The “no-hair theorem” of black holes, which greatly simplifies the way we model them, may not be true if an alternative theory of gravity known as the teleparallel formulation is correct, an unpublished paper argues. This could make the study of black holes considerably more complicated, but it would also allow physicists to understand them in ways many have feared they never will.

According to the “no-hair theorem”, a black hole’s mass, electric charge, and spin can tell us everything there is to know about that hole. Anything else we might measure, such as its magnetic moment, can be derived from these three measures.

Crucially, that means that when matter is swallowed by a black hole’s event horizon, all the information contained within it is lost, once the black hole has emitted any gravitational waves or light associated with its meal. It doesn’t matter what elements went into forming a black hole’s predecessor star, or even if it was made of antimatter rather than matter – under the no-hair theorem, it would appear identical to anyone outside its event horizon. The term “hair” is a metaphor for information streaming out of a black hole beyond the point of no return for incoming objects.

For a few hours after a star smashes into a supermassive black hole, some of the brightest light in the Universe is produced.

The subsequent flash of radio waves were thought to simmer down within weeks or months of a collision. It turns out we might have been a little impatient to turn our gaze elsewhere.

An international team of astrophysicists has witnessed radio waves bursting from material surrounding an assortment of supermassive black holes hundreds of days after they ripped apart a star, suggesting many collisions could be responsible for a serious case of cosmic indigestion.

As the universe evolves, scientists expect large cosmic structures to grow at a certain rate: dense regions such as galaxy clusters would grow denser, while the void of space would grow emptier.

But University of Michigan researchers have discovered that the rate at which these large structures grow is slower than predicted by Einstein’s Theory of General Relativity.

They also showed that as dark energy accelerates the universe’s global expansion, the suppression of the cosmic structure growth that the researchers see in their data is even more prominent than what the theory predicts. Their results are published in Physical Review Letters.