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!What calculations go into predicting eclipses?
(Advanced)
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?
(Beginner)
Can you tell time by the Big Dipper?
(Beginner)
Could someone travel the universe in his or her own lifetime?
(Beginner)
Could we be seeing dead stars?
(Beginner)
Did time go slower just after the Big Bang?
(Advanced)
Do we have to worry about relativity when studying galactic objects?
(Intermediate)
Do we really observe the edges of galaxies at different epochs?
(Advanced)
How can I calculate the position or path of the Sun for a given time and location?
(Intermediate)
How can I watch the Perseid meteor shower?
(Beginner)
How do I maximize my chances of seeing shooting stars?
(Intermediate)
How do sunrise and sunset times change with altitude?
(Intermediate)
How is the time of sunrise calculated?
(Intermediate)
How long does it take for the Sun's light to reach us?
(Beginner)
If clocks run slow in a gravitational field, how can we know the true age of the Solar System and Universe?
(Intermediate)
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)
If the Universe was infinitely dense at the Big Bang, why didn't time stand still?
(Beginner)
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What should I know about the upcoming Solar Eclipse? (2017)
What is the universe expanding into? (Intermediate)
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Why do stars twinkle? (Beginner)
Which planets have rings? (Beginner)
How do we know what other planets (and stars, galaxies, etc.) are made of? (Intermediate)
Are there any asteroids on a collision course with Earth? (Beginner)
How much money is spent on space exploration? (Intermediate)
Since Earth is spinning, why do we land in the same place when we jump or fall? (Intermediate)
Why do astronomers use telescopes? (Beginner)
How do astronauts communicate with their families from space? (Beginner)
How critical is the Earth-Sun distance in maintaining our average temperatures on Earth? (Intermediate)
Why does the Sun's apparent path through the sky change throughout the year? (Beginner)
What color is each planet? (Intermediate)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Is the distance from the Earth to the Sun changing? (Advanced)
How far is each planet from Earth? (Intermediate)
Can artificial gravity be created in space? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
Can moons have moons? (Intermediate)
What color is each planet? (Intermediate)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
How far is each planet from Earth? (Intermediate)
Can artificial gravity be created in space? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
Why do airplanes take longer to fly West than East? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
When was the last time all of the planets were aligned? (Beginner)
Which planets have rings? (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)
Is the Moon moving away from the Earth? When was this discovered? (Intermediate)
How do you measure the distance between Earth and the Sun? (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)
How long does it take for the Sun's light to reach us? (Beginner)
When was the last time all of the planets were aligned? (Beginner)
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