The object was first spotted on October 19, 2017, by the Pan-STARRS 1 telescope in Hawaii. It had made its journey around the Sun and was heading out of the Solar System, so astronomers raced to get as much data as possible.
And race they did. Using a variety of observatories, including the European Southern Observatory’s (ESO) powerful Very Large Telescope (VLT) in Chile, they were able to work out its size, color, shape, and more.
“We had to act quickly,” team member Olivier Hainaut from ESO in Garching, Germany said in the statement. “`Oumuamua had already passed its closest point to the Sun and was heading back into interstellar space.”
Now, astronomers are continuing to observe the object in the hope of getting even more data, including where it came from. There have been some suggestions so far, including a star cluster about 200 light-years away, but we don't know for sure. If it's like asteroids in our Solar System, though, it could have been born in a planetary system just like ours.
At least one interstellar object is thought to pass into our Solar System every year, but they're hard to spot, which is why this is the first. It's hoped that upcoming telescopes like the Large Synoptic Survey Telescope (LSST) could find more in the feature.
And that, well, is just freaking awesome. A tiny rock from another planetary system made its way here, waved, and headed off to space. Farewell, interstellar traveller.