Astronomers are to scan a huge cigar-shaped interstellar object for signs of alien life, amid claims it could be some kind of artefact.
Researchers involved in Seti – the Search for Extra-Terrestrial Intelligence – will turn a powerful dish telescope towards "Oumuamua", which was first spotted in October.
It is the first object discovered in the solar system that appears to have come from another part of the galaxy – and is assumed to be an asteroid.
However, its elongated cigar shape and the fact that it is hundreds of metres in length but only one tenth as wide is peculiar for a typical space rock.
At the moment there is "no consensus" on where the dark red object, which is around 400 metres (1,312ft) long, has come from.
In a statement, the $100m (£75m) Seti project Breakthrough Listen said: "Researchers working on long-distance space transportation have previously suggested that a cigar or needle shape is the most likely architecture for an interstellar spacecraft, since this would minimise friction and damage from interstellar gas and dust.
"While a natural origin is more likely, there is currently no consensus on what that origin might have been, and Breakthrough Listen is well positioned to explore the possibility that Oumuamua could be an artefact."
The team will use the Green Bank radio telescope in West Virginia to study the object, which is named after the Hawaiian word for "scout" or "messenger".
The giant dish – the largest fully steerable radio telescope in the world – will "listen" to Oumuamua across four radio frequency bands spanning one to 12 gigahertz from 8pm UK time on Wednesday.
Lead scientist Dr Andrew Siemion, director of the Berkeley Seti Research Centre in California, said: "Oumuamua's presence within our solar system affords Breakthrough Listen an opportunity to reach unprecedented sensitivities to possible artificial transmitters and demonstrate our ability to track nearby, fast-moving objects.
"Whether this object turns out to be artificial or natural, it's a great target for Listen."
Even if no evidence of extraterrestrial technology is found, researchers hope the mission could provide important information about gases surrounding the object or the presence or absence of water.
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The aim of the Breakthrough Listen project is to survey a million nearby stars and 100 nearby galaxies in the search for alien life.
So far no convincing evidence of alien life has been found by Seti, despite almost 100 projects since the 1960s.