Orbit in action: Mini black holes which could pass through Earth each year may hold objects in orbit, like the electrons orbiting an atomic nucleus pictured here Science fiction fans know them as dense, sometimes inescapable objects but black holes could be closer to home than you might imagine. While deep space is littered with black holes formed by the collapse of giant stars, a miniature form also exists – and may even be passing through the Earth on a daily basis. And unlike the larger black holes that swallow everything – even light – past a certain point, the mini black holes instead hold objects in an orbit.

According to a paper by Aaron P. VanDevender from Halcyon Molecular in Redwood City, California, and J. Pace VanDevender from Sandia National Laboratories in Albuquerque, New Mexico, the orbiting effect is similar to the way electrons orbit a nucleus without collapsing inwards. In their study, the VanDevenders theorise that some mini black holes are so small that they are able to exist on Earth as well as passing through the planet without causing any damage. The ‘Schwarzschild radius’ is the closest an object can come to a black hole before it is absorbed permanently but as some mini black holes are so small, their Schwarzschild radius can be lesser than the size of the orbit of particles nearing the mini black hole.

So while entire planets could be swallowed by a large black hole after passing its event horizon, mini black holes could gravitationally bind matter around them in orbit.  The VanDevenders have labelled this theory the Gravitational Equivalent of an Atom and have calculated that millions of kilogrammes of mini black holes in dark matter form should pass through Earth each year. And there’s potentially no risk of the Earth being swallowed up as the mini black holes would pass so quickly through the planet that particles already bound in orbit around the GEA would be rapidly stripped from the mini black hole.

Millions of kilogrammes of mini black holes in dark matter form may pass through Earth each year.

‘It would be difficult, but not impossible [to detect one of the mini black holes passing through the Earth],’ Aaron VanDevender said in research posted at arXiv.org.

‘The available power of a GEA to emit detectable radiation is small but not negligible.

It would likely be substantially easier to observe a GEA in orbit around the Earth, rather than one that is passing through at a tremendous velocity.’

The VanDevenders’ research follows a claim last month that certain black holes could include an area where space and time could exist, after being absorbed. If a charged and rotating black hole is large enough, said Professor Dokuchaev, from the Institute for Nuclear Research of the Russian Academy of Sciences in Moscow, it can weaken the tidal forces that are beyond the event horizon – the point where nothing, not even light, can escape a black hole’s gravity.

‘This internal black hole domain, hidden by two horizons from the whole external universe, is indeed a suitable place,’ he explained.

‘Advanced civilisations may live safely inside the supermassive black holes in the galactic nuclei without being visible from the outside.’

The Milky Way, where a black hole may lurk: It was claimed last month that certain black holes could include an area where space and time could exist, after being absorbed