Dark Matter and Dark Energy

Galaxy Cluster Abell 1689, NASA image Everything we see in the universe—all the stars, galaxies, gas, dust, planets, and more—are all made of the same kinds of matter that we are. But that kind of matter is only about 5% of what makes up the universe around us. The other 95% is made of two things that we’ve never seen, which we call “dark matter” and “dark energy.” We know they exist because we can observe the effects of their gravity on the kind of matter that we can see. In this talk I’ll explain the observations that let us know that most of the universe is dark matter and dark energy, what we do and don’t know about them, and some of the implications they have for the past and future of the universe.

Return to Gary's public talks page.