Space mysteries Nasa CAN’T explain – as expert admits ‘tiny super-intelligent aliens’ may have visited Earth
The prospects of finding alien life in the universe are growing each day
THERE'S plenty of evidence that our universe could support alien life – but proving it is difficult.
As a top Nasa scientist admits "tiny super-intelligent" aliens may have already visited Earth, we reveal some of the most mysterious clues for alien life so far.
Mars meteorite with 'tunnels' and 'spheres'
A Martian meteorite that fell to Earth in the Stone Age is believed by some to be proof of alien life.
The meteorite has tiny carbon-rich balls and tunnels inside. These resemble the marks that living microorganisms leave when they eat through rocks on Earth, according to a 2014 report in the Astrobiology journal.
Importantly, some scientists think the markings were pressed into Mars before it left the red planet.
At the time, Dirk Schulze-Makuch, of Washington Sate University, told : "It further strengthens the case for past life on Mars, but, of course, it is by no means proof."
Mysterious radio bursts
We've sent off dozens of our own signals into space – hoping for a call back.
But we also receive plenty of mysterious radio signals that we simply can't explain.
These Fast Radio Bursts (or FRBs) are detected by listening technology, with computer systems trawling through extensive data to spot mysterious signals.
Back in September, the Breakthrough Listen program found 72 new FRBs coming from a galaxy 3billion light years away.
FRBs are single, bright pulses of radio emission from extremely distant galaxies which last just milliseconds.
But FRB 121102 is the only one ever recorded to emit repeated bursts.
The source of FRBs are still a mystery and the nature of the object emitting them is still unknown.
Theories range from highly magnetised neutron stars and super-massive black holes to signs of an advanced civilisation.
The icy mystery of Saturn's moon
Earlier this year, scientists managed to sample organic molecules that were shot into space from deep-sea vents on Enceladus, one of Saturn's moons.
It found that these plumes of material contained "all of the basic requirements for life as we know it".
The problem is that even though life may have formed on one of Saturn's moons, the icy environment may simply be too inhospitable.
And there's no way of finding out whether life really is lurking on Enceladus unless we send a probe to the moon and start digging.
The hidden lake on Mars
In July 2018, scientists discovered a lake underneath a glacier on Mars.
It's the first known "stable" body of water on Mars, and is believed to measure around 12 miles across.
Liquid water on other planets is a major scientific opportunity for Na
sa, as water is an essential ingredient for life as we know it.
But the problem is that Nasa can't (yet) investigate the mysteries of the lake, because it's buried nearly a mile underneath the southern polar ice cap.
Earth-like planets
Scientists have discovered scores of exoplanets – planets outside of our solar system – that are described as "Earth-like".
This means they live in a "habitable zone" around their sun, where it's not too hot or too cold to sustain liquid water on the surface.
Spotting these exoplanets is tricky, but actually finding out if they contain life is even harder.
Scientists use space telescopes to spot faint traces of the existence of these planets. But they're actually often thousands of light years away, which means we simply can't investigate them – yet.
So while we know there are potential life-carrying planets out there, they'll remain a mystery for now.
The Fermi Paradox
The Fermi Paradox isn't strict evidence for alien life – but more of a thought experiment.
It's a famous contradiction posed by physicist Enrico Fermi.
Fermi suggested that the enormous size of the universe – and the billions of Sun-like stars in the galaxy, and their planets – makes it highly likely that there is intelligent life out there.
Some of these civilisations may have developed interstellar travel.
But Fermi also noted that there's a severe lack of evidence for life on other planets.
The chances of aliens being able to reach us are high, but there's no evidence that aliens ever have.
This paradox has baffled scientists for decades.
Space sugar
Back in 2012, astronomers at Copenhagen University found glycolaldehyde – a sugar molecule – in a far-off star system, 400 light years from Earth.
Glycolaldehyde is important because it's needed to form RNA, a sister of DNA that is essential to life as we know it.
This particular star system is "protostellar", which means the central star is still very young.
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What it means is that complicated organic molecules can form in early star systems, even before planets themselves have formed.
Given the enormity of the universe, it seems likely that life could exist.
But we simply no hard evidence to prove it.
Do you think we'll ever make contact with alien life? Let us know in the comments!
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