Welcome to Gaia! ::

okay
He says space and time are the same thing (sorta)

I say
If you freeze time, everything in space 'stops'

Would it really matter if you froze space or time?
Could you theoretically freeze space, and thus freeze tiem

BUT theres a question

hold on, einstein said if you wre to go c then you would end up frozen compared to everyone else

(go around the world at c and everyone else if 40 while you are the same

That doesn't make sense
or deos it?

help me out to understand Einstein

What he said.
I was going to post somethign saying "You can't freeze time or space-physically impossible." But he kind of said that. sweatdrop

Well the reason Einstein found that time and space were correlated can be explained in several experiments. For example, if you take two clocks and synchronize them so that they show the exact same time, then you take one clock on a very high mountaintop and the other clock remains at the surface of the earth, after a certain amount of time you return from the mountain top and compare the time on both clocks. What you will find is that the time on the clock you brought back is lagging behind, so that time ticked slower when you were higher up.

The reason for that is, that since you were higher up, you were circling the earth at a faster radial speed (radial just means in a circle) than the person who was standing on the surface of the earth. Thus showing that time moves slower if you travel faster with the clock. Now, the difference at those speeds is miniscule, but if you crank your speed close to the speed of light, or even like 10% of it (that's very fast!) you will observe considerable time effects.

Now I believe that Einstein started with a thought experiment, but this was experimentally verified later and if you like more the practical things (like me) you will appreciate experimental examples that help you understand concepts.

In Special Relativity, Einstein first postulated that all inertial reference frames were the same. What that means is that for all observers moving at a constant speed can be considered reference frames at rest. You observe this everyday when you take a ride in a car, plane, or bus (bus is kind of turbulent) but you realize that you can walk around a bus as if the bus was standing still. From then on, he showed mathematically that through several equations (which VorpalNeko has taken care to introduce in a thread on the introduction of Special Relativity) we can show the inter-relation of space and time. Thus that your relative velocity has inpact on your relative time, at which point since those are so co-dependent he concluded that it must be 'spacetime' we live in and that time is infact not a separate entity.

good point.


the latter two experiments have more to do with GR than SR. in GR einstein showed that a non-intertial reference frame is the same as an inertial reference frame under the influence of gravity, which is how he was able to show that since non-inertial motion meant a warping of space time, so gravity also meant a warping of space time. The reason why the beam of light bends when it's passing the sun is because the sun has warped the space in its vicinity, and since things take the route of least energy, passing in a straight line on a curved surface (or in a curved line) is the path of least energy which is the one that the light takes.



well the conceptual and the mathematical are intertwined in all of physics, you can't have one without the other. It's not that it lies in the math, it's that math is used to explain it. Keep in mind this equation:

Δs^2 = Δx^2 + Δy^2 + Δz^2 - Δt^2

Where s is the spacetime interval, x,y,z are the spatial components in three dimension and t is the temportal component.

It's very much like a vector's length where if you follow pythagorea's theorem the square of the length of a vector in any direction in R^n space is the sum of the square of its components, except that in this one we also have time as one of the components. I'm not at home now.... I don't know when I will be, maybe late at night or sunday... probably. But I was looking through my special relativity textbook, it's a first year course so it's not so bad, I can give you more information if you wish.

A way you can think about the rate of time changing as the speed changes is, if you accept that the speed of light is the absolute cap on speed and also if the speed of light is the same in all intertial reference frames then time would HAVE TO slow down if these two postulates were to hold. For example, remember that dream einstein had when he travelled 'at' the speed of light, but instead of seeing a photon freeze all he saw was that beam of light travelling in his inertial reference frame at the speed of light as well? That's the idea though, because as you speed up, the speed of light must remain the same within your inertial reference frame which means that if velocity is not additive then your own temporal framework must be working slower to compensate for the fact that you can never catch up with a light beam. Tell me if this makes sense to you.

That is the energy for an object at rest, the whole equation is
E^2 = m^2c^4 + p^2c^2
where p is the momentum of the object. If the object isn't moving than p=0 and the equation is indeed reduced to E^2 =m^2c^4 or if you take the squre root of both sides this expression is equivalent to E=mc^2.

Since the mass of the photon is zero, all it's energy comes from its momentum than the energy of a photon is E^2=p^2c^2 or E=pc and since the photon goes at the speed of light then we can convert it's energy units by dividing both sides by c to obtain E=p or as is more familiar E=hf. where h is the plank constant and f is the frequency of the photon.

You are being a little disingenuous. While is is true that you can create a particle with a higher mass than the incoming particles in the accelerator [LEP-II is a prime example because it was tuned to the Z resonance (9118.7 MeV) and was an electron-positron (0.511 MeV each) collider] you need the incoming energy to be high enough to create a particle of a particular mass. The particles are so energetic we can often neglect the mass when it comes to calculations: the Tevatron has beam energies of 980 GeV, the 0.938 GeV mass of the proton is tiny in comparison.

Well, he's been proven right on a least one thing (Link).