Questions tagged [planets]
Celestial body that orbits following an elliptical path around a star or stellar remnant.
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0answers
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Heat transfer on Mars
SCENARIO:
I have been tasked with finding the heat transfer across a composite wall on Mars.
On the left of the wall there is air maintained at Earth atmospheric conditions and room temperature (101 ...
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0answers
26 views
Long-term fate of hydrogen atoms in a rogue planet
Imagine a rogue planet drifting in intergalactic space. For the sake of specificity, suppose that it is the size of Jupiter and composed of pure hydrogen. What will happen to it over the next $10^{...
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0answers
25 views
Calculating Inital Velocity required to stablize an orbit of a moon
I am currently attempting to create a little solar system simulation and I was curious if there's a decent way to calculate what a moon or planet's initial velocity would need to be to remain in orbit ...
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5answers
369 views
Do orbiting planets have infinite energy?
I know that planets can't have infinite energy, due to the law of conservation of energy.
However, I'm confused because I see a contradiction and it would be great if someone could explain it.
...
2
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0answers
78 views
What orbit does a planet have to have to be a planet? [closed]
Other questions have dealt with where you could find a planet-like object, and what a planet has to consist of to count as a planet. But this question is directed as what orbit or path an object would ...
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2answers
81 views
What would happen if a planet's escape velocity exceeded the speed of light?
What would happen if a planet's escape velocity exceeded the speed of light? Would it also collapse into a black hole (by Heisenberg's uncertainty principle and Pauli's exclusion principle) or would ...
46
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2answers
8k views
Does a star need to be inside a galaxy?
Must a star belong to a galaxy, or could it be completely isolated?
In case it can be isolated (not belong to a galaxy), could it have a planet orbiting around it?
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1answer
37 views
Declination as a function of orbital position
Reading this Wikipedia article and following the derivations (https://en.wikipedia.org/wiki/Solar_irradiance#Milankovitch_cycles), I have found an equation I can't see where it comes from. Perhaps it'...
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1answer
40 views
Can an elliptical planet be stable?
Subsequent to This question about the Earth's actual cross-sectional shape at the equator, I'm wondering about the stability of non-spherical planet-sized masses.
Suppose there is a planet of uniform ...
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2answers
52 views
How come planets with different masses can orbit at the same velocity at the same altitudes?
Angular momentum is equal to r × p and angular momentum is also what gives planets with lower orbits a higher speed (because angular momentum is conserved). So as r decreases either m or v (p=mv) has ...
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2answers
33 views
How can I determine a planet's mass based only off of information about its orbit and its parent star?
I'm coding a video game with procedurally generated planetary systems and I want some and I want to make sure I'm at least somewhat scientifically correct. I've reached the part in my code where I ...
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3answers
98 views
If there was a hole in the north pole to the South Pole and you jumped into it how would would you come out feet first? [closed]
If I were to dig a hole in a round sphere Say the earth starting at the north pole standing on my feet I start to dig when I come out the other side would I come out of the whole feet first or head ...
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4answers
67 views
Does an object at the center of the Earth have potential energy?
"Potential energy: The energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors."
in other words, I think that potential ...
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0answers
11 views
Why spinning creates bulges? [duplicate]
Earth isnt a perfect but has bulges because of its spinning. What actually creates the bulges? Is the same reason that makes a liquid have v shape in a rotational tube?
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1answer
50 views
Treating stars and planets as a blackbody determine the temperature of a planet that has EM radiation incident upon it from a star
Consider the following question:
Power emitted by the star via the Stefan Boltzmann law is as follows:
$$4\pi\sigma T_s^4 r_s^2 $$
However the power will drop over distance and so we can say that ...
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2answers
71 views
Could a non-rotating planet, in a binary situation, have gravity?
Is it possible for a singular planet to rotate around a single sun in the same way that our moon rotates around the Earth? If so, would it be possible for that planet, if as large or larger than ...
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3answers
152 views
Why does angular momentum being constant prove Kepler's first law?
So I was watching this video and this video on Kepler's first law in order to understand the proof of Kepler's first law. He started off by saying that for an ellipse, the distance from a focus point ...
