Green Bank radio telescope (Jarek Tuszynski)One of the world’s largest radio telescopes is being used to check whether a mysterious object that is speeding through the Solar System has been created by aliens. Scientists on the Breakthrough Listen project, which searches for evidence of alien civilizations, will use the the Green Bank telescope in West Virginia to listen for radio signals being given off by the cigar-shaped object. Travelling at more than 300,000 km/h (200,000 mph) as it rounded the Sun, it is the first known object to arrive in our Solar System from interstellar space. The telescope will be turned towards the object as it speeds away and will pick up any faint signals. “Most likely it is of natural origin, but because it is so peculiar, we would like to check if it has any sign of artificial origin, such as radio emissions,” said Avi Loeb, professor of astronomy at Harvard University and an adviser to the Breakthrough Listen project.
Artist's impression of 'Oumuamua (ESO/nagualdesign)
The object, named 'Oumuamua, a Hawaiian word meaning “to reach out from afar”, or “messenger”, was first spotted on 19th October 2017 by astronomers using the Pan-STARRS telescope. The instrument, at Haleakala Observatory, Hawaii, is used to look out for asteroids on a collision course with Earth. 'Oumuamua was picked up as it swept past Earth at 85 times the distance to the Moon.
'Oumuamua passes through the Solar System (NASA)The object entered our Solar System from high above the plane on which planets orbit the Sun. The Sun’s gravity changed its path, flinging it back out of the Solar System at a different angle. 'Oumuamua is moving so fast relative to the Sun that it could not possibly have originated in the Solar System itself. Appearing to come from the direction of the star Vega in the constellation Lyra, it is not known how long 'Oumuamua has been travelling amongst the stars.
Described as an interstellar asteroid, 'Oumuamua’s elongated shape is unlike anything seen in the asteroid belt in our own Solar System. Dark red in colour (usually a sign of carbon-based molecules), it measures about 400 metres (a quarter of a mile) long, but is only about a tenth as wide. “It’s curious that the first object we see from outside the Solar System looks like that,” said Loeb. “If it’s of natural origin, there should be many more of them.” Some researchers have pointed out that the elongated shape “is the most likely architecture for an interstellar spacecraft, since this would minimize friction and damage from interstellar gas and dust."
One of the exoplanets in the TRAPPIST-1 system (ESO)The Breakthrough Listen project was launched at the Royal Society in London in 2015, by scientist Stephen Hawking. The project focuses on looking for signs of life on planets, that orbit other nearby stars beyond the our own solar system, known as exoplanets. The $100m project is funded by the internet billionaire Yuri Milner.
If, as expected, the Green Bank telescope fails to pick up any signs of alien technology from 'Oumuamua, the observations will still be of great help to scientists wanting to understand more about the object—whether, for example, it is shrouded in a comet-like cloud of gas, and whether it is carrying water and ice.
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