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Are the asteroids the remains of a planet which broke apart?
(Beginner)
Are there any dark stars or dark galaxies made of dark matter?
(Advanced)
Can artificial gravity be created in space?
(Intermediate)
Can we prove that the Moon isn't hollow?
(Intermediate)
Could neutrinos be dark matter?
(Intermediate)
Could the Universe's dark matter be made up of black holes?
(Advanced)
Do binary or triple star systems form together?
(Intermediate)
Do stars' orbits in galaxies obey Kepler's Laws?
(Intermediate)
Does the singularity in a black hole create a new Universe?
(Intermediate)
Does the Sun orbit the Earth as well as the Earth orbiting the Sun?
(Beginner)
Have the inner planets cleared their neighborhood?
(Intermediate)
How are black holes discovered?
(Intermediate)
How are black holes made? Could one be made close to us?
(Beginner)
How big was the Sun when it first "fired up"?
(Intermediate)
How can the Sun have such a strong gravitational field if it's made of gases?
(Beginner)
How do photons from distant objects maintain enough energy to reach us?
(Intermediate)
How do rockets work?
(Intermediate)
How do we know the density of some extrasolar planets?
(Intermediate)
How do we know the mass of the Earth and the Moon?
(Advanced)
How do we know what parameters to use when simulating the collision of the Milky Way and Andromeda?
(Advanced)
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Is speed of light the same everywhere ? (Beginner)
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Earth's Bow Shock (Advanced)
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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)
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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)
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Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
Why do the planets orbit the sun? (Beginner)
How far is each planet from Earth? (Intermediate)
What would happen if the Moon fell out of its orbit around Earth? (Intermediate)
Earth's Bow Shock (Advanced)
What are the requirements for being a planet? (Beginner)
How can we see the Milky Way if we are inside it? (Intermediate)
What was the bright, smoothly moving star that I saw? (Beginner)
What is that ring (or rainbow) around the moon? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
How far is each planet from Earth? (Intermediate)
What would happen if the Moon fell out of its orbit around Earth? (Intermediate)
Earth's Bow Shock (Advanced)
Why is the moon in a different place every night? (Beginner)
What was the bright, smoothly moving star that I saw? (Beginner)
Which planet is most similar to Earth? (Intermediate)
How does the position of Moonrise and Moonset change? (Intermediate)
At what speed does the Earth move around 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 would happen if the Moon fell out of its orbit around Earth? (Intermediate)
What was the bright, smoothly moving star that I saw? (Beginner)
Why is the moon in a different place every night? (Beginner)
Earth's Bow Shock (Advanced)
Which planet is most similar to Earth? (Intermediate)
How does the position of Moonrise and Moonset change? (Intermediate)
How are light and heavy elements formed? (Advanced)
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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Home
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Galaxies
Cosmology & the Big Bang
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Timekeeping
SETI & Extraterrestrial Life
Physics
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The Theory of Relativity
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The History of Astronomy
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