Orbit Definition and 1000 Threads

Hello, I will be thankful if you could explain what appears to me as a paradox. We know that a satellite on a circular orbit, let say around the earth, has a uniform speed given by v=√(GM/r0). Now I would like to accelerate the satellite by keeping it on the same circular orbit r0. The only...

I had this discussion while driving home to California from a trip to Washington state with a friend. We were discussing the stability of a completely rigid, untethered, ring-structure around Earth, and I did not know how to explain to him that such a thing must be tethered by rigid towers lest...

My question is, take Mars, say, and install a huge rocket engine on the ground pointing out the planet (obviously) and in the opposite direction of its velocity, so that if it is turned on, the planet is slowed. The rocket starts to work and Mars is slowed. If the loss of velocity goes little by...

Homework Statement I am working on a report dealing with the velocity and acceleration of objects in Earth's surface based on distance from the Earth and thus far I have used the orbital speed equation and the acceleration equation. To get dive deeper into the math I would like to attempt to...

I was listening to this lecture: and in it, sometime around the 30:00 to 40:00 minute mark, he implies that the torus' sturcture built up from the orbits of the group under addition on the real plane is the same idea as the cylinder's structure being built up from the orbits of the group under...

Do all stars orbit around the black hole in the same plane? Or some stars can have the same orbital radius but slightly different orbital inclinations?

I know when a Soyuz capsule returns from the ISS it has to orbit Earth a few times before re-entry due to all the momentum it borrowed from ISS. What would happen if your ship was in the Clarke zone? Assuming we have the radiation shielding covered already. Would it be conceivable that a ship...

Hi, everyone! I'm trying to find the period of a satellite orbiting the Earth by the next formulas with: miu= 398600.5; a=36770.48 km; I. 2*pi*(a^3/miu)^1/2 II. 84.489*(a/Re)^(3/2)min III. 0.00016587*a^(3/2)min And I got aprox. 19 hours from both formulas (I. and III.) which is correct. Can...

The essential question is can this tech be scaled up in the vacuum of space to add a substantial tangential acceleration to the orbital velocity vector of a piece of debris such as a speck of paint 1cm^2 in cross section. I am looking to deflect that speck of paint into a container or out of...

Hi! first time poster here. I'm making an orbital simulation and I am having a problem with one minor detail. The gravity is working great, and I've programmed it using this formula: A force vector is applied = DirectionOfCentralBodyNormalized * ((GravConstant * centralbodymass *...

Does GR allow for photons to be in a stable orbit around a massive body?

Homework Statement A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.70 × 104 m/s, and the radius of the orbit is 5.25 × 106 m. A second satellite also has a circular orbit around this same planet. The orbit of this second satellite has a radius of...

Homework Statement Consider the Earth's orbit around the sun orbit as circular. Suppose the sun slowly loses mass from mass M1 to mass M2. Suppose that the initial orbit is R1 and the final orbit is R2. Express R2 in terms of the other parameters. 2. The attempt at a solution The problem I'm...

If the units of angular momentum are quantised in integer amounts of ##\hbar##, does that then imply that we have restrictions on the smallest possible radius ##r## of an orbit of a given mass ##m##, given that the speed of light is ##c##. As follows, $$\hbar=m\bf{r}\times \bf{v}$$, where v is...

What happens to the path of Earth if a strong gravitational waves hit earth. Would there be a possibility of Earth moving out/changing the path of its current orbit? Can a high frequency gravitational waves knocks the Earth out from sun's gravitational field? (I know it is very unlikely that a...

Homework Statement Points on an elliptical orbit where the speed is equal to that on a circular orbit? Homework EquationsThe Attempt at a Solution I have attempted this question and my calculations show that at points on minor and major axes, the radial component of velocity is zero. Hence at...

Bear with me, this is a very specific question for a scifi book I'm writing. If we had a ring in place of the moon, and you lived somewhere in the United States, how often would the ring intersect with the sun when it's setting (or rising, if it makes it easier). I know that it can take up to...

