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Are there any 'lonely galaxies'?
(Beginner)
Has anyone made a map of the Milky Way?
(Beginner)
How can we see the Milky Way if we are inside it?
(Intermediate)
How can we tell what the interiors of planets are like?
(Advanced)
How do we know that superclusters are the largest structures in the universe?
(Advanced)
Is the Local Group expanding along with the entire Universe?
(Intermediate)
What do "homogeneity" and "isotropy" mean?
(Intermediate)
What is the largest structure in the universe?
(Intermediate)
What is the origin of spiral structure in galaxies?
(Intermediate)
Where, in relation to the entire universe, is the Milky Way located?
(Intermediate)
Why do we assume that the universe is homogeneous?
(Intermediate)
Why doesn't the ammonia and methane in Jupiter's atmosphere sink into the core?
(Advanced)
Would a planet near the galactic center have a brighter night sky?
(Intermediate)
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Do the magnitudes and colors of stars ever change? (Intermediate)
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How much does the Earth "wobble" on its orbit due to the Moon's gravity? (Intermediate)
Why is the sun red? During sunset, Northeastern US, Summer 2021 (Beginner)
Why do rays from Sun appear to converge at a point? (Beginner)
But seriously: what was there before the Big Bang? (Beginner)
How far can photons move freely in the early universe (Advanced)
How likely is it that the Solar System has had or will have a close encounter with another star? (Intermediate)
How do we know what we observe is x light years away? (Beginner)
What makes quantum mechanics and general relativity incompatible? (Advanced)
What are we doing about Space Junk?
What what a black hole merger look like from a telescope? (Advanced)
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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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But seriously: what was there before the Big Bang? (Beginner)
How are light and heavy elements formed? (Advanced)
Why can't a plane fly slowly and let the Earth pass underneath? (Beginner)
What color is each planet? (Intermediate)
Which planet is most similar to Earth? (Intermediate)
Is the speed of light constant? (Beginner)
How do we know what other planets (and stars, galaxies, etc.) are made of? (Intermediate)
How long does it take for the Sun's light to reach us? (Beginner)
Is the universe expanding faster than the speed of light? (Intermediate)
Is the distance from the Earth to the Sun changing? (Advanced)
Is the Moon moving away from the Earth? When was this discovered? (Intermediate)
How does the position of Moonrise and Moonset change? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
Why is the moon in a different place every night? (Beginner)
Why do the planets orbit the sun? (Beginner)
How are light and heavy elements formed? (Advanced)
How do you measure the distance between Earth and the Sun? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
Which planet is most similar to Earth? (Intermediate)
Is the Moon moving away from the Earth? When was this discovered? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
Why do the planets orbit the 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)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
But seriously: what was there before the Big Bang? (Beginner)
What is the universe expanding into? (Intermediate)
What color is each planet? (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)
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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The History of Astronomy
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