Theoretical Physics discussion

I'm making this, mostly, because a staff member asked for me to make a proper thread for this, but also because the other one was getting a little cramped.

In here, do the title.

Also remember that Iam not all knowing on this type of thing; Ionly read about it. Alot about it.

---

So we left off here, with this question.

"Question time!

So, let's say we put a person on a space craft which is 30 years old and let that space craft travel around at or near light speed. If 50 years would pass on earth how old would he be on the space craft? And what age would he have when he'd go back to earth, after? Would he be 80 then, or that age that he'd have on the space craft?

Also, how would that effect the human body? (Not the years in the space craft, but the time thing). Would the body age slower, too?" -Carpesir

So to find the amount of time dilated we would use the Lorentz (time dilation) equation which is:

t=to((1-(v^2/c^2)))

(t) is the time dilated. (to) is the time outside of dilation. v is the speed. and c is the speed of light.

A note to make while using this equation is that if you are traveling light speed you will get 0, which means you do not age, but if you do a speed more than light, you will get a negative number, resulting in an unreal answer (which is one of the reasons why FTL travel appears impossible).

That being the case, lets use a speed a little slower than light - say 279 792 458 m/s

So, using this we get:

t=50((1-(((279792458)^2)/((299792458)^2))))
t=17.955
Which would mean, even though the earth experienced 50 years of time, the person in the spacecraft going at the speed 279 792 458 m/s would only experience about 18 years of biological change.

KOOPA. The theory is cool and all, but... math... why... why must there be math...

10-12-2015, 12:50 AM

ShadowedGrinner Wrote: KOOPA. The theory is cool and all, but... math... why... why must there be math...

Because Math is quite literally the universal language, and, when dealing with the universe, Math will be involved.

10-12-2015, 01:00 AM

KOOPAOU812 Wrote:

10-12-2015, 12:50 AM

ShadowedGrinner Wrote: KOOPA. The theory is cool and all, but... math... why... why must there be math...

Because Math is quite literally the universal language, and, when dealing with the universe, Math will be involved.

Doesn't mean I have to like it though. :rly:
I like the realism part of this cause I know someone is going to eventually try, and die a horrible and gruesome death.
I won't say much more than this since we've already discussed things along these lines.

"For time travelling, people say stuff like "DO NOT CHANGE THE PAST, IT'LL IMPACT THE FUTURE".
But what does count as impact to the past? Isn't it an impact already to be in a time where you basically couldn't be?" -Carpesir

Once again there are many differing views and opinions on this topic so i will be giving you my preferred view, which by no means is correct.

I think that, assuming you can travel back in time, once you reach the destination you would no longer be in the same universe anymore. This is partly due to the fact that time travel backwards is a near impossibility. It seems easier to travel to a new destination than altering what has already been cemented and forcing a rewrite of time.

So you travel back and you are in a new universe which would mean that any goal you set out to do on behalf of your people is now completely irrelevant because the people who exist in this new place are not the same people who you know. If you went back in time to stop a cataclysm, well too bad, you cant save those you love, but, maybe, you could save those in this new universe.

I like this idea because it would make most, if not all, paradoxes impossible, because you are not altering the past so much as you are meddling in a different present. (and as a side note the whole idea of a present is completely debatable because of the way time works and the limits of our brain in processing information) It also opens up the argument in support of Nihilism with there being an infinite number of realities, each with an infinite number of versions of you, which, to me, really makes it hard to care about anything.

10-12-2015, 05:04 AM

KOOPAOU812 Wrote: "For time travelling, people say stuff like "DO NOT CHANGE THE PAST, IT'LL IMPACT THE FUTURE".
But what does count as impact to the past? Isn't it an impact already to be in a time where you basically couldn't be?" -Carpesir

Once again there are many differing views and opinions on this topic so i will be giving you my preferred view, which by no means is correct.

