After a powerful explosion on Tuesday, Japanese workers are still struggling to regain control of an earthquake and tsunami-damaged nuclear power plant amid worsening fears of a full meltdown. Which raises the questions: What exactly is a nuclear meltdown? And…

Feb 28

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Shuttle Debris, Explained

Viewer question: Was there any comment on the two pieces of debris that came off about 5:48 into the video? (Watch the Discovery launch here). Updated: 4:40 pm EST | By 10:47 am EST Monday morning, astronaut Steven Bowen…

We all know the stinging sensation and welling up of tears that comes from chopping onions. But why does this happen? In fact, the reason onions make us cry can be traced back to the soil. Onions are part of…

Neutrinos are teeny, tiny, nearly massless particles that travel at near lightspeeds. Born from violent astrophysical events like exploding stars and gamma ray bursts, they are fantastically abundant in the universe, and can move as easily through lead as we…

Jan 18

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Since as early as the 1930s, a variation on simple table salt has been used to keep wintry roads from getting dangerously slippery. The mechanism is simple: When liquid water freezes into ice, the loose water molecules arrange themselves into…

And what constitutes an "earthlike planet" anyway? The Kepler Space telescope has found a small, rocky planet, the smallest yet found orbiting a star outside our solar system, the Kepler team announced Monday at the annual meeting of…

Dec 14

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As a cold front settles across the Eastern seaboard, we turn wistfully to thoughts of the sun for this week's Just Ask! science post. This one comes from a reader, Amanda Teicher, who wants to know: "How does sunscreen work?"…

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