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1500 questions
16
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1 answer
How can an area be on the day side 90% of the time?
In the magazine "Ciel & Espace", it is stated that crater ridge next to Shackleton crater is an interesting landing site for future missions because it is lit up 90% of the time.
I get how an area can be in the shade 90% of the time, but how can an…
usernumber
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16
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4 answers
Why doesn't the Sun wobble towards Jupiter instead of away from Jupiter?
This is the page I am referring to. It seems counterintuitive to me that the Sun should be on the opposite side of the barycenter's wobble. I realize I am wrong, but I cannot see why I am wrong. Can someone explain why the wobble is away from…
Bookaholic
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16
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2 answers
At what distance from the Sun can planetary moons exist?
Mercury and Venus are theorized to have no moons because they are so close to the sun.
Is there a theoretical distance in which moons tend to exist based on simulations?
William
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16
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2 answers
How distorted will our galaxy be if we are viewing it from several thousand light years away?
I saw this answer and read this sentence regarding the distortion of our galaxy when viewed above the galactic plane:
Once you got to a point where the entire [sic] galaxy was within your vision, the entire galaxy would look distorted, since our…
WarpPrime
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16
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3 answers
Does General Relativity really predict Black Holes?
I'm doing some research on black holes for a science video contest. I want to explain the physics of how they work, but also want to have a little background on how they're formed. As far as I've searched, black holes are predicted by general…
AdiBak
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3 answers
Has anyone back-calculated previous close encounters between the Apophis asteroid and Earth?
The Apophis asteroid was only discovered in 2004, and shares an orbit similar to Earth's orbit, leading to many close encounters on the scale of decades.
Most of the stories about this asteroid are about predicting future encounters between Earth…
Steve Sether
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16
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1 answer
What are the current observational limits on the existence of Dyson spheres/swarms/rings?
A Dyson sphere/swarm/ring is a hypothetical structure an extra-terrestrial entity would construct to collect a large fraction of its host star's light, and would likely generate a fairly strong infrared signature that could potentially be detected…
Guillochon
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Why can I see sometimes a horizontal half moon instead of a vertical one?
Why do I sometimes see a horizontal half moon, instead of the more usual vertical one? I keep getting answers for crescent moons, but this is a half moon with its curve closer to the horizon, like a bowl of cereal.
I would like to know why it only…
Evilin Garnett
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16
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2 answers
Is it possible that the Sun and all the nearby stars formed from the same nebula?
I was looking at a map of our local stellar neighborhood, and it occured to me, the stars are really close, if one compares them to the size of some nebulae. So can it be, that the Sun, Alpha Centauri system, and all the other stars in the…
Sam
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16
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How many times brighter would full-earth-shine appear to people standing on the moon, than full-moon-shine does to people on earth?
The definition of brightness, according to Wikipedia:
the term brightness in astronomy is generally used to refer to an object's apparent brightness: that is, how bright an object appears to an observer. Apparent brightness depends on both the…
Constantthin
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2 answers
Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star?
Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star?
Curious Cat
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16
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1 answer
What is the current accepted theory for the fate of hot Jupiters?
It is well established that one main feature of many hot jupiters is their close proximity to their parent star, usually the equivalent of being within the orbit of Mercury. So, these planets are gas giants and are very hot (hence their…
user8
16
votes
4 answers
Can a star emit heat but no visible light?
Can a star emit enough heat to allow human life on its planets, however emit no visible light? If so, what problems would this pose?
user36985
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16
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1 answer
Do brown dwarfs have stripes?
Brown dwarfs (BD) are often depicted with stripes.
brown dwarf Jupiter
Pictures of BD resemble Jupiter but brown dwarfs have even more stripes.
Question:
How do we know brown dwarfs have so many stripes?
I…
Heopps
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How do satellites impede current telescopes?
As we send up more and more satellites, it stands to reason that our view of the universe becomes more and more obscured. I would certainly expect for example that a large telescope such as the LSST would be able to see the International Space…
Allure
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