I think that, assuming you can travel back in time, once you reach the destination you would no longer be in the same universe anymore. This is partly due to the fact that time travel backwards is a near impossibility. It seems easier to travel to a new destination than altering what has already been cemented and forcing a rewrite of time.

So you travel back and you are in a new universe which would mean that any goal you set out to do on behalf of your people is now completely irrelevant because the people who exist in this new place are not the same people who you know. If you went back in time to stop a cataclysm, well too bad, you cant save those you love, but, maybe, you could save those in this new universe.

I like this idea because it would make most, if not all, paradoxes impossible, because you are not altering the past so much as you are meddling in a different present. (and as a side note the whole idea of a present is completely debatable because of the way time works and the limits of our brain in processing information) It also opens up the argument in support of Nihilism with there being an infinite number of realities, each with an infinite number of versions of you, which, to me, really makes it hard to care about anything.

Wouldn't that practically make you a god though?
Considering it's basically you creating a new universe, anything you want to do to it, you can.

10-12-2015, 05:33 AM

ShadowedGrinner Wrote:

10-12-2015, 05:04 AM

KOOPAOU812 Wrote: "For time travelling, people say stuff like "DO NOT CHANGE THE PAST, IT'LL IMPACT THE FUTURE".
But what does count as impact to the past? Isn't it an impact already to be in a time where you basically couldn't be?" -Carpesir

Once again there are many differing views and opinions on this topic so i will be giving you my preferred view, which by no means is correct.

I think that, assuming you can travel back in time, once you reach the destination you would no longer be in the same universe anymore. This is partly due to the fact that time travel backwards is a near impossibility. It seems easier to travel to a new destination than altering what has already been cemented and forcing a rewrite of time.

So you travel back and you are in a new universe which would mean that any goal you set out to do on behalf of your people is now completely irrelevant because the people who exist in this new place are not the same people who you know. If you went back in time to stop a cataclysm, well too bad, you cant save those you love, but, maybe, you could save those in this new universe.

I like this idea because it would make most, if not all, paradoxes impossible, because you are not altering the past so much as you are meddling in a different present. (and as a side note the whole idea of a present is completely debatable because of the way time works and the limits of our brain in processing information) It also opens up the argument in support of Nihilism with there being an infinite number of realities, each with an infinite number of versions of you, which, to me, really makes it hard to care about anything.

Wouldn't that practically make you a god though?
Considering it's basically you creating a new universe, anything you want to do to it, you can.

Yes and no. For that example i was assuming that the destination was set. Of course with infinity anything is possible, including nothing happening. Also you are not really creating new universes, just traveling to ones which have not yet reached a certain point, like the idea that there is infinite amounts of universes still in the medieval era.

So if you could choose to go wherever you want, than, i guess, you could be considered a god, especially if you able to observe the universe traveling at light speeds. (because of the lack of ageing)

But there is a portion of Super String theory which states you cannot ever cross over into a different dimension, i can not find the exact wording for this reasoning, but it went something like "because something resonates at a different frequency it can not exist in a different universe because of that change in frequency" It was something like that, and it is frustrating that i can't recall or find that excerpt, but do know that it is thought that crossing over anyway is probably impossible.

If you would like to look into it further check out Super symmetry, Super gravity, and Super string theory.

10-12-2015, 01:00 AM

KOOPAOU812 Wrote:

10-12-2015, 12:50 AM

ShadowedGrinner Wrote: KOOPA. The theory is cool and all, but... math... why... why must there be math...

Because Math is quite literally the universal language, and, when dealing with the universe, Math will be involved.

In all honestly, I love math. While not being super good in it, nor have much knowledge about it, I still love it. Reading for example the equation you wrote makes me feel good for some reason.

Also, how often is math used in Physics? I often hear that Physics is one of the hardest things one can study while computer science being one of the easiest, if I now take a look at mathematics for IT 1 I can not imagine how physics math would be

10-12-2015, 09:37 AM

Carpesir Wrote:

10-12-2015, 01:00 AM

KOOPAOU812 Wrote:

10-12-2015, 12:50 AM

ShadowedGrinner Wrote: KOOPA. The theory is cool and all, but... math... why... why must there be math...

