Well, this is disappointing. A team of astronomers announced last year that they thought they had strong and direct evidence for cosmic inflation in the extremely early Universe. But, after follow-up analysis, it turns out the evidence is far weaker, and it appears inconclusive one way or the other. Bummer.
OK, so what’s the scoop? First, here’s the announcement from last year when it was thought that the evidence was really good. The details are there.
But here’s a summary: Right after the Universe formed, it’s thought that it underwent an extremely short (to us) period of rapid growth, way faster than the usual cosmic expansion we see today. This event is called “inflation”, and it explains a variety of conditions in the Universe today that would be pretty hard to understand without it.
The problem is, the evidence for inflation is indirect; circumstantial. It explains stuff we already see pretty well, but it also makes predictions about the Universe, too, but we haven’t seen that evidence yet. For example, inflation would have created ripples in the fabric of spacetime, called gravitational waves. These ripples would affect matter in the Universe, and that would in turn affect the light we see coming from the early Universe. Read the rest of Phil’s article here Cosmic inflation: Evidence still not in..