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Author Topic: Physics/Theory of Relativity questions  (Read 4032 times)

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Offline Vekseid

Re: Physics/Theory of Relativity questions
« Reply #50 on: June 17, 2012, 04:50:08 PM »
Spoiler: Click to Show/Hide
Easier to call them far and near rather than rear and front.

But yes, you have it. : ) The far door closes and opens before the near door does, from the runner's perspective. A runner running at such speeds in the opposite direction would claim the opposite ordering.

Offline Kate

Re: Physics/Theory of Relativity questions
« Reply #51 on: June 28, 2012, 10:56:59 PM »
The most awkward thing about physics is just one thing

Until a proven "theory of everything" exists , its hard to know with certainty ANYTHING.

Current theories of quantum mechanics and Relativity are very good STATISTICALLY, ie "these rules seem to explain ALOT, reality "seems" like this. Strangely subjective and objective reality become very different when some things get extreme

(extremely small, extremely fast, extremely dense, extremely energetic, extremely cold)
The more of an effort we use to pin down specifics the more stranger weird things seem to be all the "hard end points for any theory, are primarily more question marks than anything else"

Even if a "theory of everything" did exist, there may be SOME things that are unknowable practically.

Physics and science generally are VERY refined, educated guesses, many breakthroughs happen when previously existed notions that are accepted scientifically are questions and re-examined (or dismissed as "not the same context" due to a particular difference that wasn't deemed relent or considered before hand).

One large one is "universal constants", where did they come from ? Are they really "constant?" are they just a platua of values of a plane in a higher relativity that changes ( it just "seems flat" from where we are ). There was a recent article of some area of space where it seemed the universal constant for something was SLIGHTLY different to other places. What stunned the scientific community is that it was a basic "fundamental universal constant", that they thought all the universe was sharing.

"what is common" concerning laws of physics may vary from PLACE, TIME, and strangely ... the perspective that's experiencing it.
« Last Edit: June 28, 2012, 11:59:23 PM by Kate »

Offline AndyZTopic starter

Re: Physics/Theory of Relativity questions
« Reply #52 on: June 28, 2012, 11:53:52 PM »
Earth is spinning at roughly 1,000 miles an hour, revolving around the Sun at some speed (which probably varies to some degree), and the Sun moves around the galaxy as well.  All this adds up to some value which is greater than zero at which we're constantly moving, when compared to an absolutely fixed point in space.

I know that according to the special theory of relativity, the faster you speed up, the more time seems to speed up as well, so that you're aging less.  Theoretically, the converse should be true if you slow down, so that time would seem to slow down and you'd age more, right?

Has anyone ever tried to test it from this angle?  Reaching c would be impossible, but it should be much easier to get to a speed of absolute zero, assuming that from the perspective of a fixed point in space, we're travelling at less than half c.

Offline Vekseid

Re: Physics/Theory of Relativity questions
« Reply #53 on: June 29, 2012, 12:32:31 AM »
The most awkward thing about physics is just one thing

*snip*

Please see this thread, thank you.

Earth is spinning at roughly 1,000 miles an hour, revolving around the Sun at some speed (which probably varies to some degree), and the Sun moves around the galaxy as well.  All this adds up to some value which is greater than zero at which we're constantly moving, when compared to an absolutely fixed point in space.

It's really hard to know whether or not there even is such a thing, but we're moving at ~600 kilometers/second through the Intergalactic Medium.

Quote
I know that according to the special theory of relativity, the faster you speed up, the more time seems to speed up as well, so that you're aging less.  Theoretically, the converse should be true if you slow down, so that time would seem to slow down and you'd age more, right?

-You- wouldn't notice the change. People observing you, however, would. And you would observe the same of them until one of you decided to take a trip back and bring your concept of 'now' into agreement. Whoever undergoes the acceleration and deceleration to meet up will be the one who ages less.

Quote
Has anyone ever tried to test it from this angle?  Reaching c would be impossible, but it should be much easier to get to a speed of absolute zero, assuming that from the perspective of a fixed point in space, we're travelling at less than half c.

It's not necessary to find any such 'fixed point' in space (Relativity explicitly denies that such a thing, were it to exist, has any relevance). 600 km/sec in any direction would do. But we have much finer ways to measure such things. GPS needs to make relativistic adjustments as-is. A more startling example is decay particles from reactions in the upper atmosphere that, were Relativity wrong about this, shouldn't even reach the ground to be detected. And yet there they are.

More mundanely, just find a magnet. Or a piece of gold. Or some mercury.

