Gravitational Definition and 1000 Threads

Hi, so Newton said that gravity was like or equivalent to a force? When I learned about SR we were talking about the passing of time as defined by a photon bouncing between two parallel mirrors. So when we're sitting our two parallel mirrors in a gravitational field, even though I suppose...

Homework Statement A 60 kg skier is beginning her descent down a 26 degree slope. The frictional force between the skis and the snow is 4 N a) What is the gravitational force the skier exerts on the slope? b) What is the normal force the slope exerts back on the skier? Homework EquationsThe...

Many have claimed that if dark energy was not so small then the universe would fly apart and we wouldn't be here. However what if you increased the value of lambda and at the same increased the value of the gravitational constant ( or perhaps the amount of matter or dark matter in the universe)...

Homework Statement A particle of mass 52[kg] is at 5.0[m]ˆi a particle of mass 13[kg] is at 12[m]j, and a particle of mass 13[kg] is at −12[m]jˆ. What is the gravitational force on the 52[kg] mass due to the mass at 12[m]jˆ? answer: −1.0 × 10−10[N]ˆı + 2.5 × 10−10[N]jˆHomework Equations...

Homework Statement Two neutron stars are separated by a distance of 4.80 E 10 m. They each have a mass of 3.60 E 30 kg and a radius of 1.30 E 5 m. If they are initially at rest... How fast is each star moving when their separation has decreased to half its initial value? How fast is each star...

This pertains to a homework question but I get the concept of PE or U = -GmM/a for an elliptical orbit. I also understand the derivation of the total energy of an object in an elliptical orbit as E = -GmM/2a. However, I have a homework question that asks for the ratio of an object's kinetic...

The force of gravity is what makes things on the Earth rotate with it, instead of flying off. Doesn't this mean, however, that if you were to apply an upward force on something exactly equal in magnitude to the gravitational force on the object (so the net force on it is 0), it would cease to...

What would happen if I were to fly toward a gravitational wave pulse at relativistic speed? Would I be destroyed by the Doppler-shifted pulse? Would the wave become visible?

In the most recent postings on LIGO, it is stated that the amplitude of the signal is less than the diameter of a proton after the propagation of the wave over billions of light years. I am assuming that the wave amplitude will decay as 1/r^2, but perhaps that is an incorrect assumption. So is...

How does movement of the creator of gravity field( mass or energy density) affect the magnetude of exerted gravitational field ! Is there any relation at all ?

If a comet is orbiting a star is there any work done? I understand that work is force * displacement, but the force must be in the direction of motion. In the case of a comet and star the star exerts a gravitational force on the comet, but this force is not in the direction of the motion of the...

Hi folks. I see there is a similar thread on grav waves and time, but I have a few specific questions. Everyone talks about grav waves "in space" -- even Brian Greene was saying this on Colbert, whereas Colbert was saying spacetime. I would like to make a video on how GWs are indeed "waves in...

I was told that there are two kinds gravitational waves. One dies out as 1/r, another one dies out as 1/r^2. The former is what LIGO detected, the latter is not. While I trust the professional qualification of the person very much, as a non-physics professional, I would like to a second person...

G-Waves is a buzzword recently :) At the beginning I thought G-waves as the propagation of the changes of the curvature caused by a mass when the status of the mass (e.g. value or location) changes...But moment ago, I was told that G-waves are different from the waves that transmitting the...

I wanted to post the conjecture from this new paper which has recently been published within this past month - here's a direct link to the paper: http://arxiv.org/pdf/1602.01439v1.pdf Could an experimental apparatus consisting of oscillating masses be used to generate miniscule gravity waves...

Homework Statement Water flows from the faucet on the first floor of the building shown in the figure with a maximum velocity of 20 ft/s. For steady inviscid flow, determine the maximum water velocity from the basement faucet and from the faucet on the second floor. Assume each floor is 12 ft...

Homework Statement Choose two masses and vary their separation, measuring the force between them each time. Plot a straight line graph and use the gradient to estimate the universal gravitational constant. Include uncertainties in the results and express values with the appropriate number of...

An accelerating mass produces gravitational waves. Is there a smallest possible gravitational wave? Is there some quantum energy level lower than which a wave will not be produced? For example, would a slowly accelerated electron produce any gravitational waves at all?

According to the sticky bead argument, gravitational waves do carry energy. As such, are they, like photons (EM waves), subject to the gravitational pull of planetary bodies?

This is an unusual idea that I have been entertaining for some time, and I can't find anything about it online. However, it is so simple that someone must have conceived it before. First, I will elaborate my idea, then I will ask if it possible within the framework of General Relativity. There...

Today, someone asked me why "the warped space-time warps itself" (he read it in Kip Thorne's: The Science of Interstellar). I guess this is related to the gravitational self-interaction. But I don't really understand the gravitational self-interaction. Why the curvature in general relativity...

In order to detect gravitational waves at our present time and location, aLIGO has required a mind-boggling sensitivity, if I understand well it can detect variations in length in the order of 1/10,000 of the diameter of a proton. But space has stretched a lot during the universe's history. If...

Specifically, I am wondering if the stretching that a gravitational wave does to you as it passes through you, if the stretching was big enough (say half a meter), could it rip you apart, or does it not work that way? I know that gravitational waves that go through Earth do not get this big...

Homework Statement A spherical body of radius R consists of a fluid of constant density and is in equilibrium under its own gravity. If P(r) is the pressure at r (r<R) then the correct option(s) is(are): (more than one correct) (A) P(r = 0) = 0 (B) [P(r=3R/4)] /...

I have a couple of questions regarding the new detection of signals believed to be gravitational waves at LIGO 1. Two similar signals were detected at both facilities. Why does the Livingston signal appear to be weaker than the Hanford signal? 2. The signal in Livingston was reported to have...

