Outbound comets have alien origin, study finds

The new discovery is expected to reshape human understanding of comets reaching the solar system from interstellar space

Interstellar comet
The first color image of the comet C/2019 Q4 (Borisov), was captured by the Gemini North telescope at Hawaii's Mauna Kea. Gemini North acquired four 60-second exposures in two color bands (red and green). The blue and red lines are background stars moving in the background. Gemini Observatory/NSF/AURA/Travis Rector

A study conducted by astronomers at the National Astronomical Observatory of Japan (NAOJ) has suggested that two comets that are currently heading out of the solar system have an alien origin. Experts made this conclusion after analyzing the trajectory of two comets, and they made it clear that the comets might have originated outside the solar system.

A better understanding of the outer solar system

Scientists believe that the new finding could help humans to expand their knowledge about the outer solar system. Not all comets follow close orbits around the sun, as some comets fly through the solar system at breathtaking speed and will later enter interstellar space.

Even though it is quite easy to calculate where these comets are heading, it is often difficult to find details of their origin. Scientists who took part in this study revealed that the two comets might have originated somewhere, possibly in other planetary systems. As the comets fly through interstellar space, they might have accidentally entered the solar system, and will finally go out of the system.

Scientists also suggested that it is possible for gas-giant-sized bodies passing close to the Solar System to destabilize long-orbit comets, and will set them on paths that are very similar to the path followed by the two comets.

Oumuamua and Borisov

It was in 2017 that scientists discovered Oumuamua, the first known interstellar object. Later, in 2019, amateur astronomer Gennady Borisov discovered another interstellar comet, which is now known as 'Borisov' (C/2019 Q4).

The new interstellar comet Borisov has been discovered just before it made its pass behind the sun, and it gives sufficient time for scientists to learn about its characteristics. The discovery also made scientists understand that interstellar objects in the solar system are much more common than previously thought.