Every now and then, an astronomy story catches the popular attention and starts spinning off all kinds of weird theories.
One such case started in 2017, with the very first discovery of an interstellar body travelling through our solar system. This was Oumuamua, a very peculiar object discovered by an observatory in Hawaii. Its Hawaiian name means ‘a messenger from afar arriving first’.
Oumuamua was following a very unusual path, showing that it was not orbiting the Sun, but whipping around our star at such a speed that it was sure to shoot back out into deep space.
This was the first object ever detected that was travelling faster than the escape velocity from our Sun, and it caused quite a stir in astronomy – and a storm of claims that it was an alien spacecraft of some kind. This was encouraged by images showing a long, cigar-shaped object, although some scientists thought it was more like a wobbling flat disc, like a coin.
There were so many YouTube videos claiming it was an alien craft that I actually ignored the whole story, just because of the hype.
Since then, two more such interstellar visitors have been discovered. Borisov was detected in 2019, also travelling at high speed, but looking much more like a normal comet. In fact, the pristine cloud of dust and gas surrounding it indicates that it has never passed near a star like our Sun before, meaning that it is composed of its original material from wherever it came.
On July 1, ATLAS was discovered. Its speed of 210 000km/h indicated immediately that it was another interstellar visitor whipping through our solar system. It’s named for the Asteroid Terrestrial-impact Last Alert System, a pair of telescopes in Hawaii and South Africa that scan the sky nightly for moving objects, especially those that might hit the Earth.
Again, the media has been full of stories alleging that this object might be an alien spacecraft. There were so many reports that I checked them out this time.
It turns out that it is a Harvard astrophysicist called Avi Loeb who has been making much of the noise. He made the same sort of claim about Oumuamua, publishing a paper saying that it could be an intelligently designed ‘light sail’.
This time, he put out a paper with two researchers from the UK-based Initiative for Interstellar Studies, an independent think tank clearly looking for publicity and funding.
They pose the ‘hypothesis’ that ATLAS is possibly a hostile alien craft surveying the solar system. They have a smoking gun that proves that Earth is the probable target.
At the moment when ATLAS is closest, it will disappear from our view behind the Sun. So if it is carrying out hostile actions, ‘any manoeuvres of this kind would be obscured from Earth observation, allowing a surprise arrival on Earth to be conducted.’
The authors say ‘the hypothesis is an interesting exercise in its own right, and is fun to pursue, irrespective of its likely validity’.
Chris Lintott, an Oxford astronomer who has modelled ATLAS’s galactic origins, did not join in the fun. He said: “Any suggestion that it’s artificial is nonsense on stilts, and is an insult to the exciting work going on to understand this object.”
Publicity means everything these days for researchers. This time, a completely wild speculation with zero evidence has managed to drown out all the real science around a fascinating astronomical discovery.
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