A space probe designed to detect gravity waves in space-time, predicted 100 years ago by Albert Einstein in his general theory of relativity, has been successfully launched into orbit.
The European Space Agency's Pathfinder spacecraft was launched from Kourou in French Guiana just one day after the 100th anniversary of Einstein's groundbreaking theory being published.
Scientists had hoped to launch it on Dec. 2, the anniversary date, but the launch was delayed a day due to technical problems with the Vega launch rocket.
The better-safe-than-sorry decision didn't seem bother the scientists.
"We've waited 100 years for the anniversary of Einstein's equations. What's one more day?" said Paul McNamara, a team member on the ESA project.
In orbit, two gold-platinum cubes will be released into free-fall inside the space probe, where they will be isolated from all outside forces except for gravity.
Measuring their position relative to each other with extreme sensitivity will give researchers a chance at detecting gravitational waves, tiny ripples in space-time Einstein said should spread outward as massive objects such as neutron stars and supermassive black holes or neutron stars interact.
Despite years of experiments and studies, gravitational waves have proved to be an elusive query and have yet to be directly detected.
A series of thruster burns over the next two weeks will push Pathfinder toward its operations orbit, a point it should reach in about 10 weeks, ESA scientists explained.
On Feb. 15, pins holding the gold-platinum cubes in place will be withdrawn, allowing the cubes to float in free-fall, where their positions will be measured using lasers.
That will be another nervous moment for mission scientists.
"The release of the test masses is like a second launch campaign," says mission principle investigator Stefano Vitale from the University of Trento in Italy. "You release them in free flight and from then on nothing can touch the test masses any more."
At that point, the scientific work can begin in the mission's labs here on Earth — assuming all goes well.
"Lots of people are going to have a lot of white hair over those two days," Vitale says.
A fundamental physics experiment may not have the glamour or excitement of a comet landing or other exploratory mission, but is just as vital to our understanding of how the universe works, says ESA Director of Science and Robotic Exploration Alvaro Gimenez.
"It's not just going to a place and finding out how it is," he notes. "It is very important to do that, but this [mission] is really putting your finger in the physical laws underpinning the behavior of the universe."
