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1500 questions
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What if Earth and Moon revolved around each other like Pluto and Charon?
What would be different for us if Earth and Moon revolved around each other like Pluto and Charon do?
cd1
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How close are we to having the technology to measure planetary obliquity for exoplanets?
As far as I can tell, we do not yet have the precision to even put reasonable bounds on an exoplanets obliquity, but wikipedia seems to indicate that this may be possible in the "near future." It seems like this would have to be accomplished by…
user674
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Is it possible for a moon to orbit a planet floating free in the galaxy rather than orbiting a star
This article got me thinking, can a planet hold a moon in orbit if it is just floating in the galaxy by itself not as part of a star system? Can a celestial body even qualify as a planet if it is floating around by itself?
chaonomy
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If we found evidence of life on Mars, how would we know that it originated on Mars rather than Earth?
Consider this scenario. One of the probes sent to Mars either very soon, or within the next century, finds conclusive micro-fossil evidence that life once existed on Mars.
One theory today that is quite common is that life might that have arisen on…
RLH
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Gravitational lensing in Newtonian physics
Famously, when Eddington attempted to measure gravitational lensing during the Eclipse, it was the measured magnitude of the lensing that gave gravity [pun, obviously, intended] to General Relativity - not the measurement of lensing itself. That is,…
user1991
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How thick can planetary rings be?
This arose from a comment on Worldbuilding.
We have data from four planets in the Solar System with rings, which doesn't make for a very good sample size. Observations of exoplanets could change that, but I expect that for now, any answer will…
HDE 226868
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Is the Jupiter-Sun system considered a binary system of some type?
Since Jupiter is very massive, it is the only planet (in our solar system) that has a center of mass with the Sun that lies outside the volume of the Sun. (Source)
If Jupiter was a star, they would form a « binary star ».
If the Sun was a planet,…
Thibault
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What is the name of our Solar System?
what is our Solar System called rather than "the Solar System"?
I've found "Sol System" and "Monmatia", too, but is there more to it?
user7518
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Does Sun have a reflection on Earth?
The new Google Maps1 presents an actual view of Earth, with the current position of Sun illuminating half part of Earth in real time. It is quite an exquisite view.
My question is based on the following image:
As you can see, Sun's reflection from…
Farhan
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What is the current accepted theory as to why Titan has retained its atmosphere?
Titan (moon of Saturn) is unique in that it possesses a very thick atmosphere. However, Titan is certainly is not the largest of the moons - Ganymede being larger.
What is the current accepted theory as to why Titan has retained its thick…
user8
14
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How can we tell the difference between matter and antimatter by observation in space?
I just was wondering and searching on the internet with little luck in the topic. On Antimatter Wiki they tell the observable universe is built up by matter. I read antimatter can be detected in cosmic rays in very small quantity. But let's go in…
CsBalazsHungary
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How much mass will the Sun have when it becomes a white dwarf?
In 4 billion years, when our Sun sheds all of its outer gas layers and turns into a white dwarf, how much mass will the white dwarf have compared to what the sun has today?
Will the planets still orbit in the same way, or will the reduced mass cause…
Scottie
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Apparent size of M31
I am trying to understand something I read on wikipedia about M31.
Wikipedia says that M31 appears more than six times as wide as the full Moon.
But I remember that when I watched it naked eye it seamed a lot smaller, even considering that I was…
Mario Stefanutti
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Might Oort cloud comets be exchanged between solar systems?
Considering their distance from their parent stars, might Oort cloud object such as comets be exchanged between passing stars (assuming that other stars have similar Oort clouds)?
dotancohen
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What will happen when landing on Jupiter?
Jupiter is a gas giant, so landing on it will not be like landing on Earth, our Moon or Mars etc., as it does not have a solid surface like these.
If we have a hypothetical spaceship or probe landing on Jupiter, and it can withstand the enormous…
Farhan
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