A newly discovered object from another solar system has found its way to the Milky Way and it’s up to a quarter of a mile long.
The asteroid, which is like a giant cigar with a reddish hue, has been named ‘Oumuamua’ by its discoverers.
Our first interstellar asteroid has an aspect ration greater than any asteroid or comet observed in our solar system to date, as it’s about ten times as long as it is wide.
The long asteroid can provide some insightful clues as to how other solar systems are formed and the materials they are made up of.
Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington, said:
For decades we’ve theorised 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.
A team of astronomers led by Karen Meech of the Institute for Astronomy in Hawaii found that ‘Oumuamua varies in brightness by a factor of ten as it spins on its axis every 7.3 hours’.
This unusually big variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape.
We also found that it had a reddish color, similar to objects in the outer solar system, and confirmed that it is completely inert, without the faintest hint of dust around it.
No known asteroid or comet varies so widely in brightness, with such a large ratio between length and width.
Astronomer David Jewitt, of the University of California, Los Angeles, who led the observation team who reported on the characteristics said, according to PHYS:
I’m surprised by the elongated shape – nobody expected that.
Jewitt and his team observed the object for five nights in October, finding it to be about 100 ft by 100ft by 600 ft.
The slightly red and pale pink hue are similar to asteroids from our own solar system.
Astronomer Jayadev Rajagopal said:
It’s exciting to point the Arizona telescope at such a tiny object which, for all we know, has been traveling through the vast emptiness of space for millions of years and then by luck, passes close enough for me to be able to see it that night!
The asteroid’s name ‘Oumuamua’ means a messenger from afar arriving first in Hawaiian. It was spotted by a telescope in Hawaii on 18 October and was then seen 34 separate times in the week after.
Most comets orbit the sun, however this one doesn’t, with its orbital path suggesting it’s entered our solar system from the direction of the constellation Lyra.
Astronomers now hope to continue tracking the comet to learn more about its origin.
They don’t have loads of time though as it’s likely to stick around for just a few years before departing our sun’s neighbourhood.