-4
votes
0answers
31 views

Stable figure-8 orbit of a binary system - Could these planets be habitable? [duplicate]

I've read the only other post asking about binary systems. If you actually read this one, you will see that my setup is different. I wish to know, for my specific setup, if this would create a ...
3
votes
4answers
503 views

Why are people weightless whilst in orbit around the Earth? ISS? Satellites? [duplicate]

Had physics for 2 years now on highschool, but there is a thing I am wondering about. You know the in the height above the earth surface around where the satellites are (Or the ISS), I've calculated ...
1
vote
2answers
146 views

Why do we orbit around the sun instead of one the other stars?

I am still very new to many physics theories, however while sat in class today, a thought came to mind that I have not been able to answer from simple googling. What is so specific about our sun ...
0
votes
0answers
30 views

Relative effects of forces

Excuse me for my ignorance but I really couldn't find a solution. According to Einstein, every happening is possible to describe by both of interacted objects. Is there any other way to describe the ...
11
votes
2answers
1k views

Is it probable that planets will stop orbiting in ellipses?

I saw this video, but I had the impression that orbiting in an ellipse or a circle is quite a coincidence - it depends on how the planet got into the Solar System. Because I think that either all ...
1
vote
1answer
66 views

Could an orbiting mass generate power?

If an heavy object (e.g. 10 tons) orbiting around Earth at 370 miles high, is connected with a cable back to Earth, we assumed either Earth is going to pull the mass or vice versa (or it will fall ...
1
vote
2answers
34 views

Ground velocity of satellite

I was wondering whether there is a simple formula in order to calculate the ground velocity (the velocity with which the satellite is moving along the planet's surface) on basis of the orbital ...
0
votes
2answers
31 views

Velocity required for orbit of satellite

I am very confused about orbital velocity for satellite launched from earth. It is states that: $$ v=\sqrt{\frac{GM}{r}} $$ Some says that it is equal to 8000 m/s and some say 3.1 km/s. Please remove ...
0
votes
1answer
28 views

Duration of Satellite orbit in the shadow of the Earth

I want to determine how many minutes a satellite is in a circular orbit around the Earth at about $1000 km$ altitude. I assumed that the Sun-Earth vector lies exactly in the orbital plane of the ...
0
votes
0answers
12 views

Keplerian Orbit Estimator [migrated]

While calculating the eccentric anomaly of a satellite using the Newton-Raphson method, what initial estimate of the root for E (eccentric anomaly) should be taken for least number of iterations(best ...
3
votes
3answers
86 views

Why aren't there more natural satellites orbiting the Earth than just the Moon?

Considering that there's a lot of debris in space and that impacts fling out rocks into space all the time, why do we only have one large natural satellite - the Moon? Shouldn't there be all kinds of ...
1
vote
1answer
35 views

Why are the true variance of these orbits out by ~pi?

I have an object that is orbit around a point mass in a 2D environment with a known speed, radius and zenith. I calculate the following orbital parameters as such and can confirm that these values are ...
18
votes
4answers
2k views

Why doesn't dark matter affect planetary motion?

If the universe is made up of ~95% dark matter, and it interacts only gravitationally then why didn't Newton and Kepler discover it before ? Why does it show itself only in the radial velocity profile ...
7
votes
3answers
1k views

Kepler's third law doesn't give earth's orbital period! Why? [closed]

I tried to calculate earth's orbital period using Kepler's third law, but I found 365.2075 days for the orbital period instead of 365.256363004 which is the correct value. I checked everything, and I ...
2
votes
1answer
20 views

Are retrograde capture orbits “easier” than prograde capture orbits?

After reading up on irregular moons in the solar system - moons that are thought to be captured, most seem to be in retrograde orbit around their parent body. That led me to wonder if retrograde ...
3
votes
1answer
54 views

multibody problem and determinism

Given that there is no exact general solution to the $N$-body problem, can it be concluded that the Universe is non-deterministic, even for the Newtonian case (ignoring relativistic and quantum ...
3
votes
1answer
61 views

Where can I find the list of the planetary motion equations?

