Questions tagged [orbital-mechanics]

The application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft.

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How to derive Kepler's 1st Law?

I was going through the derivation of Kepler's 1st Law in the textbook "An Introduction to Modern Astrophysics" by Carroll and Ostlie. From there, I got stuck in a few places in their ...
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How small could an orbital system be in our solar system?

Answers to How does the Sun's gravity have so much force and pull on the solar system? How does it scale? Newton's law of gravity scales on orbits so that we can theorize very small orbits with very ...
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How does the Sun's gravity have so much force and pull on the solar system? How does it scale?

Watched this video: https://fb.watch/1U0vCFBr0L/ Ok, so the distances are huge. And the sizes are much different. But I wonder how then the sun keeps the planets etc. orbiting it. If we swap out all ...
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Throwing a baseball from orbit to the earth

I just read a thought piece about what a war in space may look like, and it changed my thoughts on what orbit actually is. From what I read about orbits, it sounds like going faster in the velocity ...
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what would the mass and density of Sirius A be if the mass of Sirius B is roughly the same as the Earth?

I am writing a blog post and while I am interested in astronomy I havent done any physics like this since high school. My question is: what would the mass and density of Sirius A be if the mass of ...
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If suddenly “knocked” or perturbed from its orbit, would gravity eventually return the Earth to its original orbit?

If suddenly "knocked" or perturbed from its orbit, would gravity eventually return the Earth to its original orbit? I am curious as to whether this is even possible. It seems to me that ...
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How does an object at L1 stay at L1?

I've recently been reading about the DSCOVR satellite, and I'm confused about it's orbit. According to NOAA A million miles away, DSCOVR orbits a unique location called Lagrange point 1, or L1. This ...
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Does the Honey moon have a precession problem?

In Steven Colbert's interview with Neil deGrasse Tyson after about 03:16 the following is explained: But wait, all the moons - all the full moons of the year have ...
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Will the United States Presidential Election (day asteroid) be back soon?

My google news feed is awash with mono-themed articles, including a near Earth asteroid that passed by around election day 2020 in the US. We can all hope that neither will lead to an extinction level ...
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What are “non-Keplerian” orbits? What are some familiar examples in our solar system, and can some still be closed?

This excellent answer to Forms of stellar orbits around the galactic center invokes the following concepts: non-Keplerian orbits closed orbits I have a fairly good idea what these mean and so might ...
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Help understanding why these two sub-Hill sphere moon stability limits are so different?

Comments under this answer to What orbital period would produce one New Moon (and one Full Moon) each year? What other effects would this produce? link to Stable satellites around extrasolar giant ...
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Why doesn't Earth's leading tidal bulge cause the Moon to start spinning in the opposite direction than its original spin?

Please refer to the image below: My question is, why doesn't Earth's leading tidal bulge (encircled in the green circle 1) pull on the moon's tidal bulge (encircled in green circle 2), leading to a ...
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Easy interactive visualization of orbital elements

To get a grip on orbital elements, I'd like to play with a ready interactive visualization like in Universe Sandbox. E.g. drag the inclination slider and see immediately what happens to the satellite ...
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Orbital Mechanics: where can I find initial conditions for orientations and angular rates of planets in our solar system?

I am looking to write the equations of motion (EOMs) for a 6DOF analysis of our solar system. I want to integrate the equations forward in time, and need a complete set of initial conditions to do so....
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How do different formulas for calculating the mean anomaly of an elliptic orbit correlate?

