A matter of fact?

FORTY years ago today, on a desolate grey chunk of rock hurtling through space 239,000 miles from Earth, one of the most iconic moments in history unfolded.

When Neil Armstrong stepped out of the lunar landing module code-named Eagle, and took his historic small step, the world below was clustered around TV screens to watch.

It was the culmination of an epic "space race" that has since been hailed as mankind's greatest achievement.

For those intrepid minds working on taking what could prove to be the next small step in our understanding of the universe however, there is unlikely to be the same kind of attention.

But while their experiments may lack the spectacle of a rocket ship blasting into the atmosphere, or the drama of a small band of explorers boldly going where no man has gone before, their findings could prove even more significant to the lives of every single thing on this planet.

Scientists from Edinburgh University are at the forefront of worldwide research into the elusive, possibly non-existent material known as dark matter.

This theoretical "stuff" – if the calculations are correct – makes up the majority of mass in the observable universe. The only snag is that, while its presence has been inferred from observations and calculations, as yet no-one has actually "seen" this invisible matter at work.

That is the challenge facing Dr Alex Murphy, of Edinburgh University, who at 39 just missed out on the moon landings – though it played a very important role in his life.

"I was actually conceived around the time of the moon landing," he says. "It would have been just before, in all the excitement leading up to them."

Forty years on he has found himself at the centre of another great space race – a race to discover what takes up most of the space in the universe.

In the UK's largest commercial mine more than a kilometre underground, Dr Murphy is leading a team of researchers looking to be the first to prove the existence of dark matter.

His challenge could be compared to attempting a landing on a moon which is miniscule, invisible and quite possibly not even real. And while it might not have the political edge of the space race between the former Soviet Union and the United States, the competition is, if anything, even more intense.

"It is a huge race," he says. "The discovery of dark matter will almost certainly be the biggest scientific find of the century, so there are labs all over the world working on different experiments to try to be the first ones to do it.

"There are lots of theories about how best to prove its existence, and we are right there at the front of the race in terms of the work we have done, and the progress of the experiments."

His team at the Boulby Underground laboratory in North Yorkshire work in a small area shielded not only by the rock above them, but also by lead walls, steel sheets and even wax sealant, in order to block out as much background radiation as possible.

Inside the lab they have built the Zeplin III, in order to detect wimps – Weakly Interacting Massive Particles – which they believe make up dark matter.

The device holds a tank of the liquid-gas xenon, super-cooled to -110C using liquid nitrogen, and charged with 20,000V, all of which they hope will allow them to take a picture of "the rarest event on the planet".

"We can't take pictures of an invisible particle, but when it interacts with the xenon – when a wimp passes through the gas – it will produce light, so we are hoping to get a picture of that," he says.

"It will also produce a small electrical charge, which we will try to measure."

The team are around six months away from what they feel could be break-through tests, following some technical problems.

Dr Murphy admits there are many people who don't entirely see the point of trying to prove the existence dark matter, given all the theoretical evidence which suggests it is there.

But he says the importance of the work cannot be underestimated.

"Everyone knew the moon was there, but the landing was momentous, and it allowed them to carry out a great deal of other tests. If we prove its existence, it will open up so many opportunities for scientific study."

Dr Murphy is far from alone in his search for dark matter. Laboratories in the United States, Italy and Japan are working on similar experiments, while closer to home some rather different studies are taking place.

Fellow Edinburgh University scientist Richard Massey, 31, is also on the hunt for dark matter. But instead of shutting himself away underground looking for one tiny particle, Dr Massey is looking out into the universe to try and find gigantic fields of the stuff.

"Light travelling from a star, for example, would, if it passed through or close to a large patch of dark matter, be distorted because of the gravity of the matter. That is what we are looking for."

The astronomer and his team have also been looking closely at colliding galaxies millions of light years away. Car crashes on a massive scale, they provide a unique opportunity to "see" dark matter.

"Normally you can't see dark matter because there is so much ordinary matter around it, because of gravity," he says. "These collisions, which take place over hundreds of years – the blink of an eye in astronomical terms – throw everything out of shape."

Their work has been greatly helped by recent upgrades to the Hubble Space telescope, one of the reasons Dr Massey is a huge supporter of manned space exploration.

"It is disappointing when you think about the fact that we landed on the moon in 1969, but where have we gone since then," he says. "The Hubble work was done by astronauts using screwdrivers, and it couldn't have been done any other way.

"A lot of people think we should use robots, that we can accomplish more, do it for less money and make it safer. But the moon landings weren't just about what was achieved – they were an inspiration, to myself and to a generation of people."

While it will be years, perhaps decades, before man again sets foot on another world, the work of scientists like Dr Murphy and Dr Massey mean that the answer to one of the biggest mysteries of the universe might just be answered long before then.