Evidence of Possible Planet Outside Milky Way

 An exoplanet is a planet that orbits a star outside of one’s solar system. Over the past years, 4,500 exoplanets have been discovered in all, but these planets have only been found in the Milky Way Galaxy. NASA’s new discovery, however, is unlike the rest.

Recently, NASA has found the first evidence for an exoplanet outside the Milky Way Galaxy. Discovered in the Messier 51 (M51) Galaxy, or most commonly known as the “Whirlpool” galaxy, scientists have observed what could be the first planet to transit a star outside of the Milky Way. Not only that, the 4,500 exoplanets that have been found so far are less than 3,000 light-years from Earth. The exoplanet in the M51 Galaxy, on the other hand, is estimated to be about 28 million light-years away.

 The finding of this potential planet was  all due to the work of the Chandra X-ray Observatory, or as NASA says, “the world’s most powerful X-ray telescope.” Unlike other NASA telescopes, which search for drops in observable light, the Chandra was designed to detect X-rays. The observatory is said to have searched for drops in the brightness or, in other words, the dimming of X-rays received from X-ray bright binaries. These are systems where a Sun-like star orbits a neutron star or black hole. A neutron star is a dense result of a supergiant star that has collapsed on itself. Using the Chandra X-ray Observatory, the scientists observed that the material near the neutron star or black hole became superheated and glowed in X-rays due to the binaries. They interpreted the X-rays as a planet passing in front of the neutron star or black hole. 

Aside from the evidence, this discovery isn’t foolproof. More data is needed to fully confirm the discovery of an actual exoplanet in M51. Unfortunately, confirmation cannot be made any time soon. The planet candidate has a large orbit and won’t cross in front of its binary partner for at least 70 years. On the bright side, this method of discovering exoplanets via X-rays could help with discovering many other exoplanets, no matter how far. Though scientists won’t be able to find out more about the potential exoplanet in the M51 Galaxy for years and years, there are many other planets or exoplanets in this solar system waiting to be discovered.