The team of researchers comes from the University of Oklahoma's astrophysics department, who report they found a population of exoplanets outside of our solar system using microlensing. As MIT Technology Review reported in 2009, Italian researchers investigating stars in the Andromeda galaxy found a star that had some variability in its light-a sign that a planet about six times the size of Jupiter might be orbiting it.
According to the Astrophysicists, the planet discovered is very small and is around the moon of the Jupiter.
"This is the first time anyone has discovered planets outside our galaxy", he added.
For the purposes of their study, the researchers relied on the gravitational microlens technique, which relies on the gravitational force of distant objects to focus light from a star. He explained that they analysed the high frequency of the signature by modelling the data. Directly viewing exoplanets within the Milky Way is almost impossible, so astrophysicists have to sift through data and use other detection techniques that give way to evidence of planet signatures.
The phenomenon that made the detection of the newly-discovered planets possible is called gravitational lensing. When a planet passes the star in relation to the observer, the light falls in a measurable way, which can then allow astronomers to determine the presence of a planet.
The technique was first used to first identify planets outside of our Solar System but inside the galaxy, known as exoplanets. So he and postdoctoral researcher Eduardo Guerras used Albert Einstein's theory of relativity to find the galaxy beyond the Milky Way. The name the distant galaxy that hosts thousands of planets is RXJ1131-1231.
So far, 53 exoplanets in the Milky Way have been detected using this method.
"This galaxy is located 3.8 billion light years away, and there is not the slightest chance of observing these planets directly, not even with the best telescope one can imagine in a science fiction scenario", he said.
More than 2,000 planets were detected, a lot of them wandering through space not orbiting a star or orbiting between several stars, National Geographic reported.
"This microlensing is amplifying something that is very small and changing colours, which makes no sense", Guerras says, "or it's amplifying a small region of a bigger object and that object has different colours".