Sunlight is the primary illuminator. Its spectrum is a familiar rainbow with maximum emittance in a color that most of us would call yellow-green — light of wavelength around 550 nanometers.
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Aristotle famously claimed that nature abhors a vacuum. True, air does rush into the space from which air has been evacuated, but not because nature has feelings of any kind about the vacuum.
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Where is ET? After nearly 50 years of searching for intelligent signals from space, astronomers have yet to receive a single verifiable signal of intelligent origin.
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Water vapor is the gaseous form of water that exists in the atmosphere along with nitrogen, oxygen and other minor gases such as argon and carbon dioxide.
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Equilibrium is a state of balance of opposing actions which is central in virtually everything that happens, from basic physics to dance and the arts, economics and social ideologies.
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Helium is No. 2. It is the second-lightest element on the periodic table with atomic number of two.
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Since the development of MRI scans from the first crude machines in the 1970s, the technology has become more efficient.
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The Standard Model is what physicists call the current theory of fundamental particles and their interactions.
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Feeling tired today? Most of us grow more weary as the day goes on and as the years pass. We say we are out of energy or getting low on energy, which is a fact.
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What is it that gives numbers their power?
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Clouds come in all shapes and sizes, but they are usually flat on the bottom.
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The aurora borealis, or northern lights, is a common sight at north polar latitudes. The name aurora borealis comes from Latin and Greek.
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Outside the window, 7 miles up, the wings of the jet airliner slice through the invisible air that seems magically to keep it aloft. It reminds me that we are immersed in Earth’s invisible atmosphere all of the time.
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The names of the 12 months that make up our Western calendar are so familiar that we do not think much about where they came from.
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All paint inside a can is black until the can is opened. Strange as it might seem, it is true. What we see as color is a matter of perception, intrinsic properties of an object and the light that illuminates it.
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The calendar is such a basic thing that we take it for granted. It consists of 52 weeks of seven days, plus one extra day, for a total of 365 days.
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Earth’s gravity creates tidal forces on the moon that keep it locked with one side always facing Earth. This is why we always see the same face of the moon and never see the backside.
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Earth is a unique planet in the solar system, and may be the only one of its kind anywhere.
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