Gravitational Definition and 1000 Threads

Hello to everyone! I am trying to understand in practice the Gravitational Time Dilation by calculating the time distortion near the supermassive black hole Sgr A* in our Galactic Center. According to Einstein's Theory of General Relativity, the time distortion near a black hole is calculated...

I was thinking through a thought experiment which led me to conclude that mass is relative. My thought process was basically this; there are two objects moving past each other. In the reference frame of either object, they are at rest and the other object is moving. Since the other object is...

Homework Statement Why does gravity force decreases below Earth's surface? Homework Equations F = G (m1 m2)/r^2 F = force of gravity G = Universal gravity constant m1 and m2 = mass of the objects r = distance between two objects g = GM/r^2 g = gravity of the object G = universal gravity...

Note: I didn't really know where to put this. It isn't a specific problem, but I've been asked by my physics teacher, who decided to give me and a few others an individual physics course of sorts, to find the means of solving similar problems. It's the first problem he assigned us, since we're...

Homework Statement A uniform solid sphere of mass M and radius R is fixed at a distance h above a thin infinite sheet of mass density σ. Obtain the magnitude of the force between the sphere and the sheet. Homework EquationsThe Attempt at a Solution I've found the gravitational field from the...

http://www.bbc.com/news/science-environment-39212305

Homework Statement Discuss the motion of a particle in a central inverse-square-law force field for a superimposed force whose magnitude is inversely proportional to the cube of the distance from the particle to the force center, that is: F(r) = -k/r2 - λ/r3 and k,λ>0 Show that the motion is...

I have never met such an idea... Can anyone comment?

So a spherically symmetric object, by Birkhoff's theorem, does not emit gravitational waves. Is this why we look to binaries, so that there is some rotation of the objects with respect to each other breaking the spherical symmetry? Or mainly because the gravitational radiation is much greater...

Hello, I noticed something odd today while removing two identical tubs of cottage cheese from the fridge. They were stacked one on top of the other with no visual way to tell if a container was half full or completely full. When picking them up at the same time by only grasping "the lid of the...

http://science.sciencemag.org/content/355/6326/673?utm_campaign=toc_sci-mag_2017-02-16&et_rid=34818699&et_cid=1169695 Bummer :frown:

I have been through following papers for research: 1)http://cdsads.u-strasbg.fr/cgi-bin/nph-iarticle_query?1990ApJ...362..584M&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf 2)https://arxiv.org/pdf/gr-qc/9905054.pdf Conclusion of the second paper given above...

It occurred to me that if the speed of gravity is the speed of light, then the universe must be accelerating due to Dark Energy, What my question is do we know the frequency of gravitational radiation, If we do then any compression or expansion of these waves will change the cosmological...

I just read Carlo Rovelli new book "Reality is Not What It Seems: The Journey to Quantum Gravity" in one sitting and quoting the relevant passage: "The world is not made up of space + particles + electromagnetic field + gravitational field. The world is made up of particles + fields, and...

Homework Statement Projectile motion questions, Kinematics questions: my physics teacher defined acceleration due to gravity as -9.81 m/s2. Specifically in questions regarding: dropping an object, throwing an object downwards, obliquely launching an object. Today we are studying a box on...

Homework Statement The string (in the pic) is L=120 cm long,has a ball attached to one end,and is fixed as its other end.The distance d from the fixed point end to a fixed peg at point P is 75.0cm.When the initally stationary ball is released with the string horizontal as shown,it will...

As a hydrogen atom approaches a Neutron star, is the probability distribution of eigenstates of the electron in that atom influenced by the gravitational field of the star?

I know the formula for calculating field strength is g= GM/r2 , however if I'm trying to show the proportionality relationship between just g and m, would g ∝ m be correct, since a larger mass equals a stronger force of gravity and vice versa?

Something is wrong in my understanding of Relativity. There is an equivalence idea running around, which says that gravity and the distortion of space time by gravity waves acts the same way on all things. That would mean that all objects and light and space experience the same distortion...

Homework Statement There are a big object and an astronaut in space. How do we calculate the gravitational force between them. I enclose a photo. I have given the mass of an astronaut, the dimensions of this giant ring and density of the ring. There is also a mistake in the photo. The astronaut...

Homework Statement A 500 kg satellite experiences a gravitational force of 3000 N, while moving in a circular orbit around the earth. c) Find the Period of the orbit Homework Equations So found the period using (Please see the attachment to review my work.) but I also found it by using...

Homework Statement In a binary star system, the centre of rotation of the system coincides with its centre of mass. If the two centres do not coincide, there arises a net moment and the system will collapse.Homework EquationsThe Attempt at a Solution But refer to the photo, isn't Fh = Fh , so...

I am trying to find a derivation of gravitational redshift from a static metric that does not depend on the equivalence principle and is not a heuristic Newtonian derivation. Any suggestions?

I was looking for a qualitative explanation on how radiation occurs classically and came across this diagram. Which is for an accelerating charge. Then I started thinking if this break can occur for the gravitational field. Does the same thing happen for the gravitational field lines for a...

I have a few conceptual issues following a standard thought experiment to argue why light bends in a gravitational field and I'm hoping I can clear them up here. Consider an observer in a lift in free-fall in a uniform gravitational field and an observer at rest in the uniform gravitational...

Homework Statement Hi, Infinitely far away from a mass-->gravitational potential is zero. As get closer-->becomes negative. At surface-->it is the smallest value of r, i.e. the radius of the mass, hence the most negative value for gravitational potential. But as you go below surface of Earth...

