It took 70 years to realize Einstein's concept of Bose-Einstein
condensation in a gas. It was first accomplished by Eric Cornell
and Carl Wieman in Boulder, Colorado in 1995. They did it
by cooling atoms to a much lower temperature than had been previously achieved.
Their technique used laser light to first cool and
hold the atoms, and then these atoms were further cooled by
something called evaporative cooling.
That looks like a pretty simple piece of equipment for such an
important experiment. Is that really all there was?
Not exactly. There is a table full of equipment associated with
the lasers, and they needed to produce exactly the right
color of light. Also there is a computer and a bunch of other electronic
equipment for controlling everything and making measurements.
Still, it was a pretty simple and inexpensive apparatus compared to
many physics experiments today. It only cost about $50,000-100,000 for the equipment, but
that does not include a lot of hard work that went into putting it all together!
So how cold do the atoms have to be to reach BEC?
Less than 1 millionth of a degree above Absolute Zero, which is
millions of times colder than the lowest temperature found in the
depths of outer space. (Click here for more
information about Temperature)
That sounds pretty cold. How do they do it?
Well it takes two stages. Sort of like taking a pan out of a hot
oven and letting it cool off in air first, and then dunking it in
ice water. Except the first step here is to shine laser light on
the atoms to cool them to about 1/10,000 of a degree above Absolute zero, and
the second step is to evaporatively cool them further.
It took 70 years to realize Einstein's concept of Bose-Einstein
condensation in a gas. It was first accomplished by Eric Cornell
and Carl Wieman in Boulder, Colorado in 1995. They did it
by cooling atoms to a much lower temperature than had been previously achieved.
Their technique used laser light to first cool and
hold the atoms, and then these atoms were further cooled by
something called evaporative cooling.
That looks like a pretty simple piece of equipment for such an
important experiment. Is that really all there was?
Not exactly. There is a table full of equipment associated with
the lasers, and they needed to produce exactly the right
color of light. Also there is a computer and a bunch of other electronic
equipment for controlling everything and making measurements.
Still, it was a pretty simple and inexpensive apparatus compared to
many physics experiments today. It only cost about $50,000-100,000 for the equipment, but
that does not include a lot of hard work that went into putting it all together!
So how cold do the atoms have to be to reach BEC?
Less than 1 millionth of a degree above Absolute Zero, which is
millions of times colder than the lowest temperature found in the
depths of outer space. 
