Astronomy

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What distinguishes earth from other planets?
Water surface, nitrogen-oxygen-co2 atmosphere
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Why is the sky blue?
Preferential scattering of light in the atmosphere
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What are the benefits to mankind of the earth's atmosphere?
Breathing, radiation shield, safety blanket, plants, sound
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How did Eratosthenes determine the circumference of the earth?
Eratosthenes knew that on the summer solstice at local noon on the Tropic of Cancer, the Sun would appear at the zenith, directly overhead (sun elavation of 90°) - though Syene was in fact slightly north of the tropic. He also knew, from using a vert
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What is the shape and diameter of the earth?
oblate spheroid/flattened sphere, 13,000km
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What is the evidence that the earth is round?
space photographs, during a lunar eclipse the earth's shadow is round- the only shape with an always round shadow is a sphere
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What is the rotation period of the earth and how long does it take to rotate through 1 degree?
rotation period of the Earth (23 hours 56 minutes) and the time to rotate through 1 degree (4 minutes)
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How does a reflecting telescope work?
A reflecting telescope (also called a reflector) is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image.
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How does a refracting telescope work?
A refracting telescope works bending light through a lens so that it forms an image.
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Why are the world's biggest telescopes reflectors?
Refractors suffer from chromatic aberration but reflectors don't
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Which electromagnetic waves is the earth's atmosphere invisible to?
Visible light, micro waves and some radio waves.
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Which electromagnetic waves does the earth's atmosphere affect?
Infra-red, ultra-violet, x-rays
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Where are infra-red, ultra-violet and X-ray observatories sited?
Above the earth's atmosphere
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What are the Van Allen Belts?
The Van Allen belts are a collection of charged particles, gathered in place by Earth's magnetic field. Explorers 1 and 3 discovered them in 1958.
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Other cards in this set

Card 2

Front

Why is the sky blue?

Back

Preferential scattering of light in the atmosphere

Card 3

Front

What are the benefits to mankind of the earth's atmosphere?

Back

Preview of the front of card 3

Card 4

Front

How did Eratosthenes determine the circumference of the earth?

Back

Preview of the front of card 4

Card 5

Front

What is the shape and diameter of the earth?

Back

Preview of the front of card 5
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