Astronomers have discovered what seems to be the first “interstellar object” speeding through our solar system at 15.8 miles per second. Discovered October 19 with the University of Hawaii’s Pan-STARRS 1 telescope, the object, dubbed A/2017 U1, is less than a quarter-mile in diameter. While scientists say it’s most likely an asteroid or perhaps a comet from elsewhere in our galaxy, they can’t be certain of its composition or where it may have come from until they collect more telescope data. (Members of UFO cults, please report for duty.) From NASA:
“This is the most extreme orbit I have ever seen,” said Davide Farnocchia, a scientist at NASA’s Center for Near-Earth Object Studies (CNEOS) at the agency’s Jet Propulsion Laboratory in Pasadena, California. “It is going extremely fast and on such a trajectory that we can say with confidence that this object is on its way out of the solar system and not coming back.”
The object approached our solar system from almost directly “above” the ecliptic, the approximate plane in space where the planets and most asteroids orbit the Sun, so it did not have any close encounters with the eight major planets during its plunge toward the Sun. On Sept. 2, the small body crossed under the ecliptic plane just inside of Mercury’s orbit and then made its closest approach to the Sun on Sept. 9. Pulled by the Sun’s gravity, the object made a hairpin turn under our solar system, passing under Earth’s orbit on Oct. 14 at a distance of about 15 million miles (24 million kilometers) — about 60 times the distance to the Moon. It has now shot back up above the plane of the planets and, traveling at 27 miles per second (44 kilometers per second) with respect to the Sun, the object is speeding toward the constellation Pegasus…“We have been waiting for this day for decades,” said CNEOS Manager Paul Chodas. “It’s long been theorized that such objects exist — asteroids or comets moving around between the stars and occasionally passing through our solar system — but this is the first such detection. So far, everything indicates this is likely an interstellar object, but more data would help to confirm it.”