Space and time Definition and 140 Threads

Anyone know what books and astrophysicist has this knowledge? Thank you, Greg

Is it true that the time increase (24 hrs becomes 25 or 26 or..)when the mass of Earth is increase? ??

Hi all, How does matter curve space (what's the mechanism)? Does this Curvature happen instantaneously or does it happen at light speed? Thanks in advance.

The question is; After an object goes through the event horizon, is it possible for the object to reach the singularity? As far as i know, singularity, bends space down and actually space moves faster than light towards the singularity. But what tells us that the singularity's bending has a...

I am interested in looking at the metric where time is everywhere normal to space, so gta=0 everywhere, where t is the time coordinate and 'a' is any of the space coordinates. I'm finding it hard to look up in the literature: does it have a name that I can search for? My main interest is in...

We are told that space is expanding and that the rate of expansion is speeding up. However, as relativity shows that space and time are inextricably linked, does this mean that time is expanding too?

Hi folks, Tell me please why in classical Newtonian physics one can say that the space and time are independent? But we have equations of motion which clearly show this dependence (x=Vt; x=x0+1/2at^2+v0t). Thank you.

If time is a dimension, what would be the dimension of a photograph in such a space?

Then is potential energy infinite (potential energy=energy that can be created)

And virtual particles potential energy is infinite too? As more and more dark energy is created does this mean that the potential energy of dark energy is infinite? Does that happen for virtual particles in vacuum and vacuum energy too?

https://en.m.wikipedia.org/wiki/Vacuum_energy And it is this type of energy dark energy or a form of it?

I have been wondering about space time and how it works like satillites putting corrections in there clocks by a few nano seconds a day because of gravity or lack of it! But I have also wondered about the effects of being super close to the sun and time that we observe there looking back at...

If there was no mass/energy would space time still exist? In other words, does on space time only exist because of an interaction between two points of energy?

Hello I just got interested into quasars and I have a question:What metric do you use for quasars?

Homework Statement The identical twins Speedo and Goslo join a migration from the Earth to Planet X, 19.0 ly away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same moment on different spacecraft . Speedo's spacecraft travels steadily at...

Is there anything in all of physics about objects "beyond" or "outside" space and time? Do black holes qualify for such a description? What about the hypothetical Big Bang Singularity?

Hello everyone, I've come across a problem that i can't solve but which i find really interesting. I'm not here to ask where the big bang was because I've already read enough about that is was a singularity, so you could say that is was everywhere. But here my problem comes in, if the big bang...

For how long will we still be able to communicate with the amazing Voyager 1?

In my post graduate course, several years now, our professor in field theory have mentioned that in field theory the fields of mass-energy seem to be space and time themselves, like electric and magnetic fields in ElectroMagnetism. Specificaly he said that "the problem is that in...

I've been told contradicting ideas about this. I've been told that light doesn't travel at a constant speed everywhere (i.e. light slowing down in speed after entering a more dense medium). However, I've also read that light speed is constant everywhere (i.e. if you could travel close to the...

Does the constancy of the speed of light for all observers naturally emerge from the Minkowski spacetime metric? Do Einstein's two postulates of relativity emerge from the Minkowski spacetime metric? Suppose we begin with Minkowski spacetime and the Minkoswki metric...

Quantum Theory perhaps isn't really quantic, as It seems to me there is an underlying continuity. There are even some reasons to suppose that in Planck scale we will not see the discontinuity most of us expect. Professor's Craig Hogan superinterferometer is opperating in Fermilab; soon we will...

According to general relativity, time is a dimension, one of four dimensions that form 4D spacetime - a structure which is mathematically symmetrical and homogeneous. Should not all four dimensions, therefore, be mathematically interchangeable? Assuming that we are 3-dimensional bodies...

I have always been fascinated by black holes And I am sure that all the answers in physics are hidden in black holes... According to Einstein nothing can go faster than the speed of light, but nothing can escape black holes not even the light. Would it mean that the gravity resulting by a fall...

The concept of the fabric of time and space is confusing to me. I understand that an object with large mass can warp it, but that only makes sense to me if the fabric had only two spatial dimensions (assuming no warps). The space-time fabric is always explained visually as a flat plane, but...

what was space and time before the big bang thank you

I've heard many theories like object with mass bends the space-time and causes object to fall for it. If that's true then the Earth should end up being colliding with the Sun right? , because the Earth's mass is 1/1 million of that of Sun according to my knowledge. If we take Earth's mass as m...

I know that in relativity space and time form the fabric of the universe, and everything exists in space time, so I keep thinking, could the universe exist without space and time, could anything exist? Is there any idea in theoretical physics where the universe could exist without space and...

