An international group of researchers has built a model of the early solar system and concluded that there may be a giant icy planet in the Oort cloud. A study on this has yet to be peer-reviewed, but has already been published on arXiv.

About 4.5 billion years ago, when our system was just taking shape, the planets did not have fixed orbits and moved chaotically. For example, Jupiter was once much closer to the Sun than it is now. Smaller objects, like billiard balls, were completely dispersed by gravity.

Researchers speculate that sometimes large chunks of “garbage” – even planet-sized ones – fly far enough to be completely hidden from the gravitational effects of giant planets. After that, they turned into space vagrants or fell under the influence of other planetary systems.

But something else is much more interesting. It seems that our solar system may have captured a giant icy gas from another system and held it in the Oort cloud. This probability is estimated at 7%. It’s also possible that one of our Neptune-like planets was stuck there in the early stages. The potential reality of this scenario is 0.5%.

But given the size of the Oort cloud and its distance from us, astronomers say we’ll never know exactly what’s hidden inside.

The Oort cloud is a hypothetical spherical region of the solar system containing objects made of water, ammonia, and methane ices. It is located one light-year from the Sun. Scientists note that its existence has not yet been proven, but there are indirect facts confirming the possibility of such an occurrence.