When astronomers see something in the universe that at first glance seems like one-of-a-kind, it's bound to stir up a lot of excitement and attention. Enter comet 2I/Borisov. This mysterious visitor from the depths of space is the first identified comet to arrive here from another star. We don't know from where or when the comet started heading toward our Sun, but it won't hang around for long. The Sun's gravity is slightly deflecting its trajectory, but can't capture it because of the shape of its orbit and high velocity of about 100,000 miles per hour.
Telescopes around the world have been watching the fleeting visitor. NASA's Hubble Space Telescope has provided the sharpest views as the comet skirts by our Sun. Since October the space telescope has been following the comet like a sports photographer following horses speeding around a racetrack. Hubble revealed that the heart of the comet, a loose agglomeration of ices and dust particles, is likely no more than about 3,200 feet across, about the length of nine football fields. Though comet Borisov is the first of its kind, no doubt there are many other comet vagabonds out there, plying the space between stars. Astronomers will eagerly be on the lookout for the next mysterious visitor from far beyond.
[...] Crimean amateur astronomer Gennady Borisov discovered the comet on Aug. 30, 2019, and reported the position measurements to the International Astronomical Union's Minor Planet Center in Cambridge, Massachusetts. The Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory in Pasadena, California, working with the Minor Planet Center, computed an orbit for the comet, which shows that it came from elsewhere in our Milky Way galaxy, point of origin unknown.
(Score: 0) by Anonymous Coward on Saturday January 04 2020, @03:56PM (4 children)
Curious about the speed quoted, when they say 100k mph (160k kph), is that absolute or relative to the 67k kph earth circling the sun and 828k kph sun circles the galaxy?
Suppose the other turtles for “speed” of milky way, local cluster and universe matter too?
(Score: 2) by looorg on Saturday January 04 2020, @04:22PM (3 children)
I would assume it's relative or comparatively to our speed, I would think that you normally don't include our speed in such equations. As an example your parked car isn't going at 107000 km/h when you consider it to be standing still just cause our rock happens to orbit the sun at the time. Not to mention the other 1675 km/h as we also rotate around our own axis.
So it this also an alien probe like Oumuamua? Scouting us for the supreme alien overlords preparing their invasion fleets, or interstellar highway depending on what you believe in.
https://en.wikipedia.org/wiki/%CA%BBOumuamua [wikipedia.org]
(Score: 3, Interesting) by inertnet on Saturday January 04 2020, @04:49PM (2 children)
I read the given speed as relative to the Sun, because to astronomers its relevance is that this comet is too fast for the Sun to keep it from exiting our solar system. For NEO's their noted speed is relative to our planet, because that would be roughly the impact speed if they ever hit us.
(Score: 0) by Anonymous Coward on Saturday January 04 2020, @07:31PM
Thanks, that makes sense.
Article value has more wow since reading https://en.m.wikipedia.org/wiki/List_of_artificial_objects_leaving_the_Solar_System [wikipedia.org]
(Score: 2) by Immerman on Saturday January 04 2020, @09:18PM
>For NEO's their noted speed is relative to our planet, because that would be roughly the impact speed if they ever hit us.
Only if their relative speed is fairly high (at least several tens of km/s). An object sharing our orbit, basically at rest with respect to Earth, that drifted in close to impact Earth would hit us going roughly 11km/s. Just as something launched from the surface at 11km/s would (neglecting atmospheric drag) just barely escape Earth's gravitational influence and settle into a shared orbit around the sun.
The higher the base speed though, the less it accelerates as it approaches Earth, since it's converting potential energy to kinetic, and kinetic energy scales with the square of speed.
(Score: 0) by Anonymous Coward on Saturday January 04 2020, @05:48PM
Surely, a better analogy would be "5700 times larger than a football", or "large enough to be made of 200 billion footballs".