Most Precise Measurement of Universe’s Expansion Achieved
The most precise measurement ever made of the speed of the universe’s expansion is in, thanks to NASA’s Spitzer Space Telescope, and it’s a doozy. Space itself is pulling apart at the seams, expanding at a rate of 46.2 plus or minus 1.3 miles per second per megaparsec (a megaparsec is roughly 3 million light-years).
If those numbers are a little too much to contemplate, rest assured that’s really, really fast. And it’s getting faster all the time. The new value reduces the uncertainty in the Hubble Constant to just 3%, and improves the precision of the measurement by a factor of 3 compared to a previous estimate from the Hubble Space Telescope. The new measurement doesn’t just tell scientists how fast the universe is expanding, but helps shed light on the mystery of why this expansion is accelerating. Dark energy is the name given to whatever is causing the universe’s expansion to speed up. Yet scientists have little idea what it is.