Astronomers have found evidence of a possible planet outside of our Milky Way galaxy. If confirmed, this is the first time that a planet has been detected in another galaxy. It is located in the spiral galaxy Messier 51, also called the Whirlpool Galaxy.
Exoplanets are defined as planets outside of our Solar System. Until now, astronomers have found all other known exoplanets and exoplanet candidates in the Milky Way galaxy, almost all of them less than about 3,000 light-years from Earth. An exoplanet in M51 would be about 28 million light-years away, meaning it would be thousands of times farther away than those in the Milky Way.
These observations were made using NASA’s Chandra X-Ray Space Telescope.
Astronomers estimate the planet is about the size of Saturn and orbits a neutron star or black hole at about twice the distance of Saturn from the Sun. The planet was discovered when dips in the brightness of X-rays were observed from the binary system M51-ULS-1.
This is fascinating because it’s the first time X-rays have been used to detect exoplanet transits and offers exciting possibilities for detecting these worlds that are outside of our galaxy.
The researchers are not totally sure if the dimming seen here was caused by a planet, it could have been a passing cloud of gas and dust. However, they believe that the dimming is more likely caused by a planet because the characteristics of the event are not consistent with the passage of a cloud of gas and dust.
Because the region producing bright X-rays is so small, a planet passing in front of it could block most or all of the X-rays, making x-ray transits easier to spot because the X-rays can completely disappear, they would simply “blink out” as the planet passes by. This allows exoplanets to be detected at much greater distances than current optical light transits, which must be able to detect tiny decreases in light because the nearby planets only block a tiny fraction of the star.
If the dimming was caused by a planet, it would be the first planet ever discovered outside of the Milky Way galaxy. However, more data is needed to confirm the discovery. Because of the calculated orbit of the object, we will need to wait about 70 years for it to cross in front of its binary partner again.
This possible planet is exciting because it opens up a new way to search for exoplanets. In the past, astronomers have only been able to find exoplanets in our own galaxy. However, by looking for X-ray transits in other galaxies, astronomers can now search for exoplanets much farther away.
The researchers are hopeful that they will be able to find more exoplanet candidates in other galaxies. They are also planning to search for X-ray transits in Milky Way X-ray sources to discover new nearby planets in unusual environments.
This discovery is a major step forward in the search for exoplanets. It shows that there are likely many planets out there in other galaxies, and it opens up a new way to find them