You know, there's black holes and what - could there be wormholes? Could - might there be a multi-verse? These are all fascinating frontiers. What is the nature of dark matter and dark energy? And what was around before the universe? And do we have access to higher dimensions?

Our planet has been around only for four and a half billion years. Let's imagine a planet that has life on it such as life is on Earth and it's seven billion years old. Let's say that planet evolved intelligence. Well, that intelligence would be way more advanced than what we call intelligence here on Earth. How long has intelligence been around on Earth as we've come to define it?

Some memories are best absorbed through your eyes in real time, even if you have no record of it later. Because then you can access that memory and how you felt in that moment. If you're looking at your cellphone screen, taking a video of something that is otherwise unforgettable, watching it later will not recover the emotion you would have had, had you witnessed it directly.

What do you call those knobby things on doors that help you open them?

Perhaps we’ve never been visited by aliens because they have looked upon earth and decided there’s no sign of intelligent life.

Astronomers do not commonly use Venereal, in favor of the less contagious-sounding Venutian. Blame the medical community, who snatched the word long before astronomers had any good use for it. I suppose you can't blame the doctors. Venus is the goddess of beauty and love, so she ought to be the goddess of its medical consequences.

They [scientists of centuries past] call on God only from the lonely and precarious edge of incomprehension. Where they feel certain about their explanations, however, God gets hardly a mention.