Gravitational waves explained: Groundbreaking discovery means we can see some of the strangest parts of space

Scientists are widely-expected to be about to confirm one of the greatest scientific discoveries this century. A group of experts from around the world are gathering to announce that they have direct evidence for one of Einstein’s wildest predictions: the existence of gravitational waves, which ripple through the universe, squeezing and stretching spacetime.

The announcement is not yet confirmed — the group only said that they would provide an update. But it's almost certain that the team will announce that they have at last seen gravitational waves — confirming a long-held theory and giving a deep insight into the beginnings of our universe.

How will we see them?

The new information comes from the Laser Interferometer Gravitational-Wave Observatory. That is made up of two installations in the US, 3,000 kilometres apart.

The system uses laser beams to measure pipes with very precise accuracy. It can detect even the tiniest change in their length — and, if that happens, the characteristic swelling and shrinking of the pipe would be evidence of the waves.

Doesn’t this just confirm everything we already knew?

Einstein predicted that gravitational waves existed, and theoretical work since then has confirmed that they almost certainly exist. In one sense, this is just practical proof of a working assumption.

But the important stuff is what receiving this signal actually means. If we gain the ability to dependably and verifiably measure the waves, it would open an entirely bit of the universe to study.

If we developed ways of looking at those waves and into the universe, it could be analogous to the development of telescopes. But instead of light, we’d be able to see messages from deep in the universe’s past.

The gravitational waves come bearing information about where they have come from. And many of them emerge from strange and early parts of the universe, like big bangs, meaning that we might receive our first ever messages from those unknown places.

If we could detect the waves properly, then it would enable us to “see” the development of black holes and the development of stars.

From there, we would be able to understand the beginnings and formation of the universe, and many of its most mysterious parts.

How do we do that?

Scientists and engineers around the world are assembling equipment that will help us detect more gravitational waves, and understand more about those that we find.

Perhaps the most ambitious is the huge eLISA mission, which will send a 1million-kilometre wide antenna into space, being carried around by three spacecraft.

That mission has already successfully sent the LISA Pathfinder, which will head out to test gravitational wave detection. That launched in December and went into orbit a couple of weeks ago.

The full mission will be able to do the same work, but away from the noise and bustle of Earth. That will allow it to listen for much deeper waves — allowing it to see into even bigger black holes.