Starts With A Bang

The biggest question about the beginning of the Universe (Synopsis)

Image credit: C. Faucher-Giguère, A. Lidz, and L. Hernquist, Science 319, 5859 (47).

“Space is certainly something more complicated than the average person would probably realize. Space is not just an empty background in which things happen.” -Alan Guth

If you go back in time, earlier and earlier, things get hotter, denser and more energetic. But there’s a limit to how far back you can go, and that limit doesn’t end in a singularity with the birth of time and space; instead, it ends with a period of cosmic inflation, which set up the hot Big Bang as we know it.

Image credit: National Science Foundation (NASA, JPL, Keck Foundation, Moore Foundation, related) — Funded BICEP2 Program; modifications by E. Siegel.

For a long time, inflation was pure theory. Recently, however, detailed observations of the density fluctuations in the Universe have not only confirmed it, but have allowed us to better understand which models of inflation might actually describe our Universe. If our modeling is correct and the data continues to improve, we just might come to understand how the Universe came to be this way after all.

Various models of inflation and what they predict for the scalar (x-axis) and tensor (y-axis) fluctuations from inflation. Image credit: Planck Collaboration: P. A. R. Ade et al., 2013, A&A preprint, with additional annotations by E. Siegel.

Here’s the status of where we are now, how we’ll head further down the path and possibly even find the ultimate answer!