Some molecules - ammonia, carbon dioxide, water - show up everywhere in the universe, whether life is present or not. But others pop up especially in the presence of life itself. Among the biomarkers in Earth's atmosphere are ozone-destroying chlorofluorocarbons from aerosol sprays, vapor from mineral solvents, escaped coolants from refrigerators and air conditioners, and smog from the burning of fossil fuels. No other way to read that list: sure signs of the absence of intelligence.

Right now people think God is dark energy and dark matter, the spirit. Go ahead and think that, but the day we can tell you exactly what it is - that it's gremlins in the vacuum of space or whatever - then what's your recourse at that point?

I'm an educator, and I'm a scientist, and I speak what is objectively true. And if that offends you, I can try to have a conversation with you to ask why it offends you, and tell you why objective truth should not offend you because that's how the world works.

There is no true understanding of Biology without Chemistry. And there's no true understanding of Chemistry without Physics.

No matter what eyewitness testimony is in the court of law, it is the lowest form of evidence in the court of science.

The people that first climbed Mt. Everest weren't scientists, right, they were adventurers. If you're an adventurer, you want to go yourself. It's different than a scientist, who is simply wanting to learn.

When I reach to the edge of the universe, I do so knowing that along some paths of cosmic discovery, there are times when, at least for now, one must be content to love the questions themselves.