The universe is expanding — and it is doing so at the same rate in all directions, according to new measurements that appear to confirm the standard model of cosmology.
Astrophysicist Jeremy Darling of the University of Colorado Boulder came to this conclusion after employing a research strategy known as “real-time cosmology,” which seeks out the tiny changes in the universe that occur over human timescales.
The idea of “real-time cosmology” was proposed in two separate papers by Alan Sandage in 1962 and by Harvard astrophysicist Avi Loebin 1998. The possibility of seeing the redshifts of sources changing in real time is thus called the “Sandage-Loeb Test”. [The Universe: Big Bang to Now in 10 Easy Steps]
“Real-time cosmology offers new ways to observe the universe, including some observations and cosmological tests that cannot be made any other way,” Darling told Space.com via email.
Researchers discovered in 1998 that the universe is expanding at an accelerating rate — a surprising phenomenon believed to be due to a mysterious force called dark energy. Scientists don’t know much about dark energy, except that it may be a property of the vacuum. In a bid to understand dark energy, researchers are making a wide array of cosmological tests and building new telescopes and instruments.
“This work asks whether the expansion today — that is dominated by dark energy — is the same in all directions,” Darling said.
To make the measurements, Darling used data previously collected by other researchers on the motion of extra-galactic objects across the sky.
The data allowed him to conclude that the cosmic expansion is indeed isotropic — in other words, the same in all directions — with a margin of error of 7 percent.
“The constraints will get better with forthcoming data from the Gaia mission,” said Loeb, who was not involved in the study.