New infrared observations from two NASA space telescopes have solved the riddle that baffled ancient Chinese astronomers nearly 2,000 years ago.

Chinese astronomers recorded a mysterious "guest star" that appeared in the night sky in A.D. 185. The ancient cosmic event, which was described in the Chinese historical book "Book of the Later Han," had only been determined by scientists in the 1960s as the first ever recorded observation of a supernova. Now observations from NASA's Spritzer Space Telescope and the Wide-Field Infrared Survey Explorer have pinpointed the star that the Chinese astronomers saw 2,000 years ago.

"I think it is very interesting that we can now say with some confidence, but not absolute certainty, that RCW 86 is the remnant of A.D. 185," said Jacco Vink of the University of Utrecht in the Netherlands, who studied the supernova remnants in 2006.

The supernova was easily observed because the RCW 86 detonated in a region that was free of space dust and gas. This allowed the explosion to travel much faster and farther than it would have otherwise.

"This supernova remnant got really big, really fast," said Brian Williams, an astronomer at North Carolina State University in Raleigh, and lead author of the study. "It's two to three times bigger than we would expect for a supernova that was witnessed exploding nearly 2,000 years ago. Now, we've been able to finally pinpoint the cause."

RCW 86 is located about 8,000 light years from Earth and is a Type1a supernova which is triggered by the death of a white-dwarf star.

"A white dwarf is like a smoking cinder from a burnt-out fire," Williams said. "If you pour gasoline on it, it will explode."

The data from the Spritzer Telescope and WISE was able to clear the mystery of why the supernova was so big. The study reveals that the white dwarf can create a cavity-like empty region in space around itself before it exploded in a supernova event. The cavity would explain why the remains of RCW 86 were spread over a relatively larger area than they should for a similar explosion. When the explosion happened, the cavity allowed the material from the star to eject without any hindrance from space dust and gas.

NASA has been in the news quite a lot lately, so we compiled photos that highlights news from the space agency. Click "START" to see the photos.

NASA