Baby, it's cold inside: Scientists measure the universe's coldest stuff

Physicists from Australia and the United Kingdom have created a new way of measuring matter -- and as a result they now can study the coldest objects in the universe.

Raise the temperature just an ice cube above absolute zero -- that’s -273.15 Celsius or -459.67 Fahrenheit, the temperature believed to be the lowest possible -- and ordinary science gets weird. Stuff acts strange, different laws of physics take over and a dilute gas forms into what’s called a Bose-Einstein condensate (BEC), a cold atomic substance.

A fraction of the stuff has been created in physics labs since the mid-1990s, an achievement that earned a Nobel Prize in 2001. But it’s difficult even to photograph this strange material without eradicating it, because if it absorbs even the tiniest piece of light -- a photon -- it can be destroyed.

'It's like trying to see if your fridge is cold without opening the door and turning on the light.'

— Michael Hush, a research fellow with the University of Nottingham in the U.K.

That’s like trying to see if your fridge is cold without opening the door and turning on the light, explained Michael Hush, a research fellow with the University of Nottingham in the U.K.

“We have a way to fix this problem,” Hush said.

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Hush and his colleagues have developed a technique called off-resonant imaging in which light bounces off atoms instead of being absorbed by it. “This means it is not destroyed by a single image. Instead, a few images can be taken,” Hush told

With this innovation, scientists can make extremely precise measurements of gravity, which can be used to find mineral deposits by mining companies, or in anti-stealth technology by the military. But the experiment requires significant heating, which has limited the application of the technique.

Hush has a way around that problem, too.

“We suggest using feedback to remove the heating,” he explained. “This works by taking the signal from the images and feeding it through a quantum filter which then controls the magnetic coils that are trapping [the matter].”

This allows scientists to watch the cold matter, “perhaps indefinitely, giving us much more information much more quickly,” Hush said. And it may be possible to control the frigid matter in real time, although that hasn’t been tried yet.

Hush published the results of his research in the New Journal of Physics, published by theInstitute of Physics and the German Physical Society.

Researchers who were not part of the project said they were impressed.

“It will be significant progress in the physics research of cold atoms if it can be verified,” Yifu Zhu, who teaches atomic, molecular physics and optics at Florida International University, told

Matter with a Bose-Einstein condensation state was observed in 1995, for which Eric A. Cornell, Wolfgang Ketterle and Carl E. Wieman were awarded the Nobel Prize in Physics in 2001.

“You increase the temperature of the atoms when you try to observe them, which means that it is difficult to see them and keep their temperature super-cold at the same time,” Zhu said. “The reported theoretical proposal may make it possible to observe the cold atoms and at the same time, not disturb their states.”

Though it is still very early in the research, it is likely the technique will make a significant contribution to atomic science, Dominik Schneble, a professor of physics at Stony Brook University in New York, said.