Expansion of course, even the recent acceleration of expansion but the mysterious theory of inflation that stands at the heart of modern cosmology for which we can not see having the size of the universe go from a speck to a boundless expanse.

I am not alone in being skeptical of the BICEPS telescope and program That may have measured nothing more than dust and not proof of an inflation event. Even a founder of that program is suspect they only measured dust..


Serendipitously but not surprisingly my question about the central issue of inflation is the cover story for Astronomy Magazine March 2016. I read it just a moment ago.
It is titled the Race to Cosmic Dawn. The writing flows nicely compared to my gross abbreviated style with most of the main characters in the race to understand inflation including Guth.