Questions tagged [orbital-motion]
The path a body takes while moving through space under the influence of the gravitational forces of other bodies
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Can perfectly stable orbits exist in GR?
Defining "stable orbit" between two bodies as one where, in the absence of other bodies or non-gravitational forces, the distance stays between some value pair $r_{min}>0$ and $r_{max}$. ...
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How accurate does the ISS's velocity and altitude need to be to maintain orbit?
We know the the ISS is not drifting weightless in space, but rather is constantly falling as it circles the Earth. To do this it must be at a specific altitude and moving with a specific velocity. ...
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What would happen to the moon's orbit if we reduce (instantaneously) its mass? [closed]
In my opinion the moon's orbit shouldn't change, because an orbiting body is a free falling object and the trajectory of a free falling object is not affected by its mass (because the inertial mass ...
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Doubt on conservation of angular momentum for Kepler's laws
Just before proving Kepler's laws, my Professor claimed that if $\vec{F}$ is a central force with center $O$ and it is the only force acting on a point $P$, then the trajectory of $P$ is a curve plane....
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Has our knowledge of astrophysics and gravity reached the point where we can accurately calculate Lagrange points?
is it possible for us today given the knowledge we possess of gravity and our success with inserting satellites in to steady/ geosynchronous orbit and any knowledge we have on the relative size (and ...
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Why does a moon's orbit get more circular with time?
I understand that there is a transfer of energy between a moon and a planet depending on whether the moon is orbiting faster or slower than the spin rate of the planet. This would obviously change the ...
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Are we certain of the mass we calculate for supermassive black holes?
If astronomers have concluded that the rotation speed of objects held firmly within a galaxy but far from a galactic center is too great to be explained by the visible matter of the galaxy alone, what ...
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Trajectories of projectile based on different speeds of projection [duplicate]
So my teacher was teaching gravitation and an interesting fact that he mentioned was the trajectory of a projectile projected from Earth at a speed equal to escape velocity, is parabolic.
Also, he ...
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Would the Moon move away if the Earth were frozen with no liquid tide?
The moon is moving further from the Earth. To the extent that after 600 million years we will no longer enjoy full solar eclipses as it will be too far away to completely block the sun.
The reason the ...
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Pseudo Orbital motion only due to Coriolis force
Planet, say of mass M and radius R is rotating with some angular velocity ω and a object of mass m (initially on the surface and rotating with the planet) was launched with velocity v vertically ...
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Better equations for modeling and simulating a halo orbit?
I'm trying to model a halo orbit at low altitude (10m from surface). The satellite is using propulsion to trace the circular halo path. It looks like this "from the top" (the blue ball is ...
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Restricted 3-body: one large mass and two smaller ones
A restricted 3-body problem is usually understood as two large bodies and one much smaller one that doesn't affect the motion of the other two.
I am curious about a 3-body problem with one large body, ...
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What changes the velocity perpendicular to radius in an elliptical orbit?
I'm working currently on a problem that asks to justify that angular momentum and kinetic energy conserves for a planet in an elliptical orbit. Although I've been taught that angular momentum should ...
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Find eccentricity of orbit given the velocity and the semi-major axis
Is it possible to calculate eccentricity of orbit knowing only the semi-major axis and the velocity of both celestial bodies? If not, what other additional information is required.
Does the fact that ...
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The magnetic force between the earth and the sun
There is a magnetic field around the earth and a stronger one around the sun. I guess there should be a magnetic force between the sun and earth. Now, shouldn't we take the magnetic force into account ...
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Gravitational attraction between two bodies
While the gravitational force between two bodies is directly proportional to their masses, and inversely proportional to the distance between them is understandable / seems logical, how did Newton ...
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Questions about speed of gravity [duplicate]
If gravity "travels" at $c$, and the sun is travelling "forward", does it mean the planets are actually orbiting various points "behind" the center of the sun? Does it ...
