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Do unmanned spacecraft like Voyager travel in straight lines?
(Intermediate)
When unmanned spacecraft accelerate in space, what causes them to slow down?
(Intermediate)
Why did the Pioneer and Voyager take only 2 years to reach Jupiter, while Galileo and Cassini took more than 5 years?
(Intermediate)
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Can we feel the Earth spin? (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)
Editor's Pick
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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Earth's Bow Shock (Advanced)
Why is the moon in a different place every night? (Beginner)
What was the bright, smoothly moving star that I saw? (Beginner)
What would happen if the Moon fell out of its orbit around Earth? (Intermediate)
How does the position of Moonrise and Moonset change? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
What is the difference between a "star" and a "sun"? (Beginner)
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)
Is it possible for amateurs to do optical interferometry? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
What was the bright, smoothly moving star that I saw? (Beginner)
How far is each planet from Earth? (Intermediate)
What kind of eyepieces do I need to look at planets? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
What would happen if the Moon fell out of its orbit around Earth? (Intermediate)
Which planet is most similar to Earth? (Intermediate)
Earth's Bow Shock (Advanced)
At what speed does the Earth move around the Sun? (Beginner)
Is it possible for amateurs to do optical interferometry? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
How far is each planet from Earth? (Intermediate)
How do you measure the distance between Earth and the Sun? (Intermediate)
How are light and heavy elements formed? (Advanced)
What was the bright, smoothly moving star that I saw? (Beginner)
Which planet is most similar to Earth? (Intermediate)
What would happen if the Moon fell out of its orbit around Earth? (Intermediate)
Why is the moon in a different place every night? (Beginner)
Earth's Bow Shock (Advanced)
How does the position of Moonrise and Moonset change? (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)
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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