The object, named C/2017U1, was first observed about a month ago. It was seen moving through space by the PanSTARRS1 telescope system in Hawaii. This system is a combination of multiple telescopes and cameras that specialize in identifying fast moving objects, like asteroids, comets, etc.
The object is moving very fast. It was moving at 16 miles per second (57,600 mph) when it was first observed. In comparison, our Voyager probes are travelling about half that fast. It is also in what appears to be a somewhat extreme orbit. Extreme enough not to actually be an orbit, in fact.
Observations published by the by the International Astronomical Union’s Minor Planet Center (MPC) suggest it could have come from deep space. If further observations confirm the unusual nature of this orbit, this object may be the first clear case of an interstellar “visitor.”
It was 14.9 million miles away from Earth (a little closer than Venus is to us) as it flashed past us on October 14. View the believed path of the object by clicking on the hyperlink below:
The object was only actually spotted after it was flung back out towards the stars by our Sun. How scientists know the object made a swing around our sun, if they didn’t spot it until after the event, is beyond me. In addition, if it did swing around our Sun, it seems like it must have had to come in at a pretty precise course (kind of like our astronauts “slingshotting” around our moon to return to Earth).
Apparently the object came within 23.5 million miles of The Sun (The closest planet to the Sun, Mercury, is 36 million miles away.) before its momentum and the Sun’s gravity hurled it back outward. Normally such a close pass of the Sun would be fatal for any object, but C/2017U1 was travelling too fast for the Sun’s heat to consume it.
According to these astronomers, the object appears to have come from the direction of the star Vega, in the constellation Lyra. And its path did not indicate the curved ellipse typical of regularly returning comets.
Best guesstimates make the object about 500 feet in diameter, or about the same size as a US Naval Guided Missile Destroyer.
Vega is a relatively close neighbor of our Sun at 25 light years distance. At the speed the object is travelling, it would take about 1.7 million years to cross the interstellar divide.
Regardless of what the object is, it was an incredibly rare event.
Note: Some of the information used in this article was taken from an article by Jamie Seidel, news.com.au.