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Questions tagged [orbit]

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

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What does an inclination of 0 degrees mean?

I understand that inclination is the measure of how tilted an orbit is. But is an inclination of 0 degrees like this or like this? I know there are many formulas relating inclination, including ...
Astrovis's user avatar
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7 votes
2 answers
2k views

What can be learned from viewing the sun on earth during a total eclipse that cannot be studied by spacecraft in orbit?

I understand that total eclipses are a fantastic time to study the sun's corona, and the reason for this is because the much brighter photosphere is blocked by the moon. But, couldn't the Parker solar ...
Curious Layman's user avatar
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33 views

Project Analog Hypothetical Planet

For my story Project Analog, I was wondering if a hypothetical planet (Let's call it Suria). It has the same size and conditions as Earth with the same axis, tilt, and rotation, as well as one moon. ...
Caemaster117 's user avatar
1 vote
0 answers
84 views

Have measurements been conducted on the position of the galactic center of mass and the orbit of the presumed black hole at the center?

Related questions have been raised before Is our central black hole actually at the CG of the galaxy? Orbiting supermassive black hole or galactic center of mass? , where explanations have been given ...
Imyaf's user avatar
  • 301
3 votes
1 answer
143 views

Is the Moon really oscillating around its orbit as seen from Earth?

While simulating today's eclipse, I see something I have never noticed or learnt: Stellarium shows an oscillation of the Moon's trajectory around its orbit as seen from Earth. Is it real or a ...
Cingonius Varro's user avatar
2 votes
2 answers
93 views

Is the Moon's orbital plane angle relative to the ecliptic constant?

I've come across a number of sources (example) saying some variation of this: The moon's orbital path around Earth is tilted by 5.1 degrees with respect to the orbit of the Earth around the sun. ...
Stephen W.'s user avatar
4 votes
1 answer
65 views

Copernican model for motion of Mars in Solar Ecliptic Coordinate System

I want to model the orbit of Mars, pretending that it is a circle around the Sun at the origin of my coordinate system, with the Earth being at (1,0,0) in terms of AU on March 19, 2024, at the vernal ...
Lawrence Fields's user avatar
2 votes
2 answers
105 views

Will a circular orbit cause doppler shift?

In a circular orbit, the orbiting body is the same distance from the central body at all times. But since the body is moving, will doppler shift occur from the perspective of the central body?
Astrovis's user avatar
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3 votes
0 answers
103 views

Kepler to Cartesian and Cartesian to Kepler inaccuracies

I am programming a computer simulation set in a star system. I've used Rene Schwarz's wonderfully concise memorandi explaining converting from Kepler orbital elements into cartesian coordinates and ...
w94n9's user avatar
  • 51
1 vote
1 answer
88 views

Traveling constantly towards West. That is clockwise

If I travel against against the Earth's rotation. Say once around the world. I will always see sunrise and never a sunset Is that accurate?
jacob kind's user avatar
1 vote
0 answers
117 views

Determining Time Based on Arc Seconds

So our arc day starts at 20°41'32 which is midnight (0:00) and ends 24 hours later at 21°42'42. According to my calculations it traveled 0 degrees, 59 minutes, and 30 seconds or 3570 arc seconds in 24 ...
dimitri33's user avatar
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2 votes
1 answer
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International dateline

In the story of Magellan in which they circled the globe ,returning to Portugal to discover that they "lost" a day. As they were traveling westward. I don't get it. They were going so slowly ...
jacob kind's user avatar
1 vote
1 answer
142 views

calculating apogee and perigee for moon and sun

The perigee does not necessarily happen when we have a full moon, using swevents we can easily determine the moon phases. Now can we use python to determine when ...
dimitri33's user avatar
  • 167
1 vote
0 answers
34 views

On the relationship between semi-major axis and the Longitude of the Ascending Node

I noticed something looking at the Longitude of the Ascending node of various planets. Mercury: 48.331° Venus: 76.680° Mars: 49.57854° Jupiter 100.464° Saturn: 113.665° Uranus: 74.006° Neptune: 131....
DanceroftheStars's user avatar
8 votes
1 answer
310 views

Orbital resonance and the precession of the periapsis

I was reading up on orbital resonance and came across something on Wikipedia stating that the 1:2 orbital resonance of Io-Europa is "imperfect". I mean that when you simply take the period ...
DanceroftheStars's user avatar
1 vote
2 answers
114 views

Determining the speed of meteor

How to determine the velocity of a meteor from two video data? I want to try to determine the orbit of the meteor, but before that I have to determine the meteor's entry velocity and apparent radiant ...
alphaaquilae's user avatar
6 votes
2 answers
2k views

Are there stars that orbit other stars, such that the barycenter is inside one of them?

