Explaining the New Discovery about the Big Bang

As you may have heard, a large team of scientists (from many universities and labs) has used a telescope at the South Pole to make ground-breaking measurements of the very first instants oftime after the Big Bang. There's been a lot of media interest in the discovery, and this morning I was part of a team of scientists (including string theorist Brian Greene) who tried to explain the measurements and the ideas behind them on KQED's Forum program with Michael Krasny. You can hear the full hour at:http://www.kqed.org/a/forum/R201403190900

In the photo, you can see the Dark Sector Lab, a research facility just 3/4 of a mile from the Earth's South Pole. It was the antenna at left (BICEP2) that detected and measured microwaves that are the "afterglow" of the big bang.

For decades, physicists have explained some of the most intriguing large-scale properties of the universe by suggesting that, a tiny fraction of time after the big bang, the cosmos underwent a period of tremendous "inflation" (like blowing up a balloon with the breath of a million people, instead of just with your own lung-power.) That sudden increase in the size of the universe can help us to understand many things about cosmic conditions today, some 14 billion years after the big bang.

But did this "inflation" really happen? That's what the experiment at the South Pole set out to discover. If it did, it would have left very subtle imprints on the "cosmic background radiation" (the afterglow of the big bang) which today comes to us in the form of cool microwaves. (Cool here meaning less energetic waves than the light from the screen on which you are reading this post.)

The imprint of inflation was so delicate that it took several years of observations and even more years of massaging the data to tease it out of the microwave maps we make. One of the leaders of the team said during the show that the effect was 1 part in 30 million. But if it's confirmed by other experiments, this will stand as a milestone in our study of the universe. It's a remarkable wedding between the small scale world of atoms and waves (gravity waves making tiny ripples in the fabric of space-time) and the large-scale world of the entire universe.

It's one more piece of evidence that we now live at a time of "precision cosmology" -- being able to measure the properties of the entire cosmos with laboratory accuracy.