Questions tagged [planets]

Celestial body that orbits following an elliptical path around a star or stellar remnant.

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What's the cause of this gap in this simulation of the Nice model?

A previous question brought me to this video (which has a spectacular change at about 0:34). It shows the orbits of Jupiter, Saturn, Uranus, Neptune, and what appear to be trans-Neptunian objects. ...
HDE 226868's user avatar
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How does Planet 9's perihelion and aphelion affect the Kuiper belt objects?

Assuming that the existence of Planet 9 is confirmed and it really exists, how does it affect the orbits of the Kuiper belt objects? My understanding is that the discovery came in part from the ...
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Protoplanetary disks, angular momentum and prograde orbits

Very similar question at Astronomy SE: https://astronomy.stackexchange.com/q/6183/4042 Given a typical protoplanetary disk made up of the usual planetary system stuff, dust and gas and whatnot, ...
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How did the radiative flux of each gas giant planet change with respect to time (since their formation)?

We know that each gas giant planet was warmest when it was young. This warmth came from internal heating from both radioactive decay and from gravitational potential energy. This warmth, in turn, ...
InquilineKea's user avatar
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Why is sunset in mars blue?

This is the Martian sunset, as captured by the Spirit rover of NASA. Notice the colors are inverted, i.e. the direct rays blue and diffused rays red, which is exactly the opposite of what you would ...
AlphaLife's user avatar
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3 votes
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Why do the planets tend to spin in the same direction as they orbit the center sun?

I mean, why do the spin angular momentum and the orbit angular momentum of a planet tend to have the same direction? As we all know, a planetesimal $m$ orbiting a sun with mass $M_{sun}$ at $r$ will ...
Harry's user avatar
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The causes of the nodal precession of a satellite in Earth orbit?

All artificial satellites in Earth orbit between the polar orbit and the equatorial orbit are subject to a nodal precession caused by the equatorial bulge of the Earth at the equator. How the ...
Sebastyen Laroche's user avatar
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Can we rule out life swimming in the oceans of Europa and Enceladus on the basis of a lack of available energy?

Jupiter's moon Europa and Saturn's moon Enceladus (and several other moons too) have large subsurface oceans of liquid water, an ingredient considered essential for life. These two moons occasionally ...
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Barycenter correction for inner planets in solar system?

I want to run simulations of the solar system, and I've read in some papers that to speed up the simulations it is useful to use the barycenter correction of the inner planets (from Mercury to Mars), ...
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How can a gas giant be said to have an atmosphere?

They are made of gas, right? So, there won't be a solid-gas or liquid-gas boundary that defines where the atmosphere starts. So, if there isn't a boundary, we can't define part of it to be an ...
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Most stable shape if Newtonian gravity was proportional to $r^\alpha$

Consider lots of mass in isolated 3D space, close to each other. Consider that only the gravitational force (Newtonian) exists. Also consider that there is no rotational motion. It is evident that a ...
whoisit's user avatar
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Are there any types of winds or waves that are produced just by Earth's rotation?

Are there any types of wind or waves caused/produced only and exclusively by Earth's rotation? Not influenced by Earth rotation, but produced solely by it? In the case of waves, are Rossby waves 1 and ...
vengaq's user avatar
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A simple proof that under Newtonian gravity rotating massive bodies are ellipsoids?

Here is my attempt at deriving the shape of an idealized rotating massive body under Newtonian gravity, assuming that the gravity force points towards the center of mass and shape of the body is ...
მამუკა ჯიბლაძე's user avatar
2 votes
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Inner and outer orbital limit of planets in single-star systems

I am trying to find a rough cut-off of the inner and outer orbits of native planets around a single star. I know about the Roche limit and Hill Sphere, but these are not the limits I am looking for. I ...
Selewirre's user avatar
2 votes
2 answers
211 views

Tidal forces between Moon and Earth

I started studying about gravitation recently and I came across the fact that when finding the gravitational force between the earth and some point mass in space, we can consider the mass of the earth ...
Megan mars's user avatar
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Theoretical lower limit to the density of a planet

If a celestial body is too dense, hydrogen fusion will ignite and it will become a star. As such, there is an upper limit on the density a planet can have. But is there a lower bound on the density ...
usernumber's user avatar
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Could a planet experiencing tidal locking have a habitable area?

