A physicist has suggested that a peculiar type of black hole could be made in the laboratory. It would be just half a metre wide and made of electrons.

Until now making black holes in the lab has been the stuff of science fiction.

The disaster scenario for an Earthly black hole usually begins with an experiment involving a high-energy particle accelerator that smashes sub-atomic particles together.

Big Bang

Particle accelerators are designed to collide particles together at incredible energies to recreate the conditions of the Big Bang. Matter and energy are indistinguishable in the explosion and obey laws that do not come into play in our everyday universe.

Accelerators use tunnels kilometres long to generate extreme particle speeds

But what if something went wrong and scientists inadvertently made a black hole that sank into the Earth, taking up residence at its core?

It would eat away at our planet, devouring it from the inside at an ever-increasing rate. Within an hour, the Earth would be gone replaced by a hole in space and time.

However, the creation of a black hole on Earth was not thought to be at all feasible - until now.

Electronic black hole

Theoretical calculations carried out by Murat Ozer of King Saud University in Saudi Arabia suggest it would be rather easy to make a black hole in the laboratory - but it would not be a black hole as we have imagined them.

It would be a black hole for electrons only. All other particles and light would be able to pass in and out of the black hole but once an electron went inside it, it would be forever trapped.

Ordinary black holes occur as a result of gravity. When an object's gravity is strong enough to prevent light from escaping it becomes a black hole.

In black holes our everyday notions of space and time break down. Nothing can emerge from a black hole once it has gone inside.

'Rather easy'

But said Dr Ozer, talking to BBC News Online: "A black hole for electrons, could be built in the laboratory rather easily. You would need a Van de Graaf generator, a metallic sphere and a supply of electrons."

"If you made one in air it would be half a metre across. If could be smaller if it was in a vacuum," he added.

Studying electronic black holes would help us understand gravity black holes, as they would have many things in common.

So perhaps the time may not be far off when we can study black holes in the laboratory. But I wonder if this would be wise? Do we really know enough about them to be sure they would not pose any danger?