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

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2
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1answer
82 views

Will the Earth's rotation someday be synchronized with its revolution around the Sun?

When will the earth act like the moon with regard to one side of the moon always facing the earth. Will the earth one day get locked in a rotational orbit that has one side of the planet facing the ...
1
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1answer
195 views

How to calculate escape velocity and orbital velocity for a cubular planet?

Given a planet that is a cube, how would one calculate the escape velocity and the orbital velocity? For a circular planet with an even distribution of mass (aka center of mass=center of volume) the ...
0
votes
1answer
150 views

What is the potential and kinetic energy of the international space station?

I know it's possible to calculate, but what formulas would I use to be as accurate as possible? I'd like to see how it works for something big and high like that.
1
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1answer
93 views

What is the outward force on the Moon that makes it go in orbit rather that falling straight to the Earth? [duplicate]

So, we know that the gravity is responsible for pulling the Moon towards the Earth. But because it moves in an orbit, it makes me think that there must be a force that is causing the moon to travel in ...
0
votes
1answer
159 views

Why are galaxies flat since it's an unstable configuration in 3d? [duplicate]

I'll probably have to delete this question because someone's already asked it, but what accounts for the stable 2-d structure of spiral galaxies in three dimensional space (assuming random starting ...
1
vote
1answer
248 views

Determining eccentricity of satellite orbit from velocity vectors and altitude

Let's say there's a satellite orbiting earth. At some random point in its orbit, it is observed with a tangential velocity, a radial velocity and some altitude. Given only this information (along ...
0
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0answers
42 views

How far inside a white dwarf Roche limit does the Earth have to be to start losing large chunks of rocks?

I have calculated that for a one solar mass white dwarf orbited by the Earth, the Roche limit is about 600,000 kilometers. I understand that any loose mass on the surface of the Earth would start ...
2
votes
2answers
2k views

What is the relation between orbital velocity and escape velocity in strongly relativistic situations?

For practical purposes, I'm considering a non-rotating black hole or neutron star, because I find Kerr black holes a little confusing. The ratio between orbital velocity and escape velocity in ...
0
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0answers
18 views

Find the velocities at the ends of a focal chord [closed]

Find the two velocity values occur at the two ends of a focal chord in case of a parabolic orbit.
2
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0answers
80 views

Shape of particle's motion [closed]

Let's a particle is moving in a orbit with force field $\vec{F}(r)= -kr^2\hat{r}$ Is there any way to tell that what would be the shape of the path of the orbital motion? Circular? Parabolic? ...
0
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1answer
42 views

General relativity and precession of orbits

The precession of the orbit of a planet can partially be explained when taking into account the impact of the other planets. Also general relativity is needed to describe this precession exactly. The ...
0
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2answers
89 views

Compass aboard the International Space Station

If an astronaut brought a compass aboard the ISS and watched it for the duration of an orbit, what would it do?
2
votes
2answers
101 views

Does The Earth appear to orbit the ISS from its point of view?

Does the International Space Station orbit the Earth with one side constantly facing the Earth? Or does it look more like the Earth is orbiting the ISS from its perspective?
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3answers
4k views

Why do we launch rockets during the day?

The clips that I have seen of rockets launching all seem to be carried out during daytime. However, we learnt at school that rockets are fired closer to the equator and towards the east to take ...
6
votes
1answer
225 views

Why doesn't space junk form a ring around Earth?

If ice and rock form rings around a planet like Saturn, why don't rings form around Earth from all of the broken satellites and other material around Earth, or will they eventually? I would expect at ...
3
votes
1answer
91 views

Pushing an object in orbit outwards

I wonder what would happen if an object in orbit were to be pushed outwards. I can imagine 2 outcomes: either it would keep spinning outwards away from whatever it is orbiting at a finite speed ...
1
vote
2answers
87 views

Why do so many galaxies in clusters have a near zero velocity?

