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Speed of Light
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How do scientists slow light down?
(Intermediate)
How do we know what we observe is x light years away?
(Beginner)
How far can photons move freely in the early universe
(Advanced)
How fast do particles travel in space?
(Intermediate)
How has light from 13 billion years ago not passed us by?
(Beginner)
How is it that we see farther out in space (farther back in time) than in the past?
(Beginner)
How long does it take for the Sun's light to reach us?
(Beginner)
How will a change in the speed of light affect the evolution of the Universe?
(Advanced)
If spacetime is curved, is it possible for us to look into space and see light from Earth from long ago?
(Intermediate)
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across?
(Advanced)
Is speed of light the same everywhere ?
(Beginner)
Is the speed of light constant?
(Beginner)
Is the universe expanding faster than the speed of light?
(Intermediate)
Is time travel possible?
(Beginner)
Traveling at light speed, how long would it take to get to the nearest galaxy?
(Beginner)
Wait, I'm still confused why information can't travel faster than the speed of light.
(Beginner)
What happens to a substance if its speed is more than the speed of light?
(Intermediate)
What is the size of a black hole?
(Intermediate)
What is the speed of gravity?
(Intermediate)
Who first measured the speed of light?
(Intermediate)
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How does the position of Moonrise and Moonset change? (Intermediate)
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How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
Why is the moon in a different place every night? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
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How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
Why is the moon in a different place every night? (Beginner)
Which planet is most similar to Earth? (Intermediate)
Why do the planets orbit the sun? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
What was the bright, smoothly moving star that I saw? (Beginner)
Why do we not have eclipses every month? (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)
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)
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How long does it take for the Sun's light to reach us? (Beginner)
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