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Physicists chilled a 10-kilogram object to the edge of ‘absolute zero’

The LIGO gravitational wave observatory in the United States is so sensitive to vibrations it can detect the tiny ripples in space-time called gravitational waves. These waves are caused by colliding black holes and other stellar cataclysms in distant galaxies, and they cause movements in the observatory much smaller than a proton.

Now we have used this sensitivity to effectively chill a 10-kilogram mass down to less than one billionth of a degree above absolute zero.

Temperature is a measure of how much, and how fast, the atoms and molecules that surround us (and that we are made of) are moving. When objects cool down, their molecules move less.

“Absolute zero” is the point where atoms and molecules stop moving entirely. However, quantum mechanics says the complete absence of motion is not really possible (due to the uncertainty principle).

Instead, in quantum mechanics the temperature of absolute zero corresponds to a “motional ground state”, which is the theoretical minimum amount of movement an object can have. The 10-kilogram mass in our experiment is about 10 trillion times heavier than the previous heaviest mass cooled to this kind of temperature, and it was cooled to nearly its motional ground state.