Seeking answers
There is no question that we are living in a golden age of cosmology. We know far more today about our universe and its history than we could have imagined only a few decades ago. But despite these successes, there are many perplexing questions that remain unanswered.
For one thing, in order to explain the simple fact that atoms exist in our universe, we know that there must have been slightly more matter than antimatter early on — or else all matter would have been annihilated by its antimatter equivalent. But the cause of this imbalance remains a mystery.
We also know that dark matter — the unknown substance that makes up the majority of the universe’s matter — was formed at some point in the first second after the Big Bang, but we don’t know how or when. Perhaps most striking of all, in order to explain the observed shape and uniformity of our universe, cosmologists have been forced to conclude that space must have undergone a brief period of hyperfast expansion during its very earliest moments. (See “Inflating the universe,” page 14.) This era of cosmic inflation left our universe utterly transformed, and yet we know very little about it.
Mysteries such as these continue to drive the field of cosmology forward. New telescopes and experiments, as well as creative new ideas, will undoubtedly reveal to us new facets of our universe and its early history, as well as the path it took from there to here.