Discovery of a Planet in a Different Galaxy!

    We know that in the Milky Way we have found many different planets in our home galaxy. There are an estimated 100 billion planets in our galaxy. Then if we take a step further, there are an estimated 100 billion galaxies in the universe. So that should mean that since our universe is so large and vast then there should be other planets in other galaxies other than just the Milky Way. Are planets also common in other galaxies or is the Milky Way just one of the special galaxies? Well, I have found that there is the first evidence of there being another planet in a different galaxy than the Milky Way.

M51 Whirlpool Galaxy

The planet that was discovered is in the M51 Whirlpool Galaxy. This galaxy is twenty-three million light-years from Earth and is near the constellation of Ursa Major! The planet is said to be a little smaller than Saturn. It is also a planet that orbits a binary system which is around ten times as far away as the Earth’s distance to the Sun. 

    The way we can detect this planet when it is so far away is because the scientists had the exact perfect conditions that they needed. The planet that is in this binary system has a black hole or a neutron star that is engulfing massive stars at a very high rate right next to this planet. Since this is happening, this emits a lot of energy which makes this one of the brightest things on the X-ray in the Whirlpool Galaxy. When thinking about how bright this is, the X-ray luminosity is a million times brighter than the SUn’s luminosity at all wavelengths! 

This is an image of the Whirlpool Galaxy from the Chandra X- ray telescope. The orange dot is the bright X- ray light that is being emitted.

    Since we now have our foot out the door already of discovering a planet in a different galaxy, we are going to be able to keep an eye out for more! There should be more discoveries of more planets in other galaxies in the near coming future! 

Works Cited

The Physics arXiv Blog. “First Evidence of a Planet in Another Galaxy.” Discover, 24 Sept. 2020. 

“X-Ray Data Reveal 1st-Ever Planet Orbiting Stars in Another Galaxy.” EarthSky, earthsky.org/space/1st-exoplanet-in-another-galaxy-whirlpool-m51-uls-1b#:~:text=Bottom%20line%3A%20Astronomers%20used%20X,23%20million%20light%2Dyears%20away.