Questions tagged [orbit]

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

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121 views

If the solar system is nearly flat, then why don't all the planets appear to lie on the same axis when viewed from earth?

For instance, consider the image below. The location of the planets seem to be so random relative to Earth. If the solar system was indeed flat, then I would expect the planets to lie on the same '...
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Are all solutions of the 3-body problem restricted to 2 dimensions?

I am not a physicist. Suppose there are two massive bodies orbiting each other. Their orbit will presumably define a plane. As far as I know, the existing solutions to the 3-body problem are limited ...
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Can we change Earth's orbit with modern technology? [closed]

It is well known that, according to Newton's 3rd law, spacecrafts entering or leaving Earth provoke tiny (insignificant) changes to Earth's orbit (see related question here). My question is about ...
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How to calculate the orbital period and the density of a planetary body?

I'm a student studying in 9th grade, I am making this fictional habitable planet named "Darwin B" for a planet making competition. It orbits a sun-like star at a distance of 1.15 AU or 172 ...
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Why do many Mars missions launch now, if the Hohmann transfer orbit is the most propellant-saving one? [migrated]

The Hohmann transfer orbit is the most propellant-saving transfer orbit to Mars. When using this kind of transfer, the rover/rocket/etc. starts from Earth when Earth and Mars are in conjunction. But ...
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155 views

If the Sun's trajectory were altered, would the solar system follow?

I was reading a text state that the sun is not stationary: "it orbits the Galactic center once approximately every 226 million years as the galaxy spins which is also traveling through space ...
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73 views

How is the average distance between 2 objects orbiting around a third object calculated?

I want to know the average distance between Io and Europa knowing that Io's semi-major axis (around Jupiter of course) is 421,800 km and Europa's semi-major axis is 671,100 km. At first I thought it's ...
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1answer
47 views

Converting orbital elements from equatorial reference frame to ecliptic

I have a bunch of orbital elements (inclination, longitude of the ascending node, mean anomaly, argument of periapsis) that are all referenced from an equatorial reference frame. But the program I am ...
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The definition of eclipsing binary star systems

In the second minimum (the 3rd step) there is a smaller decrease in light intensity. For this to happen, wouldn't you need to be looking at the plane of orbit from above rather than directly along the ...
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1answer
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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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1answer
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Why the earth orbits the sun from X to -X and not the opposite [closed]

I wonder all the time, why the earth orbits the sun as expected from east to west(X to -X) ? It could be different, for example from the west towards the east . What would happen if that were the case?...
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When graphing radial velocity measurements, whats the relationship between days and the orbital phase

I graphed the radial velocity measurements for various planets, however, I am able to calculate the RV and the phase but whats the translation between phase and days. I want it to be days vs RV.
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The newly discovered comet NEOWISE has been given the name C/2020 F3. What is the meaning of the F3 and the C in this name?

The new comet C/2020 F3 was first spotted by NASA's NEOWISE satellite in March 2020. It is now visible in the NE sky just before dawn. The C may refer to it's non-periodic nature (so far). What does ...
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How many satellites orbit their planet faster than the planet rotates?

Phobos is so close to Mars that it orbits Mars much faster than Mars rotates. This means that it rises in the west and sets in the east, even though its orbit is prograde. Are there any other known ...
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50 views

How to calculate shape of orbit when projected onto the plane of the ecliptic

I'm trying to generate an 'overhead' view of the orbits of the moons of Neptune, similar to Figure 4 in this paper, using values given here. I initially tried using both the Argument of Periapsis, and ...
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1answer
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Which solar system objects have the least stable solar orbits?

My research is not giving me anything definitive. Are the Apollo asteroids orbits less stable than the Centaurs or any Trojans, or is another class of objects in less stable solar orbits? On what ...
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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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1answer
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Isn't it absurdly unlikely that our Moon would constantly be “facing” us? [duplicate]

I never thought about this until recently, but our Moon is constantly rotating in such a way that it happens to perfectly be "looking at us" at all times. That sounds incredibly unlikely to ...
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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 doesn't the moon always follow the same path? Or why aren't the moon's apoapsis and periapsis fixed?

I have seen many times that the moon doesn't follow the same path. Sometimes the moon gets very close to earth which is shown in the news. If the periapsis of the moon is soo close then why doesn't a ...
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Which spacecraft would be moving faster?

If identical spacecraft were orbiting Mars and Earth at identical radii (distances), which spacecraft would be moving faster? Why? My reasoning is based on equation: a3 = P2 * (M1 + M2). Earth's mass ...
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Can you see the difference with the naked eye whether Venus is at the other side of the Sun or at the Earths' side?

When Venus is at an angle with the Sun from the Earth's perspective we are able to see the reflection of the Sun on Venus. But imagine that Venus is on the farthest half of its orbit around the Sun. ...
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When and how was the length of a Mars year determined?

I guess it is known for a long time that Mars has an orbital period of around 687 days. But when and how was this determined?
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When did people first measure that the Earth was closest to the Sun during January?

