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Do Aliens Exist?

The honest answer first: there is no evidence of aliens here. But ʻOumuamua is the reason the question got asked seriously, by serious people, in 2018 — and understanding why means understanding the strangest rock ever seen.

On 19 October 2017, Robert Weryk found it in Pan-STARRS1 data from Haleakalā, Hawaii: a point of light moving too fast to belong to us. It was already leaving, forty days past its closest approach to the Sun. What followed was 34 days of observation, and then it was gone forever.

A scout with a strange shape

The name is Hawaiian, ʻou.mua.mua — “scout”, chosen by the Pan-STARRS team. It also earned a brand-new designation scheme: the first I object, 1I, for the first confirmed interstellar visitor.

Nothing about its shape was normal. Roughly 180 metres long and ten times longer than wide, red like a Kuiper belt object, tumbling every seven to eight hours so its brightness swung by a factor of ten. No asteroid or comet in our solar system has those proportions. It was first announced as a comet, then reclassified as an asteroid within a week when no tail or coma appeared.

The orbit that proved it came from elsewhere

ʻOumuamua’s eccentricity is 1.20 — a hyperbola, the highest ever recorded. Anything above 1.0 means unbound: the Sun’s gravity could bend its path but never keep it. It cruised in at 26 kilometres per second, whipped around the Sun at nearly 88, and left at roughly the speed it arrived.

It seemed to come from the direction of Vega, which caused a round of headlines. The boring correction: it only looks that way now. The journey took so long that Vega was nowhere near that position 300,000 years ago. Direction of arrival says almost nothing about origin.

The speed boost that started the alien debate

In 2018, Hubble and ground tracking found something extra: ʻOumuamua had gained about 40,000 kilometres it should not have. Something beyond gravity was pushing it. The team behind the measurement — Marco Micheli of ESA and Davide Farnocchia of NASA JPL — concluded it behaved like outgassing from a comet.

The problem: there was no visible outgassing. No coma, no dust, nothing. A comet that pushes without puffing is a contradiction, and into that gap stepped Avi Loeb with the lightsail hypothesis: a thin artificial sail, pushed by sunlight, would accelerate exactly like that and show no coma. It was a real published paper, not a tweet.

It did not survive contact with better explanations. Invisible gases — hydrogen, nitrogen — outgas without the dust that telescopes can see, and later surveys found a whole population of “dark comets” in our own system doing the same trick. No new physics was ever needed, and no technosignature was ever found.

So, do aliens exist?

ʻOumuamua says nothing about that, in either direction. One weird rock, watched for a month, cannot settle the biggest question there is. What it did settle is smaller and more useful: interstellar objects pass through roughly once a year, and we were simply blind to them until Pan-STARRS got powerful enough. Better telescopes will find more, and the next one will get more than 34 days.

The alien hypothesis was worth publishing precisely because the object refused to behave. That is how the boundary moves: something strange shows up, the wild idea gets checked first, and usually the universe turns out to be stranger in a boring way. Usually.

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