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2answers
144 views
Is it possible to have a planet entirely made out of liquid water?
Earth is mostly covered in oceans, but they only go a few kilometres deep. It's obviously not possible to have a planet the size of the earth to be made entirely out of water, because of the kind of ...
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2answers
57 views
How far can you pee on the moon vs. mars? [closed]
Let's suppose you are at Elon Musk's Future Mars colony and you drank too much beer, how far can you pee on Mars if you can pee one meter on earth?
If the next day you get on the shuttle to the ...
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1answer
46 views
How does an object's volume affect its gravitational pull?
Two instances. An object is in front of two different planets with the same masses, but two different volumes. How does the gravitational pull vary from each planet? I am thinking with more given ...
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5answers
127 views
How can an electrically neutral planetary core be geodynamo? [duplicate]
The standard theory for the earth's magnetic field is that the planet's core is a geodynamo.
I know moving electric charges can induce a magnetic field, but I also know that opposite charges produce ...
3
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0answers
32 views
What if an ocean planet is covered by superfluid ocean? [closed]
It is possible that an ocean planet can be covered by superfluid state liquid. What will happens on this kind of planet? Will there be any changes to tide? Will there be strong magnetic field? Will ...
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1answer
81 views
Sound and gravity
How would heavier gravity (or lighter gravity) affect sound in terms of what I hear?
For example, say there is a planet that is capable of supporting human life, but it has heavier gravity than ...
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1answer
62 views
What is the second $r$ in this equation for the Two Body Problem?
$$r=\frac{r^2\frac{\mathrm d\theta^2}{\mathrm dt}}{\frac{Gm_2^3}{\left(m_1+m_2\right)^2}\left(1+e\cos\theta\right)}$$
I have this equation for the radial distance of a planet from the barycenter. But ...
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1answer
47 views
Bad value for sphere of influence with Venus [closed]
I would like to get value of sphere of influence than Wikipedia for Venus:
on https://en.wikipedia.org/wiki/Sphere_of_influence_%28astrodynamics%29
It is indicated for Venus: $S_{\text{OI}}=0.616\,\...
7
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1answer
478 views
How do we know the Earth's core is Molten with Seismology?
My current knowledge about how the core of the earth was discovered is the observation made from non returning/reflecting sonar signal when sent to deeper depths through the earth's crust/mantle. How ...
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1answer
59 views
How did Mars lose all its surface water?
A lot of geological evidence suggests that Mars once had quite a bit of surface water. I assume it wasn't whisked away into space, so where did it all go? What processes caused the water to go there?
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2answers
139 views
Accurate Equation for Earth's Gravitational Binding Energy
This is a relatively important question for anyone who can answer it. I am trying to find the equation that accurately solves for Earth's Gravitational Binding Energy. The information below is from ...
2
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1answer
25 views
Earth bulge and axis precession
We know that earth is not spherical because it spins. Does every object that spins bulge? for example a rotating wheel bulges? Also how moon and sun create the torque that shifts the axis of rotation (...
1
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2answers
59 views
Why do gas giants have similarly coloured stripes?
After looking at Jupiter and searching 'exoplanets gas giants' on google I found that many had stripes on them. I found that pretty peculiar. So why do they have stripes. I think it has something to ...
0
votes
1answer
64 views
Digging a hole in the moon across its diameter [duplicate]
What will occur if one digs a hole in some moon/dead-planet without an atmosphere (and without a Lava Core), such that this hole shall have a 1 meter diameter and will be so deep that shall go through ...
1
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0answers
17 views
How severe would the consequences be if the earth's moon were wrenched from orbit?
The old TV series Space 1999 from the early 1970s seems to have resurfaced on Youtube reminding me of something I watched as a child.
It is one of those obviously ridiculous SciFi series (from the ...
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3answers
896 views
Gravitational advantage of outer planets in war
The Expanse books cover a lot of aspects of war in a situation where humans inhabit many planets and moons of the solar system.
The author makes the point that, in a war situation, the outer planets ...
