A few years ago, the very first visitor from a planetary system other than our own was discovered for the first time. It circled the Sun at high speed and then behaved in a way for which there is still no complete scientific explanation.
Namely, Oumuamua began to accelerate on its way out into space.
Comets are like little rockets
Now an American chemist and a geophysicist believe they have found a completely natural explanation for Oumuamua’s odd trajectory. In the journal Nature, they suggest that the celestial body spewed out hydrogen gas as it circled the sun, similar to a comet that acquires a tail of vaporized gases near the sun. In such cases, Oumuamua would be a kind of comet, even though its tail could never be observed.
Comets are like little rockets that can gas up and change their trajectory.
– That mechanism could be sufficient to explain that extra acceleration that Oumuamua exhibited, but that does not necessarily mean that it was so, says Anders Eriksson, space physicist at the Institute for Space Physics.
Thin solar sail
The theoretical physicist Avi Loeb, on the other hand, rejects the hydrogen theory. It is physically impossible, he says, and considers himself to have a much better explanation:
– There must be a force that pushes it away from the sun and we know such a force: namely the pressure from the solar radiation on a thin solar sail.
Avi Loeb believes that observations of the light from the visitor gossip that Oumuamua has the shape of a flat pancake, which hardly exists naturally in the universe and therefore must have been made by someone.
– Absolutely that it could be a technological structure, but in science you should try to stick to the simplest solutions. In that respect, I would say that the outgassing theory is doing better than aliens, says Anders Eriksson.