Why do people think that an alien spacecraft visited our solar system last year?

A visitor to our solar system became the subject of headlines around the world last year after the cigar-shaped rock now named `Oumuamua flew past our sun.

The space object, a visitor from another star system, was promptly scanned by the alien-hunting SETI project – and UFO fans (naturally) came up with dozens of strange theories.

But while it showed no signs of life in scans in 2017, a mysterious ‘speed boost’ observed by astronomers reignited debate this year.

Now Harvard scientists suggest there’s at least a faint possibility it might be a spacecraft component, a ‘solar sail’, used to travel between star systems.

Researchers from the Harvard Smithsonian Center for Astrophysics say, ‘Considering an artificial origin, one possibility is that ‘Oumuamua is a lightsail, floating in interstellar space as a debris from an advanced technological equipment.”

Human space projects, such as Professor Stephen Hawking’s ‘Breakthrough Starshot’ project, have proposed sending a spacecraft to Alpha Centauri in 20 years using similar technology.

The Harvard researchers say that it’s more likely that the acceleration was caused by radiation pressure – but that this raises its own questions about the object’s origin.

The researchers write, ‘If radiation pressure is the accelerating force, then ‘Oumuamua represents a new class of thin interstellar material, either produced naturally, through a yet unknown process in the interstellar medium or in proto-planetary disks, or of an artificial origin.

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The mysterious ‘speed boost’ happened as the object passed through the inner solar system last year.

Marco Micheli of ESA’s (European Space Agency) said, ‘Our high-precision measurements of ′Oumuamua’s position revealed that there was something affecting its motion other than the gravitational forces of the Sun and planets.’

Comets normally eject large amounts of dust and gas when warmed by the Sun – and some suggested that this could be behind the strange ‘boost’.

But according to Olivier Hainaut of the European Southern Observatory, ‘There were no visible signs of outgassing from ′Oumuamua, so these forces were not expected.’

The object was scanned with several large telescopes, and showed no signs of life in 2017 – but that didn’t put off UFO fans.

While the initial scans didn’t show any sign of alien technology, they may have had an unintended effect, said Nick Pope, former head of the Ministry of Defence’s UFO project.

Pope – a well-known UFO enthusiast – says that the scans may have ‘awoken the intelligence inside’ `Oumuamua.

Speaking to The Sun, Pope said, ‘While nothing has been found, there’s another intriguing possibility: If this ship is an alien probe, it’s possible that our scans will awake the intelligence inside.

Pope’s views fly in the face of the scientific evidence – after multiple teams scanned the object and concluded it was simply an asteroid.

But Pope says the fact that the exterior resembles an asteroid doesn’t necessarily mean it’s not a spacecraft.

Pope says, ‘Because there’s no air in space, an alien spaceship wouldn’t need to be designed in the same way that our aircraft have to be.

‘Rather than building an interstellar spacecraft from scratch, it makes perfect sense to take an asteroid and then build your ship around it, or hollow it out and build inside it, for the protection you’d derive from being surrounded by so much rock.’