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!What calculations go into predicting eclipses?
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But seriously: what was there before the Big Bang?
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Can two lunar eclipses occur in the same month?
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Can we look back in time and see our galaxy forming?
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Can we make a movie of the Milky Way galaxy's rotation?
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Can you tell time by the Big Dipper?
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Could someone travel the universe in his or her own lifetime?
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Could we be seeing dead stars?
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Did time go slower just after the Big Bang?
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Do we really observe the edges of galaxies at different epochs?
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How can I watch the Perseid meteor shower?
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How do I maximize my chances of seeing shooting stars?
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How do sunrise and sunset times change with altitude?
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If clocks run slow in a gravitational field, how can we know the true age of the Solar System and Universe?
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If Mars is only about 35-60 million miles away at close approach, why does it take 6-8 months to get there?
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If the Earth's rotation period is less than 24 hours, why don't our clocks fall out of sync with the Sun?
(Intermediate)
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How do you measure the distance between Earth and the Sun? (Intermediate)
Why do the planets orbit the sun? (Beginner)
At what speed does the Earth move around the Sun? (Beginner)
What are constellations used for? (Intermediate)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
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Which planet is most similar to Earth? (Intermediate)
How are light and heavy elements formed? (Advanced)
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Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Why do the planets orbit the sun? (Beginner)
Which planet is most similar to Earth? (Intermediate)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
At what speed does the Earth move around the Sun? (Beginner)
What is the difference between a "star" and a "sun"? (Beginner)
What's going to happen on December 21st 2012? (Intermediate)
How does the position of Moonrise and Moonset change? (Intermediate)
What are constellations used for? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
How big is the Hubble Ultra Deep Field image? (Intermediate)
Which planet is most similar to Earth? (Intermediate)
Why do the planets orbit the sun? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
What are constellations used for? (Intermediate)
Why do we not have eclipses every month? (Beginner)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
What is the difference between a "star" and a "sun"? (Beginner)
What's going to happen on December 21st 2012? (Intermediate)
What color is each planet? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
Is the Moon moving away from the Earth? When was this discovered? (Intermediate)
Why do the planets orbit the sun? (Beginner)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
When was the last time all of the planets were aligned? (Beginner)
How long does it take for the Sun's light to reach us? (Beginner)
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