Scientists from the Massachusetts Institute of Technology (MIT) have reached the coldest temperature ever recorded.
MIT scientists have cooled a sodium gas to the lowest temperature ever recorded -- only half-a-billionth of a degree above absolute zero. The work, to be reported in the Sept. 12 issue of Science, bests the previous record by a factor of six, and is the first time that a gas was cooled below 1 nanokelvin (one-billionth of a degree).
"To go below one nanokelvin is a little like running a mile under four minutes for the first time," said Nobel laureate Wolfgang Ketterle, co-leader of the team.
How did they reach this new record of 500 picokelvin?
At such low temperatures, atoms cannot be kept in physical containers, because they would stick to the walls. Furthermore, no known container can be cooled to such temperatures. Therefore, the atoms are surrounded by magnets, which keep the gaseous cloud confined.
For reaching the record-low temperatures, the MIT researchers invented a novel way of confining atoms, which they call a "gravito-magnetic trap." As the name indicates, the magnetic fields act together with gravitational forces to keep the atoms trapped.
Here is a view into the vacuum chamber where sodium atoms were cooled down to 500 picokelvin (Credit: Ketterle Lab., MIT).
Besides breaking a world record, what can we expect from such low temperatures?
"Ultra-low temperature gases could lead to vast improvements in precision measurements by allowing better atomic clocks and sensors for gravity and rotation," said David E. Pritchard, a pioneer in atom optics and atom interferometry and co-leader of the MIT group.
The researchers also expect new phenomena to occur at such low temperatures involving, for example, how cold atoms interact with surfaces and how atoms move when they are confined to a narrow channel or layer. These gases form a remarkable state of matter called a quantum fluid, so studying their properties also provides new insights into the basic physics of matter.
And obviously, you can take your time to do your research. At these temperatures, atoms are a million times slower than at normal ones and move only at two inches per minute.
Source: Massachusetts Institute of Technology, via EurekAlert!, September 11, 2003
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