Joe Palca Joe Palca is a science correspondent for NPR.
Joe Palca, photographed for NPR, 17 January 2019, in Washington DC.
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Joe Palca

Scientists find that the whiskers of harbor seals help them distinguish predator from prey — even from a distance. Douglas Klug/Images hide caption

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Douglas Klug/Images

Need To Track A Submarine? A Harbor Seal Can Show You How

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When Mars is "in opposition," it, Earth and the sun are all in alignment. (Note: This is a diagram meant to illustrate the concept of opposition. It is not drawn to scale.) Alyson Hurt/NPR hide caption

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Alyson Hurt/NPR

Celestial Lineup Makes For A Very Bright Mars

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This is the south polar cap of Mars as it appeared to the Mars Orbiter Camera on the Mars Global Surveyor on April 17, 2000. An underground lake was found near here. NASA/JPL/MSSS, hide caption

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NASA/JPL/MSSS,

Underground Lake Found On Mars Beneath A Mile Of Ice

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An early prototype of the silicon-chip-sized particle accelerator that physicists at Stanford are working on. Eventually, miniature accelerators might have a role in radiating tumors, the scientists say. SLAC National Accelerator Laboratory hide caption

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SLAC National Accelerator Laboratory

Physicists Go Small: Let's Put A Particle Accelerator On A Chip

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The planet Jupiter now has a total of 79 identified moons. QAI Publishing/UIG via Getty Images hide caption

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QAI Publishing/UIG via Getty Images

Galileo Would Be Stunned: Jupiter Now Has 79 Moons

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This artist's impression shows the dust torus around a super-massive black hole. Black holes lurk at the centers of active galaxies. The jets emanating from the black hole send neutrinos hurtling into space. ESA/NASA/the AVO project/Paolo Padovani hide caption

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ESA/NASA/the AVO project/Paolo Padovani

A 4 Billion Light-Year Journey Ends At The South Pole

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Global map of Mars showing a growing dust storm as of June 6, 2018. The map was produced by the Mars Color Imager (MARCI) camera on NASA's Mars Reconnaissance Orbiter spacecraft. NASA/JPL-Caltech/MSSS hide caption

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NASA/JPL-Caltech/MSSS

Giant Dust Storm On Mars Threatening To End NASA's Opportunity Rover

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Two rock samples taken by NASA's Curiosity rover were found to contain organic molecules. NASA/JPL-Caltech/MSSS hide caption

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NASA/JPL-Caltech/MSSS

NASA's Curiosity Rover Finds Chemical Building Blocks For Life On Mars

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Detectors inside MiniBooNE experiment Courtesy Fermilab hide caption

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Courtesy Fermilab

Physicists Say They Have Evidence For A New Fundamental Particle

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This is an artist's concept of a plume of water vapor thought to be ejected off of the frigid, icy surface of the Jovian moon Europa, located 500 million miles from the sun. NASA, ESA, and K. Retherford hide caption

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NASA, ESA, and K. Retherford

Icy Moon Of Jupiter Spews Water Plumes Into Space

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An artist's rendition of NASA's InSight lander, which is expected to launch on Saturday morning. InSight will monitor the Red Planet's seismic activity and internal temperature. NASA/JPL-CalTech hide caption

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NASA/JPL-CalTech

NASA Is Heading Back To Mars To Peer Inside The Red Planet

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An image from an electron microscope shows a type II alveolar cell, found in the air sacs of lungs. In the cell's cytoplasm (pink) are lamellar bodies (purple), which contain surfactant. SPL/Science Source hide caption

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SPL/Science Source

Experimental Lung Treatment Could Make Breathing Easier

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First responders in the Marina District disaster zone after an earthquake on October 17, 1989 in San Francisco, Calif. Otto Greule Jr/Getty Images hide caption

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Otto Greule Jr/Getty Images

Betting On Artificial Intelligence To Guide Earthquake Response

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