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

learn more… | top users | synonyms

-1
votes
3answers
78 views

Does the Sun turn around a big star?

The moon turns around the Earth. The Earth turns around the Sun. Does the Sun turn around a big star? If so, does this big star turn around a very big star? ... etc ... What are all the intermediate ...
-3
votes
0answers
30 views

Radius and velocity of Earth's orbit around the Sun [on hold]

How do you find the radius and velocity of Earth's orbit around the Sun?
0
votes
1answer
64 views

Shouldn't all moon orbits be inherently unstable?

A hypothetical simulation starts with a planet called Earth in a perfectly circular orbit around a star called Sol. There is also a moon called Luna in a perfectly circular orbit around Earth. ...
0
votes
3answers
57 views

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 ...
1
vote
3answers
92 views

Can planets inside the Earth's orbit around the Sun appear to undergo retrograde motion?

Retrograde motion is: The apparent motion of the planets when they appear to move backward (from east to west) from the direction that they move ordinarily with respect to the stars. Can planets ...
0
votes
1answer
28 views

Precessing of the Earth

It's been known that the Earth's axial tilt varies from 22.5 to 24.5. Does this result in a wobbling while the value of the tilt varies about these two limits? If so, how does it affect the mechanics ...
11
votes
2answers
3k views

How did Kepler “guess” his third law from data?

It is amazing that Kepler determined his three laws by looking at data, without a calculator and using only pen and paper. It is conceivable how he proved his laws described the data after he had ...
2
votes
3answers
310 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
votes
1answer
31 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 ...
-3
votes
2answers
80 views

earth is spherical , does it mean the ground on earth is like a ball? [closed]

I know earth is spherical in shape. Does this means earths atmosphere is spherical in shape or the ground/(land+water combined) is in spherical shape. I have some doubts if the second is true. ...
2
votes
0answers
50 views

The tidal locking problem concerning Earth sized planets in habital 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....oh ok I'm fibbing I can't do it. ...
-2
votes
1answer
51 views

Why does the sun rise north of east between the vernal and autumnal equinox?

Can someone please explain this phenomenon? A solid explanation seems to be missing from the entire internet.
-1
votes
1answer
62 views

Collision of two Earths

Assume that two Earth-like planets orbited the same star, with elliptic orbits. Eventually, something occurs that caused the two planets to collide. What would be the outcome of such a catastrophe? ...
-1
votes
1answer
45 views

How can I predict space directions?

Did the Neptune and Pluto trajectories ever cross or was it a mere reclassification? Do studies say that I can predict an intersection between 2 trajectories or movements based on data now? Do I have ...
2
votes
1answer
104 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 ...
-1
votes
1answer
52 views

How is the path of an asteroid calculated?

How do scientists and astronomers recognize the perfect path or orbit (if it's orbiting an object) of an asteroid or a comet? Just curious! Thanks in advance!
1
vote
1answer
59 views

Question: calculating orbit using another orbit

A satellite which is moving around a planet of mass $M$ in a circular orbit of radius $R$ is given a sudden thrust into the center of the planet, so that it deviates an angle $a$. Find the ...
9
votes
6answers
1k views

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 ...
2
votes
2answers
131 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 ...
0
votes
4answers
187 views

Is it possible for a star to orbit a planet?

Is it possible for a red dwarf to orbit a gas giant? OR Has this happened and it is just assumed that the gas giant is orbiting the star?
1
vote
3answers
89 views

Would Pluto keep an orbit without its moon?

I haven't studied space that much, but I know that Pluto has very little gravity, but just enough to keep a human on its surface. Would Pluto keep a regular orbit around the sun without some extra ...
6
votes
4answers
396 views

Are the stars in constellation located in a plane or they are in different distances

Are the stars in constellation located in a plane or they are in different distances from each other and when we observe them from the Earth we think they are all in a plane?
1
vote
2answers
84 views

What is the orbit of Earth around the Sun?

According to wikipedia and other sources, a planet and a star always move in a circular orbit around the common center of mass of the both bodies, in case of Earth and sun, this center of mass lies ...
6
votes
1answer
84 views

What determines the configuration of orbits in a binary system?

