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Is the Sun always up for exactly 12 hours at the equator?
(Beginner)
Why doesn't the length of each day change much around the solstices?
(Intermediate)
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Traveling at light speed, how long would it take to get to the nearest galaxy? (Beginner)
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Can I buy or name a star? (Beginner)
If I were hypothetically wearing a spacesuit and sitting on one of the Voyager space probes at their current positions in space, how much light would I have? (Intermediate)
What makes certain lunar eclipses so special? (Beginner)
Why is Earth's core molten? (Intermediate)
What will happen to Earth's tides as the moon moves away from us? (Intermediate)
How can spiral galaxies keep their shape? (Advanced)
Does a black hole have a "surface"? (Intermediate)
How can you link telescopes to make a bigger "effective telescope"? (Intermediate)
What should I know about the upcoming Solar Eclipse (2017)? (Beginner)
Do galaxies that are receding from us faster than the speed of light disappear from our observations? (Intermediate)
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What is the universe expanding into? (Intermediate)
What do I need to do to become an astronomer? (Beginner)
What's the difference between astronomy and astrology? (Beginner)
Why is looking out into space the same as looking back in time? (Beginner)
Can we find the place where the Big Bang happened? (Intermediate)
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What do "homogeneity" and "isotropy" mean? (Intermediate)
How are light and heavy elements formed? (Advanced)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
What color is each planet? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
How far is each planet from Earth? (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)
Can artificial gravity be created in space? (Intermediate)
What color is each planet? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
Can artificial gravity be created in space? (Intermediate)
How are light and heavy elements formed? (Advanced)
Why do the planets orbit the sun? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
What are constellations used for? (Intermediate)
What is the universe expanding into? (Intermediate)
How are light and heavy elements formed? (Advanced)
What color is each planet? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
Can artificial gravity be created in space? (Intermediate)
Why do the planets orbit the sun? (Beginner)
How far is each planet from Earth? (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)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (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)
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)
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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Timekeeping
SETI & Extraterrestrial Life
Physics
General Physics
The Theory of Relativity
People & Astronomy
Careers in Astronomy
Space Exploration & Astronauts
The History of Astronomy
Astronomy in the Arts