A rogue, hyper-speed object — over 27,306 times the size of Earth — is hurtling so fast through our galaxy that it might break free of the Milky Way, according to NASA.

Scientists determined the mysterious object was cruising at a breakneck one million miles per hour when they spotted it more than 400 light years from Earth - one light-year is equal to six trillion miles.

While experts have not determined what the newfound celestial body is, they speculated it is a 'brown dwarf,' a star which is larger than a planet but lacks the mass to sustain long-term nuclear fusion in its core like Earth's sun.

If the object confirmed as a brown dwarf, it would be first-ever to be documented in a chaotic, hyper-speed orbit capable of breaking free from our home galaxy. 

A coalition of citizen-scientists with NASA's 'Backyard Worlds: Planet 9' project were the first to spot the celestial body, the US space agency confirmed this week.

'I can't describe the level of excitement,' German citizen-scientist Martin Kabatnik, a long-time member of NASA's Backyard Worlds program, said in statement. 

'When I first saw how fast it was moving,' the Nuremberg-based researcher confessed, 'I was convinced it must have been reported already.' 

Backyard Worlds citizen-scientists Martin Kabatnik, Thomas P. Bickle and Dan Caselden were the first to spot this million mph object a few years ago, earning the hyper-speed object the catalogued name CWISE J124909.08+362116.0.

According to astronomer Dr Kyle Kremer, who has collaborated with them on better understanding the object, several astrophysics theories could explain how the object, CWISE J1249 for short, could have gotten to its incredible speed. 

In one theory, CWISE J1249 rocketed out of a two star or binary star system after its 'white dwarf' sister star died off — collapsing in an explosive runaway nuclear fusion reaction called a supernova.

Another viable theory has it that CWISE J1249 originated inside a tight cluster of starts called a 'globular cluster' where it was flung free via the pull of a black hole. 

'When a star encounters a black hole binary,' Dr Kremer said in a NASA statement on the discovery, 'the complex dynamics of this three-body interaction can toss that star right out of the globular cluster.'

A host of university academics and government scientists, including members of the NASA Goddard Space Flight Center, have now drafted up a report on these volunteer citizen-scientists' observations, awaiting peer review at Cornell's arXiv site. 

These experts, including an astronomer from the University of Leicester and an astrophysicist with the American Museum of Natural History, have made their own case that the object is a 'hypervelocity L subdwarf.' 

That would make it among the smallest objects to qualify as a brown dwarf ever documented.

The international group of volunteers who make up NASA's 'Backyard Worlds' work with interstellar image data taken by NASA's Wide-field Infrared Survey Explorer (WISE) — a huge 'all sky' survey that ran from 2009-2011 and again from 2013-2024.

NASA's WISE telescope scans led to the discovery of thousands of minor planets in our galaxy, multiple star clusters and the first Earth 'trojan asteroid,' meaning a rock that orbits the same ring around the sun as our own planet.

It has been NASA's hope that members of the general public, like Backyard Worlds' team, will make even more discoveries with this vast haul of outer space data.

According to NASA, scientists plan to train further equipment on CWISE J1249 in an effort to get a better sense of its chemical make-up or 'elemental composition.'

The chemistry of this high-speed object could hold 'clues about which of these scenarios is more likely,' whether it was flung by a black hole or a collapsing white dwarf, whether it is a gas giant or a burning brown dwarf. 

Using open source software for modeling galactic orbits of celestial bodies, called galpy, these researchers tested '100 random initial conditions' alongside the identifying data they already know about CWISE J1249 to see where it might go next.

As published in their arXiv paper, which is awaiting peer-review with the Astrophysical Journal Letters, the team found multiple scenarios where this suspected 'hypervelocity L subdwarf' is likely to fling itself out of the Milky Way.

'Given the uncertainties in the inferred velocities and potential models,' the team wrote in their study, 'we find that [WISE] J1249+3621 has a significant probability of being unbound to the Milky Way.' 

'17 percent of our simulated orbits are unbound over 10 gigayears,' they added, meaning that the object could eject itself into the unknown in about 10 billion years.