Astronomers are to scan a huge cigar-shaped interstellar object, amid claims it could be some kind of artifact.
It was discovered on October 19th and has been named 'Oumuamua'.
It was found by the Pan-STARRS project at the University of Hawaii, passing Earth at about 85 times the distance to the Moon.
It is the first object discovered in the solar system that appears to originate from another star system.
Observations found the object is cigar-shaped with a somewhat reddish hue.
The asteroid is up to one-quarter mile (400 meters/1,312ft) long and highly-elongated - perhaps 10 times as long as it is wide.
Its high speed - some 315,000 kph at its peak - suggests it is not gravitationally bound to the Sun, but will continue its voyage back into interstellar space.
NASA says that is unlike any asteroid or comet observed in our solar system to date, and may provide new clues into how other solar systems formed.
It is thought the asteroid could be a shard of a shredded planet, which may have been born when a planet about 10 times the size of Earth got too close to its small, dense star and was destroyed.
Now, researchers are trying to figure out where Oumuamua came from and how it formed.
Breakthrough Listen, a programme from the SETI institute, says: "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 minimize 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 artifact."
An observation campaign will begin on Wednesday, December 13th using the Robert C Byrd Green Bank Telescope.
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.
Its first phase of observations will last a total of 10 hours.
"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," said Andrew Siemion, director of Berkeley SETI Research Centre.
"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.
So far no convincing evidence of alien life has been found by SETI, despite almost 100 projects since the 1960s.