Astronomers have discovered a dead star so bright it can only be described as "impossible".
The object was previously thought to be a black hole, but is in fact a pulsar expelling the energy of 10 million suns.
The incredibly dense object lies at the centre of the galaxy M82 ('the Cigar Galaxy') and is unlike anything ever seen before.
"This compact little stellar remnant is a real powerhouse. We've never seen anything quite like it," said Caltech's Fiona Harrison, NuSTAR's principal investigator.
"We all thought an object with that much energy had to be a black hole."
Pulsars are usually only one or two times the mass of the sun. This is also true of the M82 pulsar - but it's shining 100 times brighter than it is supposed to. Described in the journal Nature, the discovery was actually made by accident Harrison said.
"This was certainly an unexpected discovery,… In fact, we were looking for something else entirely when we found this."
You can read more detail about the pulsar and its discovery over at Phys.org.