Homework Statement Object A is at rest relative to the Earth and we want to put it in orbit around the earth, how much energy is necessary to do so? Homework Equations Ki+Ui=Kf+Uf+energy input[/B]The Attempt at a Solution what i don't understand is, if the body is at rest, Ki=0, but don't...

I'm examining if a massive superflare early in the solar systems history could be the explanation for the odd positions of certain planets and moons in our solar system (and their rotations). For this test, I've taken Mars as an example. I’m going to place Mars in the early solar system in an...

Hi, was just wondering if gravitational orbit be achieved inside the Earth's atmosphere. Or how close a satellite can be to the ground? Additionally, would the Death Star have been completely covered in solar panels?

Homework Statement Satellite m=3 000kg, circular orbit at the height h = 300km above the Earth´s surface. a/ calculate energy ( work ) for delivering satellites into orbit ? b/ during 1 month the satellite approached the Earth of Δh=13,8 km. Prove that the radial component of velocity in...

After talking to a coworker, I looked into the wikipedia article on "Gravity of Earth". I found that the Earth's gravity is not uniform, which makes sense (never thought about it). I have always wondered why satellites de-orbit over time. Someone told me that there is enough space dust to slow...

I wonder if this question will make sense, but I will do my best shot: As the electron orbits around the nucleus, I imagine there are moments when it is too far away, so it starts to be "pulled toward" the nucleus. If it gets too close, it will be "pushed away". If it is in the orbital area...

I have a satellite orbiting at a velocity of 3850Km/hr around planet Earth in a circular orbit, please help me in calculating it's height of orbit. I do know that the closer a satellite is, the faster it's orbital velocity, and the farther it is the slower it would be, and help me with the formulas?

Suppose I have to determine position and velocity of spacecraft from Range and Doppler measurements. Does range measurement only give position estimate and doppler only velocity estimate? Or range can give both position and velocity?How are they related?

The N body problem has no closed solution, and in many cases closely spaced bodies around a major body kick members out. In our solar system we have Titus Bode relationships that space orbiting bodies out in a geometric series. Various resonances are common. In Trapp1st 1, the planets are...

I had been informed that for objects in free fall orbit no proper acceleration would be measured. https://www.physicsforums.com/threads/stationary-frames-of-reference.899195/page-2#post-5658771 But I also understood it that for objects in free fall orbit gravity time dilation would be observed...

I know that moons tend to orbit their planets in a slightly elliptical orbit rather than a perfectly circular orbit. But for the purpose of this thread, let's assume that moons effectively orbit their planet in a circular orbit. So here is the question... If our moon was struck by an object...

Hello. Is there a formula describing the shape of the orbit and the size of the orbit given the tangential and perpendicular speeds? This would be based on the assumptions that the planets are point particles, everything is in a vacuum, that there are no other gravitational fields, and that one...

Homework Statement A 1 500kg satellite is in orbit 250km above Earth's surface. What minimum additional energy is needed to place this satellite in a new stable orbit 800km above Earth's surface? Homework Equations W = delta Ep = -GMm(1/r2-1/r1) Ep = -GMm/r Ek = GMm/2r or 1/2mv^2 The...

Homework Statement At a circular orbit and at an elliptical orbit when do I use 1/2mv^2 instead of the kinetic equation from which I derived from F=GMm/r^2 which is Ek = GMm/2r Homework Equations F=GMm/r^2, Ek = GMm/2r, Ek = 1/2mv^2 The Attempt at a Solution For instance, when I tried to...

Today I was doing some reading and I came across this topic. If we have a stationary hydrogen atom with a single electron in orbit around the nucleus and want to calculate the kinetic energy of the electron we would take the following approach. 1) Using Newton's second law: F = ma ⇒ FE = mac...

Homework Statement Scientists are planning to launch a rocket from the surface of the Earth into an orbit at a distance of 18000 km above the centre of the Earth. The radius of the Earth is 6400 km and it has mass 6.0x10^24 kg. What is the minimum work done to move the 150kg mass of the rocket...

