单选题
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 (南极洲) in 1983.
We encounter an interesting situation when we discuss temperatures in (52) . Temperatures in Earth orbit (轨道) actually range from about +120℃ to --120℃. The temperature depends upon (53) you are in direct sunlight or shade. Obviously, -120℃ is colder than our body can (54) endure.
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 (56) from the Sun. Scientists estimate temperatures at Pluto are about --210℃. How cold is the lowest estimated temperature in the entire universe? Again, it depends upon your (57) . We are taught it is supposedly (58) to have a temperature below absolute zero, which is --273℃, at which atoms do not move. Two scientists, Cornell and Wieman, have successfully (59) down a gas to a temperature barely above absolute zero. They won a Nobel Prize in Physics in 2001 for their work--not a discovery, in this case.
Why is the two scientists' work so important to science?
In the 1920s, Satyendra Nath Bose was studying an interesting (60) about special light particles (微粒) we now call photons (光子). Bose had trouble (61) other scientists to believe his theory, so he contacted Albert Einstein. Einstein's calculations helped him theorize that atoms
(62) behave as Bose thought--but only at very cold temperatures.
Scientists have also discovered that ultra-cold (超冷) atoms can help them make the world's atomic clocks even (63) 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 (速度) times time(d= v × t) With the long distances involved in space (65) , we need to know time as accurately as possible to get accurate distance.