Magnets are the result of electric charges moving at relativistic speeds.

Gold's color and mercury being a liquid is the result of their inner electron shells being contracted due to moving at high relativistic velocities (if you're wondering the obvious question there, an electromagnetic 'black hole' is created at about 174 protons, IIRC. Such an atom could not have electrons in its lowest orbital at rest, it'd eat them and start losing charge, probably violently >_>).

Offline Oniya

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Re: Physics/Theory of Relativity questions
« Reply #54 on: June 29, 2012, 12:39:17 AM »
The thing is, velocity is a vector:  it has direction and magnitude.  The magnitude is commonly referred to as 'speed', and must always be positive. 

Time dilation is a factor which changes based on the speed difference between two inertial frames of reference.  Two frames that are stationary, relative to each other (two cars going the same direction at the same speed, for example), have no time dilation - it's a factor of 1.  As one gets faster than the other, each perceives the other one's clock as moving slower, because if A assumes that it is the stationary one, then B is moving at the increased speed in one direction or another.  If B assumes it is the stationary one, A is moving at the increased speed.

In short, the best you can do by slowing down is to break even.


Offline AndyZTopic starter

Re: Physics/Theory of Relativity questions
« Reply #55 on: June 29, 2012, 12:43:42 AM »
Oh, so it's just perception of slowing down, and there's no actual time dilation?  That would make sense.  Otherwise one would have to go slower or faster than the other in time, based on which was moving faster in velocity.

Offline Vekseid

Re: Physics/Theory of Relativity questions
« Reply #56 on: June 29, 2012, 12:51:19 AM »
Oh, so it's just perception of slowing down, and there's no actual time dilation?  That would make sense.  Otherwise one would have to go slower or faster than the other in time, based on which was moving faster in velocity.

Time dilation is something that occurs between different frames of reference. It does not occur in your frame of reference.

And they both are going slower, until one decides to (and expends the energy to) meet up.

Offline Kate

Re: Physics/Theory of Relativity questions
« Reply #57 on: June 29, 2012, 12:51:30 AM »
Laymen view (feel free to correct me):

Time "slows down" for the object that is fast OR near a very heavy object to the "else". (if it was faster one would age faster)

What is hard to get is that if EVERYTHING is relative... and you speed yourself up relative to the world say 0.9999 the speed of light, you age SLOWER compared to the world, when you return to the world more time has passed for THEM.

Your younger than your twin brother who stayed on the world.

BUT the world was moving 0.9999 the speed of light compared to YOU.

So why doesn't the world age slower (ie those on it younger than you) to the Astronaut that returned as it was "moving at 0.9999" the speed of light for a period of X compared to the star-ship traveler ?

Is it due to "relative speed to the center of the universe", ie the one"reference point" that is universal?

Now if everything is rotating, and you go in the opposite direction to everything else, compared to the center of the universe your at te same speed. But you may be traveling at 0.5 c or something (compared to everything else around you) then what ?

It has to do with the "arrow of time", each quantum thing has its own "arrow of time" the less entangled you are with other things the more ind-pendant that arrow is (ie quantum things happen instantly going forward and backwards in time) that's when they are are only entangled with each other and nothing ELSE. What your entangled with you SHARE an arrow of time with.

But the larger you are the more things your entangled with, that why quantum fluctuations are smoothed on mass. (ie people dont generally experience quantum phenomena) - arrows of time is "resolved" ie shared, like a super-fluid / bosen (spelling ?) concentrate.

How to picture this ? a large sheet of iron, normally parts of the iron can have its magnetic field all over the place at random.
This most pieces of iron are NOT magnets.

But if you expose it to a LARGE magnetic field / surge of electicity ... over time all of its components like up and "share" a "magnetic arrow". And in turn becomes the SOURCE of the magnetic field that "keeps the arrow pointing this way"

Now swap the "magnetic arrows (field)" with "time arrow"

If all you knew was the sheet when "magnetised in this state" the arrow of time would seem "constant and universal and apply everywhere to everyone" from what you "SEE" that is true, everything else interacting with you is "sharing that background time arrow", but we dont "see everything" 90 percent of the unverse we feel with gravity but cant detect in other ways.

"the else" may not share enough constants to be "entangled" enough with us to even notice it in ways other than gravity. Ie two large sheets of iron had VERY different arrows (or whatever), interacting with each other may be HARD (ie effectively a different "dimension"

So in a localized area of space where everything can see each other "the arrow of time is shared", areas "not so entangled" may have the arrow drift differently.