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When are two object guaranteed to keep getting further and further away?
In a two-body problem, it is known (if I understand correctly) that if the specific orbital energy of the system is $\varepsilon \geq0$, then the objects must eventually escape each other. My question ...
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Deflecting a lunar mass with consecutive nuclear explosions [closed]
I'm looking for help in determining the amount of deflection an object with a mass of roughly $7\times10^{22} \,\text{kg}$ (a lunar mass) needs from colliding with a planet. Let's stipulate that the ...
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Would an Hypothetical Ringworld Positioned Inside the Moon's Orbit Around Earth, gravitationally affect Earth?
If a ringworld were to encircle Earth within the orbit of the Moon, would it induce any gravitational alterations on Earth?
I grasp that inside a circular structure, there might not emerge a ...
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Which of Kepler's laws would remain true if the force of gravity were proportional to the product of squares of each masses?
I was asked this question recently on which of the Kepler's Three law would remain if we changed the force of gravitation to be proportional to the product of squares of each masses instead of just ...
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Initial positions and velocities for the three-body problem
I have made a simulation of the three-body problem, it follows the euler's method of solving differential equations. I have tried some initial positions and velocities of the bodies and have observed ...
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Despite tides the Moon, as far as I know, doesn't slow down. Where does the energy come from? [duplicate]
Hy, I don't have anything to do with physics, so please forgive me if I explain my question in a weird way ;)
As the Moon rotates around the earth it is creating tides and waves on the earth. IE it's ...
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Speed of satellite in elliptical orbit [closed]
A satellite $S$ orbits a planet of mass $M$ in an elliptical orbit. At perihelion, $S$ has a tangential velocity of $v_1$ and is distance $r_1$ from the planet. At aphelion, $S$ has a velocity of $v_2$...
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With what vel. would you have to launch an object vertically up from the earth's surface for it to land back again at it's initial launching point?
[Can skip reading this part] First of all, Newtonian gravity shall be considered whilst trying to solve this question. It's been on my mind for a long, long time and has been bothering me since. I ...
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How do two things attracted to each other move in mechanics?
Okay very simply:
If you have two objects in 1D and they're both attracted to each other by some force (say there's a spring pulling them both towards each other, or Coulomb's Law or something)...
How ...
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Setting $u$ = escape velocity when calculating the maximum height of a thrown object
So, if I throw an object at some velocity $v$ at an angle θ, the maximum height reached by the object is $\frac{v^2\sin^2{\theta}}{2g}$ but, I know this isnt true. clearly in a weird way, the height ...
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Constant speed (at terminal velocity) and zero $g$
I have read the question What would a person experience in a free-falling elevator in a shaft long enough to reach terminal velocity? here and the answer was that you feel exactly the same if the ...
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Space-for-time Derivative Substitution in Solving for Elliptical Orbit
I am currently working on a simulation of the Newton's Cannonball thought experiment, in which a stone is launched horizontally from atop a tall mountain at a high speed (in the absence of air) and ...
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Elevation angle of LEO satellite as a function of time
Let a point on Earth be denoted with (lon,lat,altitude).
Let a LEO satellite be defined by its altitude and inclination.
I would like to compute the angular speed and elevation as a function of time.
...
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Orbit description in Schwarzschild metric
Suppose to have a restricted 2-body system (BH + star with $M_{BH}\gg M_{\mathrm{star}}$) and you want to describe the orbit of the star relative to the BH, i.e. in the Schwarzschild metric.
Usually, ...
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How to relate a gravitational plane wave to the GW from a binary system?
I have two different forms of gravitational waves that I am trying to reconcile.
A monochromatic GW with angular frequency $\Omega$ propagating in the $\textbf{n}$-direction can be expressed as
$$ ...
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How to find the length of a travel between planets using the Hohmann Transfer?
I am trying to figure out how long it would take to get from one planet to another. This is for a worldbuilding project of mine. I would put my question on the Worldbuilding Stack Exchange but I ...
