Shoutbox

Of course, you can actually make light travel faster than c (the speed of "light" in a vacuum) see here.

The idea is that only things with mass are subject to relativistic effects. The general proof for this is:


And the proof that nothing with mass can travel at the speed of light:
E(kinetic) = ½mv² . Since m->[infinity]; as v²->c², E(kinetic) -> [infinity]; as v²->c².

Of course, if you were to convert mass into a stream of information and then broadcast it as an electromagnetic wave, re-synthesising it  at the other end (you'd need to make use of Heisenberg compensators) - then you'd be able to travel at the speed of light, or faster through the super-materials mentioned in the first article above.

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It's a shame really, I had my AH Physics test today and none of this came up .

friction is always there, except on a vacuum, uti.

5000 years would still be stretching it for a race to travel from one inhabited planet to another (in the alien scenario). But considering they can reach relativistic speeds such as 0.8 times the speed of light, they will experience a significant length contraction effect (predicted by Einstein's Theory of Special Relativity which has experimental evidence). Length contraction follows the formula;


This effectively means for example, that if we have a distance of 1000 light years which we need to travel to reach somewhere and we are travelling at 0.8 times the speed of light (ie. 0.8c):
L = 1000 * (1 - (0.8c)^2/(c^2)) ^ 0.5
L = 1000 * (1 - 0.8^2) ^ 0.5
L = 1000 * (1 - 0.64) ^ 0.5
L = 1000 * (0.36) ^ 0.5
L = 1000 * (0.6)
L = 600 light years
This would mean that if we are travelling at 0.8c, it would only take us the time that it would normally take to travel 600 light years in order to actually travel 1000 light years, that is, it would take 60% the time that we would normally predict by; distance divided by velocity; The Wonders of Special Relativity!

Now imagine we are traveling at 0.999999999...9 times the speed of light (since travelling at light speed is physically impossible for any masseous object - discussed later):
L = 1000 * (1 - (0.999999c)^2/(c^2)) ^ 0.5
L = 1000 * (1 - 0.999999999999...) ^ 0.5
L = 1000 * (0.00....1) ^ 0.5
L = 1000 * (0.00..1)
L = just over 0 light years
Therefore if we are travelling at 0.999999999...9 times the speed of light it would take us much much less time to travel 1000 light years (or anywhere essentially)

Now for something hypothetical, what if we are actually travelling at the speed of light (ie. travelling at c)?
L = 1000 * (1 - (c^2)/(c^2)) ^ 0.5
L = 1000 * (1 - 1) ^ 0.5
L = 1000 * 0
L = 0 light years (or 0 distance)
Therefore if we are travelling at the speed of light, we have to travel a distance of zero (ie. it would take 0 seconds, since time = distance / speed) to arrive at any point in the universe. But wait, that would mean that we are everywhere at the same time? Uhoh But dont worry about that, because it turns out that we can never actually reach the speed of light (Sorry to get your hopes up)

Now; Why can't we (or any masseous object ie. an object made up of mass) reach the speed of light?
Firstly, when a force is exerted on a mass, the mass gains Kinetic Energy (KE) which is what makes the object move;
KE = 0.5*mv^2
m is mass
v is velocity
Now, what Einstein's Theory of Special Relativity (which is widely accepted as true and has quite a large amount of experimental evidence nowadays) predicted that as force was applied to an object (ie. as the object gained kinetic energy and began moving faster, since KE = movement energy), a smaller proportion of that gain in kinetic energy was going into the velocity itself, instead, most of it was going into the mass of the object (ie. the faster it got, the less its velocity would increase since the energy was going into mass rather than the velocity). This essentially meant that the faster you get, the 'heavier' or more masseous (greater in mass) you become, and since 'acceleration = mass / force', this means that as the mass increases you would need to provide a larger force to get the object to keep accelerating. This means that the faster an object got, the more force would have to be applied to make it get faster, and as it got faster, the heaver it would get which means you would need to apply yet again more force to get it even faster. When graphed it showed that as the object approached the speed of light (ie. as its velocity got closer to the speed of light), the amount of force necessary to make it accelerate further approached infinite, and as it is obviously impossible to provide an infinite force on an object, it is impossible to actually reach the speed of light.
For that reason, reaching the speed of light is impossible for any object consisiting of mass (ie. any object).
Ok, so howcome when I'm moving in my car I'm not fatter than when im standing on the sidewalk? Well firstly you have to realise that the increase in mass is only noticeable when you are travelling at speeds which are comparable to the speed of light (eg. 10% the speed of light or above), and since the speed of light is  299,792,458 metres per second, or 1,079,252,849 kilometres an hour then you can see that your car (average 60 kilometres an hour) is going no where near that speed. Now the fact is that you actually are fatter (or greater in mass) when you're moving your car, but the amount of mass which you gain is EXTREMELY small and is hence unnoticeable.

