Last month, Hawaiian based astronomers using the University of Hawaii’s Pan-STARRS 1 telescope discovered the first confirmed asteroid in our solar system originating from another star. While the reddish, cigar-shape object has been given the designation 1I/2017 U1, it has also received the nickname Oumuamua, which is Hawaiian word meaning messenger or scout.
Oumuamua is currently traveling at a speed of 85,000 mph, and at the start of this week was found 124 million miles from Earth, between the orbits of the planets Jupiter and Mars. The object is believed to be around 400 metres long, 40 metres wide, and completes one spin every 7.3 hours. Its unusual shape is unlike any other asteroid seen in our solar system, and according to Karen Meech from the University of Hawaii’s Institute for Astronomy, is hundreds of millions to billions of years old.
Commenting further upon the startling discovery, Meech explained: “This thing is an oddball. What we found was a rapidly rotating object, at least the size of a football field, that changed in brightness quite dramatically. This change in brightness hints that ‘Oumuamua could be more than 10 times longer than it is wide — something which has never been seen in our own solar system.”
While Oumuamua was initially believed to be a comet, further observations failed to reveal any signs of gas or dust surrounding it, prompting them to consider it an asteroid, instead. Interestingly, Oumuamua’s deep reddish colour is similar to that found in numerous objects in the Kuiper Belt situated beyond Neptune, suggesting that it too was composed of rock or metallic elements, and lacking any significant amounts of water or ice. Its color also further suggests the object has been traveling in space for a very long time, and has been irradiated by not only the light from our sun, but perhaps other stars as well.
According to scientists working at the European Southern Observatory’s Very Large Telescope in Chile, the asteroid has traveled in a direction which passes by the star Vega in the constellation Lyra, but since Vega has moved around the Milky Way galaxy over the past several hundred thousand years, Oumuamua’s origin is still unclear. Commenting on the implications of the asteroid’s discovery, Thomas Zurbuchen, associate administrator for NASA’s science mission directorate, explained:
“For decades we’ve theorized that such interstellar objects are out there, and now — for the first time — we have direct evidence they exist. This history-making discovery is opening a new window to study formation of solar systems beyond our own.”