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.
More than 30 years after they left Earth, NASA's twin Voyager probes are now at the edge of the solar system. Not only that, they're still working. And with each passing day they are beaming back a message that, to scientists, is both unsettling and thrilling. The message is, "Expect the unexpected."
"It's uncanny," says Ed Stone of the California Institute of Technology in Pasadena, Voyager Project Scientist since 1972. "Voyager 1 and 2 have a knack for making discoveries." Today, April 28, 2011, NASA held a live briefing to reflect on what the Voyager mission has accomplished--and to preview what lies ahead as the probes prepare to enter the realm of interstellar space in our Milky Way galaxy.
NASA's Wide-field Infrared Survey Explorer, or WISE, captured this image of a star-forming cloud of dust and gas, called Sh2-284, located in the constellation of Monoceros. Lining up along the edges of a cosmic hole are several "elephant trunks" or monstrous pillars of dense gas and dust.
The most famous examples of elephant trunks are the "Pillars of Creation" found in an iconic image of the Eagle nebula from NASA's Hubble Space Telescope. In this WISE image, the trunks are seen as small columns of gas stretching toward the center of the void in Sh2-284, The most notable one can be seen on the right side at about the 3 o'clock position. It appears as a closed hand with a finger pointing toward the center of the void. That elephant trunk is about 7 light-years long.
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It may seem illogical, but boiling is a very efficient way to cool engineering components and systems used in the extreme environments of space. An experiment to gain a basic understanding of these phenomena launched to the International Space Station on space shuttle Discovery Feb. 24. The Nucleate Pool Boiling Experiment, or NPBX, is one of two experiments in the new Boiling experiment Facility, or BXF.
Nucleate boiling is bubble growth from a heated surface and the subsequent detachment of the bubble to a cooler surrounding liquid. As a result, these bubbles can efficiently transfer energy from the boiling surface into the surrounding fluid. This investigation provides an understanding of heat transfer and vapor removal processes that happen during nucleate boiling in microgravity. Researchers will glean information to better design and operate space systems that use boiling for efficient heat removal.
