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

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359 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: ...
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1answer
114 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
576 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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2answers
427 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: ...
4
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1answer
218 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 ...
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1answer
140 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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Orbits in a binary star system

I know of three sets of stable orbits in a binary star system: orbiting closely around star A, orbiting closely around star B, or orbiting distantly around both stars (and their mutual center of ...
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4answers
223 views

Does Sun have a reflection on Earth?

The new Google Maps1 presents an actual view of Earth, with the current position of Sun illuminating half part of Earth in real time. It is quite an exquisite view. My question is based on the ...
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3answers
472 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
179 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 ...
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3answers
100 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
123 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.
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1answer
199 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 ...
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2answers
97 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
137 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 ...
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1answer
88 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
2k 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 ...
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2answers
138 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
1k 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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1answer
93 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 ...
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2answers
691 views

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

Is it about the same as Earth's orbital speed?
3
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1answer
57 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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3answers
401 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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2answers
54 views

Can we know the orbital planes of extraterrestrial planetary bodies?

Astronomers can tell if there are any exoplanets orbiting its parent star using but not limited to the following methods: Transit As an massive object usually a planet passing in front of a star ...
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1answer
41 views

Determination of orbital elements for Trans-Neptunian Objects, how?

How are orbits calculated for Trans-Neptunian Objects? I understand there are six standard parameters for defining an orbit (link) but I am not sure how telescope observations translate into these ...
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1answer
54 views

Leonid meteor showers and the Tempel-Tuttle comet

I've been reading about the Leonid meteor showers and am struggling to understand one piece of information. On Wikipedia (Tempel-Tuttle), it states: The orbit of 55P/Tempel–Tuttle intersects that ...
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1answer
58 views

Is there online data on asteroid axial tilts?

I am hoping to find axial tilts for asteroids and also their spring and fall equinox. Some of the asteroids I'm interested in are: 4 Vesta, 1 Ceres, 24 Themis, 65 Cybele, 153 Hilda, 624 Hektor
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0answers
74 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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0answers
32 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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1answer
151 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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1answer
113 views

Is there a general term for epicycles, deferents, and eccentrics in Ptolemaic astronomy?

According to Ptolemy's (c. 150 CE) account of the motions of planets, planets moved in circular paths ("epicycles") around center points that in turn moved around the center of the earth along a path ...
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2answers
203 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 ...
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2answers
320 views

Are there any known objects in a “dual” tidally locked orbit?

Is there any known pair of objects tidally locked with each other? I know the moon is tidally locked with the earth (e.g. one side always facing earth), but I don't know of any pair of objects that ...
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2answers
98 views

Birthdate differences calculation relative to earths orbit duration

I have got a question as i am trying to figure out what the real difference between the birthdate of my friend and me is. I am born on 1983 6th February 7 am. My Friend is born on 1984 7th February 1 ...
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2answers
58 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 ...
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2answers
74 views

Is there a lower limit for the altitude of orbiting objects?

As I understand it, one object can orbit another at a variety of altitudes, and the stability of the orbit is determined by (among other things) the speed of the orbiting object. Go too slowly and ...
2
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1answer
44 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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4answers
131 views

Moon's orbit around the Sun

The Earth revolves around the Sun and the Moon revolves around the Earth. Out of curiosity I started thinking about the orbit of the Moon around the Sun and expected (assumed) it to be as follows: ...
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2answers
104 views

How long for a complete solar system cycle

Considering the solar system as a closed system, how long until all the planets pass twice by the same position relative to each other? I would say that you'd have to get the length of the year in ...
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2answers
244 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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1answer
68 views

Is axial tilt direction correlated with semi-major axis direction?

Earth comes closest to the Sun every year around January 3. Winter solstice is at 21-22 December, merely some 12-13 days away. That means projection of Earth rotation axis onto the plane of its ...
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2answers
91 views

Satellite/Planetary Orbits

All planetary orbits contain 5 unusually stable points. These points are particularly important because they allow man-made satellites to orbit the Sun with a period equal to that of Earth’s. 3 of ...
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2answers
61 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 ...
2
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1answer
91 views

How much light does Jupiter project onto the surface of Ganymede?

I suppose the answer would be a range as the Jupiter-facing side of Ganymede passed from Jupiter's light side to its shadow side. I'd also like to know how much light the sun projects onto the surface ...
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2answers
139 views

Ramifications of black hole stellar system

Recently, I got around to seeing the movie Interstellar. In it, the characters of the movie visit a stellar system that appears to be built around a black hole instead of a star. On top of this, their ...
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2answers
110 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
233 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 ...
2
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1answer
61 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, ...
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1answer
120 views

Day Length on Double Planets

Assume two similarly sized bodies tide-locked to one another orbiting a barycenter between the two. That barycenter orbits a star. Since the two are tide-locked, their sidereal rotational period and ...
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1answer
140 views

The tidal locking problem concerning Earth sized planets in habitable zone around Red Dwarfs

Would twin planets orbiting around each other present a solution to tidal locking of habitable planets in red dwarf systems? It's an awfully easy equation to set up. I'm fibbing; I can't do it. I was ...