Evidence of a first planet discovered outside our galaxy
- Alaya Laubsch
- Nov 1, 2021
- 3 min read
For the first time in history, NASA has discovered traces of what may be a planet circling a star beyond the Milky Way galaxy. NASA revealed hints of a new exoplanet through a binary system called Messier 51, commonly known as M51 or the Whirlpool Galaxy. So far, nearly 5,000 exoplanets have been discovered, but they have all been found within the Milky Way galaxy. What differentiates this specific find from others is that the exoplanet was found in the Messier 51 galaxy, about 28 million light-years from the Milky Way.
The term “exoplanet” means a planet that orbits around other stars, and it applies to any planet beyond our solar system. Exoplanets are particularly difficult to observe when directly using telescopes. This is because of the brilliant glare transmitted from the stars they orbit around, which conceals the planets. As a result, astronomers must depend on alternative methods to uncover and study these faraway planets. Astronomers investigate exoplanets by observing the impact they have on the stars which they orbit. One method used to search for exoplanets is to scan for "wobbly" stars. A star with orbiting planets does not revolve precisely around its axis. From afar, the star appears to be swaying due to its off-center orbit. NASA has also resorted to spacecrafts in order to look for exoplanets, an example being the Kepler spacecraft, launched in 2009. Kepler discovered exoplanets using a technique known as the transit method. A transit occurs when a planet passes in front of its star. As the planet passes the star, it blocks some of the star's light. During a transit, astronomers can see how the brightness of the star changes. This can also assist them in determining the size of the planet.
This new exoplanet was discovered using the transit technique, detected by NASA's Chandra X-Ray Telescope. This transit used a specific system called an X-ray bright binary. Through this method, NASA could detect dips in the brightness of X-rays received from the X-ray bright binary. The x-rays are usually made up of a neutron star or a black hole that is sucking in gas from a nearby companion star. Superheated material near a neutron star or black hole glows at X-ray wavelengths. Since the region generating the bright X-rays is small, a planet passing in front of it may block most or all of the rays, making the transit more visible. According to the transit and other collected data, the astronomers estimate that the potential planet would be roughly the size of Saturn, and It would orbit the neutron star or black hole at around twice Saturn's distance from the Sun. The method they developed is the only one that is currently in use.
The astronomers openly state that additional evidence is required to validate their interpretation. One difficulty is the planet's enormous orbit, which presents a challenge due to the fact that it will not cross in front of its binary partner for another 70 years. This rules out any attempts to perform a follow-up observation in the near future. Another possibility investigated by the astronomers was that the dimming was produced by a cloud of gas and dust passing in front of the X-ray source. They believe this is implausible, however, because the features of the event do not resemble those of a gas cloud. This new discovery could expand future investigations and create a whole new field for identifying additional worlds. The new field would then use X-ray wavelengths to search for planet candidates, an approach that allows them to be uncovered in other galaxies.
Sources:
Comments