The antimatter mystery and the ‘Big Bang’
Scientists in a US laboratory have created the world's heaviest particles of antimatter. It's a step towards understanding one of the deepest mysteries of the universe.
Amid the debris of a lightspeed collision, in a brilliant flash of energy, the anti-atom flickered into existence. For billionths of a second it hurled itself through the vacuum before colliding with the walls of the experimental chamber.
There was a tiny explosion. Then, the anti-atom vanished without trace. The only evidence of its passing was a flare of radiation, dispersing quickly into the void.
But even with such a short lifetime, the anti-atom has caused a stir among scientists. This week they published their findings: with two anti-protons and two anti-neutrons, it was the heaviest particle of antimatter ever artificially produced.
How did they do it? The secret lies in the deep laws of physics, which say that matter and energy are fundamentally equivalent. Release enough energy in a small space, and matter will emerge from nothing.
But whenever matter is created, so is antimatter. It's like punching circles from an endless sheet of paper. For each circle you get, you also get a hole. When antimatter meets matter, it's like putting the circle back into the hole – both disappear, and you're left with nothing. The two opposed particles vanish, in a process called annihilation.
Scientists made antimatter by releasing lots of energy in a small space. Using a powerful machine called a particle accelerator, they heated atoms to temperatures of trillions of degrees Celsius.
That's hundreds of thousands of times hotter than the centre of the sun.
The last time such temperatures occurred naturally was in the instant immediately after the 'Big Bang' – the birth of our universe. As space and time exploded into being, intense waves of energy condensed into matter and antimatter. The matter that was created in that moment went on to form the galaxies and stars we see in the skies today.
By re-enacting the beginning of the universe, scientists hope to understand one of the greatest mysteries of modern physics: what happened to the antimatter? Standard physical laws predict that matter and antimatter should have been produced in the same amounts. If that's the case, there would have been enough antimatter to cancel out all the matter in the universe in an instant.
And yet here we are; and as we look into the stars, there's no antimatter in sight.
So what happened? Was more matter produced than antimatter – breaking the laws of physics as we know them? Was the antimatter somehow separated from the matter? Are there whole antimatter galaxies drifting far beyond the limits of visible space?
Scientists will keep on asking. For the moment though, all we can do is wonder at the mysterious, awe-inspiring nature of the universe in which we live.
- Is there any point studying the beginning of the universe?
- What if science solved all the mysteries of the universe? Would it be good or bad if there were no questions left to answer.
- Scientists use particle accelerators to create antimatter. Design a poster showing what a particle accelerator looks like and how it works.
- Do some research into a scientific mystery of your choice – then write an article explaining why it's so mysterious.
Some People Say...
“Ultimately science will be able to explain everything.”
What do you think?
Q & A
- What are these 'particle accelerators' you mentioned?
- They're huge machines that smash atoms together at ridiculously high speeds. When two heavy atoms collide at nearly the speed of light, you produce a huge amount of energy in a small space.
- And how do we know what the beginning of the universe was like?
- By making calculations based on the laws of physics we can learn extraordinary things about the world, from the tiniest particles of matter to the very beginning of time.
- But we can't work out what happened to all the antimatter?
- No. Astronomer Martin Rees recently emphasised the uncertainties at the heart of fundamental physics. He is 'suspicious', he says, 'of people who believe they've got anything more than an incomplete and metaphorical understanding of any deep aspect of reality.' But human curiosity will always keep us asking the big questions.