What Is the Coolest Gas in the Universe What is the coldest air temperature ever recorded on the Earth Where was this low temperature recorded The coldest recorded temperature on Earth was -91℃ which (51) in Antarctica in 1983. We encounter an interesting situation when we discuss temperatures in (52) . Temperatures in Earth orbit actually range from about +120~C to -120~C. The temperature depends upon (53) you are in direct sunlight or shade. Obviously, -120℃ is colder than our body can safely endure. Thank NASA science for well-designed space (54) that protect astronauts from these temperature extremes. The space temperatures just discussed affect only our area of the solar (55) . Obviously, it is hotter closer to the Sun and colder as we travel away from the Sun. Astronomers estimate temperatures at Pluto are about -210℃. How cold is the lowest estimated temperature in the entire universe Again, it depends upon your (56) . We are taught it is supposedly (57) to have a temperature below absolute zero, which is -273℃, at which atoms do not move. Two scientists, whose names are Cornell and Wieman, have successfully cooled down a gas temperature barely (58) absolute zero. They won a Nobel Prize in Physics in 2001 for their work not a discovery in this car. Why is the two scientists’ work so important to science In the 1920s, Satyendra Nath Bose was studying an interesting (59) about particles we now call photons. Bose had trouble (60) other scientists to believe (61) he contacted Albert Einstein. Einstein’s calculations helped him theorize (62) behave as Bose thought but only at very cold temperatures. Scientists have also discovered that (63) atoms can help them make the world’s atomic clocks even more accurate. These clocks are so accurate today they would only lose one second (64) six million years! Such accuracy will help us travel in space because distance is velocity times time (d=v×t). With the long distances involved in space (65) to know time as accurately as possible to get accurate distance.
A. wind
B. energy
C. system
D. rays
Don’t Count on Dung "Conservationists(自然保护主义者)may be miscalculating the numbers of the threatened animals such as elephants, " say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung(粪)the creatures leave behind. The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS) in New York. Biologist Katy Payne of Cornell University in Ithaca, New York, agrees. "We really need to know elephant numbers and the evidence that we have is quite indirect, "says Payne, who electronically tracks elephants Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it’s extremely difficult to determine these rates. However, researchers counting elephants in one region tend to rely on standard decay rates established elsewhere. "But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. Using the wrong values can lead the census astray(离开正道)," says Plumptre. He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon. They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon. If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around. "This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally," says Plumptre "However accurate your dung density estimate might be the decay rate can severely affect the result." Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant’s natural range. The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions, he says" If the elephant population increases within the protected area, you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached(入侵偷猎)outside. " Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests, tracks or burrows(地洞). The first word "He" in paragraph 6 refers to
Andrew Plumptre.
B. Katy Payne.
C. Anthony Chifu Nchanji.
D. the writer of the article.
Don’t Count on Dung "Conservationists(自然保护主义者)may be miscalculating the numbers of the threatened animals such as elephants, " say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung(粪)the creatures leave behind. The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS) in New York. Biologist Katy Payne of Cornell University in Ithaca, New York, agrees. "We really need to know elephant numbers and the evidence that we have is quite indirect, "says Payne, who electronically tracks elephants Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it’s extremely difficult to determine these rates. However, researchers counting elephants in one region tend to rely on standard decay rates established elsewhere. "But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. Using the wrong values can lead the census astray(离开正道)," says Plumptre. He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon. They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon. If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around. "This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally," says Plumptre "However accurate your dung density estimate might be the decay rate can severely affect the result." Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant’s natural range. The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions, he says" If the elephant population increases within the protected area, you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached(入侵偷猎)outside. " Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests, tracks or burrows(地洞). The word "threatened" in the first sentence of the first paragraph could be best replaced by
A. "endangered".
B. "frightened".
C. "killed".
D. "angered".
Don’t Count on Dung "Conservationists(自然保护主义者)may be miscalculating the numbers of the threatened animals such as elephants, " say African and American researchers. The error occurs because of a flaw in the way they estimate animal numbers from the piles of dung(粪)the creatures leave behind. The mistake could lead researchers to think that there are twice as many elephants as there really are in some regions according to Andrew Plumptre of the Wildlife Conservation Society(WCS) in New York. Biologist Katy Payne of Cornell University in Ithaca, New York, agrees. "We really need to know elephant numbers and the evidence that we have is quite indirect, "says Payne, who electronically tracks elephants Counting elephants from planes is impossible in the vast rainforests of Central Africa. So researchers often estimate elephant numbers by counting dung piles in a given area. They also need to know the rate at which dung decays because it’s extremely difficult to determine these rates. However, researchers counting elephants in one region tend to rely on standard decay rates established elsewhere. "But researchers at the WCS have found that this decay rate varies from region to region depending on the climate and environment. Using the wrong values can lead the census astray(离开正道)," says Plumptre. He and his colleague Anthony Chifu Nchanji studied decaying elephant dung in the forests of Cameroon. They found that the dung decayed between 55 and 65 per cent more slowly than the dung in the rainforests of neighbouring Gabon. If researchers use decay rates from Gabon to count elephants in Cameroon, they would probably find more elephants than are actually around. "This could mean estimates in Cameroon are at least twice as high as those derived from decay rates calculated locally," says Plumptre "However accurate your dung density estimate might be the decay rate can severely affect the result." Plumptre also says that the dung-pile census should be carried out over a region similar in size to an elephant’s natural range. The usual technique of monitoring only small, protected areas distorts numbers because elephants move in and out of these regions, he says" If the elephant population increases within the protected area, you can not determine whether it is a real increase or whether it is due to elephants moving in because they are being poached(入侵偷猎)outside. " Plumptre says that similar problems may also affect other animal census studies that rely on indirect evidence such as nests, tracks or burrows(地洞). Why do researchers estimate elephant numbers in an area by counting dung piles
A. Because elephants are difficult to catch.
Because it is not possible to count elephants from a plane.
C. Because it is not possible to keep track of elephants.
D. Because elephants are shy animals.