Superluminal motion. How's that possible?

[vish_al210]

but what is the individual energies of the two sphere's (each moving @ 0.9C) and when they collide what would be their result, (let us consider some tangible mass).
Is that energy equation the same as that of one sphere standing and the other impacting it at 0.994C.. I am really puzzled.. I believe and hope u have the answers.. as what I am considering and thinking would have already been thought of and answered...
Thank you for your patience though..

 

[Doc Al]

but what is the individual energies of the two sphere's (each moving @ 0.9C) and when they collide what would be their result, (let us consider some tangible mass).
Is that energy equation the same as that of one sphere standing and the other impacting it at 0.994C.. I am really puzzled.. I believe and hope u have the answers.. as what I am considering and thinking would have already been thought of and answered...

Realize that whether you see two objects moving at 0.9c or one stationary and the other moving at 0.994c is just a matter of reference frame. It's the same collision! (The kinetic energy of each object depends on the reference frame, of course.)

 

[vish_al210]

So .. the kinetic energy of the object is different if the observer is at different points.. How does the observer alter the kinetic energy of a moving object ?
The kinetic energy/momentum of an object is relative to the energy consumed in moving forward right?? or am I wrong??
And I do not mean the kinetic energy alone but the total energy of A.. and separately the energy of B.
I mean throwing a ball on a wall with speed V1 is not the same as throwing the wall with speed V1 on the ball... It is different right..

 

[vish_al210]

So finally the general simplified equations neither work in infinitesimal conditions or in substantially large scale conditions...

 

[DaveC426913]

but what is the individual energies of the two sphere's (each moving @ 0.9C)

Kinetic energy is frame-dependent. Two objects moving wrt each other have kinetic energy as measured by their relative speeds. Two objects at rest wrt each other have zero kinetic energy.

Picture an apple whizzing past Earth at .9c. The kinetic energy of that apple from Earth's frame of reference is dependent on exactly two properties: the apple's mass and its velocity. Its kinetic energy would be quite high, yes?

Now picture an orange whizzing alongside the apple, same speed, same path. What is the apple's kinetic energy wrt the orange? In the orange's frame of reference, the apple is at rest, therefore its kinetic energy is zero.

Now, picture the apple and orange both whizzing toward Earth from opposite directions at .9c. Earth calculates each kinetic energy based on its mass and its velocity wrt Earth.

But what does the orange calculate about the apple's kinetic energy? Well, the apple is moving towards it at .994c, so that's what's used to calculate its kinetic energy.

You add kinetic energy using the same formula that use to add their velocities, i.e.: .9+.9 = .994

 

[vish_al210]

But then what about momentum, is that also frame of observation dependent??

 

[Doc Al]

But then what about momentum, is that also frame of observation dependent??

Of course. Anything that depends on velocity is frame dependent.

 

[Dickfore]

The op needs to enroll in an introductory course in Special Theory of Relativity.

 

[vish_al210]

@ Everyone..
Thanks,...
But I am still not clear.. but understand that u all must be stating the right thing. I tried reading on this topic, but understand that just skimming the articles won't help..
So I shall try a little more indepth reading on this subject.
Well ;) pray for me guys... That I have a clearer head...(by that I don't mean blank..)
Thank you all for your patience. though I am a lot more muddled//confused in the head right now, I know that my understanding is wrong.. Now! that's a start...
All of you folks, take care... Wishing you all a merry Christmas//Kwanzaa// or well to everyone a wonderful year ending..
Take care...

 

[DaveC426913]

@ Everyone..
Thanks,...
But I am still not clear.. but understand that u all must be stating the right thing. I tried reading on this topic, but understand that just skimming the articles won't help..
So I shall try a little more indepth reading on this subject.
Well ;) pray for me guys... That I have a clearer head...(by that I don't mean blank..)
Thank you all for your patience. though I am a lot more muddled//confused in the head right now, I know that my understanding is wrong.. Now! that's a start...
All of you folks, take care... Wishing you all a merry Christmas//Kwanzaa// or well to everyone a wonderful year ending..
Take care...

Do not be shy to ask questions, even the most basic ones. We will fall all over ourselves to answer questions. That's why we're here.

