A no-tail tale.
Astronomers have spotted a first-of-its-kind comet-asteroid hybrid that may contain pristine material from the formation of the Earth itself over 4 billion years ago.
According to a new report published in the journal Science Advances, the bizarre comet, named C/2014 S3, is carrying up to 1 million times less water than any comet every recorded, and it is made up of solid rock, like an asteroid, rather than ice, like a typical comet. What’s more, the comet doesn’t have a traditional tail, so as is expected, this newly discovered hybrid has astronomers pretty thrilled, and some are even considering rewriting the definition of what a comet should look like.
"This is super exciting, because it could be a piece of what formed Earth," one of the team members, Olivier Hainaut from the European Southern Observatory, told Maddie Stone from Gizmodo.
This tailless comet appears to have traveled from the Oort cloud, which is a massive ring of debris that encases the entire solar system, and is host to countless preserved icy comets. Due to the extreme orbits of Oort cloud comets, they only enter the inner solar system once every 200 to several thousand years, and as they make their way close to the sun, some of the ice is stripped away, vaporizing behind it.
However, there is not enough ice in this comet to create a characteristic tail. And even more bizarre is that its spectrum — the pattern of light reflected off its surface — shows that its rocky exterior has not yet been baked by the sun like all other known S-type asteroids found within the main asteroid belt between Mars and Jupiter.
"If you’d shown me the spectrum, I would have just said this is another stupid asteroid," Hainaut told Gizmodo. "If you showed me the orbit, I’d say yea, it’s a standard long-period comet. But you don’t at all expect to find a rocky asteroid on an Oort cloud orbit. That’s wrong."
C/2014 S3, or the Manx comet (nicknamed after the tailless cat), was first identified in 2014 by the Pan-STARRS1 telescope — a Hawaiian telescope used to identify rogue comets and asteroids. Manx is a small comet located about twice as far from the sun as is the Earth and has an orbital period of about 860 years.
After two years of observations and analysis of the comet, Hainaut and his team suggest that it was formed somewhere near Earth about 4 billion years ago, was nudged into the outer solar system by a random collision, spent most of its life in the Oort cloud, and is finally making its way back for the first time.
"We already knew of many asteroids, but they have all been baked by billions of years near the Sun. This one is the first uncooked asteroid we could observe: it has been preserved in the best freezer there is," explained lead author Karen Meech of the University of Hawaii's Institute for Astronomy, in a press release.
So wait, is it a comet or an asteroid? Astronomers don’t know, but they are now going to try and identify more “hybrids” to figure out if they are actual remnants of the materials that first formed Earth. And if they are, they could tell us a lot about the history of early Earth.
"We’ve found the first rocky comet, and we are looking for others," said Hainaut in the release. "Depending how many we find, we will know whether the giant planets danced across the Solar System when they were young, or if they grew up quietly without moving much."
We better get a good look of the Manx comet while we can because it won’t be back for another 860 years.
You might also like: NASA’s Asteroid-Tracker Has Spotted 72 New Near-Earth Objects