NASA's Gravity Probe B Confirms Two Einstein Space-Time Theories

Discussion in 'Science and Nature' started by MelT, May 5, 2011.

  1. ScienceDaily (May 4, 2011) - NASA's Gravity Probe B (GP-B) mission has confirmed two key predictions derived from Albert Einstein's general theory of relativity, which the spacecraft was designed to test.

    The experiment, launched in 2004, used four ultra-precise gyroscopes to measure the hypothesized geodetic effect, the warping of space and time around a gravitational body, and frame-dragging, the amount a spinning object pulls space and time with it as it rotates.

    GP-B determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth. If gravity did not affect space and time, GP-B's gyroscopes would point in the same direction forever while in orbit. But in confirmation of Einstein's theories, the gyroscopes experienced measurable, minute changes in the direction of their spin, while Earth's gravity pulled at them.
    The findings are online in the journal Physical Review Letters.

    "Imagine the Earth as if it were immersed in honey. As the planet rotates, the honey around it would swirl, and it's the same with space and time," said Francis Everitt, GP-B principal investigator at Stanford University. "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."

    GP-B is one of the longest running projects in NASA history, with agency involvement starting in the fall of 1963 with initial funding to develop a relativity gyroscope experiment. Subsequent decades of development led to groundbreaking technologies to control environmental disturbances on spacecraft, such as aerodynamic drag, magnetic fields and thermal variations. The mission's star tracker and gyroscopes were the most precise ever designed and produced.
    GP-B completed its data collection operations and was decommissioned in December 2010.

    "The mission results will have a long-term impact on the work of theoretical physicists," said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington. "Every future challenge to Einstein's theories of general relativity will have to seek more precise measurements than the remarkable work GP-B accomplished."

    Innovations enabled by GP-B have been used in GPS technologies that allow airplanes to land unaided. Additional GP-B technologies were applied to NASA's Cosmic Background Explorer mission, which accurately determined the universe's background radiation. That measurement is the underpinning of the big-bang theory, and led to the Nobel Prize for NASA physicist John Mather.

    The drag-free satellite concept pioneered by GP-B made a number of Earth-observing satellites possible, including NASA's Gravity Recovery and Climate Experiment and the European Space Agency's Gravity field and steady-state Ocean Circulation Explorer. These satellites provide the most precise measurements of the shape of Earth, critical for precise navigation on land and sea, and understanding the relationship between ocean circulation and climate patterns.

    GP-B also advanced the frontiers of knowledge and provided a practical training ground for 100 doctoral students and 15 master's degree candidates at universities across the United States. More than 350 undergraduates and more than four dozen high school students also worked on the project with leading scientists and aerospace engineers from industry and government. One undergraduate student who worked on GP-B became the first female astronaut in space, Sally Ride. Another was Eric Cornell who won the Nobel Prize in Physics in 2001.

    "GP-B adds to the knowledge base on relativity in important ways and its positive impact will be felt in the careers of students whose educations were enriched by the project," said Ed Weiler, associate administrator for the Science Mission Directorate at NASA Headquarters.

    NASA's Marshall Space Flight Center in Huntsville, Ala., managed the Gravity Probe-B program for the agency. Stanford University, NASA's prime contractor for the mission, conceived the experiment and was responsible for the design and integration of the science instrument, mission operations and data analysis. Lockheed Martin Corp. of Huntsville designed, integrated and tested the space vehicle and some of its major payload components.

    For more information about Gravity Probe B, visit: NASA - Gravity Probe B: The Relativity Mission and Gravity Probe B: Testing Einstein's Universe
  2. I tried watching the nasa video feed of this but holy crap those guys know how to make anything interesting as boring sounding as humanly possible. Maybe it was just that I really really hate when people spend 15 mins reading off some list of accomplishments and then spend 5 mins talking about what the project was. That annoys me to no end, put that shit on the website and let people look it up if they want, I don't need a listing every time you talk good sir. Anyhow..

    The gyroscopes in it are really cool though. They are almost perfect sphere's that they cool to 4C (i think it was) and they become superconductive. Then they spin them with a gas and then empty out the chamber so it's in a vacuum and then it spins forever while making a magnetic field (which they use to measure the change in direction).

    If you have some spare time the nasa site has a video that is interesting if you can stand listening to them talk :D
  3. I always find it awesome when theories -- straight up informed guesses -- are proven true.
  4. ^^ seriously. shit blows my mind, this was all predicted by einstein using math and genius. It's like you know its real and true because the calculations say so, but when you REALLY see it then you realize how interconnected everything is. This makes me look at quantum mechanics differently, as many of their predictions are based soley off math and ingenuity.

    great day in science.

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