Many astrophysicists believe that the first discovered intergalactic object may be an interstellar ship. They suppose that Oumuamua may be a sailboat arriving from another galaxy. Scientists believe that this hypothesis can answer the question of where the interstellar object took the additional acceleration, which was not affected by the gravity of our luminary or other planets.
For the first time, this object was discovered in 2017. Initially, it was mistaken for a comet, but further observations showed that it was moving at a speed of 26 km/s along a hyperbolic trajectory. This means that it is temporary in our system, and after some time, it will fly away from it.
Scientists did not find signs of a comet in it and assigned it the status of an asteroid. Using optical telescopes, it was possible to find out that the object has an elongated shape, a reddish color, and a very high density.
In 2018, astrophysicists measured and calculated the flight path of an asteroid 2017 UI (Oumuamua) and noticed a strange acceleration at the object. It did not receive it from the Sun or other nearby objects. Astronomers decided that while approaching the Sun, the gas jets that began to emerge from the surface of the asteroid began to accelerate it.
The fact is that such an effect would be most strongly observed at the maximum approach to the Sun, but this did not happen. In addition, if the asteroid had such an effect, then it would have a strong and noticeable rotation around its axis, which was just not observed.
Studies have shown that acceleration could have come from a solar sail that an asteroid might have. After additional calculations, it turned out that if it had a sail, then the thickness would be 0.3-0.9 mm.
Therefore, either it is a new type of celestial body, or it is a man-made object. Its “possibly existing sail” could survive the flight in many kiloparsecs.
In extreme cases, this may be a fragment from the huge starship or a reconnaissance ship sent to our planet by aliens. At least, astronomers hope that the new LSST telescope will help in finding more such objects.