Gravitational Definition and 1000 Threads

Hello, I've been doing some research on gravitational waves since their discovery, and I found that all of the places I looked were missing an important piece of information, that is: What is the mechanism by which angular momentum is being conserved. All of places that I've searched will...

Two stones being dropped into a calm body of water at different times and sizes. The smaller one drops first, sending ripples out. Progressing in time. The second larger stone drops later, creating its own gravitational ripple which is larger than the first. Can the perception of time be altered...

The original question title was too long, so i changed it. My question is: Does the detection of gravitational waves prove the existence of space time? The question may sound odd. I had an argument with one of my friends, who says space time is only a mathematical concept, space does not exist...

When 2 black holes coalesce when is the peak energy created, when the BHs are close together or when they are fully merged.

I just wanted to ask a question, since it went through my mind after hearing about 'gravitational waves' after they have now, apparently, been identified. does everything realease gravitational waves when it collides? Since everything with a mass has gravity, wouldn't that mean that even when...

I have tried to discover if the local time as well as the local space is varied by the passage of a gravitational wave. I have seen animations and discussion of the effects of gravitational wave on space and test particles but can't find a reference to the changes in the time component of...

Dear Sirs My question relates to the recent observation of gravitational waves by LIGO. The paper PRL 116 "Observation of Gravitational Waves from a Binary Black Hole Merger -B.P Abbott et al"" depicts the chirp signal of the wave detected, where it is seen how both frequency and amplitude...

Hello, I have a basic question about the temporal duration of these newly measured gravitational waves. How long is the duration of these gravitational waves? Two black holes collided and created these gravitational waves a while ago. How long can we "listen" to these waves? When did they...

Does the discovery/confirmation of the existence of Gravitational Waves change or add to current theory in regard to Gravitons?

There seems to be considerable interest in the recent detection of gravitational waves. For the physics community this interest is fully justified. But in the popular press it seems to me to be reaching unjustified and perhaps harmful levels. When one reads overblown hype like: " A giant...

Could someone please describe the recent LIGO project, gravitational waves and their detection in simple terms. PLEASE.

The deadline for nominations for the 2016 Nobel Prize was the end of January. Since the detection and peer-review of the paper was most certainly done beforehand, who do you think is in line for the 2016 Nobel? My bets are on the three gents who spoke/got mention this morning in Washington...

Could I catch-up to a gravitational wave? Do the same rules apply as with light -- meaning the speed of GRs are frame independent, etc? Thanks.

What are gravitational waves exactly?

Following the new discovery of gravitational waves by LIGO, I just want to make sure I understand the concept of these waves. I believe I currently have a novice understanding of gravitational waves: when a large, fairly sudden change happens to the position of a particle (acceleration or its...

The LIGO paper https://dcc.ligo.org/LIGO-P150914/public puts limits on the dispersion of gravitational waves, which can be interpreted as an upper limit of 10^-22 eV on the mass of the graviton. We all know that low-amplitude gravitational waves are supposed to propagate at c according to the...

http://news.mit.edu/2016/ligo-first-detection-gravitational-waves-0211

Hello, I have read some of the posts which discuss the meaning and mistakes involving the equation: ## m_0 = \frac{h f }{c^2}.## My question has to do with gravitation. I would like to know if it is correct to associate to a photon with frequency f, crossing a region near a mass M, a...

There are rumours that scientists at Advanced LIGO have detected gravitational waves ... it is about 100 years after Einstein predicted they were there in his mathematical theory of general relativity ... Anyone know more about this rumour ...? Peter

Homework Statement A person lived 75 years in a city located 3.1km above sea level. How much longer could they have lived at sea level? (Times are measured by an observer at infinite distance). Homework Equations tr/t∞ = {1 - [ (2GM) / (r(c^2)) ]}^(1/2) Rc (Radius at city) = Rearth + 3.1km...

Homework Statement Two small objects of equal mass 3.0g are placed a certain distance apart. How many electrons must be transferred from one to the other so that the electric force between them is equal to the gravitational force between them? Homework Equations Coulomb's Law: F = K...

I am aware that the greater a body's velocity the greater its relativistic mass. As a result, I assume that the faster a galaxy is receeding from us, the greater its gravitational lensing affect is. My question is this: does the extent of a galaxies gravitational lensing continue to increase at...

https://www.sciencenews.org/blog/science-ticker/first-run-gravitational-wave-search-winds-down-rumors-abound?tgt=nr May be i was wrong and there is GR's, but this article is speculative.

How come that, in the context of discussing the search for gravitational waves, I never see the cosmological constant mentioned ? We know that ##\Lambda \neq 0##, so this seems strange to me; in the presence of a non-vanishing constant, the background is not Ricci flat in the vacuum case, so...

OK, I could probably find the answer of this simple question somewhere, but... If an astronaut stays on space station, in a weightless state, for 30 years, how much older does he/she become compared to a person who stays on the Earth all the time? I think it is about one second. Am I...

Note: I know this question has been asked before, but I wasn't allowed to ask my question on that thread 1. Homework Statement The gravitational self potential energy of a solid ball of mass density ρ and radius R is E. What is the gravitational self potential energy of a ball of mass density...

