Measuring Gravitational Vibrations in the Universe

Einstein predicted gravity waves in his general theory of relativity, but to date these ripples in the fabric of space-time have never been observed. A scientific research technique called Atomic Interferometry is trying to re-write the canon. In conjunction with researchers at Stanford University, scientists at NASA Goddard Space Center are developing a system to measure the faint gravitational vibrations generated by movement of massive objects in the universe. The scientific payoff could be important, helping better clarify key issues in our understanding of cosmology. Application payoff could be substantial, too, with the potential to develop profound advances in fields like geolocation and timekeeping.

Transcript

00:00:00 Narrator: This is the universe as we imagine it...objects floating quietly in space. This is the universe as scientists think it actually behaves. Objects in space affected ever so slightly by gravitational waves. Ripples in space-time caused for example by the merger of two black holes. The trick is to actually measure these gravitational ripples and to do that you need a remarkably precise measuring instrument. You need an atom interferometer. Babak Saif: Gravitational wave detection,

00:00:41 this new carrier would allow us to go way further back in time and we're looking at the Big Bang, and it really increases our knowledge of cosmology. Narrator: Theory says these ripples form when big objects like galaxies and stars move in the universe. Long since predicted by Einstein's general theory of relativity, they've never been directly detected. Optical interferometry--that is visible light measurements--could do the job, but previous mission concepts were very expensive. A ground based observatory called advanced LIGO may one day detect gravity waves. So why atom interferometry?

00:01:23 Mind-boggling precision, by blasting rubidium atoms with carefully calibrated lasers to super-chill them right above absolute zero, a change in position of so much as a trillionth of a meter--a picometer--will show up, thus adding evidence to the theory. So: cutting edge science or whiz-bang technology? Both, it turns out. Atom interferometry may be the best way to probe some of the most essential questions in astrophysics. But the new tools being built by The Goddard Space Flight Center and Stanford University will have other applications, too. For example, they could more precisely

00:02:05 track speed, orientation, and inertial changes in one of these... or help NASA scientists figure out what asteroid like this are made of. (beeping)