Stephen Hawking discusses the "Breakthrough Starshot" space exploration initiative during a news conference Tuesday at One World Observatory in New York City. Bryan Bedder/Getty Images for Breakthrough Prize Foundation hide caption

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Stephen Hawking's Plan For Interstellar Travel Has Some Earthly Obstacles
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(Top row, left to right) Titan, Earth's moon, Europa and Enceladus. (Bottom row, left to right) Callisto, Charon, Ariel and lo. NASA hide caption

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Hot On The Trail Of Alien Moons
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Ambitious Project Would Use 'Starchips' To Travel To Alpha Centauri
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An image from the European Southern Observatory shows the sky around the bright star Alpha Centauri — which appears so large because of the telescope optics and photographic emulsion — taken from photos in the Digitized Sky Survey 2. Alpha Centauri is the closest star system to Earth's solar system. ESO/Digitized Sky Survey 2/Davide De Martin hide caption

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An artist's rendering of the BEAM inflatable annex attached to the side of the International Space Station. Courtesy of Bigelow Aerospace hide caption

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NASA To Test Inflatable Room For Astronauts In Space
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This computer-simulated image shows a supermassive black hole at the core of a galaxy. The cosmic monster's powerful gravity distorts space around it like the mirror in a fun house, smearing the light from nearby stars. NASA/ESA/D. Coe, J. Anderson and R. van der Marel (Space Telescope Science Institute) hide caption

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Supermassive Black Holes May Be More Common Than Anyone Imagined
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The women of the Jet Propulsion Laboratory helped launch the first American satellites, lunar missions and planetary explorations. Those "human computers," as they were called, are seen here in 1953. Courtesy NASA/JPL-Caltech hide caption

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Meet The 'Rocket Girls,' The Women Who Charted The Course To Space
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Bob Ebeling with his daughter Kathy (center) and his wife, Darlene. Howard Berkes/NPR hide caption

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Challenger Engineer Who Warned Of Shuttle Disaster Dies
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A Martian gravity map shows the Tharsis volcanoes and surrounding flexure. The white areas in the center are higher-gravity regions produced by the massive Tharsis volcanoes, and the surrounding blue areas are lower-gravity regions that may be cracks in the crust (lithosphere). MIT/UMBC-CRESST/GSFC via NASA hide caption

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This image from the Hubble Space Telescope shows the central region of the Tarantula Nebula in the Large Magellanic Cloud. The R136 star cluster — the blue stars in the lower right — contains massive stars, including nine newly-identified stars more than 100 times as massive as our sun. NASA, ESA, P Crowther (University of Sheffield) hide caption

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Tina Buechner da Costa (left) hopes to become Germany's female astronaut. Claudia Kessler (right), CEO of HE Space, is organizing a campaign to send the first German woman into space. Soraya Sarhaddi Nelson/NPR hide caption

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Wanted: Female German Astronauts
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"Satellite imagery allows us to ... record information in different parts of the light spectrum ... that we simply cannot see with our human eyes." — Sarah Parcak Ryan Lash/TED hide caption

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How Can Satellite Images Unlock Secrets To Our Hidden Past?
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With this shot of Mount Fuji, astronaut Scott Kelly tweeted, "your majesty casts a wide shadow!" Scott Kelly/NASA hide caption

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Astronaut's Photos From Space Change How We See Earth
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A still image shows the Earth, as seen by Japanese geostationary satellites, during a total solar eclipse. University of Wisconsin-Madison / CIMSS and Japan Meteorological Agency and NOAA hide caption

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NASA has set a new launch opportunity, beginning May 5, 2018, for the InSight mission to Mars. This artist's concept depicts the InSight lander on Mars after the lander's robotic arm has deployed a seismometer and a heat probe directly onto the ground. NASA/JPL-Caltech hide caption

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