Now you may wonder how light travels so fast if nothing else can? Well the fact is that not much is known about the nature of light, no one really understands how it works or what it is made of - so far quantum physicists have noticed that light sometimes behaves as a self-propagating wave of electric and magnetic fields (hence the name electromagnetic radiation) which allows it to travel at the speed of light (since it has no mass), and at other times light behaves as small particles (referred to as photons) - this is known as lights particle-wave duality.
The fact is that the human civilisation's crappy level of science simply doesnt know the answer...

If the scientist ever get to create that big bang what is the guarantee that there will be life on the planet or be life sufficent in that matter as well.
Lets say the 2nd earth is done and all and we'll start taking trees up there. It would take thousands of years for it to create a normal biosphere. The human kind imo doesn't have thousands of years left. At the rate we're going now this earth will be overpopulated, overpolluted.

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Originally posted by SikStyles
If the scientist ever get to create that big bang what is the guarantee that there will be life on the planet or be life sufficent in that matter as well.

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Don't see the big bang as something massive happening. Big Bang essentially means creating something out of nothing. If scientist say they recreated the big bang or are trying to recreate it, they mean they recreated (or trying) to replicate this on a very small scale. eg: letting some exotic partical appear from nowhere which will proof this or that.

Don't see this as in SciFi movies where an alternative universe is created.

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Originally posted by CookieRevised
Don't see the big bang as something massive happening. Big Bang essentially means creating something out of nothing.

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That is what Dan Brown's Angel and Demons says but I read once in a book by Stephen Hawking that the prior to the big bang, we can't say what was happening to the universe and either way it doesn't make a difference since whatever happened before it would in no was effect the process/outcome/end result after the big bang.
All we know (or may be just I know because the book is obviously a few years old ) is that the big bang was created by a singularity. All the mass of the universe was concentrated at one point (there is evidence to support this).

So yes, we did have something before the big bang. Even in Dan Brown's book, his definition of something out of nothing is 2 particles colliding to give you some antimatter however you did need those 2 particles, didn't you? That book has a lot of holes since its not a scientific book but the machine that CERN possess in that book is quite similar (but a bit bigger) than the one we have here.

Basically my point is that you need something initially to create "something out of nothing" though I'm pretty sure that the "something" created can be explained in a few ways. I have a few ideas but without all the data at hand, it isn't right to guess

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Originally posted by John Anderton
So yes, we did have something before the big bang. Even in Dan Brown's book, his definition of something out of nothing is 2 particles colliding to give you some antimatter however you did need those 2 particles, didn't you?

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yep, but that third particle comes out of the blue, it is created. By normal means it would mean it would already have been there (matter/energy is never lost, it is converted). So where did it come from.... "creating something out of nothing". 'something' like that..

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Originally posted by CookieRevised

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Originally posted by John Anderton
So yes, we did have something before the big bang. Even in Dan Brown's book, his definition of something out of nothing is 2 particles colliding to give you some antimatter however you did need those 2 particles, didn't you?

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yep, but that third particle comes out of the blue, it is created. By normal means it would mean it would already have been there (matter/energy is never lost, it is converted). So where did it come from.... "creating something out of nothing". 'something' like that..

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So this is all under the assumption that our laws of physics might be flawed?  The one I'm refering to is "matter cannot be created nor destroyed".

This is all very strange to me simply because i am crap at science. But i think it would be cool to make a mini universe and see how it all works out Would certainly be interesting and a large step into further things

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Originally posted by markee

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Originally posted by CookieRevised

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Originally posted by John Anderton
So yes, we did have something before the big bang. Even in Dan Brown's book, his definition of something out of nothing is 2 particles colliding to give you some antimatter however you did need those 2 particles, didn't you?

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yep, but that third particle comes out of the blue, it is created. By normal means it would mean it would already have been there (matter/energy is never lost, it is converted). So where did it come from.... "creating something out of nothing". 'something' like that..

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So this is all under the assumption that our laws of physics might be flawed?  The one I'm refering to is "matter cannot be created nor destroyed".

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Exactly...

'they' say before the big bang matter is all concentrated in the singularity. They can't proof it. Hence some of those experiments I suppose. Also the "create something out of nothing" should be taken not literally I suppose... or not... who would tell... those scientists I suppose

EDIT: and then again, not quite exactly. Our laws of physics are divided into two major groups: the laws of normal physics and the laws for quantum physics. Both are totally different and the one we're talking about is quantum physics.