May 23, 2012
Universe At Peak Observation Period 13 Billion Years Ago
Lee Rannals for RedOrbit.com
Harvard-Smithsonian Center for Astrophysics theorist Avi Loeb says that modern time is not the ideal scenario to study the universe, but rather about 13 billion years ago was.
"I'm glad to be a cosmologist at a cosmic time when we can still recover some of the clues about how the universe started," Loeb said.
He said that in the universe's younger days, you see less because some early light has not quite reached you yet. Then, as the universe ages, there has been enough time for light from more distant regions to travel to you.
However, there is a point where age is too much, as the older and more evolved universe "muddies the waters" of seeing the development of the older universe.
Loeb was able to use the above scenario to pinpoint the time frame of the optimal time to study the universe.
During this era, 500 million years after the Big Bang, the first stars and galaxies began to form. Because information about the early universe is lost when the first galaxies are made, it is the best time to view cosmic perturbations right when stars began to form.
Modern observers are able to access a glimpse of the early universe by surveying distant radio emission from hydrogen gas. These radio waves take more than 13 billion years to reach Earth, giving astronomers a peak into how the universe looked in its younger days.
"21-centimeter surveys are our best hope," Loeb said. "By observing hydrogen at large distances, we can map how matter was distributed at the early times of interest."
As the universe ages, those on Earth will eventually be unable to see the galaxies that have worn out their welcome, as their light no longer makes its way to our planet.
"If we want to learn about the very early universe, we'd better look now before it is too late!" Loeb said. But it isn't quite too late yet. He said it could take sometime between 10 and 100 times the universe's current age for all this to take place.
Loeb's research was published in the Journal of Cosmology and Astroparticle Physics.