Huge, mysterious object flying past Earth might be an alien spacecraft, scientists say

A huge object that flew past Earth might be an alien spacecraft, scientists have said.

Scientists had originally thought that the cigar-shaped object was a very strange passing asteroid. But a number of things have led scientists engaged in the search for alien life to wonder whether it might actually be an "artifact" from an alien civilisation.

Researchers involved in the Seti – Search for Extra-Terrestrial Intelligence – project are now preparing to point a powerful telescope at the bizarre object and find where it came from.

The mysterious object, which has been named Oumuamua, is our first visitor from another part of the galaxy to make it into our solar system. It flew past in October when it was spotted by astronomers from the University of Hawaii.

Scientists initially presumed that it was an asteroid. But a number of strange characteristics have led them to wonder whether it might have been intentionally formed.

It is long and cigar-shaped, for instance. While it is hundreds of metres long, it's only one tenth as wide – and it is very unusual for asteroids to come in such non-round forms.

Some researchers have suggested this long needle shape would be useful for a long-distance spacecraft, since it would minimise the chance of being hit by interstellar gas and dust as it travelled through the universe.

The body is travelling quickly through the universe, at up to 196,000mph, and looks as if it will not get wrapped up in our sun's gravity but fly right through and out of the solar system.

A statement from the 100 million dollar (£75 million) Seti project Breakthrough Listen, launched by Russian digital tech mogul Yuri Milner in 2015, 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 artifact."

The Breakthrough Listen team is using the Green Bank radio telescope in West Virginia, US, to study Oumuamua, which is named after the Hawaian term for "scout" or "messenger".

From 8pm UK time on December 12, the giant dish - the largest fully steerable radio telescope in the world - will "listen" to the object across four radio frequency bands spanning one to 12 gigahertz.

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."

The object is currently about two astronomical units (AU) from Earth, or twice the distance between the Earth and sun.

At this distance it would take less than a minute for the Green Bank telescope to detect an omnidirectional transmitter with the power of a mobile phone.

Even if no evidence of extraterrestrial technology is found, the search could provide important information about gases surrounding Oumuamua or the presence or absence of water, say the researchers.

Breakthrough Listen aims to survey a million nearby stars and 100 nearby galaxies looking for alien signals.

Since the 1960s there have been more than 98 Seti projects around the world, none of which have turned up any convincing evidence of extraterrestrial civilisations.

Additional reporting by agencies