We Had a Visitor
Image credit: ESO/M. Kornmesser
The solar system had a visitor recently. A, thing, artist’s impression above, swung by the Earth and Sun late last year. What was it? Where did it come from? Where is it going? Could it really be an alien spaceship? Why is it important? And how does one pronouce ‘Oumuamua anyhow?
Last things first. ‘Oumuamua is a Hawaiian name that loosely translates as “visitor from the distant past.” It is pronounced Oh mooer mooer. A Hawaiian word was chosen because it was discovered by a telescope in Hawaii. There’s been some conflict between astronomers and native Hawaiians lately, so not sure if choosing a Hawaiian name was a sign of respect, or clueless condescension. I’ll leave that topic for another day.
What was ‘Oumuamua? At first it was thought to be a comet. As it got close to the sun it didn’t outgas like comets do, so astronomers changed its designation to asteroid. And then things got both exciting and weird. Once its orbit was calculated, they realised this bad boy wasn’t orbiting the sun. It had indeed fallen out of deep space, travelling at a speed faster than anything that orbits the sun travels at. It whipped around the sun and headed back out to deep space. But not before every telescope and scientific instrument possible was trained on it.
And what did they find out? It’s about 800 ft (230 m) by 100 ft (35 m.) It’s spinning wildly. It appears to be very similar to a D-type asteroid. So soft, organic rich silicate and carbon rock, possibly mixed in with some ice. It’s protected by a baked reddish organic coating similar to the coating seen on Kuiper Belt Objects. Scientists suspect this is from millions of years of exposure to cosmic rays. This is why if it contains any ice, it didn’t outgas as it passed the sun. However, unlike any asteroid or comet ever seen, ‘Oumuamua is eight times as long as it is wide. This is extremely unusual, no one expected this. A cigar shaped asteroid, how did this happen? No one knows.
The weird shape is what triggered speculation that ‘Oumuamua might be an artificial object of some sort. Idle speculation for the most part. First of all it is tumbling. Secondly it made no course corrections. Lastly, because scientists do like to cover all possibilities, every effort was made to detect any sign of electrical or radio activity emanating from it. Even something as weak as a cell phone would of been detected. Nada, ‘Oumuamua is as dead as, well, a rock.
So why is ‘Oumuamua important? Because this is the first time we have ever had a chance to study something that didn’t originate in our own solar system. It’s like data from an interstellar probe delivered free to our backyard. Best guess is 1-10 things like this zip through every year, but they are small and really fast, and this is the first one we’ve ever seen. Our telescopes grow better every year though, and astrononers look forward to spotting future visitors. We are indeed living in a golden age of space exploration.
Two final notes. If this was so new and cool, why didn’t we send a probe to it? Good question. And in fact as soon as it was spotted, astronomers feverishly began calculating if that was possible. Sadly, the answer is not really. ‘Oumuamua is just moving too damn fast. It’s already past the orbit of Mars, will pass Jupiter by early summer, and Saturn’s orbit by 2019. No human probe can fly fast enough to catch up with it. There are a few theoretical possibilities and ideas in the pipeline that might do the trick, but not really worth the effort. Even if we build something fast enough to catch up, it would just fly right past it, and that really wouldn’t be likely to add much to our knowledge. So goodbye ‘Oumuamua, off to wander between the stars for millions or more likely billions of years.
Lastly, wait, what about meteorites? Humans have literally gathered up tens of thousands of them, surely some of them didn’t originate in our solar system? Nope. Every single one clearly came from our solar system, either leftover junk from the creation of the solar system, or blasted free from planets and moons in the solar system. This though is a great opportunity for meteorite hunters. Eventually one will be found, they must exist. And when one is found, the lucky finder can name their price. Millions would not be untoward.
Now don’t you wish you’d looked more closely at that black rock you found on your lawn last week? Have a great 2018 everyone.
(I am resurrecting Doug’s Darkworld, will be posting once a week from now on. I have also started a site on Patreon where I will be posting these blog posts and other writing, mostly fiction. I encourage my readers to check it out. And thanks to my many faithful readers here, it’s been fun.)
Doug's Darkworld 
Every one which has been examined in any detail.
Actually, I recall mention of things like silicon carbide grains labelled as “extrasolar” … yeah – it’s a well established field. The specimens may be microscopic, but they’ve been recognised for a time. Lots of papers. In the appropriate context “we’ve found a grain from outside the solar system” doesn’t excite comment. E.g.
(http://presolar.wustl.edu/laboratory_for_space_sciences/Publications_2007_files/Zinner-TOG-07.pdf)
gravelinspector-Aidan
January 6, 2018 at 4:28 pm
Nice, reasoned overview.
One thing you could do is use an impactor probe (so the relative speed of the chasing probe becomes an advantage)…
But like you pointed out, it’s hard enough to get to. And there’s not much time to manufacture the probe because the longer we wait the bigger the rocket would have to be to catch up.. We may as well look out for the next one.
Pouncingant
January 6, 2018 at 9:07 pm
Thanks Doug, Informative and incisive as always. Really looking forward to your post again.Welcome Back !!!
John Rowley
January 7, 2018 at 3:06 am
Interesting Article Doug and welcome back.
Josh V
January 8, 2018 at 10:57 am