Physics/universe

[Boaz]

ok, I really don't have the time/energy to make this a fully functional thesis so I will just put some points out there..

 

this is in no way a truely educated theory on the process/underpinnings of the universe but is rather just what seems to make sense to me from my few readings and my own thought process.

 

First: some basic "accepted truths" of the universe

1. The universe started small and then the big bang

2. The universe is expanding

3. There is not only matter...but also darkmatter, which we known exists by being able to detect its gravitational affects.

 

Next: some points of discussion/change in theory

1. it was expected that the universe's expansion would be slowing down, but recent data seems to indicated the very opposite is happening.

2. The first point tends to indicated a universal constant force(as Al "the brain" Einstien" suggested years ago)

 

Now..I step off into the morrase that is my mental image of the universe...

 

If the universe is expanding, then it would seem apparent to me that it isn't infinite, but rather something "outside" of it exists.

 

If there is someting outside of it..that would mean there is an edge or a area where the universe ends and the rest begins.

 

Albert suggested that E=MC^2. What if outside of our universe is pure energy(in some form or another) and when the Big bang happened, a "wave" of force was created, and this force can convert energy to either matter or antimatter.

 

Now if the just stated theory is correct, it might be the cause of the continued expansion of the universe. Energy is removed from outside of the "bubble" and matter/antimatter is created inside. This should create a "vacuum/void" outside and add pressure inside. Thus the force that is accelerating the expansion of the universe, or at least ofsetting the force created by gravitational pull.

 

Simply put think of a balloon with the ability to pull air inside...or think of the osmosis proccess in some cells.

 

 

yes..boring read.and I know I have to be way off...but just felt the need to put this down somewhere and get it out of my head.

 

 

Boaz

Demigod of Madness(as this post proves)

[Mira]

If the amount of matter in the universe was increasing, wouldn't we be able to detect its gravitational effects? Also, doesn't the fact that the universe is ever expanding mean that it is infinite?

 

Just some things to think about.

[Appy]

I was also under the impression that the amount of matter isn't actually increasing, merely that the universe is expanding... that one I heard too yes

 

Interesting theme of discussion, any physics around here?

[The Portrait of Zool]

An interesting para-physics subject is Quantum Metaphysics.

 

This might seem a little off topic, but once one starts to contemplate alternative views of physics one could start to explain other odd things like Presentiment or Quantum Teleportation or even consciousness itself.

 

It is an exciting age to be in when science is able to peer into the abyss of questions previously reserved for the mystics, and actually begin to see through the blackness...

Edited June 2, 2005 by The Portrait of Zool

[Nyyark]

The outter rim of the universe should be the initail energy released in the big bang, traveling at the speed of light. So it should be expanding at that speed, meaning that one would have to travel faster than light in order to escape the universe. In a sense it would be expanding at rate that makes it impossible to escape. Or so I think

[Venefyxatu]

Also, doesn't the fact that the universe is ever expanding mean that it is infinite?

According to my trusty dictionary, infinite means "without limits in space or time". Time is not as easy to explain my point of view for, but I'll try. I'll split it in two parts : past and future.

Past : since the universe was, at one point, "started", there was no universe before that. That means that there is a point in time where the universe has an extremity, where there is a clean cut between "no universe" and "a universe".

As for the future : so far there is no end of the universe in time at our end of time (fortunately). I'm sure some mathematician could come up with a term like "infinite to one side" or something, but as far as I'm concerned, we may assume that the universe is infinite towards the future until proven differently.

 

So that means that in time, the universe is either half-infinite, for those willing to accept such a term, or not infinite at all since there was a beginning.

 

 

Next : space.

 

If the universe is expanding, then there must be somewhere to expand into. Which means that there is a space in which there is no universe (i.e. the space into which it is expanding) and a space in which there is universe (i.e. the universe itself).

So if there is a space in which there is no universe, then the universe is not infinite in space.

 

What I'm about to say might cause some philosophers / scientists / ... turn in their graves, but apparently that's good against bedsore.

All my prevous ramblings would mean that the universe is only infinite in half a dimension out of four (to those willing to accept it being half-infinite in time), or most definitely finite (to those not willing to accept that).

 

The outter rim of the universe should be the initail energy released in the big bang, traveling at the speed of light. So it should be expanding at that speed, meaning that one would have to travel faster than light in order to escape the universe. In a sense it would be expanding at rate that makes it impossible to escape. Or so I think

Interesting thought! That would make it infinite in space for all practical purposes, but still not infinite according to my previously explained theory though

 

On a related note : I've never understood why nothing would ever be able to go faster than the speed of light.

