What is fascinating to me is that we are now hoping, with modern measurements, to probe the early Universe. In doing so, we’re encountering deep questions about the scientific method and questions about what is fundamental to physics. When we look out on the Universe, we’re looking through this dirty window, literally a dusty window. We look out through dust in our galaxy. And what is that dust? I like to call it nano planets, tiny grains of iron and carbon and silicon—all these things that are the matter of our solar system. They’re the very matter that Galileo was looking through when he first glimpsed the Pleiades and the stars beyond the solar system for the first time.
When we look out our telescopes, we never see just what we're looking for. We have to contend with everything in the foreground. And thank goodness for that dust in the foreground, for without it, we would not be here.
BRIAN KEATING is a professor of physics at the Center for Astrophysics & Space Sciences at the University of California, San Diego. Brian Keating's Edge Bio page