Is anybody out there?
That's the ancient question astronomers hope to answer by listening to a newly discovered asteroid that's paying us a visit from beyond our solar system.
Scientists from Breakthrough Listen, an international program dedicated to searching for signals that may come from intelligent life beyond our own, want to listen in on the peculiar asteroid, named 'Oumuamua, to see whether any signals are coming from it.
Using the Robert C. Byrd Green Bank Telescope in Green Bank, W.Va., astronomers began listening to 'Oumuamua on Wednesday across four radio bands along the electromagnetic spectrum, from one gigahertz to 12 gigahertz.
"We're going to cover the entire range, and we're basically looking for electromagnetic emissions that are known to only arise from technology," Andrew Siemion, director of Berkeley SETI Research Center and part of Breakthrough Listen, told CBC News.
"Ultimately, we want to cover as much of the electromagnetic spectrum as we can."
- Canadian spots 'visitor' from beyond our solar system
- Astronomers unveil secrets of interstellar visitor
- Why an asteroid (probably) won't wipe us out
The asteroid was discovered by Canadian astronomer Robert Weryk at the University of Hawaii institute for Astronomy. While looking through data collected by Pan-STARRS, a survey that looks for near-Earth asteroids, he found evidence that suggested the asteroid wasn't from our solar system.
Subsequent observations supported this, and it was calculated that the small rock likely originated from somewhere in the direction of the bright star Vega in the constellation Lyra.
However, it's taken it so long to get here, that Vega wasn't in that position when it's believed the asteroid left the area some 300,000 years ago.
So what are the chances of hearing the voice of E.T.?
"We wouldn't do the experiment if we didn't think there was a chance that we would detect something," Siemion said.
"I'm an optimist. It's just an incredibly interesting scientific question, whether we detect signals from this object or not. And whether we detect signals from other interstellar objects that we might detect in the future."
Peter Brown, professor of physics and astronomy at Western University in London, Ont., said it's likely the asteroid, though oddly elongated and somewhat puzzling, is the remnant of a planetary system that happened to get ejected into space.
"It's on a trajectory that takes hundreds of thousands of years to cross between the closest stars," Brown told CBC News. "And it's coming from a direction we basically would expect randomly ejected material from another star system to get perturbed into [this sort of] orbit."
But that's not to say it shouldn't be investigated, he said. The object is unusual in many ways: the shape — it's highly elongated at 400 metres by perhaps 40 metres — the fact that it's from beyond our solar system, and the fact that it hasn't shown any signs of minerals spewing out of it that are rich in volatile minerals, which astronomers had expected.
But Brown said that it's likely just something we haven't seen before, something that will shed light on planet formation theories.
"It's a real longshot," Brown said of detecting an alien signal. "But why not? Sure, everything about this object is breaking new ground."
'Oumuamua is about 300 million kilometres from Earth, travelling at 38.3 km/s. It will pass Saturn's orbit in January 2019.
And if the eavesdropping doesn't elicit a "Greetings, Earthling," Brown said that the object is still an amazing gift to planetary scientists.
"This object is to small body planetary science as gravitational waves are to astronomy in general," Brown said. "It opens a new door. It's a little object passing through our solar system, but it may tell us a lot about how planetary systems as a whole form and about what's in space."
Siemion said that no matter what the results, 'Oumuamua presents a great opportunity for Breakthrough Listen.
If a radio source is detected, it will first have to undergo rigid testing and verification from other sources to ensure that it's not human-made.
"I'm excited about the experiment," Siemon said. "I'm excited to know the answer to this question broadly, and this experiment is a microcosm of a much broader and long-lasting multi-generational scientific endeavour. I'm excited to be part of that.
"It's exciting and fun. This is what gets us up and out of bed in the morning."