Like a snowplow in overdrive, a supernova shockwave might sweep away any gas clouds in its path.

You can make a stack high enough to reach the moon and back, and only then will you have used your 100 billion hamburgers. This is terrifying news to cows.

This influential, yet controversial idea requires that the mixture of species on Earth at any moment acts as a collective organism that continuously (yet unwittingly) tunes Earth's atmospheric composition and climate to promote the presence of life... But I'd bet there are some dead Martians and Venusians who advanced the same theory about their own planets a billion years ago.

We still refer to sunrise, sunset. That only has meaning if you think that Earth is in the center of things, and everything is moving around us. So even though we know intellectually Earth goes around the sun, the language is still pre-Copernican, as we would call it.

Something bad happened on both Mars with its dried-up watercourses and Venus with its runaway greenhouse effect. Could something bad happen on Earth too? Our species currently turns row upon row of environmental knobs, without much regard to long-term consequences.

Dark matter and dark energy are two things we measure in the universe that are making things happen, and we have no idea what the cause is.

When asked about which scientist he'd like to meet, Neil deGrasse Tyson said, "Isaac Newton. No question about it. The smartest person ever to walk the face of this earth. The man was connected to the universe in spooky ways. He discovered the laws of motion, the laws of gravity, the laws of optics. Then he turned 26.