I know binary stars exist but I mean a star which orbits with a barycenter that is inside another star, much like a moon. Why is such a system so rare?
Stephen's user avatar
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1 answer
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Earth and the Moon Question [closed]

(For the purpose of this question, I will refer to Earth's Moon as Luna to keep it separate from the general term of 'moon') I know the IAU has been hedgey about giving an official definition of what ...
user53218's user avatar
13 votes
1 answer
644 views

Are there mascons on Ganymede similar to the ones on the Moon? And if so, how will that impact JUICE when it orbits over Ganymede?

Mascons, also known as mass concentrations, are anomalous features on the Moon that tug on orbiting spacecraft and cause their orbits to decay and crash on short timescales. There are only a handful ...
user267545's user avatar
4 votes
1 answer
211 views

Do the Galilean moons' orbits around the Sun have loops (i.e. have concave parts)? And if so, how can their orbits be graphed?

The shape of the Moon's orbit around the Sun has been discussed to death, and the answer is that the Moon's orbit has no concave "loops" whatsoever. I am relatively sure that the determinant ...
user267545's user avatar
3 votes
3 answers
1k views

Celestial "orbits"

I heard that we're losing our moon, its slipping away from us in such tiny imperceptible steps that we don't notice any significant change even over kiloyears. The same must apply to planets, inching ...
Hudjefa's user avatar
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4 votes
2 answers
192 views

Are there naked eye binary stars with periods less than 100,000 years?

An optical double is two stars which appear very close together because they chance to be lined up as seen from Earth but are actually tens, hundreds or thousands of light years apart in space. A real ...
M. A. Golding's user avatar
0 votes
0 answers
36 views

Should you include aberration effects during low Earth orbit observations?

I am working on calibration of some observations of low Earth orbit satellites and I am wondering should I include aberration effects? My logic is that diurnal aberration would have neglegible ...
jlipinski's user avatar
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2 votes
0 answers
69 views

Understanding laplace plane (satellite) orbits

Working on a little project (with vex+python in houdini) to calculate the planet and satellite positions using the keplerian formulae and a database of orbital elements and progressions. Primarily ...
nuki's user avatar
  • 21
2 votes
1 answer
118 views

Is an earth-sized moon orbiting a super-earth feasible?

Is an earth-sized moon orbiting a super-earth feasible? Or would tidal forces say 'no thanks'? I'm making a system for the Kerbal Space Program Kopernicus mod and am trying to make it as realistic as ...
spaceman0x2A's user avatar
26 votes
6 answers
6k views

Definition of a moon in an exam: "A satellite of a planet that *doesn't produce light itself but reflects it*" - is there relevance for the emphasis?

In a 5th-grade exam (for 10-11-year-old pupils in Finland), there was a question, "What is a moon?" The model answer was: "A satellite of a planet that doesn't produce light itself but ...
tputkonen's user avatar
  • 369
1 vote
1 answer
174 views

What does the earth's (a planet's) orbit cause?

I know that the earth's rotation causes day and night. It seems/feels so natural to think that the earth's orbit around the sun causes the seasons, but no it's the tilt of the earth's axis that causes ...
Hudjefa's user avatar
  • 353
2 votes
1 answer
332 views

Latest apoastron of Sirius

The only date that I can find for the latest apoastron of Sirius stars is 2019. Is there a more detailed date with at least the month and/or day. Obviously, it happened in 2019 but can't find any ...
Steve8888's user avatar
0 votes
0 answers
49 views

How do the orbits of star systems V871 Centauri (septuple), Gamma Cassiopeiae (octuple), and QZ Carinae (nonuple) work?

Several years ago, I asked the question on here, "How do the orbits of Nu Scorpii and AR Cassiopeiae work?" At the time, these two stellar systems were the most populated (I don't know the ...
Curious Layman's user avatar
1 vote
0 answers
29 views

At what distance does the galactic tide significantly affect the orbit of a heliocentric object?

The title essentially explains the question. I was wondering if the galactic tide could play a role in raising perihelia of extreme trans-Neptunian objects (i.e. Sedna) versus the effect of a ...
WarpPrime's user avatar
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2 votes
1 answer
264 views

For binary stars, what is the average semi-major axis?

Note I'm exclusively considering binary stars, not 3+ star systems. Binary stars come in all extremes. Wikipedia says that their orbital periods can be a few hours, a few days, or hundreds of ...
DrZ214's user avatar
  • 1,970
2 votes
1 answer
110 views

Motion of solar system around Milky Way

As our solar system performs its +-230 million year lap around the Milky Way, is the orientation of the ecliptic plane preserved independent of the center of our galaxy, or does the plane perserve its ...
DanO's user avatar
  • 21
3 votes
3 answers
299 views

A solar system of solar systems

The moon orbits Earth, earth orbits Sol. It's true that Sol orbits the galactic center, but that's not what this question is about. Is it possible for a solar system like the Sol system, along with at ...
JBH's user avatar
  • 550
1 vote
1 answer
108 views

Does the Sun have different unique orbits around barycenters?

