Our solar system is constantly being monitored for signs of anything unusual. Most days are pretty run-of-the-mill, but the day 'Oumuamua was discovered in October of 2017, the world took notice.
Was it an asteroid, a comet, or a spaceship? Researchers scrambled to find the answers, and while there were a few certainties to go off of, other things are still up for debate - and we only have so much time to figure them out. By January of 2018 the cigar-shaped object is so far away we can no longer study it with grounded telescopes, so scientists are doing all they can to gather as much information about this odd object, and the secrets it carries, as possible.
Rest assured, 'Oumuamua is just the tip of the iceberg. With greater technology comes greater knowledge. As the years roll on, there will be more interstellar travelers to learn from and visit. And who knows? They may even carry life!
One of the strangest things about 'Oumuamua is how it appeared so suddenly and without any warning; it's almost as if it was dropped into our solar system by some giant unknown hand. It's safe to say we haven't seen anything like this before.
'Oumuamua - its official name is 1I/2017 U1 - was first spotted by the University of Hawaii’s Pan-STARRS1 telescope on October 19, 2017. NASA Planetary Defense Officer Lindley Johnson said,
"We are fortunate that our sky survey telescope was looking in the right place at the right time to capture this historic moment. This serendipitous discovery is bonus science enabled by NASA’s efforts to find, track and characterize near-Earth objects that could potentially pose a threat to our planet."
'Oumuamua has been compared to a cigar or driftwood due to its strange shape. The rotating object is longer than it is wide by at least a 10:1 ratio, which is more extreme than any asteroids or comets we've ever come across. Its shape also creates dramatic changes in its surface brightness.
Dr. Karen Meech, from the Institute for Astronomy in Honolulu, HI, explains her team has come up with various theories as to why the object looks like it does;
"Sometimes very elongated objects are contact binaries... but even so, the pieces would be longer than most things in the solar system, and our analysis shows that it is rotating fast enough that they should not stay together. One of our team wondered if, during a planetary system formation, if there was a large collision between bodies that had molten cores, some material could get ejected out and then freeze in an elongated shape. Another team member was wondering if there could be some process during the ejection - say if there was a nearby supernova explosion that could be responsible."
An object this unusual has to have a name that fits. 'Oumuamua was discovered via a University of Hawaii telescope, and its nickname is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's formal name, 1I/2017 U1, has a very specific meaning.
The "I" stands for "interstellar." Objects similar to 'Oumuamua have "C" or "A" names, which places them in either comet or asteroid categories, but 'Oumuamua is so different from what we know of both, it has been given an entirely different designation.
Initially, some astronomers believed 'Oumuamua was a comet, as it had qualities of one, but they were soon to discover that it didn't behave as a comet does.
Alan Fitzsimmons from the Queen's University Belfast, Northern Ireland, published a paper outlining what lead him to believe 'Oumuamua was a comet and not an asteroid. The object is made of ice - on the inside anyway.
Inevitably, the theory didn't hold water. "Given that this object passed relatively close to our sun as it was traveling, one would expect any ices on the surface to be heated. We should see gas streaming off the surface, we should see dust particles being ejected in the cometary atmosphere, perhaps even a tail," Fitzsimmons said. That never happened and scientists were left to believe it was either an asteroid or possibly an interstellar craft.