# Tagged Questions

The path a body takes while moving through space under the influence of the gravitational forces of other bodies

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### How would I find the velocity of an object after it doesn't fully enter the gravitational pull of a planet and is kind sling shot out of its gravity?

Obviously that question doesn't have a lot of jargon having to do with math and physics. I am not a physicist, I'm not a mathematician, I'm trying to make a game and simulate some physics found in ...
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### Is it possible for a particle to orbit a singularity inside the event horizon [duplicate]

Event horizon just means a distance from singularity, where there is no "going-away" from the black hole. But is it possible, that there are particles with enough momentum to actually orbit the ...
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### Tidal heating of body

I am trying to make a plausible, though not necessarily accurate model of tidal heating of a body moving close by a gravitational attractor, not necessarily in orbit and not considering the spin of ...
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### Experiment proving that the Earth is rotating around the Sun [duplicate]

Is there any simple experiment done on Earth proving that the Earth is rotating around the Sun? Something in the same spirit of what Foucault did proving that the Earth is rotating around itself. P.S....
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### Simulation of relativistic probe passing through an external solar system

I recently read about the Breakthrough Initiative to launch "StarShot", a nano-probe that is designed to travel to Alpha Centauri at $0.2c$. One of the challenges to be solved involves the precise ...
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### Which force transfers angular momentum in tidal locking?

The moon is in tidal lock with the earth, but a long time ago it was not. As the moon became tidally locked with the earth, its angular momentum changed and the delta went into it's orbit and possibly ...
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### Relationship Gravitational Potential and the Tangential Velocity of a Satellite

So gravitational potential is given by $V(r)={\frac{GM}{r}}$ and the tangential velocity of a satellite is the square root of $V$, i.e. $\sqrt V$. So how do these two relate, if at all?
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### Derivation of Bohr model equations (1) in his original paper

My question is rather straightforward. In his original paper ("On the Constitution of Atoms and Molecules") Bohr provides equations (1) for the frequency and major axis orbit: \begin{align} \omega &...
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### Finding mass with an estimated gravitational force

As asteroids orbit the sun, they experience gravitational force exerted on them by the sun, and they in turn exert a very minute force back on the sun. Because of their small size, asteroids don't tug ...
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### Vector interpretation of Kepler's 2nd law ( r X a = 0 )

I just read the vector interpretation of Kepler's second law and the conclusion put me in a confusion. The interpretation concludes by demonstrating that r X a = 0, where boldfaced r and a are ...
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### Why are objects (such as planets) in motion and not static? [duplicate]

I am just curious, why are all the planets, rocks etc in motion? Would they fall into objects with larger gravity if they were not in motion? What is stopping the earth from falling into the sun or ...
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### How can a Satellite's position/orbit be calculated using only range measurements from ground stations?

This task is often done in a process known as Satellite Laser Ranging (SLR). SLR stations (of known coordinates) track satellites, recording range measurements to the satellite at known times. I would ...
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### Orbital period and velocity around a Kerr black hole relative to fixed stars

I've been trying to make progress on some of the smaller pieces of this question about the environment around a Kerr black hole. In order to calculate the effects of special relativistic Doppler shift ...
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### Mathematically calculate if a Planet is in Retrograde

How do you mathematically calculate if a Planet is in Retrograde when you are given both the Earth and the Planet Keplerian Elements value and rate? Keplerian Elements are: a - Semi-Major Axis; e - ...
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### Why can't we detect the Earth's orbital motion when looking at the sky and stars?

After I read that speed of earth orbit around the sun is 30 km/s, I looked at sky and I didn't notice any change when compared to the start location. 30 km/s can be converted to (30 * 60 ) km/minute =...
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### How to calculate the mass of the orbiting body given only its orbital information

A question asks the following: Using Newton’s Law of Gravity, show that the mass of a planet can be written: $$M = \frac{4\pi^2a^3}{ GP^3}$$ where $a$ is the semi-major axis and $P$ is the orbital ...
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### In what direction should you throw a 1Kg uniform sphere in order to put it into lower earth orbit? [closed]

If you are standing on earth's surface, in what direction (and at what speed) should you throw a 1Kg uniform sphere of radius 0.1 meters in order to put it into lower earth orbit? Assume that there ...
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### Why is the matter orbiting a black hole in the shape of a disk? [duplicate]

More generally, if a blackhole is a singularity...a point in space...why is matter only circling in a flat disk-like region. It would seem to me matter would circle it in a sphere surrounding the ...
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### Tension of a string rotating a ball in a circular motion?

A ball of mass 5kg is attached to a string of length 120 cm and rotating vertically at a speed of 10 cm/s. what is the tension of the string when the ball is farthest to the right from the center? ...
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### Can a tidally locked planet have a horizontal rotational axis?

Is it hypothetically possible for a planet to be both tidally locked, and still have a rotation "horizontally"? Where the substellar point would in effect be like the point of a top, spinning and yet ...
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### Kepler Orbits: Equal areas in equal times [closed]

I've written some python code to simulate a Kepler orbit. Every 50 time-steps I draw a radial vector from the centre of the sun to the centre of the earth, as shown below. However, my ...
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### Where is the space elevator falling? And the cable holding it?

I guess the concept of a space elevator is pretty well known. The idea, first published by Konstantin Tsiolkovsky in 1895, and popularized (among others) by Arthur C. Clarke in The Fountains of ...
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### Does orbital motion cause rotation?

Assume the moon was flying freely in space, and not rotating at all. If if then happened to pass earth at just the right distance and velocity to fall into orbit, would its absolute rotation be ...