Einstein wrestled with a problem back before we even knew the universe was expanding, and he was looking for a way to keep the universe from collapsing. And so he discovered, in his theory of gravity, something like this dark energy - he called it a cosmological constant - could play this role, pushing things away.

We've known for a long time that the universe is expanding. But about 15 years ago, my colleagues and I discovered that it is expanding faster and faster. That is, the universe is accelerating, and that was not expected, but it is now attributed to this mysterious stuff called dark energy which seems to make up about 70 percent of the universe.

Your chemistry high school teacher lied to you when they told you that there was such a thing as a vacuum, that you could take space and move every particle out of it.

It's everywhere, really. It's between the galaxies. It is in this room. We believe that everywhere that you have space, empty space, that you cannot avoid having some of this dark energy.

We must promote upward mobility, starting with solutions that speak to our broken education system, broken immigration policy, and broken safety-net programs that foster dependency instead of helping people get back on their feet.

Likewise, education can direct people toward good or evil ends. When education is based on a fundamentally distorted worldview, the results are horrific.

I hope to become a better teacher. I love teaching.

If we don't empower families to be able to have a quality education, then their children - for the first time in American history, truly the first time - will not have the same economic opportunities.