Questions tagged [orbit]

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

Filter by
Sorted by
Tagged with
3
votes
1answer
106 views

Throwing a baseball from orbit to the earth

I just read a thought piece about what a war in space may look like, and it changed my thoughts on what orbit actually is. From what I read about orbits, it sounds like going faster in the velocity ...
23
votes
5answers
3k views

What makes protoplanetary disks start rotating? (Initial energy needed to rotate)

Planets form from a protoplanetary disk that has been rotating around its star. The initial energy that makes them rotate really matters to me. Why did the protoplanetary disk start rotating around ...
20
votes
4answers
6k views

If suddenly “knocked” or perturbed from its orbit, would gravity eventually return the Earth to its original orbit?

If suddenly "knocked" or perturbed from its orbit, would gravity eventually return the Earth to its original orbit? I am curious as to whether this is even possible. It seems to me that ...
3
votes
3answers
96 views

How does an object at L1 stay at L1?

I've recently been reading about the DSCOVR satellite, and I'm confused about it's orbit. According to NOAA A million miles away, DSCOVR orbits a unique location called Lagrange point 1, or L1. This ...
1
vote
0answers
43 views

Positions of planets before Christ?

All the solar system simulations I've come across showing the positions of planets only show the positions in a certain time period, at beginning of the first millenium the earliest. There was just ...
16
votes
3answers
3k views

What are “non-Keplerian” orbits? What are some familiar examples in our solar system, and can some still be closed?

This excellent answer to Forms of stellar orbits around the galactic center invokes the following concepts: non-Keplerian orbits closed orbits I have a fairly good idea what these mean and so might ...
2
votes
1answer
81 views

Is there anything like a timelapse showing the Alpha Centauri stars orbiting around each other?

It is my understanding that the angular separation between Alpha Centauri A & B is more than enough for even amateur telescopes to resolve as 2 separate stars. Going by the plot below, over the ...
2
votes
2answers
72 views

What would a moon with a six-month orbital period look like from the earth?

This is a kind of follow-up question to "What orbital period would produce one New Moon (and one Full Moon) each year?" Given the six-month orbital period that is needed to produce one New ...
0
votes
0answers
40 views

The possibility of rapidly changing the Earths orbit via a passing astronomical object

I assume that the Earth could be “gently” (without colossal tidal or volcanic catastrophe) displaced by a passing extra solar star, brown dwarf or planet and end up perhaps 10% further away from the ...
0
votes
0answers
75 views

What shape do satellites trace as they wobble in orbit around another body?

What shape does the center of gravity of a satellite trace in 3-d space as it wobbles in orbit around another body? How is this shape modeled geometrically? Is it a topological torus? Is it feasible/...
9
votes
3answers
2k views

What orbital period would produce one New Moon (and one Full Moon) each year? What other effects would this produce?

I am interested to know whether it's possible for the moon to orbit the earth at such a rate that we would see only one New Moon and one Full Moon a year. If so, what other effects would we experience?...
1
vote
0answers
38 views

Orbital Mechanics: where can I find initial conditions for orientations and angular rates of planets in our solar system?

I am looking to write the equations of motion (EOMs) for a 6DOF analysis of our solar system. I want to integrate the equations forward in time, and need a complete set of initial conditions to do so....
2
votes
2answers
1k views

Does Halley's Comet travel past the outer bounds of the Oort Cloud?

We know Halley's Comet returns every 75-76 years. We can reasonably compute its elliptical orbit. We know that the Oort Cloud is a cloud of predominantly icy planetesimals proposed to surround the Sun ...
6
votes
1answer
286 views

Cannot identify mistake in calculating orbital eccentricity vector; magnitude equals one instead of zero (with python code)

I have a gravitational nbody simulation, for which I would like to determine various orbital parameters. For each body, I have 3-D vectors (x,y,z -space) for position, velocity, and acceleration. I am ...
2
votes
1answer
106 views

Why is the height of a satellite greater than the apogee of its orbit?

I read in the German Wikipedia for the Indian Technology Experiment Satellite, that the apogee (Apogäumshöhe) is 567 km, while the height of the orbit (Bahnhöhe) is 572 km. I had always thought that ...
4
votes
1answer
60 views

What is the tightest orbit binary planets can orbit each other?

If there were two Earth-like planets in a tight orbit around each other, how close could they be to each other without colliding? How quickly would they have to orbit to be stable? Would they be ...
2
votes
1answer
94 views

Is there a possibility of finding a system where a star is orbiting a planet?

Is it possible for a star to orbit a planet IF the planet is bigger than the said star? Or is it possible even if the star is bigger than the planet and still the star is orbiting the planet? I have ...
20
votes
5answers
6k views

Was the Geocentric Model correct at all?

It's easy to find resources stating that the heliocentric model is right and geocentric is wrong. But how wrong was it? Was it correct in any way? It was built on incorrect assumptions, but despite ...
2
votes
0answers
24 views

How is solar radiation pressure included in the SGP4 orbital propagator?

TLE sets serve as input elements for the SGP4 orbital propagator. Several orbital perturbation effects are considered in the SGP4. However, it is not obvious to me how (or if) the solar radiation ...
1
vote
2answers
175 views

Is the “mean orbit” centered on ellipse center or ellipse focus?

Mean longitude and mean anomaly of a body are calculated as the angle covered by the body along a fictious circular orbit, and this is ok. But where is this orbit centered? Five different sources say ...
-5
votes
2answers
213 views

Have Earth, Mars and Jupiter and Neptune not cleared their orbits of space debris? [closed]

According National Geographic's Space Encyclopedia (p68, column 3) written and illustrated by David A Aguilar Pluto has not cleared its orbit of space debris but neither have Earth, Mars, Jupiter and ...
2
votes
2answers
138 views

Could there be a planet at the barycenter between two or more stars revolving around each other?

In binary star systems, could there be a planet the stars revolve around, with eternal day on all sides? 1st scenario: Imagine a binary system consisting of two Sunlike G5V stars of 1 solar mass each, ...
3
votes
2answers
237 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 '...
3
votes
2answers
255 views

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 ...
5
votes
2answers
1k views

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 ...
2
votes
2answers
132 views

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 ...
2
votes
2answers
164 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 ...
1
vote
2answers
99 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 ...
4
votes
1answer
129 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 ...
0
votes
1answer
47 views

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 ...
3
votes
1answer
89 views

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 ...
1
vote
1answer
87 views

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?...
2
votes
1answer
37 views

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.
16
votes
1answer
3k views

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 ...
11
votes
2answers
2k views

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 ...
0
votes
1answer
68 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 ...
2
votes
1answer
67 views

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 ...
2
votes
1answer
80 views

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 ...
4
votes
1answer
125 views

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 ...
5
votes
2answers
306 views

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 ...
4
votes
2answers
268 views

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 ...
5
votes
3answers
1k views

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 ...
1
vote
0answers
124 views

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 ...
1
vote
3answers
139 views

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. ...
3
votes
1answer
75 views

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?
23
votes
3answers
3k views

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 ...
0
votes
0answers
52 views

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 ...
2
votes
0answers
78 views

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, ...
0
votes
0answers
17 views

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 ...
0
votes
0answers
36 views

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 ...

1
2
3 4 5
13