production, as well as bronze-coin currency. The liquor monopoly lasted only from 98 to 81 BC, and the salt and iron monopolies were eventually abolished in early Eastern Han. The issuing of coinage remained a central government monopoly throughout the rest of the Han dynasty. The government monopolies were eventually repealed when a political faction known as the Reformists gained greater influence in the court. The Reformists opposed the Modernist faction that had dominated court politics in Emperor Wu's reign and during the subsequent regency of Huo Guang (d. 68 BC). The Modernists argued for an aggressive and expansionary foreign policy supported by revenues from heavy government intervention in the private economy. The Reformists, however, overturned these policies, favoring a cautious, non-expansionary approach to foreign policy, frugal budget reform, and lower tax-rates imposed on private entrepreneurs.

Who made up the bulk of the administrators of the new government monopolies?

former merchants

When was the liquor monopoly abolished?

81 BC

Which faction did the Reformists oppose?

Modernist

Which political faction favored budgetary reform?

The Reformists

In what year did Huo Guang die?

68 BC


Wang Mang initiated a series of major reforms that were ultimately unsuccessful. These reforms included outlawing slavery, nationalizing land to equally distribute between households, and introducing new currencies, a change which debased the value of coinage. Although these reforms provoked considerable opposition, Wang's regime met its ultimate downfall with the massive floods of c. 3 AD and 11 AD. Gradual silt buildup in the Yellow River had raised its water level and overwhelmed the flood control works. The Yellow River split into two new branches: one emptying to the north and the other to the south of the Shandong Peninsula, though Han engineers managed to dam the southern branch by 70 AD.

Who tried to outlaw slavery?

Wang Mang

What caused the water level in the Yellow River to increase?

Gradual silt buildup

Who created a dam in the southern branch of The Yellow River?

Han engineers

What emptied out to the south of the Shandong Peninsula?

The Yellow River

What caused the end of Wang Mang's regime?

massive floods


The period between the foundation of the Han dynasty and Wang Mang's reign is known as the Western Han dynasty (simplified Chinese: 西汉; traditional Chinese: 西漢; pinyin: Xī Hàn) or Former Han dynasty (simplified Chinese: 前汉; traditional Chinese: 前漢; pinyin: Qiánhàn) (206 BC – 9 AD). During this period the capital was at Chang'an (modern Xi'an). From the reign of Guangwu the capital was moved eastward to Luoyang. The era from his reign until the fall of Han is known as the Eastern Han dynasty (simplified Chinese: 东汉; traditional Chinese: 東漢; pinyin: Dōng Hàn) or the Later Han dynasty (simplified Chinese: 后汉; traditional Chinese: 後漢; pinyin: Hòu Hàn) (25–220 AD).

Where did the capital move to after the reign of Guangwu?

Luoyang

What era does the reign of Guangwu fall under?

Eastern Han dynasty

What can the Eastern Han dynasty also be called?

Later Han dynasty

Where was the capital located during the Western Han dynasty?

Chang'an

What can the Western Han dynasty also be called?

Former Han dynasty


The Eastern Han, also known as the Later Han, formally began on 5 August 25, when Liu Xiu became Emperor Guangwu of Han. During the widespread rebellion against Wang Mang, the state of Goguryeo was free to raid Han's Korean commanderies; Han did not reaffirm its control over the region until AD 30. The Trưng Sisters of Vietnam rebelled against Han in AD 40. Their rebellion was crushed by Han general Ma Yuan (d. AD 49) in a campaign from AD 42–43. Wang Mang renewed hostilities against the Xiongnu, who were estranged from Han until their leader Bi (比), a rival claimant to the throne against his cousin Punu (蒲奴), submitted to Han as a tributary vassal in AD 50. This created two rival Xiongnu states: the Southern Xiongnu led by Bi, an ally of Han, and the Northern Xiongnu led by Punu, an enemy of Han.

On what date did the Eastern Han dynasty begin?

5 August 25

Which state raided Han's Korean commanderies?

Goguryeo

Who started a rebellion against Han in the year AD 40?

The Trưng Sisters of Vietnam

In what year did Ma Yuan die?

AD 49

Who was the leader of the Xiongnu?

Bi


During the turbulent reign of Wang Mang, Han lost control over the Tarim Basin, which was conquered by the Northern Xiongnu in AD 63 and used as a base to invade Han's Hexi Corridor in Gansu. Dou Gu (d. 88 AD) defeated the Northern Xiongnu at the Battle of Yiwulu in AD 73, evicting them from Turpan and chasing them as far as Lake Barkol before establishing a garrison at Hami. After the new Protector General of the Western Regions Chen Mu (d. AD 75) was killed by allies of the Xiongnu in Karasahr and Kucha, the garrison at Hami was withdrawn. At the Battle of Ikh Bayan in AD 89, Dou Xian (d. AD 92) defeated the Northern Xiongnu chanyu who then retreated into the Altai Mountains. After the Northern Xiongnu fled into the Ili River valley in AD 91, the nomadic Xianbei occupied the area from the borders of the Buyeo Kingdom in Manchuria to the Ili River of the Wusun people. The Xianbei reached their apogee under Tanshihuai (檀石槐) (d. AD 180), who consistently defeated Chinese armies. However, Tanshihuai's confederation disintegrated after his death.