Hi, So the gravitational waves detected by LIGO recently were transverse right? And this is because the weak field approximation which reduces EFE to linearized holds very well at such distances and these describe that the gravtiational waves will be transverse. I've read that you also get...

Homework Statement An 18.5kg box is slid up a 5.6m long ramp that makes an angle of 33 degrees with the floor. What is the gravitational potential energy of the box relative to the floor? Homework Equations Ek = 1/2mv2 The Attempt at a Solution My teacher gave me an answer of 550J, but I'm...

In about an hour I'm heading over to a local Coffeeshop Astrophysics meeting put on by researchers and grad students at UW-Milwaukee. The topic is the gravity wave discovery. Apparently some of them contributed to the LIGO project so it will be interesting to hear what they have to say. I'll...

What are gravitational waves in general, not just in the weak field/linearized theory?

I'd like to ask whether the Lens-Thirring effect, which is also known as Frame-Dragging, produces any kind of Gravitational Waves which might be detectable by a detector more sensitive than LIGO. There was of course the Gravity Probe B experiment not too long ago, which saw gyroscopes launched...

Dear Friends! Q.There was no direct evidence of binary black holes till September 14,2015,when signals coming from about 1.3 billion light years away were captured by LIGO. Now my question is that how in advance we knew about the specific colliding pair.Did we theoretically predict the graph...

Homework Statement Here's the question: As space colonization expands, it's important to build new stations from local materials instead of bringing everything from Earth. Your latest task (besides asking for a raise) is to check the long-term stability of a proposed configuration of asteroids...

1. If the Michelson-Morley experiment were to be conducted with gravitational waves instead of light waves, would the results be any different? 2. Ought we to expect the existence of "gamma" gravitational waves and "radio" and "microwave," etc. gravitational waves? In principle, could there be...

So say that there are twins. Twin A is near a heavy planet and twin B is out far away in space. Why does time slow for twin A compared to B? Can't they say that they both are in inertial frames because there are no forces(gravity isn't a force) acting upon them? Therefore for each of them can...

So the discovery of gravitational waves observed a contraction and stretching of space-time, and I've been trying to understand how the expansion of the universe means that space itself is growing. I want to understand how this actually works in relation to 'things' like a photon and an atom...

So everyone knows that the energy of a photon is E = hf, I assume this is just because light also has a particle nature. But how do we calculate the energy of a gravitational wave, because from memory classical wave equations have a mass component to calculate 'kinetic' associated energy, and I...

Hi, So apparently electrons don't orbit the nucleus of atoms so I'm assuming the lack of movement means that no energy from the atom is radiated away from an atom due to minuscule gravitational waves, over the life of the universe. But gravitational waves have got me thinking about reference...

light waves created inside a black hole cannot. Can gravitational waves escape from inside of black holes? in classical GR. does the answer change in string theory?

Electromagnetic waves are known to travel a c in a vacuum, but at lower speeds in a material medium. What about gravitational waves? They are also predicted to travel at c in a vacuum, but what about them traveling through material mediums? Do they get slowed down? by which factor? TX

Hi, as part of my physics assignment, I have the following question: As a spacecraft approaches a planet, the following measurements of velocity and radius were taken. From these values, a graph of v2 (y axis) and 1/r (x axis) was plotted. Use this graph to obtain a value for the mass of the...

Maybe a stupid question and maybe sensless to ask, but as I don't know, I ask anyway: what is the length of the newly found gravitational waves in terms of traditional EM wavelengths?

Are spacetime and the gravitational quantum field (still hypothetical) separate entities? Would the gravitational field be more fundamental, one of the various entities from which spacetime as a whole is composed? Gravitons, which are believed to transmit the force of gravity, would surely be...

Now that we have confirmed the existence of gravitational waves, have the odds of discovering a force carrying particle changed? With my limited knowledge it kind of seems like if gravity is caused by the warping of space-time, which was confirmed by gravitational waves, would mean that there is...

The aLIGO signal is a discrete event. In addition to such events that can be resolved into individual chirps, I would think that there would be a background of gravitational waves that would look like noise, but that could be distinguished from terrestrial noise (trucks passing by, etc.) because...

A lot is being written about the recent aLIGO observations and in general the implications of GW research for our scientific understanding of the universe. We read about mostly 2 grand areas where GW research can provide novel knowledge. The astronomical / astrophysical area (i.e. mapping...

Imagine a mass that disappeared from space. I know that it is impossible, but imagine it is sucked by a wormhole or it just disapperars. Will we detect ONE gravitational wave only? Like a pulse and nothing else? Now the other way around. A mass appears from nothing. Then we will detect one...

Someone has raised an interesting discussion about how one might experience these waves closer to the merging BHs. (Let's assume we're in a heavily-shielded spaceship that will protect us from all EM radiation and other effects except gravity.) First, how big? My back of napkin calculations...

Like many others, LIGO made me curious about gravitational waves. I found the paper: Nonlocal Gravity: Damping of Linearized Gravitational Waves http://arxiv.org/abs/1304.1769 I'm having difficulty understanding. Does that mean that damping is implicit in the terms of the tensors? Does it...

How is it possible to compensate for LIGO's movement in the recent measurement of Gravitational Waves? I can understand that we are able to measure something to a tiny fraction of a proton when the subject and observer are both moving relative to each other through space but how is it possible...

The recent observed gravitational wave is claimed due to two merging black holes colliding or infusing into each other. Could it be just another local Big Bang? (Of course I am implying Big Bang occurs in various scales). So "our Big Bang" was a large scale Big Bang and was triggered by two...