The European Space Agency launched a rocket Thursday carrying two cubes of gold and platinum almost a million miles from Earth so scientists can see how they'll behave in a freefall—at a cost of more than $450 million.
What may sound like a frivolous enterprise is actually the prelude to a far more ambitious mission that hopes to measure ripples in space time caused by black holes and other massive objects lurking unseen in dark corners of the galaxy [phys.org].
Also known as gravitational waves, these ripples were predicted by Albert Einstein a century ago but have never been directly detected.
In order for that mission—tentatively scheduled for launch in 2034—to succeed, the European Space Agency first has to test whether it can shield objects from external influences well enough to measure the minute effects of gravitational waves.
"We want to see whether we can create an environment in orbit that's free of interference, and where we can conduct these high-precision measurements," said Michael Menking, senior vice president for Earth observation, navigation and science at Airbus Defense and Space. The company is the main technology contractor on the LISA Pathfinder mission.
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By mid-January, the probe will have reached an orbit about 1.5 million kilometers (930,000 miles) from Earth, where the pull from the planet's gravity is balanced by that of the sun. The cubes—made from gold and platinum to reduce their susceptibility to magnetic fields—are then carefully released inside a box that shields them from cosmic particles and other interference that might affect the measurements performed by a sensitive laser. The laser is capable of detecting movements of less than 10 millionths of a millionth of a meter.