Prisoner#1 said:

dont be so sure about that, they've discovered that light can travel faster than the speed of light

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tripp23 said:

i just thought of the weirdest paradox i have ever thought of.

alright, the speed of light in MPH is 670,616,629mph. say your traveling at 670,616,630MPH. 1 mile an hour faster than the speed of light.

so they say your always looking into the past. It takes time in order for light thats reflecting off of everything in your field of vision, to reach your eyes and to have your brain comprehend that into a picture.

so say your traveling that one mile per hour over the speed of light. what would you see???? complete darkness since your escaping light?? or would everything thats in your field of vision, just completely stand still??

or even more confusing.. say your traveling at the exact same speed of light. wtf would you see?? omg its so confusing!! its a complete paradox..

in order to travel into the past, one would have to completely switch time around backwards i.e... make light travel backwards? this is all hypothetically because apparently.. one can only travel into the future, not the past.. as far as we know now.. omg somebody help lol

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what if you travel faster than the speed of light whilst pointing a flashlight in the other direction?

DieCommie said:

Thats not going faster than 'c' though.  Light has an apparent speed through a medium that is slower than 'c', but it never goes faster than 'c'.  (It doesnt really go slower either, but that is a technicality when traveling through a medium.

I have a couple of thoughts, first off - you cant go faster than the speed of light or even reach the speed of light.  Its common for students to wonder what happens if you go faster than 'c' but its hard for them to understand thats a nonsensical premise from which you can draw no conclusion.  It would be like me asking, what if I am at the north pole and then I travel north more, what happens?  Thats a nonsensical situation you cannot conclude anything from it.  Same with traveling faster than speed of light.  Time doesn't go backwards, the equation breaks down and gives you imaginary time which has no physical meaning.

As for what you see... If you are traveling at 99% the speed of light, what would light look like to you?  It would still be traveling at the speed of light into your eyes.  It always does, no matter how fast you go.  This is a decidedly non-intuitive characteristic of our universe.  Speeds dont add like you think they would.  If you are traveling in a car at 60mph and throw a baseball at 10mph you would intuitively think that the ball will travel at 70mph relative to the ground.  This is not the case though, it would actually be a bit slower than 70mph.  Speeds dont add in the way we initially think they do.

This leads to what makaveli8x8 proposed...  Consider traveling 99% of 'c' and then within your spaceship launch a machine at .99% of 'c'.  Your intuitive thought would be that the machine is now going at .99c + .99c = 1.98c - but that is incorrect.  Velocities dont add that way.  .99c + .99c = 0.999949498c - still less than the speed of light. 

The velocity addition formula you expect is,


But they really add like this,


Its very weird that velocities add this way.  Its certainly one of the tripped out results of how our universe works that got me interested in physics.

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/end thread

I AM SWIM said:

This is not a post.

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Idiot said:

That's awesome, I was looking into some of MITs recorded lectures on physics but it was not what I expected.  I realize physics in an advanced form of math, but I figured they'd use more hypothetical situations to help describe formulas rather than just diving into the formulas.  I guess the prerequisites for a physics class at MIT would be more advanced that what I know, making physics that much more difficult for me.

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collie man said:

When i drop acid i become faster then time.

Ponder that one.

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DieCommie said:

iamu said:

can anyone here actually define time

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In physics there are what appear to me to be two different interpretations of time.  The most common one is the interpretation from relativity where time is regarded as a dimension similar to the spatial dimensions.  So you have three coordinates for your x,y and z position and then another one, t, for your time position.  This description beautifully describes many phenomenon we see but I feel is a little lacking in the intuitive 'what is time' notion. 

The other interpretation is the thermodynamic interpretation.  Here the 'arrow of time' or the direction that time goes in is defined by disorder (entropy).  The law of thermodynamics states that disorder always increases overall.  This has been interpreted to define the direction that time goes in.  So we can consider time to be the process of going from a state of order to a state of disorder. 

Now bring in a little statistics... ordered states are less probable, in general, and disordered states are more probable.  If you have a handful of pennies and throw them on the ground is less probable that they will all land heads up (ordered), its more probable that they will land in a combination of heads and tails (disordered).  Consider a tornado blows trough your room - there is a small chance that it will clean everything (ordered) but there is a much bigger chance that it will tear the room up (disordered).  Extend this to cosmology and the universe and consider the most ordered and least probable state of the universe, that is the small dense hot universe just after the big bang.  This state is highly ordered and highly unlikely.  Time then starts by having that ordered state evolve into a less ordered more probable state where space expands and matter clumps together.  This progression continues, and because of statistics after every interaction you are more likely to be in a more probable state.  That means at the end of time the universe is in its most probable state and it has nowhere else to evolve into, this is the heat death of the universe. 

So to bring this back to us, consider an hourglass.  You start it in its least probable state - with this sand up.  And it progresses to its most probable state with its sand down.  This is the progression of time.  A pendulum clock is the same way, the weight in an up position is less probable than the down position.  And as the universe evolves the weight progresses to its most probable position - down.  All clocks have this feature, all things that seem to happen at regular intervals have this feature.  In this sense time is the progression from improbable states to more probable states.

Of course fundamentally 'what is _____, really?' is a question of philosophy and not physics or science.  Much of my blabbing here is just an interpretation of the fundamental science.

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DieCommie said:

Thats not going faster than 'c' though.  Light has an apparent speed through a medium that is slower than 'c', but it never goes faster than 'c'.  (It doesnt really go slower either, but that is a technicality when traveling through a medium.

I have a couple of thoughts, first off - you cant go faster than the speed of light or even reach the speed of light.  Its common for students to wonder what happens if you go faster than 'c' but its hard for them to understand thats a nonsensical premise from which you can draw no conclusion.  It would be like me asking, what if I am at the north pole and then I travel north more, what happens?  Thats a nonsensical situation you cannot conclude anything from it.  Same with traveling faster than speed of light.  Time doesn't go backwards, the equation breaks down and gives you imaginary time which has no physical meaning.

As for what you see... If you are traveling at 99% the speed of light, what would light look like to you?  It would still be traveling at the speed of light into your eyes.  It always does, no matter how fast you go.  This is a decidedly non-intuitive characteristic of our universe.  Speeds dont add like you think they would.  If you are traveling in a car at 60mph and throw a baseball at 10mph you would intuitively think that the ball will travel at 70mph relative to the ground.  This is not the case though, it would actually be a bit slower than 70mph.  Speeds dont add in the way we initially think they do.

This leads to what makaveli8x8 proposed...  Consider traveling 99% of 'c' and then within your spaceship launch a machine at .99% of 'c'.  Your intuitive thought would be that the machine is now going at .99c + .99c = 1.98c - but that is incorrect.  Velocities dont add that way.  .99c + .99c = 0.999949498c - still less than the speed of light. 

The velocity addition formula you expect is,


But they really add like this,


Its very weird that velocities add this way.  Its certainly one of the tripped out results of how our universe works that got me interested in physics.

---