You might imagine that the coldest place in the universe would be deep in the recesses of space, far away from the warming rays of a star. On the contrary, it turns out that the coldest place in the universe is directly surrounding a star, albeit a dying one. The Boomerang Nebula is a cloud of gas that's being shed by a small dying star on its way to becoming a red giant. The nebula is expanding at an incredible rate, expelling gas at about 102 miles (164 km) per second. That's why it's so cold: as gas expands, its temperature drops. So why is the nebula shaped like a boomerang? It's not, actually. The first astronomers to spot it with a ground-based telescope in 1980 noticed it had a lopsided shape, and perhaps because they were Australian, a boomerang was the first thing that came to mind. Later, in the late 1990s, researchers took a higher-resolution glance with the Hubble Space Telescope and saw that it actually had a double-lobe structure, kind of like a bow-tie. Finally, in 2013, astronomers took an even closer look and found that it's just a round cloud of gas. A ring of dust had been blocking some of its light, making it look like a bow-tie.
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Key Facts In This Video
The Boomerang Nebula is a pre-planetary nebula: or a low-mass star that's near the end of its life. 00:52
The Boomerang Nebula is -458ºF (272ºC), or 1 Kelvin -- just above absolute zero. 01:45
The nebula isn't shaped like a boomerang. Astronomers once thought it was shaped like a bow-tie, but it turned out to be round -- a ring of dust was blocking some of the light. 02:42