Oumuamua tumbling movement
Scientists conclude that interstellar object 'Oumuamua must be very elongated because of its dramatic variations in brightness as it tumbled through space. They also conclude that vents on the surface must have emitted jets of gases, giving the object a slight boost in speed, which researchers detected by measuring the position of the object as it passed by in 2017NASA/JPL-Caltech

The first ever interstellar traveller that Earth has ever seen ­­– Oumuamua whizzed past the Earth at incredible speeds. Its unusual shape and trajectory made astronomers wonder about its origins.

Now, researchers believe that the strange object is, in fact, a comet after the celestial body had a sudden surge of speed on its way out of the Solar System. It is also a strange comet because although it has certain characteristics of one, it does not at all look like a comet. It, in fact, looks like a cigar with it being ten times as long as it is wide. NASA has now summed up everything that is currently known about Oumuamua and along with graphics to help explain the object better.

The object most definitely came from outside the Solar System. This is surprising because the Solar System is a well contained and closed-off place with the Sun protecting all its planets within layers of radiation and a massive gravitational field. Oumuamua came in at blistering speeds—about 87.3 kilometres per second—and things in the Sun's neighbourhood do not reach such speeds. When it slingshot itself around the Sun, there was no way it was moving at those speeds just based on the Sun's gravity alone, explains NASA.

Oumuamua has a hyperbolic trajectory and scientists knew when they saw it for the first time that it is not ground to be contained in the Solar System. It is moving too fast to circle around the Sun in an elliptical path. That means the object will never again be seen or heard of any time in the future.

Volatile materials on or in Oumuamua were found to be outgassing, or exiting it through a spout; this explains why the rock was behaving like a comet and accelerating away from the Solar System. It also tumbled on its way, suggesting that it had a violent past.

'Oumuamua was too small to appear as anything more than a point of light, even in the largest telescopes. But we know that it must be a highly elongated object because it varied dramatically in brightness over every 7-to-8-hour period. It appeared brightest when its full length faced the Earth (middle image), but dimmed dramatically when it was pointed towards the Earth (left and right images). The brightness variations (represented as squares on bottom row) repeated over and over as the object tumbled through spaceNASA/JPL-Caltech

As to the mysteries, NASA points out that astronomers were unable to figure out exactly what it looked like, except that it was most likely cigar-shaped. NASA is also not clear about what the rock is made of. There were speculations about it being coated with a layer of gooey carbon-rich, soft material that is deep red in colour because of all the radiation it goes through, but because of how fast it was moving, there is no way to know.

The only questions left are where it came from and where it is going and for both those queries, the answer is a simple, "no one knows". It is no more visible from Earth as its speeds were too high to keep up and it has not been seen since January this year, says NASA.

Was it a comet? Most likely. Was it from a different star system? Probably. Was it sent here by aliens as a probe to check out the Solar System? Probably not. Will we ever see it again? No.