 

 

I know, I'll never be a rocket scientist, but that won't stop me from playing with words and ideas as I have here.

 

Edit : I cna tpeay 493 wdsro pr mntiau

Edited June 2, 2005 by Venefyxatu

[Katzaniel]

Ah yes, the speed of light question. I know just enough physics to feel comfortable bungling this. (Warning: The following explanation will not make much sense, however when my prof explained it, it was enough to convert me to a believer on this issue, which I never was before.)

 

As an object approaches c, the speed of light, certain effects become more noticable. Time dilation, or distance contraction, for one. This is well-known and well-proven. A particle that has been accelerated to, oh say, 0.9c, will actually exist for more time to an unmoving observer than it would if it were moving non-relativistic speeds. The particle exists for the same amount of time as far as it is concerned, or anything in its frame-of-reference (ie, moving at the same speed in the same direction), but the observer seems to the particle to exist for longer, for exactly the same reason: both the particle and the observer are moving at 0.9c with respect to each other.

 

Light is the only thing that can travel at the speed of light for a few reasons. (Or, probably one reason, but a few ways to say it.) One is that anything travelling at c will actually be at the point where all distances are 0 and all time is infinity. (I think. I may have this backward, or be slightly confused on this point.) A photon, or "particle of light" sees everything happening at the same time, and everything in the same place. (That part I do know). And anything that travels faster than c cannot get information back to anything that doesn't. Since information is light, or some such, you can't see anything moving that fast, it just as well doesn't exist to us. I'm kind of confused here, but again, it made sense when my prof explained it. And lastly, mass is relative as well. As velocity increases to relativistic speeds, mass increases, and nothing can get to the speed of light without reaching infinite mass, except for a photon, which has a mass of 0 to begin with. Photon are intriguing little things, and I don't scientists are quite sure yet whether they're matter or waves; actually I think the current theory is that they have properties of both. Light is unique, and it has very strange properties that allow it to travel at c.

 

So, as far as I can tell, there might be things that travel faster than c, but they can't slow down to communicate with us in any way. Light, sound, et cetera all travel too slowly. This last bit is entirely my own conjecture, though... I don't know if any scientists even agree that it might be possible as far as that.

 

PS: "If the universe is expanding, then there must be somewhere to expand into." I'm not sure if everyone would agree with that. Some might say it's not space, it's not somewhere until it's universe... or some such. But I don't feel comfortable delving into that.

Edited June 2, 2005 by Katzaniel

[epinephrine]

YES!! Finally a disucssion I can get my teeth into. I am a physicist of sorts (I don't claim to be any Stephen Hawking) and this sort of discussion really flicks my bic!

 

So heres a few more thoughts for you guys and gals from my perspective.

 

Firstly all of the excellent ideas you have brought up are in the realm of physics that is currently up for debate. Your "basic accepted facts" Boaz are in themselves up for debate. Many scienctists in the USA are now starting to question the idea that the universe is only expanding. There is a new idea out there that it is expanding in some places and contracting in others!

 

But my current personal favourite mind twist is this... Einstein suggeted that space and time are somehow linked (thus the term space-time) and that space is in fact curved by the gravitiational pull of the objects within it. If this is the case then it does raise the idea of an "edge" to the universe and what is outside it if that is the case. One idea to mix in with all this is "zero point energy". This is the energy that exists in the very fabric of space-time. In other words if you could take away all the heat, enrgy, matter and everything else we can take out of a vacuum then there is still a base level of energy. And it turns out that the amount of energy is HUGE. One cubic centimeter of "empty" space has more energy than many suns. What role does this energy play in the expansion of the universe if at all? Could we harness this energy to travel faster than light? If we could would Einsteins clock paradox come to pass and would we go back in time...

 

And I've gone cross eyed. Sorry all I've done is bring so many more questions.

 

Well I have studied this for years and I still only have the bare bones of understanding. I will definately check this thread out a lot so come on all you budding physicists. Lets have a real discussion!

 

-a very excited epinephrine

[Venefyxatu]

First of all, thanks for explaining! It'll still take quite a lot of thinking on my part (or perhaps sleeping with your printed explanation under my pillow ^^ ) but I might actually understand it in the end.

 

The thing that will take me longest, though, is the part about light being able to travel at the speed of light because, for light, all distances are 0. In my mind, this is disproven by the simple fact that light needs time to cross certain distances.

I probably shouldn't take just that single piece of the theory and look at it, though, but rather look at the broader perspective.