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Average Speed in one half of an elliptical orbit
I was wondering whether the average speed along one half of an elliptical orbit (say in a star planet system) had a closed form exact solution using Kepler's laws.
My approach was using the ...
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When is an object no longer considered orbiting a celestial body during its descent?
During the Apollo mission, once the LM began its descent to the surface of the moon, was it still in orbit about the moon?
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Where can I find spectra data and light curves of a stereoscopic binary star system?
I am trying to find a suitable source of spectra data and/or a light curve of a binary star (no exact star in particular), with which I would use to find velocity and period, and then find masses etc.....
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Speed at which the Moon moves past a point on Earth's surface?
I'm trying to calculate how fast a point on the surface of the Moon is moving past a point on the surface of the Earth (I assume a point on the equator of each for simplicity).
I know the Earth is ...
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What is the locus of the velocity vectors of a spaceship moving in some distance from a black hole?
Someone with a background in mathematics and limited knowledge of physics asks the following question:
Starting from rest, a spaceship is momentarily pushed with a specific amount of kinetic energy in ...
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Impact Parameter as function of orbital parameters
In the case of a binary system (pulsar+companion), the impact parameter $\textbf{b}$ is the projection of the binary separation $\textbf{r}$ on the sky plane:
\begin{equation}\tag{1}
\textbf{b} = \...
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Kepler orbit from mass, period, and eccentricity [closed]
I want to calculate the Keplerian orbital elements in the central force case.
Given the mass M of the "sun" in kg, the eccentricity $e$ of the orbit, and the period $T$ in seconds, I believe ...
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Applying 1 gram-force for 1000 seconds to 1kg mass
I am looking into ion thrusters and the small amount of propulsion they provide.
I am really new to this, so I want to understand. If we have mass of 1 kg in space and we are able to apply to it a 1 ...
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Approximation of Nearly Circular Orbit by a Precessing Ellipse
I am self-studying the 3rd edition of Goldstein's Classical Mechanics and have hit a roadblock when working a problem (Chapter 3, Problem 20). The problem asks us to consider a planet of mass $m$ ...
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Orbiting body around a star
Let us assume there's a body with mass $m$ and velocity $v$, at a distance $r$ from another body of mass $M$. The velocity vector is perpendicular to the radial vector. With these values, how do we ...
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What is the name of this pendulum? [closed]
What is the name of a pendulum with two parallel string hung vertical to a rod, and giving the rod an initial force would make it swing left and right, doing simple harmonic motion?
What is the ...
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Parabolic(?) projectile orbits as an approximation to elliptical orbits given a rotating Earth
Why is projectile motion a parabola given that the Earth rotates and a parabola is an approximation to an orbit.
My current thought is that projectiles don't travel in a parabola because if the Earth ...
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Two bodies orbiting around barycenter
There are two bodies with masses $m_1$ and $m_2$ orbiting around barycenter. Distances to both bodies from barycenter are $r_1$ and $r_2$ . First body has known velocity $v_1$ as on the picture :
My ...
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General formula for the frequency
The orbital period of a satellite is the time it takes to complete an entire orbit around the celestial body around which it orbits. I know that the orbital period using the following formula:
$$T = \...
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How close does a dwarf star have to be to remove the corona from its neighbour in an elliptic binary system?
It is possible for a larger (wider, but less massive) star to mutually orbit a heavy dwarf companion star in a binary system. If the dwarf star gets close enough it can attract the corona of the ...
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How does moving the pericenter affect the apocenter?
A perfectly circular orbit of a constant height (distance from the center of mass of the orbited planet) around a perfectly spherical planet with smooth surface and no gravitational anomalies will ...
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Finding the Cartesian position of the lunar ascending node
What I'm trying to derive
The Cartesian position of the lunar ascending node relative to the true equator and equinox of date reference frame. My issue is I'm getting a bit tripped up with reference ...
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