Dive down, down, and down a whole lot more—until you've traveled 2,400 meters to the sea floor. Can you picture how deep that really is? Compare it with the height of famous landmarks, and you will.

What are "monkey's fists" doing out at sea? This type of seaman's knot is being used to deploy deep sea thermometers. Find out if this teacher AND her fists get to travel to the ocean floor.

For oceanographers, the work they do at sea is just the beginning. Learn more about the discoveries made by one scientist who completed more than 100 dives to the sea floor.

A meteorite that escaped from Mars 16 million years ago was found recently in Antarctica. Does it, or doesn't it, hold evidence that proves the existence of life on the red planet?

Update your image of astronomers. Today they spend most of their time peering into computer screens rather than through the eyepiece of a telescope. Learn what this new vantage point has gained them.

What are the stars made of? At 25, Cecilia Payne answered this fundamental question in her Ph.D. thesis. Her pioneering work also made it possible to read a star's surface temperature.

Today, we accept the notion that enormous rocks exist within our solar system and that some of them fall to Earth. A little over 200 years ago, though, this idea garnered skepticism and ridicule.

At this distance in time and space, can we prove that the universe was created with a single explosion? See how scientists have detected a faint remnant glow that supports the Big Bang theory.

Imagine gravity so strong that even light is contained by its force. When a country parson first described black holes in 1783, the concept was so ahead of its time that it was mostly ignored.

A dusty snowball orbiting the Sun, trailing gas and dust as it melts—a poetic and highly accurate way to describe a comet. Find out how these solar snowballs take their places around the Sun.