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We May Have Found The First Exoplanet Outside of Our Galaxy!
Rosanne Di Stefano, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics along with his team, may have discovered what would be called the First Exoplanet outside the Milky Way. The study was conducted with the collaboration of NASA's Chandra X-ray Observatory and European Space Agency's XMM-Newton space telescope. The suspected Exoplanet named M51-ULS-1b, is believed to be 28 Million Light Years away in a Spiral Galaxy named Messier 51 (M51). Astronomers and Scientists around the globe seem pretty excited as well as intrigued by the results. This is indeed history in the making.
What is an Exoplanet?
An Exoplanet or Extrasolar Planet is a planet outside of our Solar System. And before you ask if Pluto is an Exoplanet, the answer is a big NO. Pluto is a dwarf planet, still technically inside the Solar System. The first ever Exoplanet was discovered in the year 1992. Till date more than 4,800 Exoplanets in more than 3,500 planetary systems have been found out. But all of these discoveries have been within our own Galaxy, within a range of less than 3000 light-years from Earth.
How is an Exoplanet found?
First of all let me tell you, an Exoplanet is a damn hard thing to find in a dark sky, even with the help of the most powerful telescopes ever made. Being planets, they don't have their own source of light, hence remain hidden in the bright glare of their stars. This makes direct observations, next to impossible, hence Astronomers use indirect methods to find them. Basically they look for alterations and effects on Stars, a potential planet would have.
Wobbly Stars or The Astrometry Method
The first and most popular way of finding extra-terrestrial planets is to look for "Wobbly Stars". A Star which has a planet revolving around would never perfectly orbit around its center. Why? Because of Gravity, Stars and Planets constantly pull on each other. This phenomenon pulls the Star in unexpected paths, which could be witnessed from a distance. Hence, whenever a star is seen showing an irregular path in comparison to its nearby stars, it is most certainly believed to have a planet in its system.
The Astrometry Method is one of the renowned methods to look for Planets outside of our star system. Hundreds and hundreds of planets have been discovered using this method. But there resides a drawback in this system. The Astrometry Method allows only Planets, the size of Jupiter or more to be discovered. Small planets like Earth, create only small wobbles, hence much harder to be found.
The Transit Method
About 80% of all Exoplanets are discovered by the Transit Method today. Generally a Transit occurs when a planet passes between a star and its observer, causing a dip in the brightness of the star. These changes in brightness are very small depending on the distance of the observation. The dimming though could be seen in light curves received over a period of time. Transits are a very useful method of discovering planets because they help determine various characteristics of the planet like orbital time, size of the planet, its atmosphere, and temperature.
The Kepler mission assigned by NASA was specifically designed to explore the diversity and structure of exoplanetary systems, with the very Transit method. Over its 9 years of operation, Kepler led to the study and discovery of thousands of planets. Kepler is now succeeded by TESS, which is currently assigned to expand its predecessors work.
How was M51-ULS-1b discovered?
While Kepler and TESS have been pretty successful in the search for dips of electromagnetic radiations, something which humans can see. The team under Di Stefano has instead looked for dips in the brightness of X-Rays for their study. Why? Because X-rays are produced in small areas of Stars. Hence, when a planet passes in front of it, it would completely of the X-ray emissions. Thus, the transit would be more obvious, which is a necessity when observing far off objects.
The research team believes that the probable exoplanet is orbiting two large objects, which could either be a Neutron star or a Black Hole. The Black Hole (if present) could well be pulling in gases from a nearby companion star. The Transit lasted for a whole 3 hours, where the X-ray emissions dipped all the way to Zero. The researchers are confident that the planet could be roughly sized to that of Saturn, orbiting its star at a distance twice to that of Saturn's from the Sun.
Why this is one of the greatest incomplete discovery?
The search for extraterrestrial life and intelligence led to the wide scale search of exoplanets. And what followed in the last three decades, has made Astronomers fascinated about the idea of multiple life supporting worlds. Astronomers believe that the Milky Way alone could harbour 11 billion earth like worlds. Which means, planets within the Goldilocks zone of their star, or precisely planets within the habitable zone, which are ideal for supporting liquid water. This discovery on the other hand could potentially open up the gates for an already fascinating chapter of our species. But before you get to your wildest dream of finally meeting an Alien civilization, Stop.
All the above observations and studies do not confirm, the object seen 28 Million light years away is indeed a Planet. Didn't I say you, finding exoplanets ain't easy. A confirmation of that object being a planet requires more data and study. The researchers need to observe another transit of that object, and both the records must match, transit duration, orbital period etc. But here's the worst part, the object isn't expected to transit the star before the next 70 years. So, the wait would be lengthy, which makes it the greatest incomplete discovery.
There resides a possibility that all of this research might account to nothing. Considering, the dimming caused by any other agents like a dust or gas cloud passing in front of the star. It is highly unlikely, but certainly a possibility, considering the distance it is from us.
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