Questions on astronomical objects orbiting a star massive enough to be rounded, not massive enough to cause fusion, and which have cleared its orbit of planetesimals.
Questions tagged [planet]
774 questions
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Is it Possible for Planetary Bodies To Exist In Close Proximity Without Adverse Effects?
There are several sci-fi movies where planetary bodies are shown in the sky in order to indicate that the characters are on an alien planet. A good example is in Predators (2010):
Is it actually possible for such planetary bodies to exist so close…
KalenGi
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Why are planets spherical?
I am a complete novice when it comes to astronomy, but someone asked me the above question casually. It seems as though planets are all roughly spherical, whereas other celestial bodies aren't necessarily. Is there are particular reason for this?
LanceLafontaine
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How to calculate the expected surface temperature of a planet
I'm writing a program to generate solar systems but I'm having trouble calculating the expected temperature of a planet. I have found a formula to calculate this, but I haven't been able to get a remotely correct answer out of it as it doesn't…
Eegxeta
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Daylight hours on Titan?
I still cannot seem to wrap my head around Titan's day and night based off of math. From what I understand, Titan has a day of 16 earth days (384 hours) in which it circles Saturn once (its day and also 1-year orbit around Saturn). But during one…
StarbuckM
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3 years later, how strong is the evidence for planet 9?
I came across post in quora where somebody said that "most astronomers no longer think Planet 9 exists" and being somewhat shocked by that, I did a google search and found a fairly recent article that claims exactly that.
It can take several years…
userLTK
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How does the solar wind destroy the atmosphere of a planet lacking a magnetic field?
It is said that because Mars doesn't have a magnetic field its atmosphere disappeared, but how can solar wind cause that?
That the protons and electrons can changes molecules in an atmosphere I can understand, but how can solar wind cause molecules…
Marijn
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Are gas planets in hydrostatic equilibrium?
Why don't gas planets get bigger and smaller over time? Are their sizes constant? Are they in hydrostatic equilibrium like the Sun? Is there an internal force against gravity that does not allow gravity to compress the planet?
Faeze Moosazade
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Do all planets have a van Allen radiation belt?
Earth has the van Allen radiation belts. Which other planets have one? Can it be determined if distant planets in other solar systems have one?
nilo de roock
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Electrical potential difference between planets
In dealing with electricity, we usually refer to Earth as the electrical neutral or ground. Is there any evidence that other planets' ground is at the same electrical potential level as the Earth's?
If somehow, there was a lossless conductive…
Kavka
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How quickly do planetary rings form?
Just a very general question, but I haven't seen this discussed elsewhere. If a moon gets busted up for some reason, say a collision with another moon, and is at the right orbital distance from its planet, how soon would you expect the debris cloud…
Generality
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How big can a rocky planet get?
If I get the numbers right, at about 17 Jupiter masses a mainly gaseous planet would ignite into some type of star. What about rocky planets? Is there a theoretical limit to their size, so that they can grow up to size x? (I'm imagining a "liquid"…
Jorge Al Najjar
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Who first observed another planet rotating?
We knew the earth rotates, but the moon is tidally locked.
To tell that another planet is rotating, you have to be able to distinguish its surface (I guess?). Who first did this?
Phillip Harris
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Confirm: We can only notice planets if their orbit passes in front of their star and our view
If we can tell a planet exists by the dimming of the brightness of a star when it passes in front of our view of the star does that mean we cannot see a planet if it does not cross in front of our view?
If planet of a distance star goes around the…
1.21 gigawatts
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Everything always looks the same
By now I have used 3 different telescopes and a pair of binoculars and no matter what I try to look at at night, whether it be stars, planets, drones, the moon or whatever, everything looks the same. Like a round ball with a squiggly river going…
Carina
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What color is the Sky on other Planets?
On Earth, the sky is blue.
What color would the sky be on other planets in our solar system? What about outside the solar system? Are there planets with purple skies, or green skies? Or are the all just blue?
PotatoLatte
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