Astronomers never initially knew they were witnessing something a little out of the ordinary on October 19, when the Pan-STARRS 1 telescope in Hawaii picked up something hurtling past at an incredible speed of 85,700 mph. They thought it was just another comet or asteroid that had originated from within our solar system, but it turns out they were wrong.
Dead wrong. Based on its orbit, what they had witnessed was an interstellar object, or in other words, one that had originated from outside of our solar system and the likes of which have never been seen before. Sure, the color is similar to what had previously been witnessed, but that is where the similarities end.
“What we found was a rapidly rotating object, at least the size of a football field, that changed in brightness quite dramatically,” said Karen Meech, lead study author of the University of Hawaii’s Institute of Astronomy and leader of the research team. The object is 10 times as long as it is wide and spins on its own axis every 7.3 hours. These factors, combined with its trajectory, is what sets it apart from anything from within our solar system, as the longest we had previously seen had been only three times as long as they were wide.
The first big question now is what is it? It is the first object to be titled an interstellar asteroid, a category created after the discovery, officially designated A/2017 UI by the International Astronomical Union. It also has another name; ‘Oumuamua,’ a name of Hawaiian origin due to the location of the telescope responsible for its discovery, which loosely translates into “a messenger that reaches out from the distant past.”
“For decades we’ve theorized that such interstellar objects are out there, and now — for the first time — we have direct evidence they exist,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate. “This history-making discovery is opening a new window to study formation of solar systems beyond our own.”
“We are continuing to observe this unique object,” said Olivier Hainaut, one of the study authors from the European Southern Observatory. “And we hope to more accurately pin down where it came from and where it is going next on its tour of the galaxy. And now that we have found the first interstellar rock, we are getting ready for the next ones!”