We know that the dinosaur was wiped out by a big meteor. Imagine a bullet hitting a hard surface,the Impact from the bullet should have moved the surface backwards right? So imagen that the meteor represent the bullet hitting the Earth and with that kind of impact it should have moved the Earth...

Let f be a continuous function of a metric space, M, to itself with a dense orbit and a fixed point. I.e. there exists z such that the set {f(n)(z)} for all n ∊ N (where f(n) is the nth iterate of f) is dense in M, and there exists p such that f(p) = p. Does this imply that f spreads? I.e. does...

Homework Statement A stationary, axisymmetric, spacetime has two Killing vector fields [ξt, ξφ] corresponding to translation along t or φ directions. A particle of unit mass moving in this spacetime has a four-velocity u = γ[ξt + Ωξφ]. (i) Explain why we can interpret this as a particle moving...

If the sun suddenly disappeared, we wouldn't know it for about eight minutes because that's how long it would take the light to travel the distance between the sun and the earth. But I've often wondered; if the sun suddenly disappeared, would the Earth continue in its orbital path around the...

I understand that in a 2-body system a circular orbit is gravitationally stable in General Relativity. In Newtonian dynamics, an elliptical orbit is also stable, but is this also true in GR? I understand that the orbit precesses, but I do not intend that to change my meaning regarding stability...

Homework Statement A satellite is orbiting an still planet, the farthest part of the orbit is at 200 km and the closest part at 100 km. what would be the speed of the satellite at the closest part of the orbit at 100 km if the speed at the farthest part is 1 m/s? Homework Equations L=mvr The...

So, it seems there's a new twin paradox thread every day, but I don't think I've seen this particular situation looked at. The two twins move towards each other each in a circular orbit, and at one point they get close enough to each other that they can compare clocks directly (but their...

Homework Statement Using the polar formula for an ellipse, and Kepler's second law, find the time-weighted average distance in an elliptical orbit. Homework Equations The polar formula for an ellipse: $$r = \frac { a(1-e^2)} {1 \pm e cos \theta},$$ Area of an ellipse: $$ A = \pi a b $$...

Homework Statement A satellite moves in an elliptic orbit with eccentricity e=1/2 around a planet which it was launched. When it arrives at an apsis( a radial turning point), its velocity is suddenly doubled. Show that the new orbit will be either parabolic or hyperbolic depending on which of...

Homework Statement In order for the enterprise to use its transporter it must be in synchronous orbit over the beam-down point. What heigh above the planet Mars must the enterprise be for a synchronous orbit? Homework Equations Please, can someone tell me for future reference what I should use...

Homework Statement I am given this equation: where m and M are masses. I have to obtain the following as a final result: Homework EquationsThe Attempt at a Solution so far, I have done this (This may not be the most efficient or the easiest way, but it is how my professor wants it to be...

Homework Statement Find maximum possible aphelion distance for a Kuiper Belt comet with an orbital period of 216 years? What is the eccentricity of this orbit? What prevents a periodic comet from following this precise orbit? Homework Equations perihelion = a(1-e) aphelion = a(1+e) 2a =...

so imagine a rocket with module is not going into orbit but just, after loss of stages, continues to a lagrange point. At what distance, before reaching the actual point, could the module with some leftover fuel and maybe solar power or wind stay there, let us say for some months, before new...

Hi! This is a textbook problem that I need help with (I want to practice as much as I can before the exams) and I hope that there is someone who can guide me. The question is: You’re doing a first-order analysis on a new satellite in an elliptical (e = 0.2) orbit at 700 km altitude. Can you...

Let's say a single human exits the atmosphere? Why doesn't he orbit the Earth like the moon does? Why does he drift in space instead?

Disclaimer: The questions below were raised by an article that's most definitely pseudoscience. The questions themselves have nothing to do with what makes it "pseudo", though, so don't let that put you off, please. :)Quoting from [crackpot link removed by mentor] (I'd advise you only to read...

Suppose that we want to compute the total time dilation for a clock located in an orbiting satellite relative to the clock in our cell phone on the ground. Consider two different approaches below. 1. Use special relativity and compute time contraction due to velocity. Use approximation of...