Tim Radford in London
ASTRONOMERS have discovered a huge fountain of antimatter at the heart of the galaxy. The jet – from a mystery source – extends for 3 000 light years above the Milky Way.
Antimatter is a particle with the same characteristics as normal matter, except that it has an opposite electrical charge. For example, electrons have a negative charge. Its antimatter counterpart, the positron, is just an electron with a positive charge.
But antimatter is the most destructive stuff in the universe: when matter meets it both are annihilated in an explosion of unimaginable violence. This follows on from Einstein’s most famous equation, e=mc2, which says that matter and energy are interchangeable.
The cloud of antimatter appears in new maps of the universe made by Nasa’s orbiting Compton Gamma Ray Observatory. “The origin of this source of antimatter is a mystery,” one of the discoverers said this week.
The galaxy’s centre is 25 000 light years away from us, and for years radio telescopes, x-ray and gamma-ray instruments have been giving hints of something destructive – a black hole sometimes called the Great Annihilator – lurking there. But it may not be a black hole that has created the sinister cloud. It could have come from ‘starbursts”, or the fireball after neutron stars collided.
“It is like finding a new room in the house we’ve lived in since childhood,” said Charles Dermer of the US Naval Research Laboratory. “And it’s not empty – it has a boiler making hot gas filled with annihilating antimatter.”