NASA has discovered signs of a new planet and it would be the first-ever to be spotted outside the Milky Way.

The new Saturn-sized planet was discovered by NASA's Chandra X-Ray Telescope.

It is located in the Messier 51 galaxy which is approximately 28 million light-years away from our own galaxy.

Scientists used the same technique to find thousands of exoplanets. 


What is an exoplanet?

Exoplanets is the term given to planets that are out with our solar system and don't orbit the fun.

However, they can still be found within the Milky Way galaxy.

Astronomers have recorded nearly 5000 of these exoplanets and have all been found within 3000 lightyears of Earth.

How was the new planet discovered?

Researchers from the Harvard-Smithsonian Center for Astrophysics in Cambridge in the US, led by Dr Rosanne Di Stefano, used the same general technique that has detected thousands of exoplanets before this possible new world.

The team looked for dips in the brightness of X-rays they received from a type of object known as an X-ray bright binary.

The scientists could see through the Chandra X-Ray Telescope where the possible planet passed a black hole or neutron star - which is a star's collapsed core.

The possible planet blocked its light and created a dip in brightness that could be spotted on the telescope.


The binary system, called M51-ULS-1, is the only implementable method that is currently being used to identify planets in other systems, according to Dr Di Stefano.

Dr Di Stefano told BBC News: "It is a unique method, uniquely well-suited to finding planets around X-ray binaries at any distance from which we can measure a light curve."

Other techniques, which have successfully identified planets within our own system before tend to break down over large distances since the light struggles to reach the telescope. 

Instead, the objects appear close together and it is almost impossible to tell the difference between individual planetary systems.

About the X-rays, Dr Di Stefano said, "There may be only several dozen sources spread out over the entire galaxy, so we can resolve them.

"In addition, a subset of these are so bright in X-rays that we can measure their light curves.

This study was due to be published on Monday in the journal Nature Astronomy but is currently delayed but the journal still plans to publish it.

The researchers admit that they need more data for the study to be conclusive which might be a challenge.

The planet has a large orbit with the researchers estimating that it orbits the Neutron star or black hole at twice the distance Saturn lies from the Sun.

This means it will not cross its binary partner for another 70 years.

Co-author Julia Berndtsson of Princeton University, New Jersey said: "We know we are making an exciting and bold claim so we expect that other astronomers will look at it very carefully."

At the very least, the possible discovery shows early evidence that this kind of X-ray technique could be used to identify other planets orbiting neutron stars or black holes in other galaxies.


Will the new planet support life?

The short answer is, no.

If the planet does indeed exist, it is likely to have survived an explosion created by the neutron star or black hole that it's orbiting. 

This would mean that the planet would be a hub of radiation and could not support alien life.