SOME time in the not-too-distant future, three ships will circle the Sun.

Inside their holds, they will each carry a cube of gold platinum, floating in zero gravity.

At some point, the ships will arm their lasers and fire upon each other - across five million kilometres of space.

Result?

If the world's most famous scientist is right, the cubes will wobble a bit and the last piece of Einstein's theory of relativity will be proven correct.

And if it all sounds a bit fantastical, it isn't.

The mission - dubbed the Laser Interferometer Space Antenna, or LISA - is a frighteningly expensive collaboration between NASA and the European Space Agency aimed at discovering gravitational waves.

According to the theory, gravitational waves form when black holes are pulled ever faster through space by larger black holes.

If scientists can find a way to detect these waves - which are too weak to detect from anywhere near the Earth with regular instruments - then they might have found a way to study them.

Because the problem with studying black holes, if you're a scientist who looks for such things, is that they are so dense they can't be seen.

"No light or radiation escapes from inside them," Glasgow University professor Sheila Rown told The Telegraph.

"Gravitational waves from the warped spacetime around black holes could give us new ways of looking at them.

"We could also learn about the state of matter inside collapsed stars."

Just how important the state of matter inside collapsed stars is to everyday life on Earth is anyone's guess - as it hasn't been discovered yet - but NASA and ESA believe it's a worthwhile project.

They're particularly interested in the "galactic song" emitted from dying stars that resounds through the universe for millions of years, and even "the faint whispers of waves generated shortly after the Big Bang".

When LISA's finished, it will be the biggest scientific machine ever built.

It won't be launched until around 2020, but doubters will get their first confirmation of the project sometime next year, when the two agencies launch LISA Pathfinder, an experimental mission purely to test whether the technology is on track.

If that works, it's all systems go for the full lasers, gold cubes and sun-orbiting spaceship treatment.

And more than 100 years after publishing his theories, Einstein may finally get his perfect marks.