# Tagged Questions

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

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### 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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### Resources on planetary stability

I am a fifth (and last) year undergraduate student in Physics with good level of Mathematics formation and basic Astrophysics formation. I recently read some theories about Solar System formation and ...
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### Does the differences between atomic time and astronomical time affect us? [on hold]

Earth's rotational period is about 23h 56m. It means that astronomically one day. Also Earth's orbital period is 365.256 atomic days (24 hours). When Earth completes its orbital period in 365.256 ...
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I was looking for accurate and up-to-date data regarding the advancement of the perihelion of the planets in the Solar System, the only ones I've found so far are at least 90 years old bout I really ...
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### Why aren't all planets in the same plane?

Obviously all planets are not in same perfect plane. Because if at all they were in the exact same plane, it would mean that Mercury transits and Venus transits would not be that rare. Any ...
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### Directly calculating lat/lon of a satellite directly from RA/declination

I have RA/declination values of a satellite and the observer's location in terms of lat/lon. I want to convert the values for satellite into lat/lon. I have tried to use the method which uses ...
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### LLR & Orbital Motion

As I understand it, light that is emitted from a source is not imparted with the motion of the source and so always follows a "straight line". If this is correct, I am having a difficult time ...
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### Calculating orbits for beginners [migrated]

I'm a game developer, and I'm working a space game, where I have to simulate a spacecraft's orbit, traveling from the earth to the moon. I would need the apoasis and periapsis of the orbit. I have the ...
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### Inclination in Kepler's laws

So, you can determine the location of an object in an orbit at any given time via Kepler's laws, but how do you determine the orbital inclination at any given point in time?
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### How much time does the ISS take to repeat its orbit?

I used to go to my roof to see the ISS, but it is not always visible. Then it appears again but does it appear with the exact same orbit as I saw before? Thanks!
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### Does the orbital variation in planetary gravity affect the Sun's corona

Dimitris (see below) argues that the syzygies of the Earth and Venus and those of Mercury, Earth and Jupiter distort the Sun's corona, which in some way affects climate on the scale of hundreds of ...
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### State vectors of “interesting” multiple stars

I'd like to show a demonstration of Runge Kutta integration of real systems using examples of interesting multiple stars, where "interesting" means you can see through a small telescope that they are ...
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### Does the gravity of the planets affect the orbit of other planets in our solar system?

When one planet passes near another during its trip around the sun, does their gravitational pull is strong enough to disrupt noticeably each other's orbit ?
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### Why do the gas giants in the Solar System have comparatively large orbits compared to the inner planets?

Ever since I observed the depictions of the Solar System, I was obsessed with the question of why the gas giants (outer planets) have very large orbits, compared to the planets that are closer to the ...
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### Satellite'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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### What is the shape of the Sun's orbit around the Earth taking into account elliptical orbits?

Consider the non-inertial frame that is at rest with respect to the Earth's revolution around the Sun. (Ignore the Earth's rotation around its own axis.) My question is, what is the shape of the ...
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### Why do the planets in our solar system orbit in the same plane?

(Yes I'm excluding Pluto from this the same way it was excluded for not being a planet) Observing the planets orbit of the Sun they all seem relatively planar and roughly all orbit along the same ...
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### How common are Stars that have no orbiting planets? [duplicate]

How common are Stars that have no orbiting planets compared to Stars that do?
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### Two body orbit of equal masses

Given two bodies of equal mass in an elliptical orbit: I know they will be orbiting about a common center of mass, i.e. the barycenter. But, do the velocities have to be equal in magnitude and ...
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### Longitude of the Ecliptic

I originally went to math.stackexchange.com and they suggested I try here as well. I'm trying to figure out how to calculate times of moonrise and moonset for a given position on the earth on a ...
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### What would happen if we changed Earth's orbit? [closed]

If one day we have enough technology to push the Earth away a bit further from the sun to reduce global warming, is it true that it will start to distort the orbits of Mars and Venus, giving them a ...
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### What is the most populated/numerous stellar system in which the orbits of all objects are known?

I posed a question or two on here a couple months or so ago about the orbital patterns of each of the seven stars in the two septenary star systems Nu Scorpii and AR Cassiopeiae. They remain ...
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### Simulates Orbit [duplicate]

I IT developer, and I would code a small program that simulates the orbit of two bodies, the problem of two bodies eventually. I have no problem on the part programming but I have a little trouble ...
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### Why doesn't Earth's axis change during the year?

