From NPR's All Things Considered – The 20th anniversary of a photograph was recently observed. It's a very dramatic photo, even though, at first glance, it's mostly dark and seems to show nothing at all.

But if you look closely, you can see a tiny speck of light. That speck is the Earth, seen from very, very, very far away.

Two decades ago, Candice Hansen-Koharcheck became the first person to ever see that speck, sitting in front of a computer at NASA's Jet Propulsion Lab in California. "I was all alone, actually, that afternoon, in my office," she recalls.

She was searching through a database of images sent home by the Voyager 1 spacecraft, which at the time was nearly 4 billion miles away. "I knew the data was coming back," she says, "and I wanted to see how it had turned out."

Finally, she found it.

"It was just a little dot, about two pixels big, three pixels big," she says. "So not very large."

But this was the Earth — seen as no human had ever seen it before.

From NPR's Morning Edition - Can ants count? Not out loud they can’t. Not the way you and I count. But an ingenious experiment conducted in the Sahara suggests maybe ants do count. Harald Wolf of the University of Ulm and his assistant Matthias Whittlinger proposed that ants have “pedometer-like” cells in their brains that count the steps they take.