New efforts!

[Shibboleth]

A light beam heading east, collides with a light beam heading west, they meet at twice the speed of light.

We learn that velocities are additive, but that is Newtonian physics. In Relativistic physics there is a divisor calculated by the product of the velocities involved (as a percentage of the speed of light), so that the result is always less than the sum of the two velocities. If the two velocities are the speed of light the factor of division grows to 2 so that you end up with (c+c)/2 = c.

[CrimsonCapacitor]

I'm enjoying the nerdfest that is the discussion of relativistic physics.

And I'll throw this tidbit in to REALLY mess with your minds.

I'm pretty sure everyone knows that the faster you go, the more time slows down for you.  Go the right speed, and what seems like a day in your frame of reference can be multiple years to someone else with a different reference frame. 

But... 

The faster you go, to an observer outside of your inertial frame of reference, there's this thing called the "Lorentz Contraction"  (Or the Lorentz-Fitzgerald Contraction) that causes the mover to look... thinner?  Less longer?  Contracted?  Not sure what the official physics term is.  I'm a chemist, not a physicist...  Anyway, distance compresses in the direction of travel.  So to you, blasting through the cosmos at huge velocities, your 200 m long rocket looks like it's 100 m long to someone standing still.  You, however, don't notice anything.  The faster to c you get, the more that length is contracted.    Although I'm not sure if it ever goes to zero if you were able to reach the speed of light.  But I think it approaches 0.

[Shibboleth]

I'm enjoying the nerdfest that is the discussion of relativistic physics.

And I'll throw this tidbit in to REALLY mess with your minds.

I'm pretty sure everyone knows that the faster you go, the more time slows down for you.  Go the right speed, and what seems like a day in your frame of reference can be multiple years to someone else with a different reference frame. 

But... 

The faster you go, to an observer outside of your inertial frame of reference, there's this thing called the "Lorentz Contraction"  (Or the Lorentz-Fitzgerald Contraction) that causes the mover to look... thinner?  Less longer?  Contracted?  Not sure what the official physics term is.  I'm a chemist, not a physicist...  Anyway, distance compresses in the direction of travel.  So to you, blasting through the cosmos at huge velocities, your 200 m long rocket looks like it's 100 m long to someone standing still.  You, however, don't notice anything.  The faster to c you get, the more that length is contracted.    Although I'm not sure if it ever goes to zero if you were able to reach the speed of light.  But I think it approaches 0.

To get to zero would require travel at the speed of light. But at 99.5% the speed of light the contraction would be roughly 90%.

[Felderburg]

What is that 8 bit dog from?

Also, a refresher: http://paragonwiki.com/wiki/UniqueDragon

I usually refer to the two values collectively as the electromagnetic permeability of the substance.  However, you can also generate electric and magnetic fields in a vacuum, and you get a relationship between charges and fields that allow you to measure those two constants for the case where there is no intervening substance - those are referred to as the electric permitivity and magnetic permeability of the vacuum itself. 

I conceptually get that. It's just the word "permeability" implies that what is permeating is moving through "stuff," and a vacuum has no "stuff" that anything can permeate through. The wording just threw my brain off.

It is the Lorentz transformation that says that if you are moving at 0.99c and you shoot a bullet at 0.99c the bullet doesn't end up moving at 1.98c, it actually ends up moving at something closer to 0.995c.  This has been experimentally confirmed, so its not a guess or a mathematical approximation.

I'm gonna go ahead and assume that "experimentally confirmed" means that someone shot a bullet at 0.99c :p .

In other words, what we observe is not the object moving from A to B at 100 times the speed of light starting from now and ending in the future, but rather from B to A starting from now and ending in the past.

http://memory-alpha.wikia.com/wiki/Anti-time

It is like the train station in the Matrix Revolutions.

I was told by a friend that any time I thought I want to see the sequels, to just rewatch the first Matrix. So far I've only seen The Matrix once, and that's it.

[Gorgor]

I once wrote a lil' treatise on the EverQuest forums called "The Speed of Zoning", trying to reconcile the apparent freezing of time for up to a minute (in those olden days) when moving through certain regions with the apparent infinite speed of a simple whisper across whole continents.  The whispers were the only way the time stop was even detected in the first place.

