Astronomers believe that waves of supermassive black holes orbiting Earth in distant galaxies are light-years long and have been trying to observe them for decades. NASA’s Fermi Gamma-ray Space Telescope has managed to bring them one step closer.
Fermi detects gamma rays, the most energetic type of light. An international team of scientists examined Fermi data collected for more than a decade from pulsars, the rapidly rotating cores of stars that exploded as supernovae.
SEE ALSO: NASA SPOTS DRY ICE AND GULLIES IN A MARTIAN CRATER
They looked for small differences in the arrival time of gamma rays from these pulsars, which could be caused by the light traveling through gravitational waves on its way to Earth.
“We were surprised to learn that Fermi could help us in our search for long gravitational waves,” said Matthew Kerr, a research physicist at the US Navy Research Laboratory†
Gravitational waves traveling at the speed of light are produced when massive objects accelerate. The ground-based Laser Interferometer Gravitational Wave Observatory, which first detected gravitational waves in 2015, can detect ripples tens to hundreds of miles in length from top to bottom that pass Earth in fractions of a second. Launched into space, the Laser Interferometer Space Antenna will detect waves that are millions to billions of miles in length.
SEE ALSO: INDIAN ASTRONOMS DISCOVER A NEW GHOST GALAXY
Kerr and his colleagues are looking for waves that are light-years long, or trillions of kilometers long, that take years to pass through Earth. These long ripples are part of the gravitational wave background, which is a random sea of waves generated in part by pairs of supermassive black holes at the centers of merged galaxies across the universe.
Scientists need pulsar timing arrays, which are galaxy-sized detectors. These arrays use specific sets of millisecond pulsars, which rotate at the speed of blender blades. Millisecond pulsars swing beams of radiation, ranging from radio waves to gamma rays, across our field of view and seem to pulse with incredible regularity – like cosmic clocks.
For decades, radio astronomers have used pulsar timing arrays, and their observations are most sensitive to gravitational waves. The Fermi results are already 30 percent as good as radio pulsar timing arrays for potentially detecting gravitational waves. Parthasarathy claims.
Cover image: NASA/Twitter