Looking Up: Aloha

Dec 4, 2017

Artist's concept of interstellar asteroid 1I/2017 U1 ('Oumuamua) as it passed through the solar system after its discovery in October 2017. The aspect ratio of up to 10:1 is unlike that of any object seen in our own solar system.
Credit European Southern Observatory / M. Kornmesser / nasa.gov

This week on Looking Up we officially welcome 1I/2017, affectionately known as "Oumuamua". To our knowledge, it's the first ever interstellar visitor to our solar system.

Did you happen to feel the entirety of the human experience tick up just a bit in the last few weeks? No? Then you likely have not heard about an object in the Colorado sky right now. You can’t see it, it’s too small, but astronomers have spotted something never before seen in human history – a visitor from another star.

Discovered back in October, this object with the name Oumuamua is not of our solar system. First spotted traveling at an amazing speed of about 86,000 miles per hour through the inner solar system, this object is traveling in a direction and at a rate that make it impossible to be from our own neighborhood. Astronomers think it is something like an asteroid that was expelled from another star system uncounted billions of years ago, and which has been travelling through interstellar space until our own Sun’s gravity dragged it in. But Oumuamua is traveling too fast to be captured, and is even now racing back into the vast empty space between the stars. It has been given the scientific label of 1I/2017  U1. The I stands for ‘interstellar,’ the very first object so designated. It’s about 125 million miles away now, and during its brief visit, astronomers were able to get some readings that suggest that it is not round at all, like a “normal” asteroid, but rather is shaped like a fat cigar as it tumbles through space. Oh, and that unusual name? It is Hawaiian for “a messenger from afar, arriving first,” which totally fits. An interstellar visitor... Now that’s far out!

If you’d like to take a closer look at the wonderful and amazing things in the sky, please visit csastro.org for a link to information on our monthly meetings and our free public star parties!