Brrrr! JILA scientists have made some of the coldest molecules in the world. That is because the molecules were made from pairs of atoms of potassium and rubidium inside the coldest place in the Universe. Once you have got atoms a few millionths of a degree above the absolute coldest possible temperature, all you need to make molecules are some magnets and a radio signal.
The trick to making cold molecules is to avoid heating things up during the manufacturing process. The scientists do this by making really big molecules made of two atoms that are very far apart.
Here's how cold molecule manufacturing worked: First, the scientists made two clouds of incredibly cold atoms, one for potassium and one for rubidium. Next, they used beams of laser light to suspend the clouds in the same place. The beams of laser light created a light trap for the atoms.
Then they adjusted some magnets to make sure the big molecules wouldn't fall apart. They could do this because the cold atoms actually have tiny magnets inside of them that are sensitive to the magnets in the lab. Then, all the scientists had to do to make really cold molecules was to zap the atoms with a radio signal. After that, lots of cold molecules formed.
Debbie Jin, Jun Ye, and Carl Wieman are the JILA scientists who figured out how to make the cold molecules. They had a lot of help from their students and other young scientists.
Making the molecules was so much fun, the scientists decided to see what would happen to the molecules if potassium and rubidium atoms crashed into them. The rubidium atoms knocked the molecules right out of the light trap that had been keeping them inside the coldest place in the Universe.
But something funny happened when they tried to make the potassium atoms crash into the cold molecules. The potassium atoms avoided the cold molecules like the plague. There were almost no crashes, and the molecules stayed put inside the light trap.
Strange and interesting things happen in the coldest place in the Universe, that's for sure. —Julie Phillips