I'm looking at a velocity chart of the Coma Cluster: And the question occurred to me: why are there so many galaxies that have a zero velocity (relative to the core of the Coma Cluster which is ...
0
votes
1answer
72 views

Clarification of the physics involved of an orbiting body in a circular orbit

I am writing a physics simulation program to simulate a body orbiting a planet but I am a little confused about the physics involved and would like some clarification. To simulate gravity I am using ...
0
votes
3answers
152 views

Can an atoms energy levels be changed by changing the de Broglie wavelength of electrons?

So an electron can only orbit a nucleus where its wavelength makes a standing wave, leading to discrete energy levels in atoms. But the de Broglie wavelength of an electron = h/mv. So the wavelength ...
0
votes
1answer
338 views

Is it possible to determine the velocity of electron in its orbit? [closed]

I read here that the orbital speed of an electron around a proton can be calculated as: $$\frac{m_ev^2}{r} = F_G+F_E$$ where $F_E$ is the proton-electron electromagnetic force, $F_G$ is the proton-...
1
vote
1answer
77 views

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?
16
votes
2answers
391 views

Was Leverrier-Adams prediction of Neptune a lucky coincidence?

According to historians both Adams and Leverrier used Bode's law to guess the distance to Neptune, which led to a vast overestimation of its orbital period (Adams - 227 years, Le Verrier - 218 years, ...
0
votes
1answer
40 views

Does the mass change for a body with eccentric orbit?

I am a student with a programming and electronics background attempting to recap on orbital mechanics. I would appreciate anyone with a physics specialisation helping me understand where my ignorance ...
1
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5answers
5k views

Difference between circular motion and rotational motion

Are rotational motion and circular motion different or the same? If different then when can we say that a body is in circular motion, and when it's in rotational motion? I find several answers where ...
1
vote
0answers
26 views

Eccentricity of planetary orbits: What information is contained?

I'm having a little trouble understanding what makes a planetary orbit explicitly elliptical. Is it simply that the initial velocity was different from the circular orbit case for a given starting ...
0
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0answers
42 views

Can a roller coaster accelerate solely due to its weight on the top of a vertical loop?

If it were a string connected to an spinning object, I would have a second thought, because for string there doesn't exist any normal force. But for roller coaster placed on a rail, the rail acts as ...
4
votes
1answer
136 views

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 ...
1
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2answers
74 views

Guidelines for $n$-body problem inital conditions

I'm trying to solve a 5-body problem (for the sake of the argument it can be any given $n$) numerically, yet every initial condition I choose seems to eventually drive the bodies apart to infinity or ...
0
votes
1answer
72 views

Rocket thrust over time [closed]

I have calculated the thrust of a rocket, and it's burn time for an orbital manoeuvre. I need to know how much force is applied on the rocket every half-second. How would I go about doing this? ...
0
votes
1answer
593 views

Orbital Velocity and Tangential Velocity

The tangential velocity of an object is directly proportional to the radius of the circular motion. How come orbital velocity is inversely proportional to the radius?
1
vote
1answer
84 views

Which ellipse does the Earth's semi-major axis refer to?

In Wikipedia the semimajor axis of the earth is reported to nine digits of accuracy (nearest kilometer), and the eccentricity to eight. But to which ellipse exactly does that apply? Sun-at-the-focus? ...
1
vote
1answer
360 views

Why doesn't the moon crash into the Earth?

I was searching about 'why do not moon crash to earth due to its gravity?'Then by reading physics stake exchange existing questions I came to know that its the sideways motion of the moon that keeps ...
0
votes
1answer
34 views

Advent of our solar system

When the solar system was born why did Sun not consume all the planets by its immense gravity, as the planets were all gases, so it would have been very easy?
1
vote
1answer
99 views

Acceleration orthogonal to movement direction

I've been told that acceleration orthogonal to an objects movement direction doesn't require energy. Thus when a satellite goes around the earth, the change in direction caused by gravity doesn't use ...
2
votes
3answers
364 views

Solving the two body problem numerically

I'm trying to solve the two body problem numerically, setting up $G$, $m1$ and $m2$ to be equal to 1. then I located each mass on positions -5 and 5 respectively along the $x$ axis and gave them both ...
2
votes
2answers
295 views

Planetary alignment of the gas giants?

