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!What calculations go into predicting eclipses?
(Advanced)
But seriously: what was there before the Big Bang?
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Can two lunar eclipses occur in the same month?
(Advanced)
Can we look back in time and see our galaxy forming?
(Intermediate)
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 have to worry about relativity when studying galactic objects?
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Do we really observe the edges of galaxies at different epochs?
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How do I maximize my chances of seeing shooting stars?
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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?
(Intermediate)
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 far is each planet from Earth? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
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How far is each planet from Earth? (Intermediate)
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How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
Which planet is most similar to Earth? (Intermediate)
What was the bright, smoothly moving star that I saw? (Beginner)
Why is the moon in a different place every night? (Beginner)
What would happen if the Moon fell out of its orbit around Earth? (Intermediate)
Earth's Bow Shock (Advanced)
How does the position of Moonrise and Moonset change? (Intermediate)
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)
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