The Skinny on Our First Interstellar Visitor

In case you haven’t heard, the astronomy community is all atwitter over the first confirmed visitation from beyond our star system

No, we’re not talking aliens, not even the kind that look suspiciously like extras wearing costumes. No, Oumuamua as this visitor is called, is an oddly elongated asteroid currently whizzing through our solar system, having made its closest approach to the sun about two months ago.

Artists representation of interstellar visitor, the asteroid Oumuamua

We’ve known for a while that interstellar junk must come and go on a regular basis, but this is the first confirmation of such an event. Traveling at a whopping 45 km/s, Oumuamua is on a long hyperbolic orbit that swung it near the sun at nearly 60 km/s, and is now delivering it back whence it came. By the time it passes our heliopause, it’ll be back down to about 26 km/s, about the same relative speed as other nearby stars, one of which probably sent it our way to begin with. Objects orbiting the sun do not generally exceed 40 km/s even at closest approach.

Oumuamua is rather odd, even for interstellar junk. Wide fluctuations in its brightness lead scientists to think it’s about ten times longer than it is wide. That really shouldn’t happen, which means there may be something to learn from it. On the other hand, one does wonder if it might really be two objects stuck together, or one object with markedly different coloration on one side. Of course, it’s easy for us to speculate, but the pros have all the data and all the training, so we’ll have to go with their findings.


Even if it isn’t looking for long lost whales, Oumuamua is an odd duck, and tells us this class of objects is still worth a concerted look. Understanding our neighborhood helps us understand our own origins. It’s also part of the fundamental quest that makes us human.