Looking for ET
‘Best equipment on the planet’ to scan interstellar asteroid for any sign of extraterrestrial tech
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 tomorrow, 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 Pan-STARRS1 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, on Wednesday, the University of California, Berkeley’s Breakthrough Listen project — a global astronomical program searching for life beyond Earth — used 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 was expected to 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. “In the last several centuries, despite all of the astronomical investigations that we’ve done — looking at the universe in many, many different ways, with many telescopes, sending probes to other bodies in our solar system, digging under the dirt on the planet Mars — we have found no examples of any kind of life, intelligent or otherwise, anywhere in the entire universe expect for here on Earth,” Siemion said.
However, 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 extra-terrestrial 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.
The fact that we’re now seeing an interstellar interloper for the first time is special, Delaney said, but not particularly unusual. “These things are relatively small, they’re relatively faint and unless they get really close to us, it’s easy to miss them,” he said.
That said, “maybe some interstellar civilization put a radio beacon on it to signal ‘Hi, hello.’ You can think of all sorts of speculative ideas as to how this object might be used by some sort of spacefaring interstellar civilization.”
He thinks that’s highly unlikely, but still worth listening for some artificial signal from the rock.
The asteroid’s unusual 10-to-one dimensions are based on its huge variation in intensity in brightness as it rotates, Delaney said. “If it was created during some sort of planetary formation and flung out by its parent star, it could have been travelling for literally billions of years.”
It’s not clear where ‘Oumuamua is next headed. But, at the speed that it’s moving as it exits our solar system, the travel time to another star would be on the order of tens of thousands of years, Delaney said — which is why the Green Bank telescope is unlikely to pick up signals from any sort of transmitter on the rock, he believes.
“Most civilizations are probably going to perish in that time before they get a signal back.”