Ian Tattersall, author of Masters of the Planet, talks about the origin of humans, and how Homo sapiens became a dominant species. Aired Apr. 6, 2012 [38:44 min]

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

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.

In her new book of photography, The Oldest Living Things in the World, artist Rachel Sussman documents the oldest continuously living organisms on the planet.

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?

We'll talk with author Michael Specter about his book 'Denialism: How Irrational Thinking Hinders Scientific Progress, Harms the Planet, and Threatens Our Lives.

Planet hunters say they've identified the first planet orbiting a distant star with conditions right to sustain liquid water and, perhaps, life.

Climate change is changing the world on every continent, and is affecting yields of staple crops like wheat and corn. With a growing population and an increasing demand for food, the future looks unsettling. Aired Apr. 18, 2014 [21:40 min]

In this audio lecture, scientists are reviewing data from a flyby of the planet Mercury earlier this week. Learn how the MESSENGER spacecraft is collecting images and other data about the planet. [24:23]

Bacteria locked under Antarctic lake ice may shed light on life's limits, and the possibility of life on other worlds.

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

Earlier this week, an amateur astronomer in Australia spotted signs of a massive impact on the planet Jupiter. We'll talk with him about his find, and about the international community of astronomical observers.

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

Biologists are using data tags and a National Geographic Crittercam to study the dining habits of the largest animal on the planet.

In this segment, Ira talks with Jeffrey Sachs, author of the new book "Common Wealth: Economics for a Crowded Planet."

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...

Climate change may transform how and where farmers grow the food to feed rising numbers of mouths. [34 mins. 24]

Find out about the journey and progress of the New Horizons Mission to Pluto.

In this segment, guest host Joe Palca checks in on the Mars rovers, and gets a preview of the Mars Phoenix mission.

What's it like to live -- and cook -- on Mars? To find out, researchers are simulating Mars missions in Russia and on the slopes of a Hawaiian volcano.

In A Planet of Viruses, Zimmer writes of viruses that cause cancer and others that cure disease.

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.

The latest mission to Mars, Mars Phoenix, is scheduled to touch down on the Red Planet this coming Sunday. We'll talk about the mission and what the scientists behind it hope to achieve.