Astronomers believe they've spotted first planet outside Milky Way
A group of astronomers believe they may have spotted the first planet in another galaxy, according to a study published Monday.
The potential new planet was spotted in the spiral galaxy Messier 51. Discovered by researcher Charles Messier in 1773, the galaxy is also known as the Whirlpool Galaxy and is approximately 31 million light-years from Earth in the constellation Canes Venatici, according to NASA.
"It is exciting to the find possible planets in external galaxies, which were first thought of as potentially large systems like the Milky Way and called 'Island Universes,' over 200 years ago," Harvard-Smithsonian Center astrophysicist Rosanne Di Stefano said in a statement to CBS News. "We may have assumed that these distant systems host planets, but it is of critical importance to actually find them."
The findings, published by seven researchers from Princeton, Harvard, the Sydney Institute for Astronomy and University of California Santa Cruz, show that researchers used a new way of looking for planets outside of our galaxy called the X-ray transit method.
The study said that finding planets can be extremely difficult since each galaxy outside of our own "occupies such a small area of the sky." These planets are so small and bright that they can confuse radial velocity measurements or transit detection, the most common ways to identify planets.
But the X-ray method marks the passage of potential planets using X-rays. Researchers record when an object moves over a star and blocks its X-rays. The duration and intensity of the object's movement can tell researchers more about the size and orbit of the potential planet.
Researchers believe their findings will enable other astronomers to find other extragalactic planets with wide orbits, hopefully leading to larger discoveries for the scientific community. But confirmation of the planet's existence could take a long time, as its orbit is estimated to occur every 70 years.
"The most important follow up is to continue the search for more planets around X-ray binaries," Di Stefano said. "In this way we will establish the statistics, learn about possible formation mechanisms and better insert these distant populations."
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