‘Oumuamua is unusual for visiting from beyond our solar system.

October 19, 2017. The astronomer Robert Weryk is poring through data collected by the Panoramic Survey Telescope and Rapid Response System, or Pan-STARRS for short, a network of telescopes that sits atop the mountains of Maui, in Hawaii. As he looks at the day’s observations, he notices something strange.

Pan-STARRS has picked up an object jetting away from the Sun at 58,900 miles per hour. At such speeds, the object is set to soon leave our solar system forever. Yet, the object’s trajectory is even more interesting. Judging by its path, it appears that it must have come from outside our solar system!

Weryk is stunned. He’s just stumbled upon the first interstellar object ever detected by mankind.

The key message here is: ‘Oumuamua is unusual for visiting from beyond our solar system.

When Weryk delivered the news of his discovery to the International Astronomical Union, they dubbed the object ‘Oumuamua. This Hawaiian word roughly translates to “a messenger from afar arriving first,” or more simply, “scout.” It’s a fitting name, as ‘Oumuamua is the first nearby object – astronomically speaking – ever detected that does not have origins within our solar system.

So, if ‘Oumuamua isn’t a local, where is it from? Well, we don’t know exactly. What we do know is that it comes from the direction of Vega, a star located about 25 light-years away. We also know that it entered our solar system on a hyperbolic trajectory. This means that it doesn’t orbit the Sun like an asteroid or comet, but instead, it comes from the outer reaches of space, passes by the Sun once, and then escapes off into space again.

Prior to detecting ‘Oumuamua, astronomers had observed both objects within our solar system and objects very far away, like distant stars and planets. Yet, they had never seen an item from interstellar space pass through our solar neighborhood. Of course, they knew it was possible. Humans themselves have already launched five objects into interstellar space, including the Voyager, Pioneer, and New Horizons space probes.

Since this initial discovery, scientists working at Pan-STARRS have already discovered several more interstellar objects swinging by our Sun. Yet, ‘Oumuamua still stands out – and not simply because it was the first object found. In fact, ‘Oumuamua has many particular qualities and unusual traits that leave scientists puzzled. We’ll look at those in the next blink.