Rare Binary Stars Provide A Better Yardstick For The Cosmos, And Could Help Illuminate Dark Energy
Eclipsing Binary As the two stars orbit each other, they pass in front of one another and their combined brightness, seen from a distance, decreases. By studying how the light changes, and other properties of the system, astronomers can measure the distances to eclipsing binaries very accurately. ESO/L. CalçadaMeasuring the distance to cosmic neighbors helps calculate the expansion of the universe as a whole. Something is making the universe expand at an ever-faster rate, and since no one knows what it is or how it works, we call it dark energy. A new super-precise observation of a nearby galaxy could help shed some light on it, however. Astronomers have measured the distance to the Large Magellanic Cloud better than ever, and this is a crucial step in a special calculation called the Hubble constant, which helps scientists figure out how quickly the universe is speeding apart. To measure the universe, you need...