[Arcana]

It is pretty easy to derive from the base premise. Consider how the path a beam of light take between appears between the two frames. The most obvious thing that is different is the distance travelled. Relate those two. From there the basic equations fall out. We were presented with this (I won't admit how many years ago) in first semester, freshman physics.

It is more complicated than that because time isn't invariant between the two frames of reference.  The Einsteinian derivation takes the axiom of the constancy of the speed of light to assert that for a given event sequence corresponding to a light beam being emitted and then absorbed in a vacuum the distance observed between the two physical coordinates of the events must be equal to the distance light would travel during the time interval observed between the two events.  If the distance between the two events is the normal Euclidean distance formula SQRT(dx^2 + dy^2 + dz^2) and the distance light travels during the time interval is c(dt) then c^2(dt)^2 must be equal to dx^2 + dy^2 + dz^2, or (space distance)^2 - c^2(dt)^2 = 0.  This is called the spacetime interval between events, and this must be invariant under transformation to any reference frame.  From there, the Lorentz transformations (eventually) fall out.

[Vee]

I was told by a friend that any time I thought I want to see the sequels, to just rewatch the first Matrix. So far I've only seen The Matrix once, and that's it.

You should keep it that way and hang on to your nice memories. The first sequel was so bad it actually made the original bad by association. I had the wisdom not to see the second sequel.

I later rewatched the original and came to realize that the original was not only bad by association but also pretty bad on its own and we were all suckers to cool effects in 1999 (ok we still are, but they were more novel then).

[Shibboleth]

It is more complicated than that because time isn't invariant between the two frames of reference.  The Einsteinian derivation takes the axiom of the constancy of the speed of light to assert that for a given event sequence corresponding to a light beam being emitted and then absorbed in a vacuum the distance observed between the two physical coordinates of the events must be equal to the distance light would travel during the time interval observed between the two events.  If the distance between the two events is the normal Euclidean distance formula SQRT(dx^2 + dy^2 + dz^2) and the distance light travels during the time interval is c(dt) then c^2(dt)^2 must be equal to dx^2 + dy^2 + dz^2, or (space distance)^2 - c^2(dt)^2 = 0.  This is called the spacetime interval between events, and this must be invariant under transformation to any reference frame.  From there, the Lorentz transformations (eventually) fall out.

There was no assumption of time being invariant between frames in the derivation we did way back when. That time was perceived differently also fell out. 8.01 was some time ago but the memory seems clear enough (though of course we all know they are quite fallible).

[Felderburg]

What about the Animatrix? I hear that was pretty good.

[Arcana]

There was no assumption of time being invariant between frames in the derivation we did way back when. That time was perceived differently also fell out. 8.01 was some time ago but the memory seems clear enough (though of course we all know they are quite fallible).

I'm not sure which derivation you did back then, I was just commenting on your description above: you have to be careful when asserting that it is distance that must be altered when changing reference frames because the velocity of light depends on both the apparent distance traveled and the apparent time elapsed for each observer.  In other words, without going through the math you can't say with certainty that it isn't time dilation alone that is responsible for the speed of light being invariant in the two frames you describe above.

Imagine a spaceship with two light clocks, one in which the beam of light is bouncing back and forth between the walls of the ship and the other where the light is bouncing from the floor to the ceiling, and the ship takes off in the direction of the ceiling of the ship while you stand on the ground.  Assume the ship is moving at a high percentage of the speed of light but is not accelerating.  To an observer in the ship both clocks are running normally and at the same rate: there's nothing unusual happening.  But to the observer on the ground the light clock bouncing between the walls must be running slower: the distance light must travel as it zigzags between the walls is longer, so the clock ticks less frequently.  We observe this as time dilation within the ship.  But if we believe the ship is lorentz contracted in the direction of motion we should see the light pulses from the vertically aligned clock ticking faster because that light pulse has less distance to travel.  It should tick faster.  But that seems to be a contradiction, because time can't run differently for the two clocks.  Something in the oversimplification is wrong.

You have to be very careful with special relativity because it is easy to overlook a small issue that causes problems.  It is easy for oversimplifications to wallpaper over what is actually happening.

[Ulysses Dare]

What about the Animatrix? I hear that was pretty good.

It's been a decade or so, but I recall enjoying it at the time. It's actually a series of individual stories though, not one long movie. So you mileage may vary.

