The Coldest Spot in the Known Universe
 
Jan. 30, 2014:   Everyone knows that space is cold. In the vast gulf between
stars and galaxies, the temperature of gaseous matter routinely drops to 3
degrees K, or 454 degrees below zero Fahrenheit.
 
It's about to get even colder.
 
NASA researchers are planning to create the coldest spot in the known universe
inside the International Space Station.
 
"We're going to study matter at temperatures far colder than are found
naturally," says Rob Thompson of JPL. He's the Project Scientist for NASA's
Cold Atom Lab, an atomic `refrigerator' slated for launch to the ISS in 2016.
"We aim to push effective temperatures down to 100 pico-Kelvin."
 
http://www.youtube.com/watch?v=J9_LmSTtpkI
 
A new ScienceCast video explores the strange quantum realm of NASA's new Cold
Atom Lab.   Play it
 
100 pico-Kelvin is just one ten billionth of a degree above absolute zero,
where all the thermal activity of atoms theoretically stops. At such low
temperatures, ordinary concepts of solid, liquid and gas are no longer
relevant.  Atoms interacting just above the threshold of zero energy create
new forms of matter that are essentially ... quantum.
 
Quantum mechanics is a branch of physics that describes the bizarre rules of
light and matter on atomic scales. In that realm, matter can be in two places
at once; objects behave as both particles and waves; and nothing is certain:
the quantum world runs on probability.
 
It is into this strange realm that researchers using the Cold Atom Lab will
plunge.
 
"We'll begin," says Thompson, "by studying Bose-Einstein Condensates."
 
In 1995, researchers discovered that if you took a few million rubidium atoms
and cooled them near absolute zero, they would merge into a single wave of
matter.  The trick worked with sodium, too.  In 2001, Eric Cornell of the
National Institute of Standards & Technology and Carl Wieman of University of
Colorado shared the Nobel Prize with Wolfgang Ketterle of MIT for their
independent discovery of these condensates, which Albert Einstein and
Satyendra Bose had predicted in the early 20th century.
 
If you create two BECs and put them together, they don't mix like an ordinary
gas. Instead, they can "interfere" like waves: thin, parallel layers of matter
are separated by thin layers of empty space. An atom in one BEC can add itself
to an atom in another BEC and produce - no atom at all.
 
http://coldatomlab.jpl.nasa.gov/documents/CAL_sci_poster_0709e.pdf
 
[I wish you could]
Click to download the Cold Atom Lab mission poster "The Cold Atom Lab will
allow us to study these objects at perhaps the lowest temperatures ever," says
Thompson.
 
The lab is also a place where researchers can mix super-cool atomic gasses and
see what happens. "Mixtures of different types of atoms can float together
almost completely free of perturbations," explains Thompson, "allowing us to
make sensitive measurements of very weak interactions.  This could lead to the
discovery of interesting and novel quantum phenomena."
 
The space station is the best place to do this research. Microgravity allows
researchers to cool materials to temperatures much colder than are possible on
the ground.
 
Thompson explains why:
 
"It's a basic principle of thermodynamics that when a gas expands, it cools.
Most of us have hands-on experience with this. If you spray a can of aerosols,
the can gets cold."
 
Quantum gases are cooled in much the same way.  In place of an aerosol can,
however, we have a `magnetic trap.'
 
"On the ISS, these traps can be made very weak because they do not have to
support the atoms against the pull of gravity.  Weak traps allow gases to
expand and cool to lower temperatures than are possible on the ground."
 
No one knows where this fundamental research will lead.  Even the "practical"
applications listed by Thompson-quantum sensors, matter wave interferometers,
and atomic lasers, just to name a few-sound like science fiction. "We're
entering the unknown," he says.
 
Researchers like Thompson think of the Cold Atom Lab as a doorway into the
quantum world.  Could the door swing both ways?  If the temperature drops low
enough, "we'll be able to assemble atomic wave packets as wide as a human
hair--that is, big enough for the human eye to see."  A creature of quantum
physics will have entered the macroscopic world.
 
And then the real excitement begins.
 
For more information about the Cold Atom Lab, visit coldatomlab.jpl.nasa.gov
 
Credits:
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:
Science@NASA
 
 
Regards,
 
Roger

--- D'Bridge 3.98
 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)