Space time Definition and 162 Threads

Hallo I'm new to this (wonderful) forum, and to SR too... I've a general question about the space time interval invariance. Say we have two points A and B, at rest each other, at distance AB. Now A and B simultaneously in their reference frame emit a flash of light. The space time interval...

Is this a possibility?

Homework Statement In frame S, Herman drops a pizza at the same time that Pavel drops a marker. In frame S', Alice is moving relative to their S frame - What is the space time interval she sees? A. S' > S B. S' < S C. S=S Homework Equations Lorentz transformations is what we've been...

"Temperature" can it alter space time why is temperature not taken as a dimension to study space time ... when the temperature of a particle increases it emitts light or radiations which travel at very high speed . according to speciel relativity when an particle moves at speed of light the it...

so you place worldlines on space time diagram, does anyone know how to do this? or any pdf on it?

Homework Statement Homework Equations s2=c2(t2)-(x2) The Attempt at a Solution so.. s=72ly and t=100y c=c (72)2=(1)2(1002)-(x2) solving for x which is the distance i get x=69.39 aprox= 69. my question is when do we know to let c=1 or c=3*108 m/s how do we go back and forth between light...

was it that singularity? what makes us so sure? what does GR predict? please be as detailed as you can and take your time if you have good information even if there are any equations. thanks in advance !

Has anyone looked at this, it seems interesting to me. arXiv:1006.0007 [pdf, ps, other] Title: Testing quantum-spacetime relativity with gamma-ray telescopes Authors: Giovanni Amelino-Camelia, Antonino Marciano, Marco Matassa, Giacomo Rosati Comments: 5 pages Subjects...

hello i understand that in a flat space the metric is \eta_{uv}dx^udx^v...i know that this means that the light follows straight geodesic in this space time... but ¿what would means that metric is f(t)\eta_{uv}dx^udx^v where f(t)=infinite in t=0 and f(t)=0 in t=infinite...obvious i...

hey guys, i jus got a question regarding space time fabric...if we take an example of a 2d fabric...it is distorted in the third dimension...now if it is a 3d fabric ( which is what it is supposed to be ) then in which dimension will it get distorted??

Can you rip the space time fabric!? if there is a fabric of space, the four dimension you could call it, space time, is it possible to rip it or open it up, for example do black holes do that, if not what, what would happen?

Ok, I have been wondering. I heard that Space/time is Curved when it comes into contact with mass correct? If this is so, then would it be possible to calculate the volume(or some equation) for the curvature of space/time around my own mass or a mass larger then mine? I have already...

hi, Zee in QFT in nut shell says "The most unsatisfying feature of field theory is the present formulation of gauge theories. Gauge symmetry does not relate 2 different physical states but the same physical state. We have this strange language with redundancy which we cannot live without" He...

If the Mass of an object is said to warp space time, could it be said that "gravity" is really an object trying to come to equilibrium within the warped space time, i bit like a cork in water. the reason we feel force at the Earth's surface is that the Earth is already at equilibrium which...

As you know 99.9999 % of our world is empty. Does this empty space correspond to Einstein 4D space-time.

http://arxiv.org/abs/0909.3456 Antigravitation Sabine Hossenfelder (Submitted on 18 Sep 2009) We discuss why there are no negative gravitational sources in General Relativity and show that it is possible to extend the classical theory such that repulsive gravitational interaction occurs...

Space Time "Fabric" limit? Has a study ever been conducted on the limit of mass that can exist at ant one point in space time? i.e.; Could the fabric of space time reach a breaking point with enough mass concentrated on a very small area?

Hi Was just going through this site http://casa.colorado.edu/~ajsh/sr/centre.html As i was going through i tired drawing the spacetime geometry for two objects approaching each other. So we would have both the space time planes intertwining each other.Does this mean that the even...

Homework Statement I am bit confused about the expression for finding the space time intervel. Some books say it is, (spacetime intervel)^{2}=(time intervel)^{2} - (space intervel)^{2} while some books say it is, (spacetime intervel)^{2}=(space...

I know the answer is many, some of them I already understand very well, time dilation etc, some other I might be able to grasp the idea (like light cone) and I will not be able to understand some others (i can't name it because i don't know what i don't know) I am a 2nd year physics major...

Hi Everyone, First post here. I'm a 37 year old man who has just recently begun dabbling in the basics of Physics, purely for the academic enjoyment of making by brain go "ow!". Upon reading the "bowling ball on a bed sheet" description of how the gravity of large objects can bend the...

I've looked (googled) but can't find any info on this experiment other than the apparent AP news release that is duplicated on several websites. If this is a real experiment in a lab somewhere, anyone know where to find info on it? I realize this story is just barely accurate fodder for the...

Please have pity on a poor ignorant layperson struggling for understanding... and keep in mind that I am mathematically impotent. I am trying to wrap my mind around the concept of expanding space-time with regard to quantum foam. Could someone please explain whether the "density" of quantum...

Hello guys. Is this even a valid question? Just curious. Thanks,

I've been wondering since a long time how does the space time curve affect the apple. If the apple isn't attracted by any force but because of the space time, then help me visualise the correct picture of space time which makes the apple fall on the earth.

