A bizarre object 10 million times brighter than the sun defies physics, says NASA

Astronomers call them ultraluminous X-ray (ULX) sources, and they emit about 10 million times more energy than the sun. This amount of energy violates a physical law known as the Eddington limit, which determines how bright something of a given size can be. If something crosses the Eddington limit, scientists expect it to explode into pieces. However, ULXs “regularly exceed this limit by a factor of 100 to 500, puzzling scientists,” according to a NASA statement.

New observations published in The Astrophysical Journal from NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR), which views the universe in high-energy X-rays, confirmed that one particular ULX, called M82 X-2, is definitely too bright. Previous theories suggested that the extreme luminosity might be some kind of optical illusion, but this new work shows that’s not the case—this ULX somehow defies the Eddington limit.

Astronomers used to think that ULXs could be black holes, but M82 X-2 is an object known as a neutron star. Neutron stars are the leftover, dead cores of stars like the sun. A neutron star is so dense that the gravity on its surface is about 100 trillion times stronger than Earth’s. This intense gravity means that any material pulled to the surface of the dead star will have an explosive effect, according to LiveScience.

„A meringue dropped on the surface of a neutron star would hit it with the energy of a thousand hydrogen bombs,” according to NASA.

The new study found that M82 X-2 consumes around 1.5 Earth’s worth of material every year, siphoning it off from a neighboring star. When this amount of matter hits the surface of the neutron star, it is enough to produce the unknown brightness observed by astronomers.

The research team believes this is evidence that something must be happening to M82 X-2 that allows it to break the rules and breach the Eddington limit. The intense magnetic field of the neutron star changes the shape of the atoms, the researchers believe, allowing the star to stick back even as it grows brighter.

„These observations allow us to see the effects of these incredibly strong magnetic fields that we could never reproduce on Earth with current technology“, the study’s lead author, Matteo Bachetti, an astrophysicist at the Cagliari Astronomical Observatory in Italy, said in a statement. “That’s the beauty of astronomy… we can’t really set up experiments to get quick answers; we have to wait for the universe to show us its secrets.”