New photos of a rare interstellar comet reveal details in its glowing head and growing tail as it gets closer to the sun.
The images of Comet 3I/ATLAS were captured by the Gemini South telescope at Cerro Pachón in Chile on Aug. 27 as the icy traveler flew through the inner solar system. It’s now about 238 million miles away from Earth in space, in the constellation Libra, according to TheSkyLive.com.
These pictures allow scientists to study the comet’s light, which can give them insight into its chemical makeup. So far the data suggest 3I/ATLAS is made of dust similar to the comets native to our own solar system, perhaps indicating that the ingredients for making planets around other stars is similar.
“As 3I/ATLAS speeds back into the depths of interstellar space, this image is both a scientific milestone and a source of wonder,” said Karen Meech, a University of Hawaii astronomer, in a statement. “It reminds us that our Solar System is just one part of a vast and dynamic galaxy.”
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Unlike the swarm of comets circling the sun, Comet 3I/ATLAS formed in another star system and got ejected into interstellar space, perhaps by the gravity of a nearby planet or star. After drifting for hundreds of millions of years, the massive space snowball has arrived in our neck of the galaxy.
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Comets are icy, rocky objects that glow when they’re warmed by the sun, streaking the sky as they leave a trail of gas and dust in their wake. They’re thought to be the leftover building blocks of the solar system when it was formed 4.6 billion years ago. Scientists have identified over 4,000 of them, though many more are thought to hide beyond Neptune in the Kuiper Belt or in the distant Oort Cloud, a shell of frozen debris about 50 times farther from the sun.
But unlike Halley’s Comet and other regular visitors, 3I/ATLAS ain’t from around here. First discovered on July 1 by NASA‘s Asteroid Terrestrial-impact Last Alert System telescope, it was found more than 400 million miles from Earth and traveling 137,000 mph. That’s far too fast for the sun’s gravity to capture.
Despite its feverish speed, it poses no danger to Earth. The closest it will come to the planet is about 149 million miles away — over 1.5 times the distance between Earth and the sun. At that point in October, it will be hidden on the other side of the sun, according to the European Space Agency, but it’s expected to reemerge out of the glare in November.
Scientists say this is only the third interstellar comet ever confirmed. The first, a weird cigar-shaped object called ‘Oumuamua, passed through in 2017. Two years later, 2I/Borisov, which more closely resembles native comets, showed up.
This image combines red, green, blue, and ultraviolet exposures that cause the background stars to appear as colorful streaks while the comet stays centered in the frame.
Credit: International Gemini Observatory / NOIRLab / NSF / AURA / Shadow the Scientist / J. Miller & M. Rodriguez / T.A. Rector / M. Zamani
Computer simulations suggest 3I/ATLAS could have originated in a lesser-known part of the Milky Way rife with older stars. If that’s true, the comet might be over 7 billion years old — nearly twice the age of our own solar system — preserving material from an earlier period of the galaxy.
Because it is already venting gas and dust in the warmth of the sun, astronomers know it’s a comet. Still, some people are floating an idea to the media that this icy interloper could be some form of alien technology.
“Extraordinary claims require extraordinary evidence,” Larry Denneau, one of ATLAS’ co-principal investigators, told Mashable in August, “and the object is behaving very much like a comet.”