If you want grown-ups to recycle, just tell their kids the importance of recycling, and they'll be all over it.

You stop planetary exploration, those people who do that extraordinary work are going to have to go do something else.

By the way, most of the light that comes from the sun is green.

Climate change is happening, humans are causing it, and I think this is perhaps the most serious environmental issue facing us.

Science is the key to our future, and if you don't believe in science, then you're holding everybody back.

Hard to find anything lovelier than a tree. They grow at right angles to a tangent of the nominal sphere of the Earth.

America has had many other discoverers besides Columbus, but he seems to have made more satisfactory arrangements with the historians than any of the others.