There is this nice and new applet of the orbits of the planets around the sun: Solar System Orrery You can click and drag any planet and watch their relative orbits evolve in time. I was curious ...
-2
votes
3answers
334 views

Infinite acceleration

Let's say we have two planets at a stand still within reasonable distance of each other. They will accelerate towards each other and subsequently collide. If instead we give them a sufficient (but ...
1
vote
2answers
45 views

How can contact binaries persist?

This answer discusses contact binaries, which I did not even know existed. I can understand how they could exist for a short time (maybe) as gravitational waves carry off energy that causes the stars' ...
2
votes
1answer
51 views

What kind of orbit would be needed to map the surface of a nonrotating planet?

I am not a mathematician and it may even take me weeks to understand the math involved but I have an odd question on orbital mechanics that I hope will be worth the experts' time. I am a hobbyist ...
1
vote
2answers
154 views

How long will it take before the orbit of the earth is 365 days exactly?

I understand that the number of days per year has changed throughout the history of the Earth. Apparently there were once over 400 days per trip around the sun. How long will it take approximately ...
0
votes
0answers
45 views

Calculating initial velocity to achieve orbital motion using verlet integration

I'm attempting to build a simple computer programme which models bodies orbiting other bodies. I've implemented a Verlet integrator (https://en.wikipedia.org/wiki/Verlet_integration) and I can ...
8
votes
2answers
2k views

Why we don't see time dilation in stars orbiting black hole?

We have images of stars orbiting black holes or black holes destroying near stars, but why do we see the stars moving normally? I mean, if time dilation does exist, shouldn't we see that stars slow ...
3
votes
1answer
74 views

Can stable non-circular orbits exist in 2 or 3 dimensional hyperbolic space

I know that stable non-circular orbits in euclidean space exist only in 3 spatial dimensions but what about if the spatial dimensions are hyperbolic instead? Are there any stable non-circular orbits ...
3
votes
1answer
274 views

How does the Pluto-Charon orbital 'dance' affect Pluto's elliptical orbit around the Sun?

Like many Scientists (and people in general), I have been watching the New Horizons mission results with great interest. One aspect in particular caught my attention - the Pluto-Charon orbital 'dance'...
0
votes
2answers
40 views

Earth “satellite” breadcrumb: Have we ever placed an object orbiting our Sun and the Sun only?

Have we ever placed an object orbiting our Sun and the Sun only? like a breadcrumb of our orbit... I was reading about VLA for satellites and wouldn't this breadcrumb be a viable solution to create a ...
0
votes
1answer
38 views

What velocity do I need to get the moons orbit perfectly aligned with the earths center [closed]

I have a simulation for universal gravity with two objects. How can I calculate the velocity or instantaneous force I would need to apply to object 2 (the moon) to get it to orbit so that the origin ...
0
votes
0answers
217 views

Central Force Scattering in Goldstein

On page 108 in Goldstein 3rd edition in the paragraph after equation (3.94) he says that $\psi$` can be obtained from the orbit equation (3.36) using the limits as $r_0=\infty$ $r=r_m$ which the ...
0
votes
1answer
110 views

How do spacecraft gain kinetic energy by passing near planets? [duplicate]

When a a spacecraft like Voyager travels close to Jupiter, it somehow gains kinetic energy. I'm not sure how this energy isn't simply lost again as it moves away from Jupiter. I'm also hoping this ...
2
votes
3answers
202 views

General Relativity 2-Body Closed Form

Is there a closed form solution in general relativity to the 2-body orbit problem?
5
votes
4answers
259 views

Calculating how fast a mass needs to travel in order to launch itself from a hill

Today I was driving on a hill side and on the opposite lane this very careless gentleman was traveling at a very high speed on a large truck that I surely thought his truck would of lifted off the ...