It's not the sequel to War of the Worlds! Astronomers at the Very Large Telescope (VLT) site in Chile are trying to measure the distortions of Earth's ever changing atmosphere. Constant imaging of high-altitude atoms excited by the laser -- which appear like an artificial star -- allow astronomers to instantly measure atmospheric blurring. In this case, the VLT was observing our Galaxy's center, and so Earth's atmospheric blurring in that direction was needed.
At the center of the Milky Way is Sagittarius A -believed to be a supermassive black hole, which lurk at the center of all spiral galaxies. If we can observe Sagittarius A*'s surroundings we can confirm once and for all whether it's a black hole - and prove Einstein right (or wrong!) . Relativity theory predicts the existence of black holes. If relativity breaks down, we might not see a black hole at all, but something totally weird.
Relativity describes how large masses can bend space, and a black hole is where the mass is so large that space gives up altogether and becomes a singularity. Black holes are already well understood, we think, but we've only ever observed them at second hand - the behavior of orbiting objects or bent light rays. To actually view the shadow of a black hole, the cut-off point where light is swallowed and cannot escape, would be a massive advance - and only the beginning.
Detailed observation of the area around the Sag A* border would be a goldmine of information. The spin and rate of matter inflow into the central black hole will tell us about the Milky Way's creation, as well as providing further extreme tests of general relativity. We could even see frame dragging, which sounds like a video game hardware issue but is actually something that could happen to reality - where a spinning black hole grabs hold of space and literally pulls reality around after it.
The rock star at center of Earth's microwave eye will be in the high deserts of Chile, where the Atacama 66-dish Large Millimeter/Submillimeter Array (ALMA) is being built, which should be up and running by 2012. In concert with other scopes across the planet. ALMA will should provide a much clearer picture of Sag A*
ALMA is a giant, international observatory composed initially of 66 high-precision telescopes, operating at wavelengths of 0.3 to 9.6 mm. The ALMA antennas will be electronically combined and provide astronomical observations which are equivalent to a single large telescope of tremendous size and resolution, able to probe the Universe at millimeter and sub-millimeter wavelengths with unprecedented sensitivity and resolution, with an accuracy up to ten times better than the Hubble Space Telescope.
Casey Kazan with Luke McKinney
Image Credit: Yuri Beletsky (ESO)