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 in Antarctica in1983.
We encounter an interesting situation when we discuss temperatures in .Temperatures in Earth orbit actually range from about +120℃ to -120℃.The temperature depends upon you are in direct sunlight or shade.Obviously，-120℃ is colder than our body can safely endure.Thank NASA science for well-designed space that protect astronauts from these temperature extremes.
The space temperatures just discussed affect only our area of the solar .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 .We are taught it is supposedly to have a temperature below absolute zero，which is -273℃, at which atoms do not move.Two scientists，whose names are Comell and Wieman，have successfully cooled down a gas to a temperature barely 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 about special light particles we now call photons.Bose had trouble other scientists to believe his theory， he contacted Albert Einstein.Einsteins calculations helped him theorize that atoms behave as Bose thought but only at very cold temperatures.
Scientists have also discovered that atoms can help them make the worlds atomic clocks even more accurate.These clocks are so accurate today they would only lose one second six million years! Such accuracy will help us travel in space because distance is velocity times time.Withthe long distances involved in space , we need to know time as accurately as possible to get accurate distance.
51.A.opened B.occurred C.opposed D.operated
52.A.Earth B.space C.planet D.star
53.A.whether B.where C.what D.when
54.A.foods B.beds C.tools D.suits
55.A.wind B.energy C.system D.rays
56.A.education B.status C.knowledge D.location
57.A.reasonable B.wonderful C.impossible D.necessary
58.A.above B.below C.within D.beyond
59.A.invention B.theory C.paper D.experiment
60.A.convincing B.begging C.ordering D.forcing
61.A.and B.though C.but D.so
62.A.will B.would C.must D.can
63.A.ultra-small B.ultra-fast C.ultra-hot D.ultra-cold
64.A.any B.each C.every D.some
65.A.travel B.research C.walk D.station
答案：BBADC DCABA DBDCA