The planetary motion equations are written in the ellipse equation format, i.e. $x^2/a + y^2/b = 1$. Can anyone please tell me where I can find the list of all the planetary motion equations, ...
3
votes
1answer
107 views

Mars Circular Intercept Orbit

I've been trying to simulate a spacecraft entering a circular capture orbit about Mars using Mathematica, but am having a little trouble. The simulation starts when the spacecraft enters Mars' sphere ...
0
votes
3answers
50 views

Orbital motion with varying radius

The model of a orbital motion in many Physics textbooks and online resources (e.g., Wikipedia on circular motion) assumes that the orbit is a circle, i.e. the radius is constant and the speed is ...
0
votes
1answer
85 views

Gravitation - why is it so confusing?

First, does gravity emit from all directions around a star or planet equally. Secondly, how is it that gravity pulls a planet closer, then it goes further out, without the planet changing orbit ...
1
vote
1answer
59 views

What are Lagrange points in gravitation fields? [closed]

What are Lagrange points in gravitation fields? Additionally, what are their properties? For example, if a satellite or asteroid rested at a Lagrange-point.
1
vote
1answer
55 views

Is sun revolving around certain mass in space with reference to some other galaxy?

Every planet and satellite revolves around their mother planet and about their own axis as we know. So they are compacted as a system. Then why not sun?
6
votes
4answers
115 views

What's is the origin of Orbital Angular Momentum of electrons in atoms?

Consider the Hydrogen 1s electron. We know that, in the quantum picture, the electron isn't orbiting or rotating at all, rather we simply state that the electron is spread over the entire space with ...
1
vote
0answers
26 views

Ratio of position error of orbiter to the size of the orbit

This is an assignment question for online AP physics. As if it isn't already tough. This question is killing me. I even asked my physics teacher from last year and my calculus teacher. It stumped ...
8
votes
2answers
498 views

What causes the orbital eccentricity?

I found some websites trying to attribute this to the external other forces affecting the 2 body problem to follow an elliptical rather than a circular orbit, but I am not convinced though. I think ...
1
vote
0answers
26 views

What will change if we have another Earth in the space near Earth? [duplicate]

If a new Earth came and orbit our Earth within 300,000 km to Earth? I just did not know. thanks.
1
vote
2answers
33 views

Why do we have a galactic and a solar plane [duplicate]

Why do all of the planets in our solar system move is (more or less) the same plane? It would seem that the planets should all have very different orbital planes, each at a different angel to each ...
0
votes
2answers
57 views

A small object on the opposite side of the earth's orbit with 0 velocity,“in line” with the core - would it collide with the earth?

If a small object (say mass 1 kg), at the opposite side of the earth's orbit (six months away), was placed in the same orbital position as the earth's core, at zero velocity in all directions, would ...
2
votes
2answers
136 views

Why do the planets orbit the Sun? [duplicate]

Why do the planets orbit the Sun? If it's because the gravity of Sun then why don't they just fall in and burn up?
2
votes
1answer
60 views

Energy/Momentum required to deflect earth from its orbit

This question occurred to me when thinking about the firepower people have on earth. How hard is it to change the characteristics of the orbit of the earth when an explosion happens on its surface, ...
0
votes
0answers
55 views

Calculate trajectory of projectile with gravity from disk planets in 2D?

I'm making a 2D game where you control a spaceship and fly between disk-formed planets of differing size (mass/pull). The planets are small and you can fly near several at once. I need to calculate ...
4
votes
1answer
50 views

How to derive Kepler's equation?

The Internet lacks, so far as I know, a derivation of Kepler's equation $$ M = E - e\text{sin}(E) $$ where $M$ is the mean anomaly, $E$ the eccentric anomaly and $e$ the eccentricity. Since there ...
2
votes
2answers
54 views

What may be effect of air friction to the velocity of satellite?