When we talk about the reason for the seasons, we usually have to dispel the misconception that seasons are caused by being close and far away in the Earth's elliptical orbit. And usually, we ...
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Theory on why Venus rotates differently to the other planets [duplicate]

When a body A orbits a body B and both bodies are rotating, gravitational friction will gradually slow down the rotation of the bodies over time and eventually tidally lock them. The effect will of ...
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Can a habitable planet orbit in a L4 or L5 Trojan position? [closed]

Can a Planet Massive enough to be Habitable have a stable orbit in the L4 or L5 Trojan position? This is a simple question with maybe complex answers. In fact, I have found three separate answers, ...
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Multiple satellites traveling same path [duplicate]

Wednesday morning April 15,2020 we stopped counting at 50. We were looking at Mars,Saturn and Jupiter just above the moon. When we start seeing satellites, one after another traveling NW to SE right ...
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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 ...
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1answer
52 views

Comparing orbits between a planet and Red Dwarf

I have a MATLAB problem, so I have an earth like planet orbiting around a sun like star and then there is a red dwarf on an elliptical orbit around the star that passes close to the planet. I want to ...
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I sighted a group of satélites moving in a interesting pattern in a way I never seen from this area where I live is this posible? [duplicate]

I live in the rural area of the state of São Paulo in brasil (mata atlántica). the sky is absolutely clear, when there is no clouds you see the milky way perfectly and a sky full of stars. I just ...
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How close would the sun have to get to a supermassive black hole to have Jupiter stripped and slingshot into interstellar space?

Please make whatever assumptions are needed. Assume sun approaches black hole on some sort of hyperbolic trajectory. Assume size of supermassive black hole is same as the one at center of our galaxy....
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246 views

Definition of Rotation versus Revolution

Let there be a planet for which the duration of a solar day is equal to a year around the sun such that: ...
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1answer
174 views

How feasible would it be to get to a planet orbiting directly opposite Earth?

Imagine that in addition to Earth, there was a second planet, say of one Earth mass, orbiting the sun - but on the opposite side of the Sun, and at the same orbital radius. My question is - given ...
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2answers
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How Does Earth Move In Relation To The Stars

In my simulation, I have stars scattered around Earth, all stars are the same distance from the center of the Earth and positioned based on their right ascension and declination like so: I am ...
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Is it possible to affect Earth's orbit so that, say, aphelion happens sooner?

As part of its natural cycle, the sun is currently drifting away from the Earth, it's predicted to reach its farthest point by July 4th in 2020, at which point the distance between the Sun and Earth ...
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Is the angle of the Earth's orbit on the Galactic plane changing (towards 180 degrees)? [duplicate]

Currently the angle of Earth's orbit is aroun 60 degrees on the Galactic plane. But is this angle changing?
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1answer
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Peculiar Amplitude of Earth's Orbit in Z Axis

I'm currently building an N-body simulator for my masters project and I'm using JPL's Horizons system to compare against. I started with just a couple orbits and everything seemed to be working ...
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1answer
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How to calculate the true length of day on a celestial body?

When I only know the sidereal rotation period, how do I determine the true length of day on a body? We know the Earth's sidereal day doesn't have full 24 hrs unlike the true length of day. It's ...
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1answer
103 views

Path of Mercury and general relativity [duplicate]

I have read that many physicists challenge the theory of general relativity, and it has been proved many times that it is correct; my question is on Mercury's orbit. And we know that many of ...
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1answer
739 views

What is Charon's ascending node in reference to?

NASA's orbital elements given for Charon's orbit are given at https://ssd.jpl.nasa.gov/?sat_elem. The ascending node is defined as being "measured from the node of the reference plane on the ICRF ...
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Where and when will someone on Earth be standing with the floor parallel to the Ecliptic plane?

I have been trying to figure this out and I think the answer might be - once per day for anyone living on the Tropic of Cancer or Capricorn. Is that right? To be clear - I want to know where on Earth ...
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1answer
100 views

If you put all planets between earth and moon what would happen?

It's often discussed that you can fit all the planets in the space between the Earth and the Moon. But if they actually did teleport there instantly what would happen next? Assuming their initial ...
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1answer
85 views

Can there be a three-moon system where only two are visible most of the time?

I am trying to build a moon system for a sci-fi work in collaboration with my boyfriend. He's the main writer and wants there to be three moons circling the planet in a way that most of the time, only ...
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1answer
95 views

What is the exact time of sun stay in each zodiac every year on sidereal year duration?

I tried to reverse engineer from astro-chart times at which sun stays in a zodiac. Here is the list. ...
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Gravitational Slingshot

If a spacecraft slingshots around a planet P (with escape velocity V) at an angle $\theta$, I understand that the resulting velocity is $${ v }_{ 2 }=({ v }_{ 1 }+2u)\sqrt { 1-\frac { 4u{ v }_{ 1 }(1-...
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1answer
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Does the orbits of stars in a binary system have a common focus, which is the center of mass of the stars?

I know that when a planet orbits a star (and assume the star is stationary because its mass is >> the mass of the planet), the orbit is an ellipse, and the star sits at one of the foci of the ellipse. ...
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66 views

Orbitally convenient Mars-to-Earth transit times?

Are there any peculiar solar system layouts that would result in highly efficient transits between Mars-to-Earth? I am aware of a Hohmann transfer orbit, but can other planets be used to "sling-shot" ...
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98 views

What's the difference between semi-major axis and apoapsis?

The semi-major axis is half of the diameter of the major axis of an ellipse by definition. So how does that make it any different from apoapsis, the furthest point an object is from a parent body in ...
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1answer
80 views

Can Kepler's 3rd Law be applied in higher dimensions to describe orbits (quadric surfaces)?

Motivation for asking: The 2-D orbital path of a celestial body revolving around another celestial body due to the force of gravity can be described by a conic section; this is the curve formed by ...

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