All Questions
Tagged with stability celestial-mechanics
37 questions
10
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How "large" is a Lagrange point?
When placing an object at a L-point, the natural assumption, as with all things gravity, is that you needn't place it in an exact spot to achieve a stable configuration. How much room do you have to ...
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15
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2
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Regularization: What is so special about the Coulomb/Newtonian and harmonic potential?
I wanted to know if the procedure for regularization of the Coulomb potential outlined in Celletti (2003): Basics of regularization theory could be generalized to arbitrary polynomial potentials. So ...
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What is the difference between Saddle points and Lagrangian points between Earth and the Sun?
I am studying MOND bubble effects in the Solar System (Paper). In "mond habitats.." (last reference) first page, the author says MOND bubbles reside on the saddle points but I fail to understand the ...
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Is there a rigorous proof regarding the non-linear stability of the $L_4$ and $L_5$ Lagrange points?
I have found that many proofs regarding the stability of the $L_4$ and $L_5$ Lagrange points are based on linear approximations of the equations of motion near these points. However, from a dynamical ...
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3
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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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9
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Why are $L_4$ and $L_5$ lagrangian points stable?
This diagram from wikipedia shows the gravitational potential energy of the sun-earth two body system, and demonstrates clearly the semi-stability of the $L_1$, $L_2$, and $L_3$ lagrangian points. The ...
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Equation of Hill sphere when the mass ratio is not large
I know of the equation for determining the Hill sphere. Which is $a(1-e)(m/3M)^{1/3}$. However I noticed that during the derivation of this formula that the assumption that $m\ll M$ is used. But what ...
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2
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1
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Is a 3 body system with a permanent eclipse possible and stable?
Is it possible to have a star, planet and moon where the moon orbits the planet in the opposite direction with the same period of the planet orbiting the star? So that there would be a never-ending ...
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15
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Why is the orbital resonance of the Galilean moons stable?
It is well known that the orbits of Ganymede, Europa and Io are in a 4:2:1 resonance. Most online sources (including but not limited to Wikipedia) say that such an orbital resonance, along with the 3:...
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Can Binary Stars Escape Each Other?
updated 8/27/2020
While the recession of our Moon from the Earth may slow and even stop,
(see When will the Moon reach escape velocity?)
binary star systems will
(1) never stop experiencing mutual ...
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Is a satellite orbit around the Earth Lyapunov stable?
Presume there is a satellite orbiting the Earth in an orbit that follows a closed path around the planet (that is, escape orbits are not permitted here). As I understand it, there are two ...
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How wide is the $L_4$ and $L_5$ Moon-Earth Lagrangian point?
How far would an object need to be displaced from the $L_4$ and $L_5$ Lagrangian points so that it can escape returning to those points?
- 213k
1
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1
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Why can't we have trinary or multiple sytems, like binary systems?
We usually come across close binary systems in Astrophysics. Also, we can have hierarchical systems in which there is a close binary. The Alpha Centauri is an example of an hierarchical triple.
But ...
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0
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0
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5 Lagrangian points: why isn't there a line of stability between $L_1$ and $L_4$ and $L_1$ and $L_5$ respectively? [duplicate]
Given the 5 Lagrangian points of two large orbiting bodies:
(from wikipedia),
why isn't there a line of stability between L1 and L4 and L1 and L5 respectively (as depicted in red in the modified ...
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8
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4
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How is it possible for orbits to maintain stability?
According to $a = v^2/R$, the circular velocity and radial distance between two attracting objects (such as planets), must remain in perfect proportion in order for orbital motion to take place. How ...
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1
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2
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On Planets orbiting binary stars
Several years ago a discovery was made of planet orbiting a star of a binary system (two stars orbiting each other). Since binary star systems are plentiful in our galaxy, I presume we will be ...
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Why are so few inclined circumbinary planets known?
For a research project I'm studying the orbits of circumbinary planets, most of these planets orbits are coplanar. However I was wondering if orbits with a high inclination could be stable. I made a ...
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2
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2
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526
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Multiple star system, stable orbits?
Inspired by worldbuilding SE, I know that there are relatively stable star systems with two or three suns, but any more than that and they start to become very unstable (e.g. trapezium systems), but I'...
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Lagrange points and gravity
I have just found an article talking about the L1 to L5 equilibrium positions of gravitation around stars, planets, etc. As far as I could learn from this website and other research I have done the ...
