In many ways stars are like living beings. They're born; they live; they die. And they even have a heartbeat. Using a novel technique, astronomers have detected thousands of stellar "pulses" in the galaxy Messier 87 (M87). Their measurements offer a new way of determining a galaxy's age.
The astronomers studied the elliptical galaxy M87, located 53 million light-years from Earth in the constellation Virgo. They examined a unique series of images taken with the Hubble Space Telescope over the course of three months in 2006. They quickly found what they were looking for.
"Amazingly, one in four pixels in the image changes with time," said Pieter van Dokkum, a professor and chair of the astronomy department at Yale University. "We tend to think of galaxies as steady beacons in the sky, but they are actually 'shimmering' due to all the giant, pulsating stars in them."
Analysis of the Hubble data showed that the average pixel varies on a timescale of approximately 270 days. The regular up and down changes in brightness are reminiscent of a heartbeat. "It's as if we're taking the pulse of the galaxy," said Conroy.