Is Oumuamua A Normal Asteroid?
The first scans for alien technology aboard a mysterious object that is barreling through the solar system have found no evidence it is the work of an intelligent civilisation. The cigar-shaped object was spotted hurtling through the solar system in October, and while astronomers suspected it was an interstellar asteroid, its unusual shape led them to propose sweeping it for radio signals in case it happened to be an alien craft. While the long, slender object may have been well suited to flying through clouds of interstellar gas at breakneck speed, as some researchers noted, the observation that the body was tumbling through space suggests any aerodynamic advantage was at best minimal.
Scientists on the Breakthrough Listen project, funded by the internet billionaire Yuri Milner, used the Green Bank telescope in West Virginia to eavesdrop on the 400m-long body named ‘Oumuamua, from the Hawaiian word for “messenger” or “scout.” The body is twice as far from Earth as the sun, but the telescope is so sensitive it could detect transmissions as weak as those produced by a mobile phone. But on Thursday, the astronomers declared that the first observations across four bands of the radio spectrum had found no evidence that ‘Oumuamua is anything other than a long lump of space rock. Scientists on the project have released the data from the observations so that anyone can study the information. “This is a fishing expedition,” said Avi Loeb, professor of astronomy at Harvard University and an adviser to the Breakthrough Listen project. “We are most likely not to find anything, but it is worth checking our fishing hooks steadily. We will keep searching for artificial signals from ‘Oumuamua or any other interstellar object in the future.”
The first batch of four observations ran from 8.45pm UK time on Wednesday until 2.45am on Thursday morning and spanned a frequency range from 1 to 12 GHz. While the search for alien signals has so far found nothing in the 1.7 to a 2.6GHz range, processing is still going on for the rest of the data. Andrew Siemion, director of Berkeley Seti Research Center, told the Guardian that a review of all four bands observed Wednesday night had come up blank. “We don’t see anything continuously emitting from ‘Oumuamua,” he said. “We’re now digging into some of the intermittent candidates, and trying some new machine learning-based techniques. We expect our next observation window to be scheduled for Friday or Saturday when we should get a view of additional phases of ‘Oumuamua as it rotates.”
Researchers on the Pan-Starrs telescope project in Hawaii first spotted the interstellar asteroid as it swept past Earth at 85 times the distance to the moon. As ‘Oumuamua sped towards the sun, it gathered speed, reaching 196,000mph. The body is moving so fast it will eventually leave the solar system altogether.
Credit: Ian Sample for The Guardian, 14 December 2017.