After reading this question and seeing its image I thought about this question I'm going to publish. Does the Sun have different unique orbits around the barycenter for its multiple planets? If yes, ...
Snack Exchange's user avatar
2 votes
1 answer
169 views

Calculating Position of Sun in GPS Frame Relative to 0°00'00.0"N 0°00'00.0"E: Determining Vernal Equinox Offset

I am trying to calculate the position of the sun, in GPS coordinates terms, from a given date. As of right now, I know how to accurately calculate the equatorial Right Ascension and Declination, and ...
Michael Bonnet's user avatar
1 vote
2 answers
2k views

Why isn't a month 28 days?

1 days is a rotation of earth. 1 years is an orbit of the sun. I've always beleived that one month is 1 period of the moon orbiting earth but the inconsistent distribution of days throughout the ...
Ethan's user avatar
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12 votes
3 answers
5k views

How do we know the Moon was much closer than it is now?

We know that right now, by measurement, the Moon is moving further away from the Earth. So I've heard the conclusion that the Moon was much closer to the earth in the past. How do we know that part? ...
scm's user avatar
  • 301
7 votes
2 answers
2k views

Position of the Moon viewed from same spot couple of months apart

In the below image, the position of the moon as viewed from the same spot is displayed. The drawing to the left is from today at local time of 2am. The drawing to the right is from a couple of months ...
Pika-Chu's user avatar
  • 103
3 votes
1 answer
160 views

Do all orbits emit gravitational waves?

In principle, all orbits in the universe should progressively decay due to the emission of gravitational waves. However, does this always happen? Are there any kind of orbits that do not decay as they ...
vengaq's user avatar
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-2 votes
1 answer
207 views

Planets revolving counter clockwise around the Sun

Planets revolving around the Sun Hypothetical case: What could have been or no impact if the planets viz Earth, Jupiter, Saturn, Mercury, Venus, Mars, Pluto, Uranus, Neptune in different orbits ...
Prashant Akerkar's user avatar
1 vote
0 answers
27 views

Does Trappist-1 have a Periodic Configuration? [duplicate]

Trappist-1's planetary system is notable for having 7 planets in a resonance chain. I would think, since all the planets are in resonance, the system would have a repeating configuration that could be ...
skout's user avatar
  • 309
2 votes
0 answers
40 views

Satellite angular velocity at an angle

Suppose I am observing a satellite that is not at my zenith. I know the altitude(α) and azimuth(γ) of my telescope and I was able to get a relative angular velocity of the satellite. Based on this ...
ryanx's user avatar
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0 votes
0 answers
86 views

How do I calculate the positions of an artificial satellite for a decade?

We are trying to solve what I think should be a simple question: suppose there is a satellite that is launched into a certain orbit, where will it be as a function of time? Let's say we know that it ...
VBB's user avatar
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5 votes
0 answers
178 views

Why does the tropical year have a ~161 years cycle?

Using PyEphem, I calculated the time difference between consecutive summer solstices in the south hemisphere for the last 4000 years, and plotted them in a graph. It seems like random noise around the ...
ordptt's user avatar
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2 votes
2 answers
111 views

How to find the numerical positions of objects in the sky?

How do star locator applications such as SkyGuide, SkySafari and Stellarium get the current and future positions of moons, planets, stars and artificial satellites in the sky? Is there a public ...
User44356's user avatar
-2 votes
1 answer
65 views

Can a star with a stellar mass of 1.176 with a similar composition to the Sun have a planet with these characteristics?

Imagine a solar system similar to ours that has a star with a similar composition to the Sun and a stellar mass of 1.176 and an Earthlike planet with about 1.18 times the mass of Earth in its ...
Galactic's user avatar
  • 113
0 votes
1 answer
79 views

What stellar conditions and orbital distance are needed to produce a year length of 515 Earth days and 9 Earth hours on an Earthlike planet?

A planet has a year length of 515 Earth days and 9 Earth hours. It is the same size and has the same climate as Earth. What stellar conditions would be needed to produce this and what orbital distance ...
Galactic's user avatar
  • 113
1 vote
1 answer
88 views

Which coordinate system should one use for simulating a spacecraft trajectory to the moon? [closed]

Which coordinate system is most suited for this type of problem? ecliptic? equatorial?
Blobmou's user avatar
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0 votes
0 answers
98 views

Difficulty simulating trajectory of moon and sun for Apollo 11 mission

As an engineering student, I am doing a project about Kalman filtering and the mission Apollo 11. Now I tried to simulate the trajectory of the moon and sun for 3 days (the duration in which the ...
Blobmou's user avatar
  • 55
2 votes
1 answer
96 views

largest balanced mass objects in Earth's L4 & L5 Lagrange points?

What is the largest single-object mass that would allow two objects of equal mass to have a stable orbit, one each, in Earth's L4 and L5 Lagrange points?
JBH's user avatar
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