I wonder if it would be possible that, on a planet that always shows the same face towards the sun, there is a habitable area for some life-form similar to that of the Earth. I guess, since one face ...
Quaerendo's user avatar
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Uranus: The Spin

In his prog. , on the outer planets, Brian Cox stated that Uranus spins on its side because it once endured an interplanetary collision. Such a cataclysm would normally be devastating for both ...
tony's user avatar
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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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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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Jupiter's formation

Two days ago i went to a mathematics conference where there was a paper presented on Jupiter's formation via disk-instability model. I know that there are two different theories for the formation ...
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What happens when a planet's core freezes?

We know the Earth's interior is differentially rotating -- the core is rotating much more quickly than the crust. This is possible because the outer core is liquid and is presumably low enough ...
Chris Dolan's user avatar
2 votes
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How strong can tidal forces get?

I am imagining a planet the size of Earth being in close proximity to something of high mass such as a gas giant or a star, but ultimately I'd be more interested in how to figure this out myself. So (...
Tim Seguine's user avatar
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Could there be a planet just as the Earth, but bigger?

Could there be a planet twice or thrice the size of Earth but while being the same? and by the same I mean, hosting the same life as Earth, having a day last 24 hours and a year 365 days. Basically, ...
IamVeryCuriousIndeed's user avatar
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247 views

Only gravitation and Newton's $2^{\mathrm{nd}}$ law needed to derive Kepler's laws?

It is known that Kepler's laws of planetary motion can be derived from Newton's laws of motion and his law of universal gravitation. However, are all of Newton's laws of motion necessary? According ...
Herng Yi's user avatar
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What speed should have an alone planet to have a habitable zone due to relic radiation?

What speed should have an alone planet to have a habitable zone due to relic radiation, without any star involvement? How much time the planet will be able to remain in the habitable zone before the ...
Anixx's user avatar
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Stable planetary rotation states

In reading an article about theories as to how the slow retrograde rotation of Venus may have come into being, the article Why Venus Spins the Wrong Way (Franzen, 2001) stated that it is bound to ...
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850 views

For two planets in a 2:1 mean motion resonance , where will their periastron and apastron points be?

I want to animate the changing orbits of planets when they enter a mean motion resonance. Using a 2:1 resonance, I want to show a low-mass inner planet and a low-mass outer planet being tugged by a ...
user27603's user avatar
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861 views

How do I find equations for the distance of the planets relative to one another?

I know I should be able to piece together some basic Newtonian equations for this, but I'm not sure where to start. I want to be able to choose one planet as the center and calculate its distance ...
youdonotexist's user avatar
2 votes
2 answers
182 views

How can you calculate the atmospheric layers on another planet?

I'm working on a program that procedurally generates planets, and I'd like to make a realistic atmosphere with realistic pressures at different altitudes. I know that for earth we have 7 layers to our ...
Mike's user avatar
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1 answer
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Earth surface acceleration and inertial geodesics

I hope this is an appropriate question for this forum. It is one I have struggled with for a while. I read that in GR gravity is not a force, and that the apparent force we feel and can measure (eg ...
Jeff Roberts's user avatar
1 vote
0 answers
23 views

What are the Equations for Climate modeling of alien planet?

I am studying complex dynamic system and I would like to analyze the climating formation of a possible alien planet considering climate as a complex system . For this I do not want to use a whole ...
1 vote
1 answer
69 views

Falling at the centre of the Earth

Let’s assume to drill a hole at Earth surface at the point P1. The hole passes throughout the centre of the Earth and finishes at the opposite side at the point P2. Let’s assume then that 1) Earth ...
gryphys's user avatar
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Does the Lagrange Point $L_3$ exist in practice in the multi-body solar system?

Lagrange Points ($L_1$ through $L_5$) in a restricted 3-body system are well documented. Traditionally body 1 (M1) is the central object with a mass much greater than the other two objects. M2 is ...
Carlos N's user avatar
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1 answer
67 views

How do we find the centripetal forces of 3 planets revolving around a point given that they have the same mass?