Which Basin did the Han lose authority of?

Tarim

When did Chen Mu die?

AD 75

Where did the Northern Xiongnu flee to in AD 91?

Ili River valley

Who was the Protector General of the Western Regions?

Chen Mu

Who conquered the Tarim Basin in AD 63?

the Northern Xiongnu


Ban Chao (d. AD 102) enlisted the aid of the Kushan Empire, occupying the area of modern India, Pakistan, Afghanistan, and Tajikistan, to subdue Kashgar and its ally Sogdiana. When a request by Kushan ruler Vima Kadphises (r. c. 90–c. 100 AD) for a marriage alliance with the Han was rejected in AD 90, he sent his forces to Wakhan (Afghanistan) to attack Ban Chao. The conflict ended with the Kushans withdrawing because of lack of supplies. In AD 91, the office of Protector General of the Western Regions was reinstated when it was bestowed on Ban Chao.

Which ruler requested a marriage alliance with the Han in AD 90?

Vima Kadphises

Who was the Protector General of the Western Regions in AD 91?

Ban Chao

Which empire was asked to help subdue Kashgar?

Kushan

Which empire sent armies to attack Ban Chao?

Kushan

Who was allied with Kashgar?

Sogdiana


In addition to tributary relations with the Kushans, the Han Empire received gifts from the Parthian Empire, from a king in modern Burma, from a ruler in Japan, and initiated an unsuccessful mission to Daqin (Rome) in AD 97 with Gan Ying as emissary. A Roman embassy of Emperor Marcus Aurelius (r. 161–180 AD) is recorded in the Hou Hanshu to have reached the court of Emperor Huan of Han (r. AD 146–168) in AD 166, yet Rafe de Crespigny asserts that this was most likely a group of Roman merchants. Other travelers to Eastern-Han China included Buddhist monks who translated works into Chinese, such as An Shigao of Parthia, and Lokaksema from Kushan-era Gandhara, India.

Which member of the Han Empire was sent to Daqin in AD 97?

Gan Ying

Who translated written works into Chinese?

Buddhist monks

Who reached the court of Emperor Huan in AD 166?

A Roman embassy

When did Emperor Huan's reign begin?

AD 146

Which empire sent the Han gifts?

Parthian


Emperor Zhang's (r. 75–88 AD) reign came to be viewed by later Eastern Han scholars as the high point of the dynastic house. Subsequent reigns were increasingly marked by eunuch intervention in court politics and their involvement in the violent power struggles of the imperial consort clans. With the aid of the eunuch Zheng Zhong (d. 107 AD), Emperor He (r. 88–105 AD) had Empress Dowager Dou (d. 97 AD) put under house arrest and her clan stripped of power. This was in revenge for Dou's purging of the clan of his natural mother—Consort Liang—and then concealing her identity from him. After Emperor He's death, his wife Empress Deng Sui (d. 121 AD) managed state affairs as the regent empress dowager during a turbulent financial crisis and widespread Qiang rebellion that lasted from 107 to 118 AD.

Who was prevented from leaving their house?

Empress Dowager Dou

When did Emperor He's reign end?

105 AD

Who managed the state after the death of Emperor He?

Empress Deng Sui

When did the Qiang rebellion end?

118 AD

Who concealed the identity of Emperor He's mother?

Empress Dowager Dou


When Empress Dowager Deng died, Emperor An (r. 106–125 AD) was convinced by the accusations of the eunuchs Li Run (李閏) and Jiang Jing (江京) that Deng and her family had planned to depose him. An dismissed Deng's clan members from office, exiled them and forced many to commit suicide. After An's death, his wife, Empress Dowager Yan (d. 126 AD) placed the child Marquess of Beixiang on the throne in an attempt to retain power within her family. However, palace eunuch Sun Cheng (d. 132 AD) masterminded a successful overthrow of her regime to enthrone Emperor Shun of Han (r. 125–144 AD). Yan was placed under house arrest, her relatives were either killed or exiled, and her eunuch allies were slaughtered. The regent Liang Ji (d. 159 AD), brother of Empress Liang Na (d. 150 AD), had the brother-in-law of Consort Deng Mengnü (later empress) (d. 165 AD) killed after Deng Mengnü resisted Liang Ji's attempts to control her. Afterward, Emperor Huan employed eunuchs to depose Liang Ji, who was then forced to commit suicide.

Who had forced a large number of Empress Dowager Deng's clan members to kill themselves?

Emperor An

Which person plotted to overthrew the regime of Empress Dowager Yan?

Sun Cheng

Who did Emperor Huan hire to depose Liang Ji?

eunuchs

Relatives of what family were exiled after Sun Cheng had overthrown the regime?

Yan

How did Liang Ji die?

forced to commit suicide