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A Recipe for a Small Planet

Kepler 62f: A super-Earth-sized planet

Air Date: 01/20/2015
Run Time: 28:50

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Topics: Chinese human spaceflight, Huygens, Cassini, Titan, human spaceflight, Planetary Radio, extrasolar planets, Saturn's moons, Bill Nye

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Astronomer and planetary scientist Courtney Dressing is the lead author of research that may have found the formula for the mass and composition of Earth-like planets. She reveals the ingredients and why she spent time at JPL while in high school. It was exactly 10 years ago that Emily Lakdawalla began her blogging career at the landing of the Huygens probe on Titan. Bill Nye says Europeans will visit the Chinese space station, and India is preparing a capsule that will send astronauts into space. Did a Chinese astronomer beat Galileo by almost 2,000 years? That just one piece of this week’s What’s Up segment with Bruce Betts and Mat Kaplan.

Kepler-22b: Closer to Finding an Earth

NASA / Ames / JPL-Caltech

Kepler-22b: Closer to Finding an Earth
This artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star. It is the first planet that NASA's Kepler mission has confirmed to orbit in a star's habitable zone - the region around a star where liquid water, a requirement for life on Earth, could persist. The planet is 2.4 times the size of Earth, making it the smallest yet found to orbit in the middle of the habitable zone of a star like our sun. Scientists do not yet know if the planet has a predominantly rocky, gaseous or liquid composition. It's possible that the world would have clouds in its atmosphere, as depicted here in the artist's interpretation. Read more about the discovery here.

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Trivia Contest

This week's prize is a stylish Planetary Radio t-shirt!

This week's question:

Of the five currently IAU-recognized dwarf planets, which has the longest orbital period or year, and how long is that year?

To submit your answer:

Complete the contest entry form at or write to us at no later than Tuesday, January 27, 2015 at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

To the nearest half-hour, how long did it take the Huygens probe to descend from the top of Titan’s atmosphere to the surface?


The answer will be revealed next week.

Question from the week before:

Besides Galileo (the man, not the spacecraft) who was the first person to discover a moon circling another planet? (Not Earth’s moon, but you might earn extra points if you tell us who discovered that moon, too. Also, a Nobel prize.)


Christiaan Huygens found Saturn’s moon Titan in 1645.


No trivia contest spoilers please!

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