Questions regarding an object 'falling around' another object, due to a combination of gravity and momentum.

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503 views

What is the difference between Sphere of Influence and Hill sphere?

Wikipedia's definition of Hill sphere is: An astronomical body's Hill sphere is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit ...
6
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1answer
110 views

Best approximation for Sun's trajectory around galactic center?

What is the current best approximation for the path the Sun takes around the center of the Milky Way? I have found some information on the approximate position of the Milky Way's center, the speed of ...
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1answer
1k views

Calculate angle of inclination for a certain angle in a planet's orbit?

The background is that I'm trying to write a computer program to show at what angles each planet would be able to be seen transiting in front of the sun from an observer outside our solar system. My ...
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2answers
84 views

Are there ever any simultaneous transits of both Mercury and Venus as seen from the Earth?

Transits of Mercury happen fairly frequently due to its short period, but transits of Venus are less frequent. I've looked over the data available to me and found that there have been transits of ...
5
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3answers
181 views

Is there a ceiling for stable L4 or L5 masses?

L4 and L5, the Lagrange points 60 degrees leading and trailing an orbiting body, are famous for being stable. A well known example are the Trojan aseroids at the Sun Jupiter L4 and L5. Nodding to ...
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3answers
221 views

How do you calculate the effects of precession on elliptical orbits?

Kepler's first law states that planets (and all celestial bodies orbiting another body) travel in elliptical orbits, which have well-known formulas that make it relatively easy to calculate the ...
5
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1answer
128 views

Is it possible to create a traditional clock solar system?

Is it possible to create the following system of satellites?: Place a satellite that orbits the some object X, once per day. Call it D. Place a satellite that orbits D, once per hour. Call it H ...
5
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1answer
130 views

What is the optimal escape trajectory from near a black hole?

Consider a space ship that is being drawn closer to a black hole. The crew begins to notice the effects, and discovers that they are nearing the black hole. They then manage to halt their ...
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2answers
536 views

How to plot orbit of binary star and calculate its orbital elements?

I have a set of dates, position angles ($\theta$) and angular separations ($\rho$) for visual binary star. For example: ...
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154 views

How do I calculate the positions of objects in orbit?

In a model of the solar system, given the Sun is at the point $(0, 0, 0)$, an given the six orbital elements for each object in orbit ($a$, $\epsilon$, $i$, $\Omega$, $\omega$, $M_0$), how can I ...
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2answers
876 views

What mechanism causes oscillations of the solar system's orbit about the galactic plane?

In a recent paper (news release here) Lisa Randall and Matthew Reece propose that a dark matter disk coinciding with the galactic plane together with the solar system's oscillations through the ...
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3answers
477 views

Spotting the International Space Station (ISS)

Recently, I visited the NASA website which provides sighting locations to see the International Space Station (ISS). As we all know, we can even see ISS with the naked eye in a clear sky as a passing ...
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1answer
356 views

How to compute satellite coordinates (lat,long) given antenna's coordinates, angles and satellite height

Given an Earth station (antenna) coordinates (in lat,long) ant its Elevation (El) and Azimuth (Az), how to compute the satellite coordinates (lat,long), known its height? For simplification purposes, ...
5
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1answer
170 views

How can one explain the apparent motion of the Sun from a heliocentric point of view?

From a horizontal frame of reference, the path of the Sun looks like a part of a circle in a tilted plane, as shown in this picture: ...
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2answers
533 views

How did Kepler determine the orbital period of Mars?

As I understand it, Kepler used the orbital period of Mars, along with observational data of Mars' and the sun's position in the sky to derive the orbits of Earth and Mars. (As described, here: ...
4
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1answer
162 views

Do all moons orbit their planets on the ecliptic?

Do all moons orbit their planets on the ecliptic? Do they all follow this same process as the moon that orbits Earth, or is their some random distribution with some even having extreme polar orbits.
4
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1answer
156 views

What is the correct ratio of Newtonian to General Relativistic gravitational effects for Sun + single planet orbital system

For a hypothetical orbital system (Sun + single planet) the Newtonian model and the General Relativity (GR) model produce different expressions for the gravitational effect of the Sun on the planet. ...
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2answers
161 views

Why do objects all orbit in the same direction?

In a solar system or a planet that has many moons, why do their orbiting objects all orbit in the same direction? Is it possible for two orbiting masses to orbit in the opposite direction of each ...
4
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1answer
113 views

Can orbital migration cause a planet to crash into the sun?

If the planets move out of their current orbits into other orbits over long periods of time could this cause a planet to crash into the sun? Maybe the term crash is a little dramatic, could the orbit ...
4
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1answer
89 views

Ambiguity in Earth's “Tilt”

It’s well-known that the axial tilt of the Earth (with respect to the ecliptic) is about 23.4 degrees. However, two angles is needed to specify the orientation of any rigid body, so it’s unclear to me ...
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48 views

How (un)stable are the Lagrangian points 1, 2 and 3?

A couple questions, please: I know that the Lagrangian points 1, 2 and 3 are unstable and special Lissajous orbits plus some station-keeping are required to place a spacecraft around them. But I was ...
4
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1answer
252 views

Why are most planetary orbits nearly circular

In our solar system, with the exception of Pluto all planets follow a relatively circular orbit around the Sun, at the same inclination. They also all rotate in the same direction, none are ...
4
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1answer
174 views

Where did this famous Planetary Precession Formula come from?

The following equation (which I shall term the Planetary Precession Formula, PPF for short) famously appeared in a 1915 publication by Einstein where he indicated how it could be derived from his ...
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0answers
97 views

Why are retrograde orbits more stable than prograde ones?

