Today, scientists led by Stephen Hawking are using high-tech scanners to discover if a huge, cigar-shaped 'comet' is in fact, an alien probe.

Now, one astronomer claims that the space rock, named Oumuamua, could be an alien spacecraft with broken engines that is tumbling through our solar system.

Dr Jason Wright from Penn State University suggests that a broken alien spacecraft move in exactly the same way as the interstellar comet.

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Last month, a mysterious cigar-shaped asteroid sailed past Earth, marking the first time an interstellar object has been seen in the solar system

OUMUAMUA A cigar-shaped comet named 'Oumuamua sailed past Earth last month and is the first interstellar object seen in the solar system. It was first spotted by a telescope in Hawaii on 18 October, and was observed 34 separate times in the following week. Travelling at 44 kilometres per second (27 miles per second), the comet is headed away from the Earth and Sun on its way out of the solar system. The comet is up to one-quarter mile (400 meters) long and highly-elongated - perhaps 10 times as long as it is wide. That aspect ratio is greater than that of any asteroid or comet observed in our solar system to date. But the comet's slightly red hue — specifically pale pink — and varying brightness are remarkably similar to objects in our own solar system. Advertisement

Oumuamua is about a quarter of a mile long, 260ft wide and currently travelling at 196,000mph.

Rather than moving through space like other space rocks, astronomers believe that it is 'tumbling' through our solar system.

Writing in his blog, Dr Wright, an associate professor of astronomy and astrophysics at Penn State University, says: 'Such derelict craft would, if they are not travelling so fast that they escape the Galaxy, eventually 'thermalize' with the stars and end up drifting around like any other interstellar comet or asteroid.

'In fact, since they (presumably) no longer have attitude control, one would expect that they would eventually begin to tumble, and if they are very rigid that tumbling might distinguish them from ordinary interstellar asteroids… and in fact, just because their propulsion is broken doesn't mean that their radio transmitters would be broken.'

Dr Wright suggests that the object could be a 'Von Neumann probe' - a theoretical self-replicating spacecraft that visits star systems.

He added: 'Such a discovery would imply that there are lots of these things in the solar system at any given moment (even if they are deliberately targeting the sun, they are hard to spot and we'll miss most of them), and so lots of opportunities to study them.'

Dr Wright previously suggested the mysterious dimming of star KIC 8462852 – also known as Tabby’s Star – could be caused by an alien megastructure called a Dyson Sphere.

His latest comments come ahead of a project later today in which scientists will use high-tech scanners to discover if Oumuamua was sent by an alien civilisation.

The cigar-shaped object, named 'Oumuamua by its discoverers, sailed past Earth last month and is the first interstellar object seen in the solar system

WHO IS DR JASON WRIGHT? Dr Wright is an associate professor of astronomy and astrophysics at Penn State University. Dr Wright achieved global fame after suggesting that the dimming of star KIC 8462852, also known as Tabby’s Star, could be caused by an alien megastructure called a Dyson Sphere. This is a hypothetical structure that could be used by an advanced alien race to harness the energy of a star. First proposed by theoretical physicist Freeman Dyson in 1960, the sphere would be a swarm of satellites that surrounds a star. They could be an enclosed shell, or spacecraft spread out to gather its energy - known as a Dyson swarm. If such structures do exist, they would emit huge amounts of noticeable infrared radiation back on Earth. But as of yet, such a structure has not been detected. Advertisement

The team of scientists, called Breakthrough Listen, will use the world's largest directable radio telescope, at Green Bank in West Virginia, to follow it for ten hours today at 3pm ET (8pm GMT).

They are listening for electromagnetic signals, no stronger than those emitted by a mobile phone, that cannot be produced by natural celestial bodies.

If they find them, it would be proof that extraterrestrial forces really could be at play.

For the moment, they are trying to contain their excitement. But the name they have given this bizarre object betrays their optimism.

Oumuamua is a Hawaiian term meaning 'a messenger from afar arriving first'.

Most intriguingly, it is the wrong shape for an asteroid — they are typically round.

Professor Hawking and his colleagues at Breakthrough Listen report: '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.'

Scientists led by Stephen Hawking, pictured, are today using high-tech scanners to discover if a huge, cigar-shaped space object currently hurtling through our solar system was sent by an alien civilisation

Another oddity is that Oumuamua is flying very 'cleanly', without emitting the usual cloud of space dust that astronomers observe around asteroids.

Experts say this suggests it is made of something dense: probably rock, but possibly metal.

It was first detected on October 19 by a long-running research programme called Pan-STARRS, which uses powerful telescopes to photograph and monitor the night sky at the University of Hawaii.

WHERE DID IT COME FROM? Most comets follow ellipse-shaped orbits around the sun. But this comet appears to orbit at an angle, and doesn't circle the sun. Its orbital path suggests it entered our solar system from the direction of the constellation Lyra, looped around the sun, and will never return. But others have suggested that the comet did come from Earth, but interacted with Jupiter or another planet, which changed its orbit. Advertisement

Its amazing speed has led some experts to conclude it is the first such object to have come towards us from outside our solar system.

Analysts also say its faintly red colour indicates it has been subjected to interstellar cosmic radiation which is harsher than we experience in our solar system.

The fact that it doesn't seem to have engines or show signs of propulsion may wreck the interplanetary-spacecraft theory.

If a radio signal does come back from the object, Professor Avi Loeb, Professor of Astronomy at Harvard University, suggests that we will need to proceed with caution.

Speaking to MailOnline, he said: 'My recommendation, as in any dialogue, is that we first listen and do our best to understand what we are hearing.

'Once we figure this out, we can decide how to respond.

'Overall, I am an optimist. I believe that a very intelligent civilisation will be peaceful, and we could save ourselves millions or billions of years by learning from it.

'But there is also the possibility that such a civilisation will have hostile intentions and risk our existence, so we should deliberate carefully in any future contact with them.'