 

I'll think on it, and then probably come back with more (and hopefully more intelligent / better funded) questions

 

 

PS: "If the universe is expanding, then there must be somewhere to expand into."  I'm not sure if everyone would agree with that.  Some might say it's not space, it's not somewhere until it's universe... or some such.  But I don't feel comfortable delving into that.

That's also an interesting idea ... the idea of there being nothingness. Just like infinity, a very hard concept for our human minds

 

 

 

By the way, has anyone ever read the Dark Tower series from Stephen King? Not exactly a scientific work, but it had another interesting theory ... that of our universe being only a bit of matter in another universe. I believe this is rather close to another theory I once heard about the resemblance between solar systems and atomic structures. I don't know too much about either, though.

[Vlad]

Ah, the light-speed conundrum. I'll try and keep the math out of it. [At least for now. ] Also, remember that I'm not cliaming to be completely right. I'm just relating what is, to my knowledge, accurate theoretical information. That, and I needed a better way to review for my final, which is tomorrow.

 

There's two defenitions of the world that we live in - Classical [isaac Newton's method] and Relativistic [Albert Einstein's method]. For all of these scenarios, it is assumed that we are in an ideal physical plane. Mostly, that just means no friction.

 

Let's start with how Newton and Galileo would answer some simple physics questions.

 

I throw a ball at you with a velocity of 10 m/s. When you catch it, it decelerates by 10 m/s. So far, no conflict.

 

We're both riding in a car going 40 m/s. I'm in the back seat, and you're in the front. I throw the same ball at you at 10 m/s. When you catch it, it decelerates by 10 m/s. No conflict.

 

I'm running forward at 5 m/s. You're stationary at a point in front of me. I throw the same ball at 10 m/s, with respect to me toward you. When you catch it, it decelerates by 15 m/s.

Why? Because we're in different inertial reference frames - The ball is already going 5 m/s before I throw it, and I add 10 m/s to its velocity. Still no conflict.

 

That's pretty standard, and most people won't argue that. Now let's get into the more complex ideas.

 

Einstein had two postulates that he based most of his work regarding relativity. The first is that different objects exist in seperate inertial frames. That's what I tried to demonstrate a few paragraphs ago. He goes on to say that relative to all other inertial frames, any one frame may be at rest.

If I'm riding in a car going 40 m/s, and I see you pass me at 45 m/s, I can say that I'm not moving and you're going 5 m/s. You can say that you're not moving and I'm going 5 m/s in the opposite direction. As long as there's no acceleration, it's completely irrelevant who's really at rest, and who's really moving.

 

That was the easy one.

 

The harder one to grasp is that the speed of light, c, is constant for all observers. If you can accept this one statement, then the rest of the explanation will flow quite naturally.

 

The Twin Paradox: Two twins are born on earth. One flies off in a rocket ship, while the other sits at home watching through a telescope. When the first twin returns he has aged very little compared to the second twin.

How can this be explained?

 

Let us suppose that every ten minutes, the twin left on Earth flashes a giant lamp. This sets up a very crude form of clock for our thought experiment. Because the twin in the space ship is travelling, he will experience a sort of Doppler effect with the flashes of light. For the sake of simplicity, we'll assume that he is travelling at such a speed that each flash takes 20 minutes to reach him when going away, and only 5 when approaching.

The math on this checks out, I can go through it if you wish. Either way it's not crucial.

 

The two twins have agreed that the space-ship will travel one hour out, and one hour back to Earth. This is where Newton's mothed stops being so elegant.

 

Knowing that each flash of light is spaced at ten minutes, it takes simple multiplication to figure out that he should keep going until the sixth flash, turn around, and arrive home on the twelfth flash.

So he flies out counting the flashes. Remember the doppler effect I mentioned earlier? Because of this, by the time the sixth flash reaches the space-ship, it's already been two hours for that twin.

Heading back, it takes him six more flashes, at five minutes apart to return to Earth. Thirty minutes.

 

Upon returning home the two twins check their watches, which were synchronized before lift-off, of course. The twin on Earth sees that the planned two hours have elapsed. The travelling twin sees that two hours and thirty minutes have passed.

Oops, looks like that time dialated.

 

Tell me when I can go on to explaining the Lorentz Contraction and why photons [light particles] have to be massless.

I've got to go review kinematics for an hour or so...

[Mira]

I suggest everone who is interested in such theories read Brian Greene's "The Elegant Universe". Its a great book that uses many clear examples to explain Quantum Mechanics, General and Special Relativity, and String Theory, as well as a whole slew of other crazy physics stuff.

[Katzaniel]

The thing that will take me longest, though, is the part about light being able to travel at the speed of light because, for light, all distances are 0. In my mind, this is disproven by the simple fact that light needs time to cross certain distances.