Homework Statement I'm reading the book Relativity, Gravitation, Cosmology by Ta-Pei Cheng. I'm in the part where he derived the gravitational time dilation formula for static gravitational field, τ1=[1+(Φ1-Φ2)/c2]τ2. This implies that clocks at a higher gravitational potential will run...

In section 4.4 of gravitational radiation chapter in Wald's general relativity, eq.4.4.49 shows the far-field generated by a variable mass quadrupole: \gamma_{\mu \nu}(t,r)=\frac{2}{3R} \frac{d^2 q_{\mu \nu}}{dt^2} \bigg|_{t'=t-R/c} I have the following field from a rotating binary...

I am doing an Astronomy GCSE. I have to work out the orbital period for a satellite. I have got quite far with it, but I am really stuck. I have spent hours at it! This is the question:- A space laboratory is in circular orbit around the Earth at a distance of 6000km from the Earth's centre; its...

I know that this question has been asked many times before on this forum, but on every existing thread either the question or the answers, or both, were too vague. I understand that inertial mass is defined as the property of an object to resist change of its velocity, that is the mass that...

Orbiting bodies are often stressed and twisted by the tidal forces of the larger body. My question is, if these stresses cause the planet to heat up then what system provides the energy to do this? Does the larger body lose energy? Can the gravitational field act as a medium for energy exchange?

Hi everyone I'm kinda new here, your support will really be appreciated ! :D 1. Homework Statement Let's say the cylinder has radius R, and height T. Homework Equations U = ∫GmdM/x The Attempt at a Solution My attempt is shown in the picture, I took a tiny element of the cylinder with...

We know gravitational force is created from the curvature in space time by the mass of the planet, but why doesn't it run out?

Can gravitational waves be treated like light or water waves? E.g. what would happen if two waves intersected at their max amplitude? Or what would happen if they intersected at a peak and trough?

Homework Statement A large sphere exists in space, which has a mass of 1 * 10^28 kg The sphere has a radius of 100,000 km What will be its gravitational pull (aka: "relative gravity") on its surface in terms of gs (1 "g" being equal to the gravitational pull of the Earth which is 9.807 m/s^2)...

For example if there were two objects orbiting each other and one was much heavier than the other, for instance a dwarf star and a neutron star. Would the lighter object have a greater gravitational pull than it's mass would say it should because it's pull was operating longer on the heavier...

Here is a gravitational slingshot figure from some homework exercise : ##m_1## is a small mass, say, a space probe, and ##m_s## is Saturn. The direction of ##m_1##'s velocity completely reverse direction due to Saturn's pull. ##m_1## come from very far away and end up very far away as well at...

Homework Statement Three uniform spheres are fixed at positions shown in the figure. i) What is the magnitude of the force on a 0.0150-kg particle placed at P? ii) What is the direction of this force? iii) If the spheres are in deep outer space and a 0.0150-kg particle is released from rest...

To note this is not for any piece of homework. Anyway, what possible masses and a distance between them are required for there to be a gravitational field strength of 1 Newtons per kilograms, when these figures are put into Newton's equation of F= G (m1 * m2 / r sqaured) Many thanks!

Please see the attached file if I have calculated the gravitational field g at the centre of a hemisphere correctly.

Here is the question with two parts The fastest that a human has run is about 12 m/s. a) If a pole vaulter could run this fast and convert all of his or her kinetic energy into gravitational potential energy, how high would he or she go? 7pts b) Using the 1990 pole vault world record of 20...

why is gravitational force always attractive in nature?

Hello, in nuclear physics we have a mass defect by the binding energy of the nuclides. A similar effect appears in the theory of gravitation induced by the gravitational binding energy, which reduces the mass. But for example at the ISCO of an Kerr black hole we have binding energys about...

My understanding of electromagnetic radiation is this: When a charged particle accelerates, there is a change in its associated electric field at all points in space, though not instantaneously. The "electric field wave" is basically the propagation of the disturbance that occurs when the...

Hello all, I could be looking at this the wrong way but here it goes: From what I understand, if a star collapses into itself to form a neutron star, it would become more compact, denser and heavier with a larger gravitational attraction. Now, if I understand correctly, the size of...

Question: There is a large parallel beam of incoming particles with mass m and uniform velocity v0 (v0≪c) in the presence of a gravitational field of a (spherical) planet with mass M and radius R. (without GR) The question is what fraction of the particles will eventually arrive at the planet...

Hi, I have often read that at large enough distances, the gravitational effect of a black hole is no different than the gravitational effect of a star or other body of the same mass. But that at close distances the difference shows up, for example the notion of the photon sphere at 1.5 times...

Hello PF members, Source of the gravitational field in the Einstein field equations is energy–momentum tensor and the curvature of space-time is directly related to the energy and momentum of whatever matter and radiation are present. Suppose a electron at rest . 1- Can this electron be...

Homework Statement Suppose an object of length “l” is located a distance “r” from a gravitating object of mass “M.” From physics you will learn that the gravitational acceleration is GM/r^2. Derive the difference in gravitational acceleration between distance “r” and distance “r+l” from the...

I'm trying to write a class for the gravitational field of any planet (I tested it with values for Earth though), and it gives completely the wrong answer! I suspect this is either a mathematical error, or an issue with my declarations of stuff as public, private, static etc. Compiles, just...