I need to calculate the mean anomaly of an elliptic orbit at a specific point in time. I found two different formulas for $M(t)$ and I'd like to know how they correlate and if they result in different ...
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Why doesn't sunrise shift as we revolve around the sun (ignoring seasonal variations - so at the equator) [duplicate]

If the Earth rotates at a constant speed why doesn't sunrise change as we orbit the Sun? For example if viewing the Earth's orbit from above at time N let's assume the Earth is at the 3 'o' clock ...
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Cannot identify mistake in calculating orbital eccentricity vector; magnitude equals one instead of zero (with python code)

I have a gravitational nbody simulation, for which I would like to determine various orbital parameters. For each body, I have 3-D vectors (x,y,z -space) for position, velocity, and acceleration. I am ...
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Small changes to Earth's orbit caused by a large impact on the Moon

Is there any scenario where a large impactor striking the far side of the Moon would perturb the Earth's orbit enough to reduce the distance from the Earth to the Sun and still remain within the ...
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Explanation of an imaginary transformation occurring in the determination of trigonometric series for the elliptical equation of the center

One of the oldest problems in astronomy, which dates back to to the time of Kepler, is the problem of development in infinite trigonometric series of the "equation of the center" - to ...
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How would a retrograde satellite experiencing tidal deceleration affect the rotation of the primary?

There are two common scenarios like this one, where an orbiting body orbits its primary slower than the primary rotates, resulting in the orbiting body moving away and the primary experiencing a ...
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Apparent Centering Problem When Using the Perifocal System to Draw Orbital Ellipses [closed]

I am attempting to render orbital ellipses in software. Given a set of orbital elements, I am using the Perifocal system to determine a set of points along the curve of the ellipse. I am using the ...
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Does gravitational radiation change the eccentricity of binary orbits?

Do the eccentricity of a binary orbit change with change in the semimajor axis due to loss of orbital angular momentum by gravitational radiation?
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What meteor shower has the radiant that appears furthest west after sunset, and why?

When it finally gets answered, answers to How to calculate the position of a meteor shower's radiant point based on its associated comet's orbit? will help us understand why the radiant points ...
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Would a satellite that has a retrograde orbit and a shorter orbtial period than its planet's rotational period be tidally accelerated or decelerated?

There are 4 configurations to consider. A satellite orbiting a planet that: Has a prograde orbit and larger orbital period than its planet's rotational period (example: The Moon) Has a prograde ...
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Speculative Question Concerning the Planet Theia [closed]

I am a writer and I'm building a paradigm wherein the planet Theia did not strike the Earth, but settled into a orbit around the sun a third of the distance between the Earth and Mars. I wanted to ask ...
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How to calculate the position of a meteor shower's radiant point based on its associated comet's orbit?

Below this answer to Why are Delta Aquariids “for the southern hemisphere” while the Perseids are “for the north”? I wrote the comment: +1 To make this complete, ...
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What effects does the motion of the Sun have on the perihelion precession of Mercury?

According to the wikipedia page, there are multiple effects contributing to the perihelion precession of Mercury. Of course, according to this link and this link we know that the Sun is itself ...
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Closest stable orbit about the sun of an asteroid?

What is the closest perihelion an asteroid in stable orbit could have? Is there a limit defined by orbital mechanics or could an object be in stable orbit, only too close that melting or sublimation ...
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Comet Neowise c2020 f3 will return in ~6800 years, how can we be sure Earth will be in the right place to see it then?

I have read in several places that the orbital period of comet Neowise c2020 F3 is about 6800 years. In several popular media sources it is said that we will be able to see the same comet after ~6800 ...
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Why Comet C/2020 F3 Neowise returns even it's orbit is near- parabolic?

I have read in Wikipedia about Comet C/2020 F3 Neowise that it's orbit is near-parabolic. But in another section, it says that it is a non-periodic comet whlith orbital period ranging from 4500 years ...
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Can the paper narrowing Solar System's barycentre to within 100m help find Planet Nine?

I've just read this recent news article, Astronomers Have Located The Centre of The Solar System to Within 100 Metres, reporting on a paper[1] that claims narrowing the Solar System barycentre to ...
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What is the orbital velocity of Pluto around the Pluto-Charon barycenter?

I know the formula for orbital velocity but that doesn't seem of much help when I'm trying to calculate how fast the primary wobbles, or since the barycenter is outside Pluto in the Pluto-Charon ...
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Can I calculate the apparent position of comet NEOWISE C/2020 F3 from a topographic position with Skyfield?