What is the effect of air friction to the velocity of satellite? I have heard satellite's speed increases with air friction. But I'm in confusion how is it possible?
1
vote
2answers
30 views

Finding sphere of influence in multibody system

I would like to draw a boundary illustrating the sphere of influence of each body in a 3 body system. What is the best way to find such a boundary? My understanding is at the edge an SoI is the ...
0
votes
1answer
41 views

Cheap launching objects to orbit [closed]

Why slingatron hasn't been successful ? Same thing with gigantic nail clipper. Since we dont need great force when arm length increases, why couldn't we build gigantic nail clipper orbital launcher ...
2
votes
2answers
72 views

How many celestial bodies could be in stable orbit at roughly the same distance from a star?

How many planet-like celestial bodies of roughly the same mass (say within 50%) could orbit a star at roughly (say within 10%) the same distance from the star and be in stable orbits. By stable I ...
0
votes
0answers
110 views

How explain this perturbing equation about the 43 arcseconds?

The planetary orbits have been studied as ellipses but the solar system is in motion in relation to the distant stars. Their path is along the tip of an helix and the ecliptic plane is a convenient ...
2
votes
3answers
113 views

How do scientists place satellites into orbit?

How do scientists place satellites into orbit? How do they calculate the gravity acting on the spacecraft in order to generate exact opposite force by means of Kinetic energy to keep the satellite ...
2
votes
2answers
109 views

Two suns, one moon, and one planet?

I have a question about how would seasons and the moon cycle be affected in a system where one planet orbits Sun #1, and Sun #1 orbits a second sun. Online I found this description: "Type II: ...
0
votes
1answer
71 views

Where does the potential energy go when mass is lifted out of Earth's gravitational field?

There is a finite amount of energy needed to be spent on a rocket or a rock that is taken out of the Earth's gravitational field. Lets suppose the rock is taken far enough to have no effect of Earth's ...
0
votes
2answers
83 views

Energy to move The Earth to mars' orbit?

How much energy would it take to add to the earth's orbital velocity to push the earth into mars' orbit? My thoughts: So, in 1-2 billion years, the sun will gradually get brighter. Suppose a future ...
5
votes
1answer
77 views

How did Kepler arrive at his laws?

How did Kepler arrive at his laws? If one already knows the distances to the planets (and the eccentricity of the orbits etc.) it is understandable how one might proceed to establish the second and ...
0
votes
0answers
76 views

Simulating orbits using Newton's Law of Universal Gravitation

I've been having a go at programming an orbital simulator from scratch (without using any existing libraries) using the formula below to find the acceleration first for particle A and then for ...
3
votes
0answers
63 views

Isn't the Jacobi constant just the Lagrangian times 2?

At this wikipedia page the Jacobi constant is expressed as: $$C_J=2\left(\frac{v^2}{2}-U\right)$$ where $U$ is the potential energy and $v$ is velocity. If kinetic energy $T$ is defined (as it ...
4
votes
3answers
110 views

Using 2D position, velocity, and mass to determine the parametric position equations for an orbiting body

I have a gravity-related question. I am programming an orbit simulator. I have everything up and running, but I would like to render the smaller body's orbital path (the larger body is fixed). To do ...
0
votes
0answers
80 views

True or false: the Moon was touching the Earth 1.2 billion years ago

A creationist website makes this argument for the 6,000 year old earth. I'm embarrassed to say I don't know how to do the math to evaluate the claim myself. However, the time scales involved seems ...
4
votes
1answer
145 views

Would a considerably big asteroid be disintegrated by the Earth's Roche limit?

If there was a big asteroid with a diameter of say 50km+ in a collision course with the Earth (not orbiting), would it disintegrate into smaller chunks due to the Earth's Roche limit, or the time it ...
1
vote
2answers
87 views

What are the correct initial conditions for the moon (in a simulation)?

So I've modeled the interactions between the sun and all the planets (and the interactions between the planets) using Verlet integration. I've used data from Wikipedia for masses, distance from the ...
4
votes
5answers
241 views

Does Gravity / curved space cause rotation?

Does Gravity / curved space cause rotation? Meaning, if a spaceship is heading not directly toward Earth, but slightly off to one side, and when finally being close to the Earth it falls into earth ...
5
votes
3answers
649 views

Binary Star system with one star stationary?

Can a Binary Star system be possible where in one star is stationary and the other star revolves around it? (Just like a planet revolving a star. i.e planets in the system and the star revolving ...