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9
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1
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Orbit through L4 and L5
I was reading the Wikipedia article on Lagrangian points and doing the requisite wiki walk through the various quasi-satellites of Earth when a question occurred to me:
Could there be a stable or ...
- 213k
1
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1
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150
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How to understand $L_4$ and $L_5$ Lagrange points gravity balance? [duplicate]
It's relative easy to understand gravity balance of Lagrange points $L_1$, $L_2$ and $L_3$. But I am having a hard time to understand how a body would be "kind of" balanced out on Lagrange points $L_4$...
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22
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3
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Why is Larry Niven's Ringworld Unstable?
In his 1970 science fiction novel Ringworld, author Larry Niven describes the eponymous Ringworld, a gigantic structure shaped as a ring with a radius of around 1 AU, rotating around a star in the ...
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Can a satellite park between the Earth and Sun?
If you put a satellite at Geostat altitude travelling the wrong way, will it remain between the Earth and Sun?
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2
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Why are planets in unstable equilibrium in a stable orbit? [closed]
It is well known that a planet in stable orbit is in unstable equilibrium. If e.g. the moon was just a few m/s slower in velocity, or a few m closer to the earth than it is, the gravity would ...
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5
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3
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Is it possible to have stable orbits around Lagrange point $L_1$?
Is it possible to have stable orbits around Lagrange point $L_1$?
If yes, is there an upper limit to the mass of a body on such an orbit?
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6
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1
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Is the orbit of the planets around the Sun chaotic?
The orbit of the earth seems to be very predictable. But as it is a many-body problem having sun, earth, moon, jupiter and so on, is it really that stable or will it start making strange movements ...
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0
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Stability of solar system
As far as I understand, the stability of the Solar system means that planets do not collide and will not in near future. The only thing that is stated on Wikipedia is that scientists are concerned ...
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2
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0
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81
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Plausibility of a Dyson sphere [duplicate]
So Dyson spheres are generally considered implausible for two main reasons. One, it would an incredible amount (and type) of resources to build one. And two, a Dyson sphere would be unstable because ...
- 213k
4
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1
answer
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Moon's orbital plane inclination causes Moon to fall
I read somewhere that if Moon's orbital plane would be perpendicular to the Earth's orbital plane - Moon will fall on Earth within 4 years (given today's position)
Can this be shown analytically ...
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3
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3
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Could the Earth-Moon rotation period equal one Earth year?
I just stumbled on this rather confused QA. The point seems to be if the Earth-Moon rotation period was identical to the Earth-year, then ...
... all three would stay in a line at all times.
Could ...
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1
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1
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Can a natural satellite have a synchronous orbit?
I was thinking about space-elevators and large masses being put into geosynchronous orbit, when I considered the possibility of a natural satellite being in a synchronous orbit. I did a little digging ...
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1
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Can 4 collinear planets exist?
Imagine 4 planets, A has moon a and B has moon b. A and B are binary planets. Is it possible that a and b and A + B all have same the period, so that the 4 planets are collinear?
- 213k
0
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2
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687
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Why are L4 and L5 Lagrange points stable as points and not part of a circle? [duplicate]
I read this Phys.SE thread which is similar
Why are L4 and L5 lagrangian points stable?
but I did not want to necro that thread. It seems that most discussions of a three body problem are presented ...
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2
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Gravity effect on moving bodies
If we imagine two suns of equal mass, and a small object in their combined center of gravity, which is not moving, it will stay there forever.
If the object is displaced a little bit towards one of ...
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2
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1
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93
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Coexistence at Lagrange points
I was wondering how precise the location of an object in a Lagrange point needs to be to maintain stability, since it seems that several natural objects (asteroids) exists together in some of these ...
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1
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2
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810
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Mars and Jupiter colliding [duplicate]
I was going to post a comment on my own theory about Mars and Jupiter colliding, but I just read the rules and it breaks it...badly. I was looking for informal peer review.
So my question is, has ...
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3
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1
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Earth-Sun Lagrange points L4/L5 existence
Why do Lagrange points L4 and L5 exist at all?
Consider the mass of Jupiter equals 320 Earth masses, and distance from Lagrange point to Jupiter is about 4-6 A.U. We get that the gravity of Jupiter ...
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