As the universe persists in its expansion, cosmologists in the future will continue to understand less. In fact, according to one theory, the best time to learn about the cosmos was more than 13 billion years ago.
The universe expanded from the Planck epoch – a hot and dense phase in its beginning – 14.6 billion years ago to its present form. Our universe, which many theoretical physicists believe is one of many universes in a pool of bubbles, has significantly changed throughout its time. Although humans have evolved and become conversant in astronomy, cosmology and science, it seems we may have arrived late to the feature presentation.
Calculations by Harvard theorist Avi Loeb suggest that the best time to study the cosmos was actually more than 13 billion years ago, which was approximately 500 million years following the Big Bang. The theory proposes that the farther into the future you travel the more information you lose about the universe’s origins.
“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,” said Loeb in a news release. “If we want to learn about the very early universe, we'd better look now before it is too late!”
So why is the past the best time to observe the universe? There are actually two competing stages to study the cosmos. During the young universe the cosmic horizon is closer to you and as the universe gets older you can see more of it due to light having more time to travel. As time goes by, however, matter collapses. This stage “muddies the water” of the cosmic sea because you misplace reminiscence of original conditions of minute scales.
In the end, the first grows better as the second becomes worse.
The best time for observers to research the cosmos was about half a billion years following the Big Bang because the formation of galaxies and stars began. However, it’s not too late for astronomers.
“21-centimeter surveys are our best hope," said Loeb. "By observing hydrogen at large distances, we can map how matter was distributed at the early times of interest.
Eventually, in approximately 10 and 100 times the universe’s current age, researchers will not be able to study the stars because of the expansion; galaxies are moving beyond our horizon and the light that leaves the distant galaxies will never reach us in the future.