Hm... I could definitely be wrong about that part.

 

Tell ya what, I get back home (and therefore to my textbook) in a few days. I'll see if I can't figure out what the problem is then.

[Nyyark]

Good job explaining it Vlad. For the more math oriented (like me) I think I made sense of it by thinking that the speed (velocity actually) of light is measured by distance over time. Since it is an absolute but others could see it differently then either the distance or the time has to be a variable amount. While both seem constant I suppose distance wins out (in our current system) because time is treated as variable.

 

ofcourse that only explains the time thingy not the absolute thingy...drat.

 

Umm I think it was something like 'To increase speed(velocity) you have to accelerate. To acclerate you have to apply energy. Since energy can neither be created nor destroyed you have to get it from somewhere. More mass means more inenertia which means more energy. When its worked out to acheive the speed of light you need either all the mass in the universe, or no mass, like light' Atleast I think thats how I made sense of it...

[The Big Pointy One]

Ah, yes.. the universe. First off, I know very little of physics, but I like to think I have some valid points that rely more on logic than math. The first thing I'd like to address is the whole 'the universe is expanding' theory. I think the main problem with that theory is the definition of the word 'universe'. I think a more accurate statement would be 'The universe as we know it is expanding'. I don't know about anyone else, but to me, the basic definition of the universe is the infinite space and everything that resides within it that starts at wherever you're standing currently. To me, this includes all areas with stars, energy, etc. but also the areas without all of that. I'd need a diagram to explain it properly I think, but I look at like this. Anywhere that we can 'see' in this universe, anything that we can learn about with our tools, our science, our math, is only but the smallest fraction of the actual universe. We could explore for millions of years, and come to the 'edge of the universe' defined by the point where there is no matter, however assuming that that would be the whole of the universe seems grossly incorrect. I'm going largely on assumption as well, but I'd think it's fair to say that there could be other star systems across some void that we define as the 'edge' of our known universe. It's not like we get to some point, and it just stops; you can't go any further. Long story short, the universe is infinite in form. You can go X amount of distance one way, for all eternity even, but it's irrelevant. The universe just keeps going and going. It's hard to understand, because it's a paradox, but that's the way the universe is.

 

It's the same with time. This is the harder concept to grab, because it makes the least sense, but it is just unacceptable to believe that there was a beginning to time. What about before the beginning? There had to have been something there. It makes sense to ours minds to have a beginning, because everything we know has a beginning and an end; our own lives are the best example. Not to mention, that's probably why we have a hard time understanding any other concepts, because we as humans understand that *we* must have a beginning. Before we were born, there was no before. We just started one day. However, I do not think this could apply to the universe. It just doesn't make sense, no matter your teachings, no matter your faith, no matter your whatever. There has to have been *something*, but it just keeps going backwards. Damn, that messes me up everytime. Which brings me to the 'big bang' theory. Simply put, I believe that it's totally possible that there *was* some sort of big bang that started our solar system, our galaxy, etc... but I don't think that's how the universe got going.

 

I don't know, it all comes down to definitions. To re-itirate... our universe by my books, is *all* of space. Every particle of matter, and every blank space, the void, whatever you want to call it. Just because there's nothing there, that doesn't mean it isn't part of the universe. I'm sure there's other systems out there, way out there that we'll never find.

 

At least, that's what I believe. When I say these things, I'm not expecting anyone to agree with me; if I come across as vehement, it's because of how firmly I believe in what I'm saying, that's all.

 

/rant

[~O~]

A thought in two dimensions:

~O~

A couple of dots on a flat surface (labelled neatly "A", "B" and "C") would have to take up more room if they were to get further apart. Correct? So the "universe" would have to expand in order to continue expanding.

~O~

A couple of dots on a ballon can expand, and get very far apart (relatively), taking up space. But what's actually happening is that "space" is being moved from outside the ballon into it.

~O~

Let's define the universe as "everything". If so... then it includes nothingness. As a good friend of mine debated with our science teacher for a year during 8th grade... "nothing" is something. Even if it's nothing (ha ha) else, it's a concept. So it's part of the universe. So... by the "expansion" of the universe, what's actually happening is that different types of universal items are rearranging. If nothing becomes an element (Atomic number 0?), then it can trade space with any other element at will, then there's nothing outside the universe, making it infinite in respect to space. On the other hand... it can't constantly be expanding, either. We'd have to settle for merely rearranging.

~O~

And now a thought in the fourth direction:

~O~

I'm not a time-travelling tunafish. Evidently.