Regarding solar system dynamics, i.e. planets in stellar systems and moons in planetary systems, this is often mentioned in the literature, but it is difficult to find a good analysis/explanation of ...
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38 views

Are trojans in L5 more likely than in L4?

Mars has much more trojans in L5. Does it reflect a common pattern?
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51 views

Orbital resonances and position of planets

I am interested in quick generation of planetary systems for programs similar to Space Engine or Pioneer Space Simulator. As far as I understand, formation of planets is a complex process and the ...
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1answer
225 views

What are the azimuths of the planets' orbits?

I am creating a virtual solar system model and I want it to be as realistic as possible (e.g. orbits are ellipses, not circles, and orbits are oriented correctly, not all coplanar). In order for me ...
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2answers
243 views

Is the ratio between earth's distance from the sun and the speed of light just a coincidence?

I was doing some calculations to see how hard it would be to observe the speed of light and discovered an interesting correlation between the speed of light and the average distance from the earth to ...
3
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3answers
726 views

Circular orbits

First of all, I'm studying orbits for a hobby: world building. Unfortunately, my mathematical abilities approach a ridiculous low threshold, which means I am stuck with reading the simplest ...
3
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1answer
190 views

Could a habitable satellite of a gas giant have a stable subsatellite?

I have set a science fiction story on a moon, orbiting a gas giant (which orbits its star at approximately the same orbit as the Earth around the Sun), and given this moon its own satellites. The ...
3
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1answer
115 views

What does the orbit of multiple star systems look like?

How can I find simulations of trinary, 4-nary.. etc. star systems? What do they look like? For example the Alpha Centauri system has 3 stars and possible planets. What does that orbit look like? I ...
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3answers
116 views

Are multiple satellites required to handle geostationary orbits?

Do geostationary satellites need to have the equator as the plane of rotation, and the earth's centre to be the centre of rotation? Can it rotate over, say, the Tropic of Cancer, focusing on a single ...
3
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1answer
223 views

How long does it take Dawn to orbit Ceres?

I haven't been able to find the orbit time of Dawn around Ceres. Do you know how long it takes?
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2answers
70 views

How common are exoplanets in distant orbits?

Are there many single transits in the Kepler data, which might be exoplanets with a longer orbital period than the time they have been observed for transits? Can any conclusions be drawn about how ...
3
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1answer
104 views

Capturing Ceres

Would it be possible to slightly change the trajectory of Ceres to make it end up orbiting the Earth without messing up the Solar System? How much energy would be required and how long would the ...
3
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1answer
4k views

Average amount of annual daylight at any place on earth

If this is the wrong group please direct me to the correct one. It seems intuitively obvious that the amount of daylight per annum should be the same for any latitude on earth. For example, 12 hours ...
3
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1answer
264 views

What is the orientation of planetary orbits?

I'm working on a planetary motion simulator. I've been working through the equations anomaly, eccentricity, etc. The one thing I'm curious about is if all the ellipses are oriented the exact same way ...
3
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2answers
98 views

Is there an orbit that could cause regular debris showers like in the movie Gravity?

[some spoilers] If you were in the ISS and orbiting the Earth roughly every 90 minutes, would it be possible for debris to be orbiting such that it passes you every 90 minutes? While Neil DeGrass ...
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2answers
2k views

How fast is a comet moving when it crosses Earth's orbit?

Is it about the same as Earth's orbital speed?
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176 views

Apogalacticon and Perigalacticon

What is the length of the apogalacticon and perigalacticon of the Sun and Milky Way? The general terms seem to be apoapsis and periapsis. My greatest efforts at Googling have failed miserably. If ...
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1answer
2k views

How can I calculate the orbital periods in a binary star system?

I have two stars, with known masses and known orbital radius. How do I calculate the orbital periods of both stars?
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2answers
71 views

How do kepler orbits account for planetary migration?

This article got me thinking if kepler orbits explain how a planet moves in a solar system how can a planet migrate as explained in the article. At some point don't the kepler orbits must need some ...
3
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1answer
56 views

Is the size and heat of a star important in the development of a solar system?

How do the size and heat of stars affect development of solar systems and what kinds of planets can develop? Is it possible to orbit supermassive stars? Furthermore, would star's unleashing violent ...
3
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1answer
108 views

What is meant by matter distribution?

Frustratingly, I find this could be a very simplistic question and may leave me feeling a little stupid for asking it. But I have to ask this. My lecturer keeps refering to "matter distributions" for ...
3
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1answer
132 views

How is it that all planets (and moons) in our solar system are in equilibrium orbits?

Previously, I was told that in order for any bodies to orbit each other for over a long period of time, the orbital period, distance and masses have to be precisely matched such that the bodies won't ...
3
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1answer
48 views

Orbiting and landing on non-sperical objects

If we orbit a non-spherical asteroid or moon at a sufficient distance I believe that we can consider it to be a point mass. Therefore we can take up a conventional orbit. Assuming our lander craft is ...
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2answers
442 views

Is it possible that the Sun has a binary partner (the Nemesis Theory) that has eluded detection?

I just recently learned about the theory that our Sun has a small companion star with a 26 million year orbit. This theory came about when it was realized that mass extinction events happened ...
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277 views

Orbiting supermassive black hole or galactic center of mass?

One of the ways they measure the (supposed?) supermassive black hole at the galactic center of the milky way is to measure those tens of stars right at the galactic center that are orbiting what ...
3
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1answer
70 views

Sattelite's orbit

What is the maximum distance for a satellite to orbit the earth? Does earth's gravity has the impact on satellite? I do know that earth's gravity will never be zero and it's gravity is inversely ...
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1answer
82 views

Calculate apsides without knowing eccentricity

How would one go about determining the apsides of an orbit, knowing only the current distance between the 2 bodies, the orbital velocity, and the period? Every formula I've seen requires eccentricity, ...