I'd like to get .altaz(next_several_weeks) of this comet from Skyfield and .separation_from() other planets. It reads the JPL ...
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Hypothetical planet jump: Will it perturb star systems?

In a more speculative corner of SE somebody was dreaming up a story of planets traveling between star systems through wormholes. I was wondering how much the appearing/disappearing of a planet the ...
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Is the gravitational field of the sun uniform?

I understand that rocky bodies in the solar system all exhibit gravitational anomalies. Does the sun exhibit any gravitational anomalies? If so are they distinct enough that it effects the orbit of ...
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How to project an arbitrary elliptical orbit onto the night sky plane?

An ellipse E is arbitrarily oriented in 3-D space with the origin at one of its foci. Use the standard elements provided in the figure. Assume the reference direction $\gamma$ or $\gamma'$ is the ...
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How large were the deviations of Uranus's positon from predicted which led to the discovery of Neptune?

After Uranus was discovered and its orbit calculated, its future orbit was calculated, and its future positions as seen from Earth were calculated. And observers of Uranus began to notice that Uranus ...
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Why is the Moon's orbit so complicated?

I like to think I have a good enough understanding of astrophysics but there's still one thing that I just can't explain. Why does the Moon orbit the Earth the way it does? Many other moons in the ...
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Keplerian Elements for Approximate Positions of the Major Planets

Simple question here. I am working on something that needs to compute an orbital path using Keplerian Elements. When doing some research I came across this JPL page: Click Here. Within that link is a ...
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Understanding the JPL Ephemerides

I'm working on an animation that replicates our Solar System. I know this has been done before, but I'm working on something that requires me to make one myself. With that being said, I'm having a ...
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Why does the Parker Solar Probe slow down as the distance from the Sun increases?

Why does the Parker Solar Probe slow down as the distance from the Sun increases? Image credit: Wikipedia user Phoenix777, CC BY-SA 4.0
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Can you create an orbit in a space station using balls?

Would it be possible to spin a ball in a space station, and for it to create its own orbit for a smaller ball to rotate around it?
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What kind of triangle is formed by three unequal masses in a circular restricted three body orbit?

This answer to Are the orbits of all triple star systems at least technically unstable? mentions: There are known solutions to the gravitational three body problem that can be shown to be stable. ...
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Have meteor showers been predicted for planets or solar-system bodies other than Earth? Have attempts been made to detect them?

Per the linked Q's and A's in Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit? and it's answer, meteor showers happen on Earth when it passes ...
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Roughly what fraction of comet orbits that intersect Earths' orbit result in known meteor showers?

Per the linked Q's and A's in Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit? and it's answer, meteor showers happen on Earth when it passes ...
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Why do particles from a comet that result in meteor showers spread out mostly along the comet's orbit?

My understanding of the meteor showers that repeat yearly is that the Earth passes through the orbit of a comet that is nowhere near us, and might not even exist anymore, yet it's orbit is filled with ...
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Do Astronomers really never call Lagrangian points “libration points”?

In this answer to Who called the Lagrangian points as “Libration” points and and why was the terminology “Libration” used? I described my feeling that Lagrangian points were also sometimes called &...
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Is the vernal equinox always in zenith somewhere on the equator?

I'm trying to visualize the satellit orbital parameter "right ascension of the ascending node" (RAAN). Measuring the angle from the vernal equinox to the point where the satellite's orbit crosses ...
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Why does the closest approach of star S2 to Sgr A* not appear to be near the focus of its elliptical orbit?

Phys.org's Very Large Telescope sees star dance around supermassive black hole, proves Einstein right links to several ESO videos, including The star S2 makes a close approach to the black hole at the ...
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What was that single file line formation of flashing plane lights flying in the sky at night? [duplicate]

It was here on the west coast at 5 am pacific standard time when I went outside for a smoke when out of the corner of my eye what looks like a plane with flashing lights going across the sky when all ...