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A line drawn perpendicular to a line through the tips of the horns of the crescent moon doesn't point to the Sun! Why not?
(Advanced)
Can we look back far enough in time to see the Big Bang?
(Beginner)
Can we look back in time and see our galaxy forming?
(Intermediate)
Can you use an infinite line of reflectors to send light to the edge of the Universe?
(Intermediate)
Could dark energy come from matter anti-matter pairs forming spontaneously and then annihilating?
(Advanced)
Could photons be dark matter?
(Intermediate)
Has there been an experiment that measured speed faster than the speed of light in vacuum?
(Advanced)
How can we see galaxies if their stars are so faint?
(Intermediate)
How do we know that nuclear fusion is still going on in the Sun?
(Intermediate)
How has light from 13 billion years ago not passed us by?
(Beginner)
How long does the supernova stage of a star last?
(Intermediate)
How much power is contained in a beam of light?
(Intermediate)
If light has no mass, then what draws it into a black hole?
(Intermediate)
If photons have zero mass, why do they feel the effects of gravity?
(Advanced)
Is it possible to measure the temperature of the Sun?
(Beginner)
Is light blueshifted when it is gravitationally lensed?
(Intermediate)
Is the green flash real?
(Beginner)
What color would Mars be if you were standing on it?
(Advanced)
What do a galaxy's colors mean? Are they its true colors?
(Intermediate)
What is a star's "spectrum"?
(Beginner)
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What what a black hole merger look like from a telescope? (Advanced)
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Our universe is still expanding, does that mean things in our daily life are expanding? (Intermediate)
What was the bright, smoothly moving star that I saw? (Beginner)
What happened to the Arecibo Telescope? (Beginner)
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)
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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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How are light and heavy elements formed? (Advanced)
How do you measure the distance between Earth and the Sun? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
Why do the planets orbit the sun? (Beginner)
What kind of eyepieces do I need to look at planets? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Can artificial gravity be created in space? (Intermediate)
What color is each planet? (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 do you measure the distance between Earth and the Sun? (Intermediate)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
How are light and heavy elements formed? (Advanced)
Why do the planets orbit the sun? (Beginner)
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)
What color is each planet? (Intermediate)
Can artificial gravity be created in space? (Intermediate)
How does the location of sunrise and sunset change throughout the year? (Advanced)
What is the difference between a "star" and a "sun"? (Beginner)
What kind of eyepieces do I need to look at planets? (Intermediate)
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 long could life on Earth survive if the Sun stopped shining? (Beginner)
What color is each planet? (Intermediate)
Why do the planets orbit the sun? (Beginner)
Can artificial gravity be created in space? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
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)
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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Physics
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