Listen as scientist discuss that the moon is not the only body in space following Earth's path. Learn how planet Earth has a new found neighbor, an asteroid that shares our orbit around the sun. [17:30]

Researchers are studying our moon's effects on the Earth to guide their search for habitable worlds elsewhere.

What steps should planetary explorers take to prevent contaminating other planets with life from Earth?

Changes on the surface can change the way the planet spins.

NASA's Kepler telescope has discovered the first Earth-sized exoplanets, and another which orbits its star in the "Goldilocks zone," where liquid water could exist.

New research finds a small -- but present -- chance of a collision between Earth and one of its planetary neighbors in the next few billion years.

Planetary scientists and future explorers are trying to learn about our neighboring planet without ever leaving Earth.

The US spends $4 million each year to search for comets or asteroids that could threaten the planet. That's not enough to get the job done, according to a new report from the National Research Council.

A look beneath Earth's surface at what may be causing the planet's poles to wander back and forth.

We'll talk with researcher studying a community of bacteria that has been isolated from the surface for millions of years. They describe some of the biochemical processes that have allowed the bacteria to survive below glacier ice, and...

Astronomers weigh in on how to keep the planet safe from near-Earth objects.

What would the world be like if humans were to disappear from the planet?

Could Mars have been a better starting point for the origins of life on Earth?

In this segment, we'll get the big picture on science on the planet Mars. From orbiting observatories to roving rovers to the ditch-digging Phoenix -- what have planetary scientists learned about Mars, and what remains to be discovered?