pioneer98 wrote:The Dark Energy Survey started last year, but I just learned about it. The upshot is that they are trying to measure very precisely how quickly the expansion is speeding up in the hopes that they learn something about dark energy. They will end up taking extremely detailed digital pictures of about 1/8th of the night sky.
http://www.symmetrymagazine.org/article ... vey-begins
Scientists are searching for the answer to a fascinating mystery: Why is the expansion of the universe accelerating? The Dark Energy Survey will use four methods to probe dark energy, the phenomenon believed to be pushing the universe apart:
1. Counting galaxy clusters. While gravity pulls mass together to form galaxies and clusters of galaxies, dark energy pushes it apart. The Dark Energy Camera will see light from galaxy clusters billions of light years away, and counting those clusters at different points in time will offer insight into the cosmic competition between gravity and dark energy.
2. Measuring supernovae. A supernova is a star that explodes, becoming as bright as an entire galaxy of billions of stars. By measuring how bright it appears on Earth, scientists can tell how far away a supernova is and then use that information to determine how fast the universe has been expanding since the star’s explosion.
3. Studying the bending of light. When light from distant galaxies encounters dark matter in space, it bends around it, causing those galaxies to appear distorted in telescope images. The survey will measure the shapes of 200 million galaxies, exploring how gravity and dark energy mold the lumps of dark matter throughout space.
4. Using sound waves to map the universe’s expansion. Sound waves created hundreds of thousands of years after the big bang left an imprint on the way galaxies are distributed across the universe. The survey will measure the positions in space of 300 million galaxies to find this imprint and use it to infer the history of cosmic expansion.
I put some numbers in bold.
There was a recent report that came out (called "P5") which gave recommendations for future experiments. In the worst case funding scenario, the Dark Matter experiments will continue to receive full funding (although the "third generation" experiments will receive reduced funding, but the "second generation" which has the most immediate impact will continue at full).
This P5 report was very well written, for one thing they broke out how they used to categorize experiments. They used to have these "frontiers" - and the problem as that it was sometimes hard to decide which frontier an experiment sat. For example, any neutrino experiment is going to have a potential impact on Dark Matter, however the experiments are not really all related to dark matter specifically. Neutrino research is a priority.
Anyway, boring funding stuff (but it's important to me because I need a job, and it looks like for neutrinos might be the ticket I need to pay the mortgage and kids college bills). The good news is that it looks like some of the most important physics research in the world will continue to be hosted in the U.S. Many of our labs have the plumbing to do these experiments, and this has been recognized by the P5 report. One of the things the U.S. is going to have to get over though, is that just because we host an experiment doesn't mean it's ours. There has to be international collaboration, and the P5 report clearly states that this. The discovery of the Higgs was international - while hosted at CERN the analysis was done world wide, including a major portion in the U.S.