According to Special Relativity, the same event could have a different time duration and a different space extension for different observers, depending on their frame of reference. Relativity subsequently introduced the the notions of Spacetime as a continuum ( as opposed to the classical...

How did he figure out the many properties of the Universe such as time dilation/relativity and energy matter equivalence and his numerous other contributions. This might be a dumb question but was this all just done on paper? I don't recall reading that Einstein ever conducted experiments...

In "The Hidden Reality", Brian Greene mentions almost off-hand that inside the event horizon of a black hole, space and time are reversed. But no details are given. What, precisely, does this mean? Does it mean that in one's equations, if one is using a (-,-,-,+) signature, then everything...

I'll ask that you forgive me if my question seems to "basic" or simple for some of the more professional posters. I am simply a physics/cosmology enthusiast who has been captured by it all since I was a child, however, there is one issue that as I continue to learn more is bothering me. I...

In relativity spacetime is usually visualized by placing something on a stretchable fabric of some sort. The object placed on the fabric will bend the fabric, just as a planet or star would in real space. Time can be manipulated when something extremely massive like a black hole is in space. But...

Homework Statement My question is part C of problem 1.9: http://facultyfiles.deanza.edu/gems/lunaeduardo/4DHW.PDF Homework Equations Pythagorean Theorem? The Attempt at a Solution I have c vector of lightwave going upwards and v going rightwards forming a right angle with the other...

I know the general theory as proposed by Einstein but how has it been proved beyond a reasonable doubt?

I do not understand the difference between separation in space and separation in time. Could someone please explain the following positions to me? I would be very thankful and appreciative if so. Position of event 1: Separation in time (lightyears) = 20. Separation in space (lightyears) =...

Hi what constitutes a vacuum? I mean it has to be made of something, since it it part of the space time continuum. In school you learn that a vacuum is empty space or area without matter, but it occurs to me that a vacuum must be made of something and there must be something there. What is it...

is spacetime not the same as space and time ?? please explain what's the difference between "spacetime" and, space and time ? i heard space has it's own properties and time has it's own properties but "spacetime" has completely different properties. Please explain. Thanks

Einstein, in his paper "On the Electrodynamics of Moving Bodies", part 1, sec. 3, writes: "Primarily it is clear that on account of the property of homogeneity which we ascribe to time and space, the equations must be linear." What has the homogeneity of space and time to do with the degree of...

Its known that the speed of light is constant...(if you emit a light Eastward while your physically traveling East c will still be the same as if you were still) but also, through an experiment i am imagining, the speed of matter should be relative as well...(if your traveling Eastward and you...

Obviously before the big bang there was no space and no time, so how comes the big bang singularity itself existed without space and time? do black holes' singularities not need space and time to exist too? or at least in order for them to come and exist there has to be space and time at first place

--I understand that the original basis of string theory was as explanation for the ontological origin quanta . I have a few questions: 1) What is the origin and material make-up of the string? (How can we avoid the metaphysical pit-fall of an infinite regress in regards the ontological...

Are space and time things to themselves? Or are they just what things occur in? For example, fish occur in water, but water is a thing to itself and things occur in it (e.g. "fish"). Are space and time the same way?

Greetings! I'm new coming to this page but I have a question whose answer goes beyond my understanding of physics...really,even the question goes beyond my understanding but I feel comfortable enough to ask the question, just forgive me if I use the wrong wording... I've read and heard about...

Hello there, Some time ago, I saw a talk by a nobel prize winner. He quoted two other scientists, one was Witten, the other I cannot remember. Since that day I have imagined that it must be correct. Why? Because relativity predicts singularities are nonphysical nonsense. Yet, we can...

For -\frac{1} {4} F_{\mu\nu} F^{\mu\nu} We can write -\frac{1} {4} F_{i j} F^{ij} -\frac{1}{2}F_{0i} F^{0i} Where F_{\mu\nu} \equiv \partial_\mu W_\nu-\partial_\nu W\mu If there are 3 indices how can I separate them like this? I want to separate \frac{1} {12} G_{\mu\nu\rho}...

Is it really true that space and time are quantized or is it just a mathematical abstraction? If it is true, then what happens to this quantization under special relativity and general relativity? Is the minimum quantized distance different at the surface of a black hole than it is in the middle...

Say, we have empty flat spacetime; there is a lab frame and 2 particles - bradyon and tachyon. While movement of bradyon is stable, tachyon is believed to lose energy because of Cherenkov radiation: http://en.wikipedia.org/wiki/Tachyon#Cherenkov_radiation if it is charged and even if it is...

In the context of all the very latest theories of: The expansion of the universe, The effects of dark matter and energy, Gravitation and the other fundermental forces of nature, General and Special Relativity, Black hole singularities, Inflation, The size of the whole universe and...

How much matter or energy density can be allowed in space and time before it closes in on itself?