The first planets beyond the Milky Way may have been discovered
For the first time ever, we have discovered planets beyond our own Milky Way galaxy.
We have long been unable to find exoplanets outside the solar system beyond the confines of the Milky Way. After all, our galaxy is a warped disc about a hundred thousand light-years across and a thousand light-years thick, so it's incredibly difficult to see beyond that.
But now, a new study is saying there could be extragalactic exoplanets and have been located in a galaxy some 3.8 billion light-years away, which is too far away to be observed directly even with the biggest telescopes now in existence.
Astrophysicists at the University of Oklahoma say they were found those exoplanets by using data from NASA’s Chandra X-ray Observatory space telescope and with the help of gravitational microlensing. That’s a phenomenon predicted by Einstein’s general theory of relativity in which the gravitational field around celestial objects can focus light just like a lens so that distant objects can be observed at high magnification.
Microlensing of quasars allows astronomers to determine the presence of such planets, even though no telescope yet built would be able to see them.
While studying the light emitted by the lensed quasar RXJ1131−1231 with the Chandra X-ray Observatory,the gravitational field of the galaxy 3.8 billion light years away, between us and the quasar, bends light in such a way that it creates four images of the quasar. The researchers found that there were peculiar line energy shifts in the quasar’s light.
So by modeling their results, the researchers concluded that the shifted energy signature was most likely caused by a huge population of planets with masses ranging from our Moon to Jupiter. The model that best matched the data found a ratio of 2,000 planets for every main sequence star in the galaxy and these planets are specifically “unbound” not orbiting a star but wandering freely.
This is one of our best chances for examining exoplanets from other galaxies in detail. With current telescope technology, microlensing can point to a detection in other galaxies, but it cannot fully probe the properties of these candidates.
We tend to assume that other galaxies have planets ,after all, why should the Milky Way be unique?
But this could be the first, albeit indirect, evidence for these distant worlds.
Phedias Hadjicharalambous.
Cyprus Astronomy Organisation
