If This Interstellar Asteroid Is an Alien Spaceship, Astronomers Say It's Keeping Quiet
Back in October, researchers using the Pan-STARRS1 telescope in Hawaii spotted a long, red asteroid passing through our solar system and determined that it was the first known object to reach our solar system from another star system. They named the asteroid Oumuamua, which means "a messenger from afar arriving first" in Hawaiian.
To see if Oumaumau is really a cigar-shaped alien spaceship secretly carrying extraterrestrial life, a team of astronomers in Western Australia used a powerful telescope to essentially tap the asteroid's phone and listen to its calls.
Using the Murchison Widefield Array (MWA) telescope, the Australian team checked their data for radio transmissions that could have originated from the 400-meter-long asteroid.
They searched within the frequency ranges of 72 and 102 megahertz because, according to the study pre-printed in arXiv and approved for publication in The Astrophysical Journal, "These transmitter powers are well within the capabilities of human technologies, and are therefore plausible for alien civilizations."
The results of the study are that the asteroid is probably not an unusual alien spacecraft, or at the very least, it is not transmitting any detectable radio signals at the transmitter powers that the researchers deemed "plausible" for an alien civilization.
"We didn't set out to observe this object with the MWA but because we can see such a large fraction of the sky at once, when something like this happens, we're able to go back through the data and analyse it after the fact," said study lead Steven Tingay in a statement. "If advanced civilizations do exist elsewhere in our galaxy, we can speculate that they might develop the capability to launch spacecraft over interstellar distances and that these spacecraft may use radio waves to communicate...Whilst the possibility of this is extremely low, possibly even zero, as scientists it's important that we avoid complacency and examine observations and evidence without bias."
As a hopeful believer, my usual follow-up comment is that maybe the alien civilizations that we are searching for don't operate within the range and rules that our (very smart) Earthling scientists deem plausible.
Maybe we're looking for microbes with a metaphorical magnifying glass because we don't know what tools the job actually requires yet. Or maybe it's just a big empty rock from far away.