My understanding is that the Earth's axis points in the same direction in space during its entire orbit around the sun. And this is what causes our seasons. My question is why doesn't the axis follow ...
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### How old is our Sun in Galactic years?

A year is measured as the amount of time it takes Earth to orbit the Sun once, a Galactic year is the time it takes our sun to make one full orbit of the center of the Galaxy. In Galactic years, how ...
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### Can we apply Kepler's law of planetary motion to the moons motion around the earth?

I have been trying to understand Kepler's law of planetary motion for a while. So I was thinking, if it would even apply to the moon orbiting around the earth. Does the moon too orbit in an ellipse ...
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### Are there any hot jupiters orbiting red dwarfs?

Do we know of any hot jupiters that could be orbiting a red dwarf (or, more probably, orbiting a barycenter between the two)? Is this scenario even physically possible?
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### Determining distance from semi-major axis and eccentricity

I am trying to obtain the distance covered by an object in orbit around the earth within a specified amount of time past its perigee passage. The object is in an elliptical orbit with eccentricity 0.2 ...
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### 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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### 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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### 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/Tempelâ€“Tuttle intersects that ...
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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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### Would it be possible to equip an asteroid to collect space junk in Earth's orbit? [closed]

We all have heard about the problem with space junk in low earth orbit. NASA has a plan to put an asteroid in orbit around the moon. Would it be possible to equip propulsion systems onto an asteroid ...
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### Best planets profile for a tattoo of the solar system [closed]

I want to get a tattoo of the solar system. The gap between the planets should not be preserved and the differences in sizes will only be symbolic. I found the following My question is if all stars ...
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### 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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### Is this Universe scenario correct? [closed]

I will try to give you my reasoning behind my scenario. Ok I've researched and found That 95 percent of the galaxy has been formed already, And the other 5 percent is still to ...
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### Lack of objects between heliopause and Oort cloud?

If we take a look at a logarithmic scale of the Solar System, there appears to be a large gap between the heliopause and the Oort cloud: Why is that? There are some objects in the gap, but why are ...
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### Stability of orbital resonance

Recently I've become more interested in the topic of the stability of planetary systems. IÂ have been reading about it and it seems that orbital resonances play an important role in the stability of ...
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### How were the orbits of planets first mapped out?

I'd like to know how the orbits of planets were first 'mapped out' and to understand the maths behind it. e.g. How do we know what position in space a planet will be at certain time so that spacecraft ...
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### 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 ...
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### Do all planets rotate in the same direction in relation to each other?

In other words, does everything spin counterclockwise according to their axes (in relation to each other)? I suppose my question goes for stars, moons and other objects too. But then again, all you ...
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### What is the centre of rotation of Pluto?

I know that Pluto and Charon have been found to circle round each other, hence the reason Pluto is no longer a planet I believe, which would mean that the centre of rotation is an arbitrary (!) point ...
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### Are there accurate equinox and solstice predictions for the distant past?

I am trying to find information on the equinox/solstice dates before 1600, more exactly referring up to 10,000 BCE so as to create a sort of calculator on an Excel spreadsheet. I have read about the ...
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### Accuracy of Laplace Method for determining orbital elements

Recently I had to implement Laplace method and apply it to 3 observations of Mars (10 days in between two observations). The results were pretty good, with discrepancies with real data well below 5% ...
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### Is the duration of a sidereal year stable?

According to this essay by Phil Plait, the duration of Earth's sidereal year is 31,558,149 seconds. Is this figure stable? If I were to meaure Earth's orbit several million (or billions) of years in ...
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### Why doesn't Jupiter increase the chances of an asteroid to strike the Earth?

I often hear the hypothesis that Jupiter decreases the chances of an asteroid strike on the Earth, but my question is, why does it only decrease the chances ? While Jupiter can deflect some ...
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### Is there any point on earth where the moon stays below the horizon for an extended period of time?

When I was teaching a class why the earth has seasons today, I mentioned how the poles of the earth experience months of daylight and darkness. Then one of my students asked whether the moon ...
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### How to get the longitude of the perihelion to find the Heliocentric Equatorial coordinates of a planet

I'm writing a program to randomly generate star systems and I have been having a difficult time figuring this out. I've found the equations I need to get the heliocentric equatorial coordinates, but I ...