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3answers
227 views
The acceleration in Earth's gravity
The acceleration in earth's gravity is $9.807 m/s^2$ at my location. But is this value uniform in the entire earth? For example in the inner core or outer core. What is the acceleration in the center ...
3
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2answers
94 views
Relativistic space rocks. Are they possible?
I was thinking that the Universe is full of extreme events. Colliding galaxies, exploding stars, colliding planets (like in one of models of our Moon formation), colliding black holes...
Can it be ...
35
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12answers
12k views
If gravity disappeared, would Newton's third law make everything that was pressed to the ground by gravity get pushed upwards? [closed]
If gravity disappeared, would Newton's third law make everything that was pressed to the ground by gravity get pushed upwards?
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3answers
166 views
Why is Mars so cold when it has so much atmospheric $CO_2$?
Mars has 1/10 of Earth's atmosphere but that atmosphere is 95% CO2. Why is Mars so cold when it has so much atmospheric CO2?
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1answer
27 views
Gravitational/electromagnetic effect of planets on solar activity?
Does the gravitational and/or electromagnetic influence of planets have any effect or correspondence to solar activities (e.g. solar flares/CMEs) - and if so, does the planetary position (where they ...
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1answer
26 views
What's the difference between a convection and a polarization electric field?
In the ionosphere and magnetosphere communities, studies frequently refer to the "convection electric field" and the "polarization electric field". What is the relationship between them, and what are ...
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1answer
28 views
Can a planet have multiple significant sized moons?
The Earth has one moon at about 1/80 of Earth's mass. Is it possible to have two moons large enough each to subtend a >30 minute disk as viewed from the surface?
I have tried with various ...
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0answers
44 views
How fast would the Earth have to spin to lose the atmosphere?
I have read these questions:
How fast would the Earth need to spin for us to feel weightless?
Why can't we feel the Earth (or being in any non-inertial frame) rotating?
And it made me curious....
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2answers
89 views
How do astronomers explain trajectories of planets?
I'm wondering how astronomers can explain the trajectories of planets because:
planets spin, so have angular kinetic energy. Thanks to the mass-energy relationship this means space-time curvature.
...
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1answer
40 views
The Earth's Equatorial Bulge [duplicate]
It is stated that the Earth is a 'squashed sphere' due to the very slight bulge at the equator. (Thought in reality it's such a small difference, it's essentially spherical)
Typical values:
...
0
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2answers
131 views
Does the Earth emit heat?
I'm reading my first book on physics "Seven brief lessons on physics" by Carlo Rovelli, and in his chapter on "Probability, time and heat of black holes", he mentions that Stephen Hawking showed that ...
2
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3answers
149 views
Why should asteroid coming towards a star deflect away from star if gravity is an attractive force?
I was finding the closest approach of an asteroid (whose energy is sufficient to exit the gravitational field of the star )so that it can escape the gravitational field of the planet .The asteroid ...
9
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1answer
360 views
How would the rotational and orbital mechanics differ on a torus-shaped planet as compared to a spherical planet?
I am making the attempt to develop some computational models of Star systems and I was wondering how the a torus shaped planet would compare to a traditional spherical planet in the context of ...
1
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1answer
80 views
Is there any moon without its planet?
Is there any planet without its star?
Is there any moon or any planet wandering in outer space without a definite orbit?
(The name moon or planet used here serves only for size and spherical shape ...
1
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1answer
98 views
Could there be a minimum black hole within each moon, every planet, every star?
It's the spherical aspect of these celestials bodies that makes me think about this.
Could planet Earth have started itself with a tiny black hole?
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2answers
130 views
Why do all the planets and stars in our solar system have such similar average densities?
This table lists the average density of all the planets in our solar system. We could also consider the Sun (average density 1.41 g/cm³) and Pluto (average density 1.88 g/cm³). The densest body (Earth)...
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3answers
45 views
Planetary Gravitational Pull
I have read that Jupiter and Saturn apparently have no surface. I have a hard time believing that a ball of gas can have such a strong gravitational pull without any kind of a solid surface. Can ...
