Just a week after the September 11th attacks, nerves still raw, America was hit with its worst-ever biological attack. The anthrax letters set off a new wave of panic, and reminded scientists how little we understand some of the world’s most dangerous germs.

We may not think of it this way, but we hear in 3-D. Good thing, too. It’s how we know what direction to turn when we hear footsteps or where to look for our kid in a crowded playground. But this depth of field is almost impossible to capture on tape.

Do you ever get the feeling we’re all living in an illusion, man? And, like, what we see is really just a movie, you know, projected from the edge of the universe? And stuff?

Photosynthesis is one of the oldest biological processes on earth. Microorganisms figured it out more than two billion years ago, and completely transformed the planet.

As we human beings have come up against our limits throughout history, we’ve managed to invent tools that can overcome them. Using tools we can fly, restart a human heart, photograph galaxies and amoebae.

Say the original Declaration of Independence burned up. No problem, you might think – we have pictures of it. But then say someone discovered that a word had been scratched out and replaced.

Scientists love a quest, and so does the media. Just about every field has some “holy grail” or other. A database search for just the last six months shows about a thousand instances of this phrase popping up in relation to science.

Last time around on Clever Apes we dipped into realms of science that some might consider disgusting. Now we turn to the science of disgust itself. What is disgust, and where does it come from? There are a few places where scientists can look for clues, starting with what disgusts people.

Let’s consider the beauty of a seething swarm of carrion beetles picking clean the carcass of a dead rat.Sorry – were you eating breakfast?To a scientist, that grisly scene might evoke the cycles of ecosystems, the connectedness of life and death, and the elegant efficiency of a life form sculpted b

Brontosaurus? A sham. Triceratops? Awkward adolescent. Tyrannosaurus Rex? A total wuss. OK, maybe T-Rex was no wuss, but it definitely lacked dignity. It walked all bent over, may have been an opportunistic scavenger and possibly even had feathers.