Space is famously cold. The number repeated in textbooks, documentaries and trivia lists is about 2.7 kelvin, or roughly −270.4 °C — less than three degrees above absolute zero.That number is real and extraordinarily well measured. NASA's C...
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Ask a child to draw the Sun and there is a good chance they will reach for a yellow crayon. Search for a Sun emoji and you will find the same convention. For centuries, artists have painted...
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On November 20, 1969, Apollo 12 astronauts Pete Conrad and Alan Bean left the lunar surface and rejoined Richard Gordon in orbit. Their lunar module's ascent stage was no longer useful, so m...
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Look up from a truly dark place and the Milky Way appears as a pale river of light crossing the sky. That glow is produced by stars so numerous and distant that most cannot be distinguished...
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Imagine falling feet-first toward a black hole. At first, if the black hole were isolated and you began far enough away, the experience would not feel supernatural. You would be in free fall...
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The sky is so reliably blue on a clear day that the color can feel like a property of the atmosphere itself, as though Earth were covered by an enormous blue ceiling. It is not. Air is essen...
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Every few years, a headline or social-media post seems to announce the same piece of cosmic good news: Pluto is a planet again. For anyone who learned the old nine-planet Solar System in sch...
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If Mars can come within roughly 55 million kilometers of Earth, why does a spacecraft sent there travel something closer to 480 million kilometers — and spend around seven months doing it? T...
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A thirsty tomato plant can be surprisingly noisy. Not to us: stand beside it in a greenhouse and you will probably hear nothing beyond leaves rustling and the ordinary sounds of the room. Bu...
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High on a mountain in late spring, a patch of snow can suddenly look as though someone spilled watermelon juice across it. The surface turns pale pink, rose red or even crimson, sometimes st...
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