Coldest place in universe has ghostly shape

By Casey Frye, CCNN Writer

nebulae
The Boomerang Nebula is expanding very quickly.

According to NASA, one of the coldest cosmic bodies in space is the Boomerang Nebula, where temperatures can get as low as -458 degrees Fahrenheit. This “planetary nebula” doesn’t have any actual planets, but rather the forms of dying stars that have lost their outer layers and give off that beautiful glow. Now, scientists have taken a closer look at the mysterious frosty region with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope, and discovered it actually looks nothing like a boomerang at all!

When astronomers originally gazed at this particular cosmic body through old telescopes, it appeared slightly lopsided, which is how it earned its name. Then, researchers took another look though the Hubble telescope and saw it actually had a bowtie-like appearance. Now, astronomers using the ALMA realized that Hubble only told part of the nebula’s story.

“When astronomers looked at this object in 2003 with Hubble, they saw a very classic ‘hourglass’ shape,” said Raghvendra Sahai, a researcher and principal scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, and lead author of the paper. “Many planetary nebulae have this same double-lobe appearance, which is the result of streams of high-speed gas being jettisoned from the star.” The much broader structure of the Boomerang is more ghost-like and is actually expanding into space very quickly.

It’s this very process of expanding that’s causing it to be freezing cold. The researchers were able to identify its temperature by measuring how quickly the Boomerang Nebula absorbs energy from the rest of space. “This ultra-cold object is extremely intriguing and we’re learning much more about its true nature with ALMA,” said Sahai.

According to the scientists, these results will help shed light on how stars die and become planetary nebulae.

Featured image courtesy of National Radio Astronomy Observatory