Monday, 9 May 2011
NASA concludes Gravity Probe B space-time experiment, proves Einstein really was a genius!
Well, it looks like Einstein knew what he was talking about, after all. Earlier this week, researchers at NASA and Stanford released the findings from their six-year Gravity Probe B (GP-B) mission, launched to test Einstein's general theory of relativity. To do so, engineers strapped the GP-B satellite with four ultra-precise gyroscopes to measure two pillars of the theory: the geodetic effect (the bending of space and time around a gravitational body) and frame dragging (the extent to which rotating bodies drag space and time with them as they spin on their axes). As they circled the Earth in polar orbit, the GP-B's gyroscopes were pointed squarely at the IM Pegasi guide star, while engineers observed their behavior. In the universe outlined by Einstein's theories, space and time are interwoven to create a four-dimensional web, atop which the Earth and other planetary bodies sit. The Earth's mass, he argued, creates a vortex in this web, implying that all objects orbiting the planet would follow the general curvature of this dimple. If the Earth's gravity had no effect on space and time, then, the position of NASA's gyroscopes would have remained unchanged throughout the orbit. Ultimately, though, researchers noticed small, but quantifiable changes in their spin as they made their way around the globe -- changes that corroborated Einstein's theory. Francis Everitt, a Stanford physicist and principal investigator for the mission, poetically explained the significance of the findings, in a statement:
"Imagine the Earth as if it were immersed in honey. As the planet rotated its axis and orbited the Sun, the honey around it would warp and swirl, and it's the same with space and time. GP-B confirmed two of the most profound predictions of Einstein's universe, having far-reaching implications across astrophysics research. Likewise, the decades of technological innovation behind the mission will have a lasting legacy on Earth and in space."
The GP-B mission was originally conceived more than 50 years ago, when the technology required to realize the experiment still didn't exist. In fact, the experiment didn't actually get off the ground until 2004, when the satellite was launched into orbit 400 miles above Earth. After spending just one year collecting data (and an impressive five years analyzing the information), NASA has finally confirmed something we always quietly suspected: Einstein was smart. Head past the break to see a more in-depth diagram of how the GP-B gathered its data.