There are essentially two configurations of orbits a system with two bodies can have: A configuration where the paths do not cross: A configuation where the paths cross: Note: Size of the ...
1
vote
3answers
90 views

Stable polar solar orbit with the Earth continuously observable

Is there a stable polar solar orbit such that the Earth is always in view and not eclipsed by the Sun?
1
vote
0answers
46 views

Data for Sun's Orbit

The planets generally kindof orbit around the sun, but a more precise statement is that the planets and the sun all orbit around a common barycenter. Because the sun is so massive, this barycenter is ...
1
vote
1answer
51 views

How to convert a gravitational force to speed and direction

I am doing some calculations, and I wanted to know that after using the gravity equation, $$F = G \frac{m_1m_2}{r^2}$$ if you can use $F$ and convert it into a speed, such as km/year, and also a ...
5
votes
3answers
104 views

How do you calculate the effects of precession on elliptical orbits?

Kepler's first law states that planets (and all celestial bodies orbiting another body) travel in elliptical orbits, which have well-known formulas that make it relatively easy to calculate the ...
2
votes
1answer
46 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 ...
2
votes
2answers
93 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 ...
3
votes
1answer
50 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 ...
1
vote
1answer
60 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 ...
3
votes
1answer
115 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 ...
1
vote
1answer
118 views

Can General Relativity indicate phase-dependent variations in planetary orbital acceleration?

In a previous question about differences in Newtonian and GTR gravitional force for the case of star-planet gravitational interactions an approximate relationship was noted between the expressions for ...
7
votes
1answer
125 views

Explanation for the mathematics behind Venus' retrograde motion

I've always been interested by the pattern within Venus' orbit around the sun. I found this image and formula of its retrograde motion in the upper right hand corner which confused me. What does it ...
2
votes
2answers
140 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 ...
5
votes
1answer
480 views

Exercise: 2D orbital mechanics simulation (python)

Just a little disclaimer beforehand: I have never studied astronomy or any exact sciences for that matter (not even IT), so I am trying to fill this gap by self-education. Astronomy is one of the ...
1
vote
2answers
87 views

Is there a standard mapping of symbols to terms for celestial and orbital mechanics

Is there a standard mapping of symbols to terms for celestial and orbital mechanics (and physics in general)? For example here are some ambiguities Angular Momentum: L, H, J, $\Gamma$, Orbital ...
5
votes
1answer
86 views

How to compute satellite coordinates (lat,long) given antenna's coordinates, angles and satellite height

Given an Earth station (antenna) coordinates (in lat,long) ant its Elevation (El) and Azimuth (Az), how to compute the satellite coordinates (lat,long), known its height? For simplification purposes, ...
2
votes
1answer
216 views

What would be the dynamics of a double-planet system, similar to Earth / Moon, but with both bodies nearly Earth-sized?

Researching a sci-fi story involving a "twin-planet" system. Is such an arrangement (however unlikely) physically possible? And if so, must they be tidally locked with each other, similar to the moon, ...
4
votes
1answer
126 views

What is the correct ratio of Newtonian to General Relativistic gravitational effects for Sun + single planet orbital system

For a hypothetical orbital system (Sun + single planet) the Newtonian model and the General Relativity (GR) model produce different expressions for the gravitational effect of the Sun on the planet. ...
7
votes
1answer
104 views

Is Earth's orbital eccentricity enough to cause even minor seasons, without axial tilt?

I was reading the answers to this question about an exoplanet having seasons without axial tilt, and several responders mention that orbital eccentricity could cause a similar effect, but that the ...
1
vote
2answers
87 views

Why Earth's perihelion occurs 3rd January rather than 1st?

Why Earth's perihelion occurs 3rd January rather than 1st January? Is there any effort to correct this discrepancy?
2
votes
2answers
63 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 ...
1
vote
0answers
31 views

Advancement of perihelion, data

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 ...
1
vote
1answer
64 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 ...
3
votes
2answers
130 views

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

Is it about the same as Earth's orbital speed?
5
votes
1answer
162 views

What is the difference between Sphere of Influence and Hill sphere?

Wikipedia's definition of Hill sphere is: An astronomical body's Hill sphere is the region in which it dominates the attraction of satellites. To be retained by a planet, a moon must have an orbit ...
6
votes
3answers
194 views

Can you explain the pattern of Hill sphere sizes of the objects of the Solar system?

I found this image on calculations of Hill sphere for planets/dwarf planets of the Solar system. From http://en.wikipedia.org/wiki/File:Hill_sphere_of_the_planets.png I found it interesting that ...
2
votes
2answers
67 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 ...