Gamma ray bursts are the most energetic events in the universe. What if one hit Earth?
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来自MSNWhat Happens If an Asteroid Comes Too Close to Earth? Don't Panic — NASA Already Has a Plan.NASA scientists are already finding ways to make sure that the end of the world will not be caused by an asteroid.
From magnification to letting in enough light at night, here's how to choose the perfect monocular for stargazing and astronomy.
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