Until recently, every asteroid and comet that zipped by Earth came from within our solar system – but scientists believe they may have just observed an object with a trajectory not tied to our Sun. The direction of its approach suggests the asteroid came from Vega, one of the closest stars beyond our Sun. Based on preliminary observations, astronomers believe this is the first visitor of its kind to be observed.
The preliminary findings were published earlier today by the International Astronomical Union’s Minor Planet Center (MPC). Said Gareth Williams, the MPC’s associate director, “If further observations confirm the unusual nature of this orbit, this object may be the first clear case of an interstellar comet.”
When the object — named A/2017 U1 — entered the solar system, it moved at 26 km (16 miles) per second. At that speed, it could travel 8,200,000,000,000,000 km (more than 850 light years) in 10 million years.
Researchers failed to see it approach the Sun on September 9, partly because of the path of its approach and also because it is estimated to be just 160 meters (525) across. On October 18, however, observers using the PANSTARRS 1 telescope in Hawaii noticed something peculiar about its orbit. After attention was given to the comet, it was later declared to be an asteroid.
Reportedly, the PANSTARRS asteroid entered the solar system from the direction of the constellation Lyra. That’s very close to Vega, a star located 25 light years away. If calculations are correct, it took the asteroid nearly 300,000 years to reach Earth. When it passed by our planet on October 14th, it was 24,000,000 km (15,000,000 miles) away. Now, A/2017 U1 is headed out of the solar system, never again to return.