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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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What is that ring (or rainbow) around the moon? (Beginner)
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Is speed of light the same everywhere ? (Beginner)
How does Venus have sulphuric acid in it's clouds? (Beginner)
Earth's Bow Shock (Advanced)
How much does the Earth "wobble" on its orbit due to the Moon's gravity? (Intermediate)
Why is the sun red? During sunset, Northeastern US, Summer 2021 (Beginner)
Why do rays from Sun appear to converge at a point? (Beginner)
But seriously: what was there before the Big Bang? (Beginner)
How far can photons move freely in the early universe (Advanced)
How likely is it that the Solar System has had or will have a close encounter with another star? (Intermediate)
How do we know what we observe is x light years away? (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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Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Why is the moon in a different place every night? (Beginner)
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)
How can the Universe expand faster than the speed of light during inflation? (Advanced)
What was the bright, smoothly moving star that I saw? (Beginner)
At what speed does the Earth move around the Sun? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
How far is each planet from Earth? (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)
Why is the moon in a different place every night? (Beginner)
Which planet is most similar to Earth? (Intermediate)
How far is each planet from Earth? (Intermediate)
What was the bright, smoothly moving star that I saw? (Beginner)
Why do the planets orbit the sun? (Beginner)
How can the Universe expand faster than the speed of light during inflation? (Advanced)
At what speed does the Earth move around the Sun? (Beginner)
How can we see the Milky Way if we are inside it? (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 far is each planet from Earth? (Intermediate)
Why is the moon in a different place every night? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
Which planet is most similar to Earth? (Intermediate)
Why do the planets orbit the sun? (Beginner)
What was the bright, smoothly moving star that I saw? (Beginner)
Why do we not have eclipses every month? (Beginner)
At what speed does the Earth move around 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)
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)
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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The Theory of Relativity
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