Do you ever wonder if there is any other life out there? Or perhaps that there might be other civilisations we could meet and learn from? Or do you think we are alone in the Universe?
Stephen Spielberg’s movie, ‘E.T.’, imagined what might happen if an alien being landed on Earth and made friends with a young boy.
The Universe is so big that it is hard to believe that we are the only planet where life has evolved.
So far, we have found no evidence of life anywhere else in our Solar System – but that hasn’t stopped us from looking! Some of the places astronomers are exploring for indicators of life include Mars, Jupiter’s moon Europa, and the moons of Saturn -- Enceladus and Titan. It is even thought that Venus might harbour life in its atmosphere. A number of missions are currently under development to send spacecraft to these Solar System moons and planets.
Our First Visitor From Outer Space (that we know of)
Science fiction is full of alien worlds. Our imaginations wonder what is out there – beyond the Solar System. Have we ever had a visitor from outer space do you think?
In 2017, astronomers spotted an object speeding away from the Sun way too quickly to be bound by the Sun’s gravity. This was the first time we had seen an object which must have come from outer space – from outside the Solar System!
Astronomers called this object ‘Oumuamua’ (pronounced ‘oh moo ah moo ah) which means ‘scout’ in the Hawaiian language. At 400m wide, it was long and looked a bit like a cigar. It was believed to be made from rock rather than ice, dust and rocky particles like a comet. Because it was so unusual, there was a great deal of speculation about this object – was it a comet or an asteroid, where is it from, is it an alien artifact or what?
Here is an artist’s image of Oumuamua from NASA. Do you think it could be an alien spaceship? Looks like a rock to me, but who knows – this is just an artist’s impression not a real image. We may never know its true nature because it is long gone.
Artist's concept of interstellar object1I/2017 U1 ('Oumuamua) as it passed through the solar system after its discovery in October 2017. The aspect ratio of up to 10:1 is unlike that of any object seen in our own solar system. Image Credit: European Southern Observatory / M. Kornmesser
Image Address: https://solarsystem.nasa.gov/internal_resources/3577
Then Another One Turned Up In 2019!
We had just gotten over the surprise of discovering the first interstellar object, when another one was discovered by a Crimean amateur astronomer called Borisov,in 2019. Named after its discoverer, Comet2I/Borisov was very different to Oumuamua – it had a small nucleus and a tail, more like a run-of-the-mill comet. Except in this case, astronomers figured out that it came from far beyond the Solar System, because of its speed (177kph) and its trajectory. It has now been confirmed that 2I/Borisov is a rogue comet from the constellation Cassiopeia (about 268 light years from Earth).
And Then There Were THREE!!
This year we found yet another one! On July 1 2025, an unusual object was spotted heading towards the Sun. Called Interstellar Object 3I/ATLAS, the object was travelling at around 245kph, the fastest object ever detected in our Solar System. And it is big – about 20km long. Because we found it early in its journey through the Solar System, we will have the chance to observe it more closely before it heats up closer to the Sun.
Right now, 3I/ATLAS is within Jupiter’s orbit – about 430 million kilometres away. The closest it will get to Earth is about 270million kilometers on 19 December 2025.
If you like, you can track its path by clicking here:
https://theskylive.com/c2025n1-tracker
We expect to learn a great deal from our visitor. 3I/ATLAS could be a relic from another planetary system and so could help us understand more about how other systems have evolved over time. An astronomer from Harvard, Avi Loeb, has also suggested that we should be investigating whether there is any evidence to suggest that 3I/Atlas could be of alien origin.
Watch this space!
Here is an image showing the three interstellar visitors – that we know about anyway!
Only three known interstellar objects have been detected in the solar system to date: ‘Oumuamua (left), 2I/Borisov (center) and 3I/ATLAS (right).
ALAN FITZSIMMONS/NASA, ESA; D. JEWITT/UCLA; DAVID RANKIN, SAGUARO OBSERVATORY
Expect more exciting updates over the next few months!
Why Are We Finding Them Now?
You might be wondering why we are suddenly spotting these mysterious interstellar visitors.
Well, these objects don’t emit their own light – we can only see them when they reflect the light of the Sun. Smaller objects don’t reflect much light, so we usually only manage to see the larger ones.
But we have now got much more powerful telescopes which can detect much smaller and darker moving objects. The new Vera Rubin Telescope (VRO) based in Chile can make videos of the southern sky and so detect moving objects. The first images released from VRO last month, identified about 2000 new asteroids in the Asteroid Belt -- in just one night’s worth of observation! Our chances of spotting more interstellar visitors have increased by A LOT!
Check out Vera Rubin’s asteroid observations here:
https://www.youtube.com/watch?v=TDjXiuNFntU&t=17s
It is worth having a look at the first release shots from VRO – they are mindboggling!
Look Up Yourself!
Join members of the ASV outside Discovery on Friday 1 August at 6pm to look at the night sky through their telescopes (Weather permitting).
Who knows what heavenly wonders we might see!
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