Now if its "not so entangled" it interacts LESS with other things. Typically when things are heated / more energy they react MORE with other things, so the faster you go the more likely it is your hitting stuff etc (chemical reactions 1 degree higher are reacting 10 times as quickly, 2 degrees 100 times, three degrees Celsius 1000 times as fast a chemical reaction change compared to something 3 degrees cooler. ). This flow of thought is a "catch" though to this issue, and where rules of thumb / general knowledge / common sense / assuming shared contexts doesn' serve you.

Something moving at X mps relative to "BACKGROUND time arrow (a time-magnetic field) while entangled with it"
experiences what we know as "relativity". "Disentangling that" or having a change of "background arrow"

 => One of MANY hopes that a "theory of everything" (Assuming its knowable from what we can experience or do) .. may provide.

Now if everything that exists is vibrating in 11 dimensions (current view shared by most, not "the truth"). 3 or so are Drawn out and large ( spacial ) the others are very tightly bunched together. How many degrees of freedom things have due to these dimensions is amazing, now these "dimensional vibrations" behave and what they can do, how they change things is something that hopefully the theory of everything can provide.

In short, until we have a "workable" theory of everything "seems" is as close as we can get. If we do find a "theory of everything" it may just apply to our CURRENT conditions, and not explain that much of the "else" as we hoped, nor be able to predict when the current conditions will change and invalidate our current "theory of everything".

Everything gets stranger and stranger the more you know, the less you realize you know.

One famous quote that makes me believe we may be able to "get it" anyway was famous scientist who said something like

"The strangest thing I feel about the universe is that it seems to be bending over backwards TRYING to show its secrets to us"

For any "firm and hard theory" there seem to be contradictions. Like English "i before e except after c .. with the exceptions of this word oh and that one .. oh and this one also ... and also this one, oh wait another" ... if so many exceptions exist when do rules become useful at all ? For equations in physics Trying to have them minimalistic and still inclusive of describing everything is

... "When do you apply X assumption, rule Y ?"

... its a bitch and has our physicists in a state where they don't all agree on ANYTHING.

This MAY be true for different parts of the universe, or very differnt perspectives (Real in their own regard)
they may not agree on ANYTHING.
« Last Edit: June 29, 2012, 01:04:31 AM by Kate »

Offline AndyZTopic starter

Re: Physics/Theory of Relativity questions
« Reply #58 on: June 29, 2012, 12:55:25 AM »
Time dilation is something that occurs between different frames of reference. It does not occur in your frame of reference.

And they both are going slower, until one decides to (and expends the energy to) meet up.

Yeah, that explains my confusion.  There was some Sci Fi story (I think part of the Ender's Game series) where they would travel at close to the speed of light in order to slow down, so somebody stayed young even though hundreds of years passed on Earth.  Knowing that it's an equal and opposite perception and that time isn't actually affected helps make things make a lot more sense.

Offline Vekseid

Re: Physics/Theory of Relativity questions
« Reply #59 on: June 29, 2012, 02:05:35 AM »
Yeah, that explains my confusion.  There was some Sci Fi story (I think part of the Ender's Game series) where they would travel at close to the speed of light in order to slow down, so somebody stayed young even though hundreds of years passed on Earth.  Knowing that it's an equal and opposite perception and that time isn't actually affected helps make things make a lot more sense.

One way to think of this is, several hours later, they're a hundred light years away, but only a few seconds have passed on Earth. Earth starts chasing them at a similarly obscene velocity a few of Earth's hours later. Earth will catch up to them in several hours from Earth's frame - but will take centuries from the perspective of the people in the ship for Earth to reach them.

Naturally, at that point they'll have traveled a ridiculous distance from Earth's original frame of reference.

So why doesn't the world age slower (ie those on it younger than you) to the Astronaut that returned as it was "moving at 0.9999" the speed of light for a period of X compared to the star-ship traveler ?

The one who undergoes the actual acceleration is the one that experiences the time dilation, generally. The Astronaut accelerated to .9999c, decelerated to 0, than accelerated back.

Quote
Is it due to "relative speed to the center of the universe", ie the one"reference point" that is universal?

There is no such point. There can be no such point, as parts of the Universe are receding from us faster than light. You can make the math work by declaring the IGM to be a 'special frame', but that space is still expanding, and for our purposes, it isn't necessary to consider. That 'special frame' is no longer a single point, it's an abstraction of the Universe in its entirety.

Quote
Now if everything is rotating, and you go in the opposite direction to everything else, compared to the center of the universe your at te same speed. But you may be traveling at 0.5 c or something (compared to everything else around you) then what ?

