The asteroid, named 1I/2017 U1 or 'Oumuamua, was first detected by the Pan-STARRS 1 telescope in Hawaii, according to a release from the European Southern Observatory. The asteroid that was discovered last month is the first time scientists have confirmed an object near Earth originated from outside of our solar system. As you can see in the image, it's at least ten times longer than it is wide; a ratio more extreme than any asteroid or comet observed in our solar system.
Its shape is puzzling to astronomers who say it could help unlock the mysteries of how other far-flung solar systems were formed.
The latest analyses with ground-based telescopes show that 'Oumuamua is quite similar to some comets and asteroids in our own solar system.
The long and rocky cigar-shaped object has a burnt dark-reddish hue due to millions of years of radiation from cosmic rays.
"For decades we've theorised 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 in Washington DC. Our observations reveal the object to be asteroidal, with no hint of cometary activity despite an approach within 0.25 au of the Sun. 'Oumuamua (whose name means "a messenger from afar arriving first" in Hawaiian) is now about 124 million miles (200 million kilometers) from Earth and is zooming away from us at about 85,700 mph (137,900 km/h) relative to the sun, NASA officials said. Aren't there tons of asteroids in our solar system?
ESO's Very Large Telescope was immediately called into action to measure the object's orbit, brightness and colour more accurately than smaller telescopes could achieve.
Now, courtesy, not of instruments on board spacecraft, but of detectors firmly based on the ground, we have observations of something that seems to be somewhere in the spectrum between comet and asteroid - but with a unusual orbit that sets it apart from any other body in the solar system.
In honour of this interstellar tourist - and perhaps in the hope that we might start to observe more of them, the International Astronomical Union has come up with a new cataloguing system for interstellar asteroids. In fact, this turned out to be the first-ever documented interstellar asteroid to fly by Earth.
It's believed that one alien asteroid visits our solar system every year, but they are often very hard to spot.
"We are fortunate that our sky survey telescope was looking in the right place at the right time to capture this historic moment", NASA Astronomer Lindley Johnson said. 'Oumuamua appears to have come from the general current direction of the star Vega, but when the asteroid was in that part of space, about 300,000 years ago, Vega wasn't there yet.
The asteroid is now heading towards Jupiter and is predicted to leave our solar system in 2019, continuing its long journey towards the Pegasus constellation.
The new paper is based on observations taken by telescopes in Hawaii and Chile, with astronomers from institutions around the world chipping in. This very brief, nearly missed blush of the first recorded interstellar visitor might give scientists more motivation to be on the lookout for more curious objects, especially now that we have equipment powerful enough to detect them.