Planets are often discovered orbiting one or more stars. However, scientists have long doubted the existence of "wandering planets" - worlds that are not bound by any star and drift freely in interstellar space.
Recently, astronomers for the first time confirmed for sure such a planet, when determining both its mass and distance from Earth.
The newly discovered rogue planet is located nearly 10,000 light-years from Earth, in the center of the Milky Way.
Estimates show that its mass is about 70 times that of Earth, equivalent to a gas giant planet, only smaller than Saturn - which has 95 times the mass of Earth.
Previously, in 2000, scientists recorded the first signs of the existence of planets without host stars. However, it was not until 2024 that a research team observed an object that distorted the light of a distant star, both from Earth and from space.
These observations were carried out by multiple ground observatories, combined with the European Space Agency's (ESA) Gaia space telescope, before Gaia ceased operation.
Thanks to this light bend phenomenon, scientists can infer that the interference object is a real vagrant planet, not a brown dwarf star - a type of "failed star" with a larger mass than a planet but not enough to maintain nuclear reactions like stars.
According to researchers, the number of planets wandering in the Milky Way may be significantly more than what humans once imagined.
Mr. Andrzej Udalski, a astrophysicist at the University of Warsaw (Poland) and co-author of the study, said that theoretical models of planetary formation show that such worlds may be very common, even more than the number of stars in the galaxy.
The collection of more data on wandering planets is expected to help scientists better understand how planets form and evolve.
However, detecting planets of this type is a major challenge. Due to the lack of host stars, they rarely emit light strong enough for current telescopes to observe directly. The only way to detect them is through gravitational effects.
The new discovery, with data from both Earth and space, is seen as an important step, helping to further confirm that "orphaned planets" actually exist and may be much more common than previously predicted.
