Robert Krulwich

These are baby bats — embryos actually. They remind me of those See No Evil, Say No Evil, Hear No Evil monkey pictures I saw growing up, but these little guys are much, much cuter. And, of course, being bats, the hearing thing doesn't apply. Bats don't hear with our kind of ears, so of course, there's no covering-ears-up picture. That wouldn't make bat sense.

This photograph was taken by Dorit Hockman of Cambridge University. It's the 20th place winner in the Nikon Small World 2012 Photomicrography Competition.

Add all of us up, all 7 billion human beings on earth, and clumped together we weigh roughly 750 billion pounds. That, says Harvard biologist E.O. Wilson, is more than 100 times the biomass of any large animal that's ever walked the Earth. And we're still multiplying. Most demographers say we will hit 9 billion before we peak, and what happens then?

I guess everybody, even the smartest people who ever lived, have days when they feel dumb — really, really dumb. Oct. 1, 1861, was that kind of day for Charles Darwin.

In a letter to his friend Charles Lyell, Darwin says, "I am very poorly today," and then — and I want you to see this exactly as he wrote it, so you know this isn't a fake; it comes from the library of the American Philosophical Society, courtesy of their librarian Charles Greifenstein. Can you read it?

It says:

Whoah! You know the feeling, right?

Oh, dear.

First off, this lizard? It's not really a lizard. It's an almost vanished species, a reptile like no other.

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This is the moon as Morse code.

In this video, we are flying over the Earth, looking down and seeing what astronauts see when it's nighttime, when lightning storms flash like June bugs, when cities look like galaxies, when you can see where people are. It's quietly astonishing.

This montage of space footage was assembled and narrated by NASA scientist Justin Wilkinson. There's another one, which takes us around the Earth in daytime.

Here's a question you probably didn't know was a question: Why is the sky dark at night?

Look at this map, and notice that deep, deep in the Republican South, there's a thin blue band stretching from the Carolinas through Georgia, Alabama and Mississippi. These are the counties that went for Obama in the last election. A blue crescent in a sea of red.

This is how we do it.

This is how they do it.