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Can "tired light theory" explain the observed redshifts of galaxies?
(Intermediate)
Can gravitational lensing from intervening galaxies cause the observed ripples in the Cosmic Microwave Background?
(Advanced)
Can we look back far enough in time to see the Big Bang?
(Beginner)
Could photons be dark matter?
(Intermediate)
Could the Universe have expanded faster than the speed of light at the Big Bang?
(Intermediate)
How big is the Universe?
(Intermediate)
How do we know the age of the Universe and the Earth?
(Intermediate)
What makes up most of the Universe?
(Beginner)
What's the difference between dark matter and dark energy?
(Intermediate)
Where, in relation to the entire universe, is the Milky Way located?
(Intermediate)
Why is the Cosmic Microwave Background not absorbed by interstellar hydrogen?
(Advanced)
Why is the WMAP picture of the CMB an ellipse?
(Intermediate)
Wouldn't the Big Bang theory be considered a hypothesis and not a theory?
(Intermediate)
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What month was it when Odysseus saw Orion in 1000BC? (Advanced)
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Do galaxies that are receding from us faster than the speed of light disappear from our observations? (Intermediate)
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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)
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What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
What color is each planet? (Intermediate)
How far is each planet from Earth? (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)
How do you measure the distance between Earth and the Sun? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How are light and heavy elements formed? (Advanced)
Why do airplanes take longer to fly West than East? (Intermediate)
Where did the name 'Earth' come from? (Beginner)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
What color is each planet? (Intermediate)
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)
When was the last time all of the planets were aligned? (Beginner)
Why do airplanes take longer to fly West than East? (Intermediate)
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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