What is spacetime? Where does it come from? Oft asked questions here. I recently posted the summary of a Scientific American article (found by Marcus) under the thread title, Emergent Quantum Spacetime, https://www.physicsforums.com/showthread.php?t=294666 Here is another view of how...

Hi guys, I got a question that has been in my head for a while. Is the Newtonian gravitational force equivalent to the "tension" in the space time fabric caused by the depression of 2 masses? If it is equivalent, does it means that gravitational force does not act in a straight line but it...

I have become very interested in physics and astronomy recently and have started dabbling. I have been reading about curved space time and its association with gravity. I've also been reading about time as it is related to travel at the speed of light. Can anyone explain the concept of...

http://arxiv.org/PS_cache/arxiv/pdf/0812/0812.3857v1.pdf Quote. In the first part of this contribution, we review the development of the theory of scale relativity and its geometric framework constructed in terms of a fractal and nondifferentiable continuous space-time. This theory leads...

Hi members, Can someone tell me the simple analogy of curved time & space.I've searched the google but have not been able to find an A-LEVEL STUDENT stuff.I need an introductory & beginner level idea.Thanks...

Why is matter not uniformly distributed across space time?? I was wondering why there is varying densness across space time and not uniform distribution of matter. and slighty linked to this, what is it that holds matter together, but also keeps it apart if that makes sense?? ie atoms bond...

Forgive me if this is a stupid question, I'll be trying to come up to speed over the next few weeks.. I am trying to recall a model of the universe that stuck in my head from a few years ago. -Does space-time's existence rely on the presence of mass? -When people say that space-time...

I recently read that space time is curved by and object with mass. The example given was of a trampoline with a bowling ball and pool balls moving across the surface. I can understand or at least visualize this easily. However, Since all objects do not exist on the same plane or do they, I...

hello every one m new in this blog ..... and also new one want to learn about special theory of relativity. can anybody please help me by giving explanation about how we can draw space time curve and how gravity work

If black holes stretch the space-time fabric because of their mass existing in singularity, if you were near a black hole, wouldn't there be a time-stretch?

Homework Statement A space-time is said to be conformally flat if there is a frame in which the metric is g_{ab} = \Omega^2 \eta _{ab} \text{ with } \eta_{ab} the metric in Minkowski. Is the general Friedmann-Robertson-Walkers space-time with line element ds^2 = -dt^2 +a^2(t)(dx_1^2 +...

the basic theory is that if you travel fast enough then time will go slower for you then the rest of the universe. doese anybody know if this is true or not?

HI, Is space time influencing by the speed or the acceleration ? Here the following problem : Marc and lisa are on earth. Marc takes his super spaceship and (from the lisa's point of view) almost reaches the speed of light. Then marc remain still for a few minutes. He doesn't accelerate...

Due to mass Space time curves. Consider the case of sun & earth. Sun,since it is heavy will curve the space more than earth.isn't it? Then how come the sun and Earth are being pulled towards each other with same force? The Earth has to straighten the curve (caused by sun)first,and then has...

in black holes it is said that space curves into itself and flow of time is not predicatble. what does these actually signify? what is "space curves into itself "?

keep in mind i am just an average high schooler who likes to read, but i was just wondering about something that i couldn't find in books or the internet. i know that the speed of light is 186,390 miles per second, so in turn you would have to travel that many miles to "go" back in time one...

Instead of calculating relative mass and density of an object to quantify gravity and gravitational forces, could Em field density be inserted into these calcs? why the shift from EM to Gr, relative to size? I know string theory is all the rage for unification, but why complicate an already...

Or how a metric can have an encoded evolution, quite simply a none intelligent evolution must have at least some (natural) rules, define those rules within known and testable scientific principles and methods

Is it energy? how is the unit of quantum space time (given) a value, so it can multiply several times over, is there a limit when the (energy) will be exhausted ?

Given that Dark energy supplies negative pressure: Does it have mass? Does it curve space? If so, does it help to close the universe? Can something that has negative pressure also make space more closed? Does it affect time dilation? How do you achieve a flat universe when there seems to...

It is just a thought, but how can space time be detected? i guess gravitational radiation is one way, is this the only way?

I have read that, on the scale of clusters (million light years) the effect of the expansion of the universe is 10 million times smaller than the gravity binding the cluster. So space time, (flows) through the cluster (like a super fluid) or akin to a group of logs staying in a fixed...

According to General Relativity the stars and planets cause a warp in the fabric of space time, right? Now, if planets' orbits are governed by the warping of the fabric of space time, then how are the gas clouds in Nebulas affecting that fabric? Also how do galaxies affect that fabric? Do they...

Everything that I've read about GR says that gravity is caused because mass wants to "slide" down the warping of ST like a marble falling to the center of a warped trampoline. But the marble falls because of gravity! We are trying to find out what gravity is! Some articles explain that...

I've heard there is a maximum magnetic field intensity in a neutron star. could this be related to the properties of the fabric of space time. I'm thinking of the idea that mass distorts spacetime for example the bowling ball in the sheet demonstration. My question is, is the max magnetic...