Milky Way
The Milky Way is seen in the sky above a path and huts on Lady Elliot Island located north-east of the town of Bundaberg in Queensland, Australia, June 10, 2015. Reuters/David Gray

Scientists may have discovered planets beyond the Milky Way for the first time, a new study suggests. A team of astrophysicists identified extragalactic planets approximately 3.8 billion light-years away.

Planets were only previously detected within the galaxy, which has hundreds of billions of stars, according to NASA. But a new study provides evidence of extragalactic exoplanets beyond the confines of the Milky Way.

The study, recently published in The Astrophysical Journal Letters, suggests that over a trillion exoplanets could exist beyond the Milky Way. Scientists at the University of Oklahoma have utilised information from NASA's Chandra X-ray Observatory and through microlensing, a planet detection technique. They examined a distant quasar galaxy and found evidence of about 2,000 extragalactic planets for every star beyond the Milky Way.

These exoplanets come in different sizes. Some are said to be as huge as Jupiter, while some are as small as the moon. Most of them are not tightly bound to stars.

Astronomy and astrophysics professor Xinyu Dai, who led the study, expressed excitement about the discovery as it is the first time that planets outside the Milky Way galaxy have been discovered. It is possible to estimate that the number of planets in this faraway galaxy is more than a trillion.

“These small planets are the best candidate for the signature we observed in this study using the microlensing technique,” Dai said. He also explained that they analysed the high frequency of the signature by modelling the data.

'Very cool science'

Dai worked with Postdoctoral Researcher Eduardo Guerras for the study. Guerras explained that there is not the slightest chance of observing these planets directly.

“However, we are able to study them, unveil their presence and even have an idea of their masses - this is very cool science,” he added.

The researchers are hoping that other scientists will develop another technique to confirm whether or not these extragalactic planets exist.

Researchers have earlier announced that they may have discovered the first moon outside of the solar system. In a separate study, they used data from the Hubble Space Telescope and identified exomoon candidate Kepler-1625b. The moon orbits the star Kepler-1625 and is about 4,000 light-years away. A light-year measures distance in space. It equals 6 trillion miles.