National Post (National Edition)
Checking out an interstellar visitor
It doesn’t look like a typical asteroid (it’s cigar shaped) and it doesn’t behave like one (it’s not orbiting the sun). It’s shaped, in fact, like an old spacecraft, and researchers are preparing to explore the possibility it is one.
Beginning Wednesday, astronomers will aim the largest steerable telescope on the planet at a curious interstellar interloper — the first confirmed object in our solar system from another star unlike any seen before.
The reddish rock, possibly 10 times as long as it is wide, was serendipitously discovered in October by the University of Hawaii’s PanSTARRS1 telescope, funded by NASA’s Near-Earth Object Observations Program.
Astronomers dubbed it ‘Oumuamua (pronounced oh MOO-uh MOO-uh), Hawaiian for “a messenger from afar arriving first.” According to NASA, the interstellar asteroid sling-shot past the sun on Sept. 9 at a “blistering speed” of 196,000 miles per hour or 87.3 kilometres per second.
Astronomers say the odds are exceedingly slim the object is an abandoned spacecraft or some alien, interstellar probe.
However, starting at 3 p.m. ET on Wednesday, the University of California, Berkeley’s Breakthrough Listen project — a global astronomical program searching for life beyond Earth — will use the Green Bank telescope in West Virginia to check for signals of extraterrestrial technology from ‘Oumuamua across four radio bands. The first phase of observations will last a combined 10 hours.
“With our equipment at Green Bank, we can detect a signal the strength of a mobile phone coming out of this object,” Yuri Milner, the Russian billionaire (along with Stephen Hawking) behind Breakthrough Listen, told Scientific American.
“We don’t want to be sensational in any way and we are very realistic about the chances this is artificial, but because this is a unique situation, we think mankind can afford 10 hours of observing time using the best equipment on the planet to check a low-probability hypothesis,” Milner said.
‘Oumuamua’s bizarre shape has tantalized astronomers since its discovery. According to Listen, “A cigar or needle shape is the most likely architecture for an interstellar spacecraft, since this would minimize friction and damage from interstellar gas and dust.”
On Friday, it was 50 to 70 times closer to the Earth than NASA’s Voyager-1 spacecraft. It is now a little more than two astronomical units away — more than two times as far as the Earth is from the sun. There’s no evidence it is travelling under its own propulsion. It doesn’t have any thrust. “It appears to be moving at an orbit affected only by gravity,” said Listen’s lead scientist Andrew Siemion, director of the Berkeley SETI Research Centre.
Researchers will be looking for electromagnetic emissions — radio signals or optic or infrared light fundamentally different from any known astrophysical background. “The object is rotating and we want to make sure to catch every face of it,” he said.
There is every expectation the object is natural. But, should something clearly outside the norm be detected, it would indicate “that either there is some very exotic physics going on, in and around the object,” Siemion said, or that ‘Oumuamua is artificial — meaning “that an advanced, extraterrestrial civilization had created it and perhaps sent it to our solar system for purposes that are unknown.”
The strange-shaped asteroid bears similar dimensions to the cylindrical alien starship that enters Earth’s solar system in science-fiction writer Arthur C. Clarke’s 1973 book, Rendezvous with Rama, noted astronomer Paul Delaney.
According to NASA, the asteroid is up to 400 metres long and “completely inert, without the faintest hint of dust around it.”
The rock (and it’s believed to be made of rock, possibly metals, but not water or ice) “is definitely from beyond our solar system,” said Delaney, a professor of physics and astronomy at Toronto’s York University.
“We’re not implying anything here with respect to artificial intelligence or extraterrestrial life,” he said. However, “It’s on a trajectory that is well-defined, moving at a speed that says it had to have entered from interstellar space. So it came from elsewhere, if you will.”
There’s some speculation out there — was it targeted at our solar system? Delaney doesn’t think so. “There’s a lot of stuff flying between the stars. We eject material from planetary systems all the time, especially during formation processes,” he said.