At approximately 11 p.m. EST Wednesday, the European Space Agency will launch the LISA Pathfinder spacecraft, equipped with tech able to measure some of the most minute gravitational echoes imaginable.

To watch the launch live, click HERE

The scheduling of this launch is also quite particular, as December 2 happens to be the 100th anniversary of Albert Einstein’s general theory of relativity.

The goal is to eventually detect gravitational waves, infinitesimal ripples in space (that Einstein predicted by way of his theory) would occur in response to massive celestial events—such as the collision of galaxies or the explosion of a star. We already understand the magnitude of such events—but as Earth’s magnetic and gravity fields shields us from easily registering such massive far-off happenings from the ground, the hope is that today’s launch of the Laser Interferometer Space Antenna Pathfinder — LISA — will one day give science the ability to detect the ripples—which would also help further prove Einstein’s theory in the process.

How big is a gravitational wave? Despite its ability to distort space, it’s measured in picometers: a picometer equals one trillionth of a meter, or one hundredth the size of an atom.

The package aboard the Pathfinder—the LISA Technology Package—if calibrated correctly, should generate an internal gravitational force no more than somewhere in the neighborhood of one-tenth of a billionth of Earth’s gravity—freeing it for the use of gravitational measurement in a way no earthbound device ever could.

However, all this is only the beginning stage in the process of eventually acquiring such measurement ability, as the Pathfinder only contains the package of tech that would be used to make such measurements. The actual LISA isn’t scheduled to launch until the mid-2030s.

Photos via ESA/ATG medialab