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Can gravitational lensing from intervening galaxies cause the observed ripples in the Cosmic Microwave Background?
(Advanced)
Can the acceleration of the Universe be analogous to apparent acceleration in a airplane?
(Intermediate)
Can you see the future as you fall into a black hole?
(Intermediate)
Could there be objects orbiting interior to Mercury?
(Intermediate)
Did time go slower just after the Big Bang?
(Advanced)
Do supermassive black holes cause galaxy rotation?
(Advanced)
Have gravitational waves been proven to exist?
(Intermediate)
How are planets detected around other stars?
(Intermediate)
How do gravitons escape black holes to tell the universe about their gravity?
(Advanced)
How does astronomy benefit humankind?
(Beginner)
How does the Moon stay "suspended" in the air?
(Intermediate)
If clocks run slow in a gravitational field, how can we know the true age of the Solar System and Universe?
(Intermediate)
If gravity is a "curvature of space" rather than a force, why do a ball and bullet follow different paths?
(Intermediate)
If gravity isn't a force, how does it accelerate objects?
(Advanced)
If light has no mass, then what draws it into a black hole?
(Intermediate)
If photons have zero mass, why do they feel the effects of gravity?
(Advanced)
If the universe is 13.8 billion years old, how can it be larger than 13.8 billion light years across?
(Advanced)
Is light blueshifted when it is gravitationally lensed?
(Intermediate)
Is light of different colors affected differently by gravity?
(Intermediate)
Is there such a thing as hyperspace?
(Intermediate)
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Our universe is still expanding, does that mean things in our daily life are expanding? (Intermediate)
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Can I buy or name a star? (Beginner)
If I were hypothetically wearing a spacesuit and sitting on one of the Voyager space probes at their current positions in space, how much light would I have? (Intermediate)
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What is the universe expanding into? (Intermediate)
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How can we see the Milky Way if we are inside it? (Intermediate)
How does the location of sunrise and sunset change throughout the year? (Advanced)
How are light and heavy elements formed? (Advanced)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
What color is each planet? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
Why do the planets orbit the sun? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
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 is the difference between a "star" and a "sun"? (Beginner)
How are light and heavy elements formed? (Advanced)
How do you measure the distance between Earth and the Sun? (Intermediate)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
How does the location of sunrise and sunset change throughout the year? (Advanced)
How does the position of Moonrise and Moonset change? (Intermediate)
At what speed does the Earth move around the Sun? (Beginner)
Are there telescopes that can see the flag and lunar rover on the Moon? (Beginner)
Which planet is most similar to Earth? (Intermediate)
What is the difference between a "star" and a "sun"? (Beginner)
How are light and heavy elements formed? (Advanced)
Why do the planets orbit the sun? (Beginner)
How do you measure the distance between Earth and the Sun? (Intermediate)
How long could life on Earth survive if the Sun stopped shining? (Beginner)
How does the position of Moonrise and Moonset change? (Intermediate)
How does the location of sunrise and sunset change throughout the year? (Advanced)
At what speed does the Earth move around the Sun? (Beginner)
Which planet is most similar to Earth? (Intermediate)
Are there telescopes that can see the flag and lunar rover on the Moon? (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)
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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