 

[vish_al210]

Thanks Dave. And well I am not ashamed or shy of asking questions... It is good that finally the question/condition boiling in my head for over a few years is at least broken down...
I am not all satisfied as it shattered a myth in my head(well that was expected!).
But better shatter the myth than enjoy its fancy..
But I suppose that if eventually, something does travel faster than light what would we be able to see.. I mean see of the object...as our perception is light. I know we got equations and inferences to showcase that it wld not be possible... But just suppose that the equation has a loop hole.. as with everything else there is an exception..
What would we see or observe(I mean seeing in plain simple terms)

 

[DaveC426913]

But I suppose that if eventually, something does travel faster than light what would we be able to see.. I mean see of the object...as our perception is light. I know we got equations and inferences to showcase that it wld not be possible... But just suppose that the equation has a loop hole.. as with everything else there is an exception..
What would we see or observe(I mean seeing in plain simple terms)

Well, what you're asking is "What would the laws of physics be like if the laws of physics were different than what they are?"

The problem with that is that the answer can be anything you want.


But I know that's never satisfactory, so I'll give you a teaser.

Relativity does not forbid massive particles moving faster than the speed of light; it only forbids them from reaching and transitioning the speed of light. This leads to the hypothetical possibility of particles existing that always travel faster than the speed of light. These hypothetical particles are collectively known as tachyons (fast ones). They normally travel much faster than c, but when they absorb energy, they actually slow down closer and closer to c. The closer they get to c, the more energy it takes to push them closer. No amount of energy can get them to slow down to c or slower. They are mirrors of our slower-than-light particles.

What is interesting about them is that, to us, they would be traveling backwards in time. In their interactions, effect would precede cause.

 

[vish_al210]

If I consider an object moving past me ..(not through me.. I want to live ;) ) with a speed greater than light...
then I could draw lines form each of its state towards me in the path to indicate the light traveling from the object @ C.. Now as the light would take different time intervals to reach me(slower than the passage of the object), is there a possibility of me seeing the object as an extended line or multiple objects...I mean if we do find an object moving at speed greater than C, how would we identify it?

 

[Dickfore]

Tachyons (from Greek takhus = swift) are particles considered from a purely theoretical point of view that can and always travel faster than c. They have the peculiar property that they accelerate when their kinetic energy decreases, reaching infinite speed when the kinetic energy is zero (or having zero kinetic energy when they accelerate to infinite speeds). Mathematically they should have imaginary rest mass.

 

[henryc09]

I think something you need to get your head around is that there is nothing fundamentally that you can measure velocities with respect to. On Earth we tend to measure velocities w.r.t the earth, but when you consider the universe as a whole there is nothing you can do this with. It therefore only really makes sense to consider measuring velocities w.r.t a given frame of reference. However, experimentally it was found that regardless of an observer's relative motion to a beam of light, the same speed of light is ALWAYS measured. Special relativity provides a way of knowing what people in different reference frames will observe, and leads to the velocity addition formula used earlier which prevents anything from traveling faster than the speed of light! It's strange, I know! But it all follows from the experimental fact that the speed of light is the same regardless of relative motion.

 

[DaveC426913]

Tachyons (from Greek takhus = swift) are particles considered from a purely theoretical point of view

Actually, as previously mentioned, they're not even theoretical; they're hypothetical. There is really no reason to even suppose they might exist. It is simply that they do not violate relativity.

 

[Dickfore]

Actually, as previously mentioned, they're not even theoretical; they're hypothetical. There is really no reason to even suppose they might exist. It is simply that they do not violate relativity.

As much as I read, there are theoretical reasons to suppose their existence in some theoretical models. Thus, 'theoretical' = 'hypothetical' as long as those models are just hypotheses.

 

[vish_al210]

Well.. I was presenting a hypothetical situ.. Anyway... thanks a lot everyone...for your guidance and patience.
And yes I am clear that my assumption was wrong (about the two bodies moving at 0.9c relating to 1.8c).. and I will do the reading required to make me understand the same.
You needn't discuss the hypothetical case as (well it is hypothetical and) it has been discussed in http://en.wikipedia.org/wiki/File:Tachyon04s.gif
And I understand that the discussion on that is hypothetical and does not prove their existence as such. And my knowledge on this is very menial or non-existence... ;)
Well thanks a lot... take care...