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Are aliens or UFOs real?
(Beginner)
Can I listen to the SETI@home radio signal?
(Beginner)
Can life exist on the recently discovered extrasolar planets?
(Beginner)
Can supernovae hinder the formation of life in galaxies?
(Beginner)
Could there be life in the galaxies nearest to the Milky Way?
(Intermediate)
Do similar laws of physics throughout the Universe imply that all life must be like life on Earth?
(Beginner)
Do you believe in UFOs?
(Beginner)
Do you think it's possible to maintain life on other planets?
(Beginner)
Have astronomers observed any phenomena that could be produced by extraterrestrial civilizations?
(Intermediate)
Is it worthwhile to continue the search for extraterrestrial life?
(Beginner)
Is there oxygen in the atmospheres of other planets?
(Intermediate)
What do meteorites tell us about life on other planets?
(Intermediate)
What is a Dyson Sphere?
(Intermediate)
Where is everybody?
(Intermediate)
Why does the SETI project search for radio signals?
(Intermediate)
Why search for only Earth-like life on other planets?
(Beginner)
Would extraterrestrial civilizations know that there is life on Earth?
(Beginner)
Wouldn't the vast distances of space distort SETI signals into unintelligeble forms?
(Intermediate)
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Has there been an experiment that measured speed faster than the speed of light in vacuum? (Advanced)
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What should I know about the upcoming Solar Eclipse (2017)? (Beginner)
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)
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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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What color is each planet? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
Why do stars twinkle? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Can artificial gravity be created in space? (Intermediate)
Why can't a plane fly slowly and let the Earth pass underneath? (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)
Why do airplanes take longer to fly West than East? (Intermediate)
How does the location of sunrise and sunset change throughout the year? (Advanced)
What color is each planet? (Intermediate)
Can artificial gravity be created in space? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How far is each planet from Earth? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
Why do airplanes take longer to fly West than East? (Intermediate)
Why do stars twinkle? (Beginner)
Why do the planets orbit the sun? (Beginner)
Why are there high tides during a Full Moon? (Intermediate)
What color is each planet? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
What is the significance of the Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Can artificial gravity be created in space? (Intermediate)
How far is each planet from Earth? (Intermediate)
Why do stars twinkle? (Beginner)
At what speed does the Earth move around the Sun? (Beginner)
Why do airplanes take longer to fly West than East? (Intermediate)
Why do the planets orbit the sun? (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)
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)
How long does it take for the Sun's light to reach us? (Beginner)
When was the last time all of the planets were aligned? (Beginner)
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