Let's say we have three planets revolving around a point. We know that the force of gravity acting on all of these planets can be taken from $g = G{m_1m_2 \over r^2}$. We can derive the velocity of ...
hmmhmm hmm hmm's user avatar
1 vote
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33 views

How would water pool on a disc-shaped planet of Earth mass?

All this flat-earthism stuff is best ignored (although that is sometimes difficult) but it did get me wondering about the physics behind the pooling of water on a disc-shaped planet. Not for the sake ...
Max Williams's user avatar
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1 vote
2 answers
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How are the locations of solar system planets expressed in their orbits?

and where can I find the data about the locations of the solar system planets during their entire year? I would like to find the data on the orbits of solar system plantes. Also I would like to know ...
Travis_Dudeson's user avatar
1 vote
0 answers
71 views

Find minimum radius of an asteroid before it becomes round using bulk modulus and hydrostatic equilibrium

How big must an asteroid be before gravity makes it round and hydrostatic equilibrium comes into the equation? Let's say that being a round planet requires a radius error of $\frac{\delta R}{R}$ that ...
alwaysq2000's user avatar
1 vote
2 answers
116 views

Is there a smooth transition from inverse quadratic gravity to linear gravity?

I can't remember exactly what it was, but I remember going through a problem in physics related to gravity on and inside a sphere, and found that inside, gravity acts linearly as a result of some ...
CheeseMongoose's user avatar
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0 answers
30 views

When do planets formed via core accretion in a proto-planetary disk stop gaining mass?

I was just trying to go over some of the contents in my exo planets course and wanted to know that if all the planets that form via core accretion continue to attract all the dust in a proto-planetary ...
Vishal Jain's user avatar
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1 vote
1 answer
51 views

Between Mercury and Venus, which planet produces a longer transit? Assuming both planets describe same path on the solar disk

Is it even possible to give a definite answer to this question? There are a lot of factors involved in this like Earth's position and motion relative to the planets and of course their own motion and ...
peakcipher's user avatar
1 vote
0 answers
19 views

How does the NASA InSight lander determine the depth of a Marsquake?

With only one lander with this type of equipment at one location, how can the InSight lander's investigators be so sure of the depth of the Marsquakes it detects?
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101 views

Does frame-dragging affect planets?

The question has come up many times as to why the planets in our solar system lie in essentially the same plane. The most common answer is that they started out that way due to the accretion disk ...
Oortcloud's user avatar
1 vote
0 answers
145 views

On a planet with winds faster than sound, what would it sound like?

I'm watching a Youtube video of the strangest planets and some of them have atmospheres/winds that constantly go at like 20x the speed of sound, ex: HD 189733-b .On earth, fast winds is actually ...
user6472523's user avatar
1 vote
0 answers
22 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 ...
matt_black's user avatar
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1 vote
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135 views

Gravity train and fastest path

As a fun exercise to kill some time, I have been thinking in the gravity train. For a point mass falling through a tunnel dug from pole to pole in an spherically symmetric planet of radius $R$, the ...
Alejandro Menaya's user avatar
1 vote
0 answers
48 views

Which planets would be visible from the Saturn system using the Naked Eye?

I was wondering which planets would be visible using the Naked Eye from Saturn? Would these planets always be visible or disappear as they got further from Saturn? Plus which planets wouldn't visible ...
Merlin Rowlands's user avatar
1 vote
1 answer
130 views

Why can't planets scoop up dark matter?

The density of dark matter is way too low to affect solar system dynamics a measurable amount, see this question. High-speed particles will zip right through the planet (see this question), but what ...
Kevin Kostlan's user avatar
1 vote
0 answers
188 views

How is the precession rate of planets calculated? For which planets do we know the precession rates?

From what I've read, precession rates of Earth, Mars and Moon are known. Why is that? And how is it calculated?
Sonakshi Arora's user avatar
1 vote
0 answers
86 views

How does the Greenhouse Effect of $CO_2$ modify the classical explanation for atmospheric lapse rate?

Classical physics theory relating to gravity and the properties of gases seems to dictate that the lapse rate of a planetary atmospheres is determined by just 2 factors. The equation being $-g/c$, ...
BetterBuildings's user avatar