What's the Coolest Place in the Universe?

The coolest place in the Universe is nearly at absolute zero. CREDIT: International Falls Chamber of Commerce/Pete Schultz View full size image

It's not Miami Beach, if that's what you were thinking. Nor is it the North Pole.

The coldest place known is inside the Boomerang Nebula. It is in the constellation of Centaurus, 5000 light-years from Earth. Planetary nebulae form around a bright, central star when it expels gas in the last stages of its life.

The Boomerang Nebula is one of the Universe's peculiar places. In 1995, using the 15-metre Swedish ESO Submillimetre Telescope in Chile, astronomers Sahai and Nyman revealed that it is the coldest place in the Universe found so far. With a temperature of -272°C, it is only one degree warmer than absolute zero (the lowest limit for all temperatures). Even the -270°C background glow from the Big Bang is warmer than this nebula. It is the only object found so far that has a temperature lower than the background radiation.

The general bow-tie shape of the Boomerang appears to have been created by a very fierce wind, some 310,000 mph, blowing ultracold gas away from the dying central star. The star has been losing as much as one-thousandth of a solar mass of material per year for 1,500 years, astronomers say. This is 10-100 times more than in other similar objects. The rapid expansion of the nebula has enabled it to become the coldest known region in the universe.

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