'[The] chances of observing microlensing are extremely slim because three objects - source, lens and observer - must be almost perfectly aligned, ' said paper author and astronomer Przemek Mroz of the California Institute of Technology.
Astronomers from the United States and Poland say that this so-called "rogue planet" is the smallest ever identified to date.
Gravitational lensing occurs when a massive galaxy or cluster of galaxies bend the light emitted from a more distant galaxy.
A roughly Earth-sized, "free-floating" planet roaming across the Milky Way - while gravitationally unattached to any star - has been discovered, a study reported.
Microlensing comes from Einstein's theory of general relativity - a massive object (the lens) may bend the light of a bright background object (the source). "When this happens, the closer body can act as a gravitational lens, bending and magnifying the star's light in ways that can reveal the foreground object's mass and other characteristics".
Gravitational microlensing is only possible when an astronomer's telescope lies in nearly ideal alignment with the observed object and the source star.
"That is why modern experiments looking for microlensing phenomena observe hundreds of millions of stars located in the centre of the Milky Way, where the probability of this phenomenon is greatest". Most of the observed events, which typically last several days, are caused by stars. They call this event 'the most extreme short-timescale microlens discovered to date'. Andrzej Udalski, the PI of the OGLE project.
The search for life beyond Earth and the scope of one day settling down on another planet is something that everyone has thought about at least once in their life. NASA, which is also working on a telescope that will be able to observe free-floating planets, has said that rogue planets can help us learn about how planets are formed. Thus studying free-floating planets enables us to understand the turbulent past of young planetary systems, such as our solar system.
The full findings of the study were published in Astrophysical Journal Letters.
Data from the Kepler space telescope combined with the "Drake Equation" has revealed that there are at least 300 million potentially habitable planets within the Milky Way galaxy, but outside of our Solar System.