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Planetary RadioAugust 9, 2017

Dark Energy Attracts? Astrophysicists Jason Rhodes and Alina Kiessling

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On This Episode
Jason Rhodes head shot
Jason Rhodes

Principal Scientist, Jet Propulsion Laboratory

Alina Kiessling head shot
Alina Kiessling

Research Scientist, Jet Propulsion Laboratory

JPL astrophysicists Alina Kiessling and Jason Rhodes were brought together by their fascination over the mystery of dark energy. They talk with Planetary Radio about their research and the many missions they are contributing to, including WFIRST, a unique new space telescope. Director of Space Policy Casey Dreier reviews the US Senate’s 2018 NASA budget proposal. CEO Bill Nye says enjoy the Great American Eclipse, but be careful! All this and What’s Up with Bruce Betts.

Jason Rhodes and Alina Kiessling

Alina Kiessling

Jason Rhodes and Alina Kiessling
WFIRST Telescope

NASA / GSFC / Conceptual Image Lab

WFIRST Telescope
Artist's concept of NASA's Wide-Field Infrared Survey Telescope (WFIRST).
Mixing galaxies

Adam Block / Mount Lemmon SkyCenter / University of Arizona

Mixing galaxies
NGC 6340, captured in May/June 2014. View additional information

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Trivia Contest

This week's prizes are the brand new Chop Shop-designed Planetary Radio t-shirt, cheap but effective Bill Nye solar eclipse glasses, and a 200-point astronomy account.

This week's question:

When is the next total solar eclipse on Earth after the one on August 21, 2017?

To submit your answer:

Complete the contest entry form at or write to us at no later than Wednesday, August 16th at 8am Pacific Time. Be sure to include your name and mailing address.

Last week's question:

Just before totality in a solar eclipse, the sun is blocked except for sunlight streaming through lunar valleys along the limb. Who are these brief, bright “beads” of light named after?


The answer will be revealed next week.

Question from the week before:

Mars’ orbit is elliptical, of course. How much closer is it to the sun when it is at perihelion (closest to the sun) than it is at aphelion (farthest from the sun)?


Mars is roughly 42.5 million kilometers closer to the sun at perihelion than at aphelion, or .285 AU, or about 354 billion Mars bars.

Listen more: astronomy and astrophysics spacecraft, the Sun, solar eclipse, astronomy, FY2018 NASA Budget, events and announcements, Planetary Radio, Earth, the Moon, Bill Nye

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