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Can you use an infinite line of reflectors to send light to the edge of the Universe?
(Intermediate)
Could someone travel the universe in his or her own lifetime?
(Beginner)
How are photons created and destroyed?
(Advanced)
How do photons from distant objects maintain enough energy to reach us?
(Intermediate)
How do planets capture satellites?
(Advanced)
How do you calculate the lifetime of the Sun?
(Advanced)
How long do supernova remnants last?
(Intermediate)
How much power is contained in a beam of light?
(Intermediate)
How powerful are quasars?
(Intermediate)
Is cosmic expansion happening on microscopic scales?
(Advanced)
Is light of different colors affected differently by gravity?
(Intermediate)
What causes a particle to decay?
(Intermediate)
What is the photoelectric effect? Why can't multiple low-frequency photons free an electron?
(Intermediate)
What type of energy does a black hole have?
(Intermediate)
When the Sun converts mass to energy, do the orbits of the planets change?
(Advanced)
Where did the matter in the universe come from?
(Intermediate)
Where did the Universe come from?
(Intermediate)
Where does the kinetic energy of infalling bodies come from?
(Intermediate)
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Why do humans want to go in space? (Beginner)
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Do galaxies that are receding from us faster than the speed of light disappear from our observations? (Intermediate)
Why are astronomers interested in gravitational waves? (Intermediate)
Can two galaxies move away from each other faster than the speed of light? (Intermediate)
What is a graviton? (Intermediate)
Why are there high tides during a Full Moon? (Intermediate)
Why is Neptune still considered a planet when Pluto crosses its orbit? (Intermediate)
Could there be objects orbiting interior to Mercury? (Intermediate)
Have the inner planets cleared their neighborhood? (Intermediate)
What caused the Big Bang and created the Universe? (Beginner)
If spacetime is curved, is it possible for us to look into space and see light from Earth from long ago? (Intermediate)
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What should I know about the upcoming Solar Eclipse? (2017)
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)
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What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
How are light and heavy elements formed? (Advanced)
What color is each planet? (Intermediate)
How far is each planet from Earth? (Intermediate)
How is it proved that the Universe is expanding? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
When was the last time all of the planets were aligned? (Beginner)
How does the location of sunrise and sunset change throughout the year? (Advanced)
What direction do planets rotate? (Beginner)
What is the difference between a "star" and a "sun"? (Beginner)
What color is each planet? (Intermediate)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
How are light and heavy elements formed? (Advanced)
How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
Why do airplanes take longer to fly West than East? (Intermediate)
When was the last time all of the planets were aligned? (Beginner)
What is the difference between a "star" and a "sun"? (Beginner)
How is it proved that the Universe is expanding? (Intermediate)
How does the location of sunrise and sunset change throughout the year? (Advanced)
What color is each planet? (Intermediate)
How are light and heavy elements formed? (Advanced)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
How far is each planet from Earth? (Intermediate)
When was the last time all of the planets were aligned? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
Why do airplanes take longer to fly West than East? (Intermediate)
How does the location of sunrise and sunset change throughout the year? (Advanced)
How is it proved that the Universe is expanding? (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)
How long does it take for the Sun's light to reach us? (Beginner)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
What is the universe expanding into? (Intermediate)
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