Do we need more proof of dark matter than this?: https://en.wikipedia.org/wiki/Weak_gravitational_lensing

First off, I'd like to note that I am by no means a physics expert. I am merely a high school student and a physics/maths enthusiast, nothing more, so if my thoughts are completely dysfunctional and downright incorrect, which is more than a distinct possibility, please tell me. I recently took...

If my understanding is correct, all particles are sources of gravitational fields (albeit minor ones), and the gravitational potential energy between two bodies is given by: U = -GMm/r So, if we have two Z bosons (or any other bosons with mass but no repulsion due to charge) which are traveling...

say i were standing next to something very massive, like a battleship in drydock, and i were to hold a feather (not massive) very close to it. Would i witness any gravitational attraction between the feather and the ship? If not, why not? What if i did the same with a single filament of spider...

Homework Statement I know that in general it is when the gravitational field is not constant, so that part is fine. To find the gravitational force between a sphere with mass M and a radius R and a thin rod of length L and mass m which has one end a distance x away from the center of the...

https://arxiv.org/pdf/astro-ph/0006077v2.pdf page 5. Tensor Perturbations "Tensor perturbations do not couple strongly to the thermal background and so gravitational waves are only generated by quantum fluctuations, as in standard supercooled inflation". Why? Tensor perturbations are created...

Homework Statement On December 25, 2004, the Huygens probe separated from the Cassini spacecraft orbiting Saturn and began a 22 day journey to Saturn's giant moon Titan (see the figure below (Figure 1) ), on whose surface it landed. It is useful to know that Titan is 1.22×106 km from the...

I understand that any source of gravitational waves loses energy, which is carried away by the waves. But since the waves are perturbations in spacetime rather than a physical field, they cannot carry energy the way photons do. I have read that this used to be a source of considerable...

Hello all, I'm starting to learn the math in physics and have the following thought experiment I want to use to work through something I own. The setup: There is a wall 10m from the center of a 1m diameter sphere. There is a 1m diameter light source casting a 1m diameter shadow on the wall...

I am reading papers about dark matter and MOND. As they often mention this effect, I wonder how they know / measure / quantify how much gravitational lensing a particular galaxy causes? Thanks.

I was watching a show on one of the science channels a couple of nights ago and I think I heard that Jupiter's gravitational pull on the sun is around half a million miles (or could have been kilometers). Now, depending on Jupiter's position in relationship to Earths, at any time does it...

As the universe expands and is per definition gravitationally decoupled on long distances and the overall metric therefore is "flat" and apparently no gravitational background exists, the question in some discussion arose: Can GWs propagate in in a gravitational empty space at all? If not, and...

X has a mass of 55 kg and hangs from a rope. As a result of this the rope stretches by 0.6 m. Calculate the energy stored in the rope as a result of stretching. Solution: F = kx and E = 0.5x^2. Using this fetches the answer as 161.5 However, the change in potential energy (calculated using mgh )...

1. Homework Statement Homework Equations g = (Gm)/r2 The Attempt at a Solution I tried doing (Gm1)/a2 = (Gm2)/(r-a)2 where a is equal to the distance from the position we're trying to find to the center of the most massive object but end up getting a quadratic in the denominator on the right...

Homework Statement I wanted a proof that an object's center of gravity is the same as the center of mass by breaking the object into tiny pieces and then integrating over them. Homework Equations Well, the gravitational equation g=Gm1m2/r^2 The Attempt at a Solution I tried using some calc...

Pretend that we do not know gravitational law at all, and want to investigate the gravitational law by dimensional analysis: Let's suppose the gravitational force are proportional to both masses, distance, hence: F \propto m_1^am_2^br_{12}^c But obviously, there is no way to equal the...

Homework Statement I am told that the gravitational force of a mass m located inside an isotropic distribution of spherical radius R and total mass M is given by Fg = -GmM(r)/r^2 where r is the distance between m and the center of distribution and M (r) is the mass contained below the distance...

I was wondering how the energy and amplitude change over a distance

Homework Statement Halley’s Comet orbits the sun about every 75 years due to the gravitational force the sun provides. Compare the gravitational force between Halley’s Comet and the sun when the comet is at aphelion (its greatest distance from the sun) and d is about 4.5 x 10^12 m to the force...

One of my students asked if the graviational force at the Earth's centre is zero. The question was thrown open to the other students and two possible answers were given: zero or infinite! One way of reasoning is to say that the graviational force sums to zero as (assuming uniformity of the...

Homework Statement Question :- Two stars, each of a solar mass and radius ##10^7 m## are at a distance of ##10^{12} m## from each other. Find the speed of each star before collision if initial speed is negligible. Homework Equations $$V(r) = {-G Mm \over r}$$ The Attempt at a Solution...

Gravitational potential energy between 2 objects is ##-{G\times M\times m\over R}.## My question is, does the value of this equation of this equation mean total gravitational potential energy of both objects ? i.e, say the gravitational potential energy of object with mass ##M## is ##p## and...

Homework Statement What is the gravitational potential both inside and outside a spherical shell of inner radius b and outer radius a? Homework Equations φ = ∫g⋅da = -4πGMencl g = d∅/dr in the r hat direction The Attempt at a Solution I can get as far as getting the gravitational field for...

https://www.ligo.caltech.edu/video/gravitational-waves How do gravitational waves get emitted here? Is it in a sphere or on a flat(?) surface?