Because Math is quite literally the universal language, and, when dealing with the universe, Math will be involved.

In all honestly, I love math. While not being super good in it, nor have much knowledge about it, I still love it. Reading for example the equation you wrote makes me feel good for some reason.

Also, how often is math used in Physics? I often hear that Physics is one of the hardest things one can study while computer science being one of the easiest, if I now take a look at mathematics for IT 1 I can not imagine how physics math would be

In plain physics Math is pretty standard, the equations make sense as do there variables.

Like F=ma for force, acceleration, and mass. Or (1/2)at^2+Vit+s (the i is in the sub area, meaning initial) this is the position equation, which can be used to find distances, acceleration, time, velocity, and displacement.

With this stuff.... Well, it might just be easier if i show you.

https://upload.wikimedia.org/math/2/0/e/...93.pngThis is a fairly basic looking one, It represents the spacetime of general relativity when concerned with Riemannian manifolds. I dont know what that means, but it sounds interesting and definitely worth a read.

Than we have something like this:

https://upload.wikimedia.org/math/8/0/3/...330ca7.png

That is the equation for the general quantum state of n (any amount) of bosons. Now, the majority of this equation is greek, but you can see that there is a wheel and s straight pi in there. I don't know what those mean. at all. Although it would seem part of it is the Sum of the absolute value of Phi Norse wheel to Norse wheel Phi N. (Phi is used in standard physics to represent Azimuth angles, not sure if there is a difference.)

Physics is all math. All really really hard math. The only reason we have these theories is because of Calculus, since we can prove there validity by methods of integration and derivation.

10-12-2015, 04:55 PM

KOOPAOU812 Wrote:

10-12-2015, 09:37 AM

Carpesir Wrote:

10-12-2015, 01:00 AM

KOOPAOU812 Wrote:

10-12-2015, 12:50 AM

ShadowedGrinner Wrote: KOOPA. The theory is cool and all, but... math... why... why must there be math...

Because Math is quite literally the universal language, and, when dealing with the universe, Math will be involved.

In all honestly, I love math. While not being super good in it, nor have much knowledge about it, I still love it. Reading for example the equation you wrote makes me feel good for some reason.

Also, how often is math used in Physics? I often hear that Physics is one of the hardest things one can study while computer science being one of the easiest, if I now take a look at mathematics for IT 1 I can not imagine how physics math would be

In plain physics Math is pretty standard, the equations make sense as do there variables.

Like F=ma for force, acceleration, and mass. Or (1/2)at^2+Vit+s (the i is in the sub area, meaning initial) this is the position equation, which can be used to find distances, acceleration, time, velocity, and displacement.

With this stuff.... Well, it might just be easier if i show you.

https://upload.wikimedia.org/math/2/0/e/...93.pngThis is a fairly basic looking one, It represents the spacetime of general relativity when concerned with Riemannian manifolds. I dont know what that means, but it sounds interesting and definitely worth a read.

Than we have something like this:

https://upload.wikimedia.org/math/8/0/3/...330ca7.png

That is the equation for the general quantum state of n (any amount) of bosons. Now, the majority of this equation is greek, but you can see that there is a wheel and s straight pi in there. I don't know what those mean. at all. Although it would seem part of it is the Sum of the absolute value of Phi Norse wheel to Norse wheel Phi N. (Phi is used in standard physics to represent Azimuth angles, not sure if there is a difference.)

Physics is all math. All really really hard math. The only reason we have these theories is because of Calculus, since we can prove there validity by methods of integration and derivation.

Very interesting, thanks! I love the first equation, the second one is meh imo.

How would you calculate the time an object needs till it hits the ground? I often think about this, yet I do not want to google it because I want to get "my own" equation lol.
I thought up for something like t=om/h*s
Where; t=time the objects needs, om=object mass, h=height of where the object falls down, s=speed of the object