Again, there is no such thing as the Universe having a 'center', except for one that is omnipresent.

Quote
It has to do with the "arrow of time", each quantum thing has its own "arrow of time" the less entangled you are with other things the more ind-pendant that arrow is (ie quantum things happen instantly going forward and backwards in time) that's when they are are only entangled with each other and nothing ELSE. What your entangled with you SHARE an arrow of time with.

The 'arrow of time' merely defines our perception of time, in that entropy represents an irreversible process and thus we can conceive of a 'past' and a 'future'. It is not, in and of itself, time.

Quote
*snip*

I think you've been reading stuff that has confused more than enlightened you. : /

Quote
This MAY be true for different parts of the universe, or very differnt perspectives (Real in their own regard)
they may not agree on ANYTHING.

All frames of reference, after working the proper math, will agree on what is happening to all other frames of reference, at least within the observable Universe to some suitably obscene precision. While e.g. a quasar moving away from us at .99 of c seems to be moving forward in time rather slowly, we know that a sapient observer living 'now' in said quasar will see the Milky Way much the same way (if our rather uneventful galaxy can be noticed so easily from such a distance, anyway - just pretend they have a better funded space program with bigger telescopes >_>).

While we do permit the idea that e.g. the 'Universal constants' may be able to 'change', e.g. the fine structure constant might have changed on the order of something like one part per billion or less over aeons - it's of somewhat limited relevance to this discussion. For one, we can observe that and take it into account, if it exists, but for two, even on the observable large-scale structure of the Universe, these variations, if they exist, are extremely tiny.

Offline Kate

Re: Physics/Theory of Relativity questions
« Reply #60 on: June 29, 2012, 09:57:40 PM »

AndyZ, one thing i thoroughly agree with V on is this post -

this thread

(My subjective stance)

Regardless if V has the "right take" on what happens if the theory of relatively is applied in your examples,
and indeed if relativity does seem to hold true in the macro sense in the same way as it does for smaller objects,
or higher order consciousness also.

you asked in a thread titled "Theory of relativity questions" but its also titled "physics" (Exploration of the real)

Like what V implied in his post, Concerning physics, its NOT the theory of relativity and quantum mechanics, theory of relativity and quantum mechanics are just imperfect (but VERY useful) TOOLs for physics at the current time.

Know that science often has a LIST of exceptions which doesnt seem to make common sense with the currently established understanding of some "Universal rules". "Faith" in any one of them that is thorough isnt met, if it was all would agree to one take of the theory of everything.

Still relativity has been shown many many times to be highly accurate at guessing what happens if ... then giving it a go to confirm - its a very close approximation to a lot of phenomena.

To me Stay inquisitive be open minded, stay awed, what "feels right and true and wonderous" and 'what this space" is something I hope you view as important as the views of any "experts" in a field.

Maths and science fields, all experts have a subjective lean on what they believe also, and yes although their work does remove filtered bias lenses most have, they are not immune to be ignorant or dismissive of the relevance of their own set.

Offline Oniya

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Re: Physics/Theory of Relativity questions
« Reply #61 on: June 29, 2012, 11:25:33 PM »
(My subjective stance)

Regardless if V has the "right take" on what happens if the theory of relatively is applied in your examples,
and indeed if relativity does seem to hold true in the macro sense in the same way as it does for smaller objects,
or higher order consciousness also.

One thing here - the 'take' that you refer to is not merely Vekseid's, or mine, or any one person's.  This is the 'take' of decades of research.  The general theory has been verified in ordinary gravitational fields. Citation.  Time dilation was observed - get that, observed - by Ives and Stillwell in 1938, and with more precision as better instruments came on the scene Citation (2010).  Labeling these theories as 'imperfect' is disingenuous at best.

Offline Kate

Re: Physics/Theory of Relativity questions
« Reply #62 on: June 30, 2012, 12:30:20 AM »
You have a point O,

But wasn't implying he was wrong  :)
« Last Edit: June 30, 2012, 12:37:57 AM by Kate »

Offline WhiteyChan

Re: Physics/Theory of Relativity questions
« Reply #63 on: July 10, 2012, 05:05:40 PM »
D'aww. I just missed out on all the fun of this topic. I'm doing an MSc in Physics, and one of my modules is 'Theories of Matter, Space and Time', which covers mostly Special Relativity (applied to motion, electromagnetism, and the standard model) and Lagrangian physics. I could have had fun with this topic. Anyway yes, Veks is pretty much right on everything.