[Shibboleth]

I'm not sure which derivation you did back then, I was just commenting on your description above: you have to be careful when asserting that it is distance that must be altered when changing reference frames because the velocity of light depends on both the apparent distance traveled and the apparent time elapsed for each observer.  In other words, without going through the math you can't say with certainty that it isn't time dilation alone that is responsible for the speed of light being invariant in the two frames you describe above.

Imagine a spaceship with two light clocks, one in which the beam of light is bouncing back and forth between the walls of the ship and the other where the light is bouncing from the floor to the ceiling, and the ship takes off in the direction of the ceiling of the ship while you stand on the ground.  Assume the ship is moving at a high percentage of the speed of light but is not accelerating.  To an observer in the ship both clocks are running normally and at the same rate: there's nothing unusual happening.  But to the observer on the ground the light clock bouncing between the walls must be running slower: the distance light must travel as it zigzags between the walls is longer, so the clock ticks less frequently.  We observe this as time dilation within the ship.  But if we believe the ship is lorentz contracted in the direction of motion we should see the light pulses from the vertically aligned clock ticking faster because that light pulse has less distance to travel.  It should tick faster.  But that seems to be a contradiction, because time can't run differently for the two clocks.  Something in the oversimplification is wrong.

You have to be very careful with special relativity because it is easy to overlook a small issue that causes problems.  It is easy for oversimplifications to wallpaper over what is actually happening.

As memory serves things started from a consideration was a train and a pulse of light directed from a source on the train perpendicular to direction of motion at a mirror on the floor of the train and the difference in observed pathing between the those on the train and those at the station the train is passing at a constant velocity.

[Shibboleth]

It's been a decade or so, but I recall enjoying it at the time. It's actually a series of individual stories though, not one long movie. So you mileage may vary.

I found it to be okay but then I didn't hate the 2nd and 3rd movies as much as others (2nd was better than the 3rd but I did not hate the 3rd).

[Arcana]

You should keep it that way and hang on to your nice memories. The first sequel was so bad it actually made the original bad by association. I had the wisdom not to see the second sequel.

I later rewatched the original and came to realize that the original was not only bad by association but also pretty bad on its own and we were all suckers to cool effects in 1999 (ok we still are, but they were more novel then).

I actually like Reloaded although I don't think it is as strong as the first one.  I think there's a good story buried in the third one but its extremely muddled in the Wachowskis' tendency to deploy overwrought allegories.

[Joshex]

I had a big long reply to several posts mostly written up,  but then I was forced to leave home for the rest of the day, then that night I had to prepare a powerpoint for a lecture this morning.. then I decided not to post it.

to say a few things; it does bother me to withhold my theory, but the world just isn't ready for that yet. we're far too corrupt and self serving. Imagine what star trek would be like if things were like this after the war. A money less economy where all jobs are respected equally and goods are there if you need them? no, instead it's a severe class system with lock-outs to competition in most of the market, and people starve every day because they can't afford food.

all such knowledge and tech would do would be to empower the current overlords and subsidize more lies and corruption.

private ownership of a planet? hey I didn't know Donald Trump owned that planet, I thought Arcana placed a flag on it.. Shame she got no commission.

person finds planet> person cannot own it due to international law> government takes ownership> government decides to build resort to pull in tax money> government needs someone with money to pay for, build and own the resort> Donald Trump gets transferred ownership of the planet because he's a real-estate mogul with billions needed to buy it from the government who lawfully own it.

Thankyou so much 'person' your service to the international community is heavily appreciated.

can I visit the resort when it's finished?

lol, no. it costs 1 million per visit, I don't think you have that much.

or

warning citizen: this part of space is forbidden for civilian spacecraft, leave now or face legal action.

or

in a horrible turn of events millions of tourists to the Kic star system were murdered in what can only be described as the most vicious suicide bombing in history.

really just take any current event and give it a space twist;

woman visits Rancor park and walks up to and pets sleepy rancor while others film it. she will face a citation and appear before a federal court if identified.

or

a wormhole from mexico to the trump resort planet was found containing a transmission of 32 mega tons of cocaine.

I'm all for giving knowledge freely, but giving it to these people? no. I sympathize with any aliens who refrain from contact with earth at all costs.

Captain! there's a fire in engineering, the nacells are unstable, we've lost the warp drive and the food replicators are all giving error 53, the sewage dis-integrator has malfunctioned and flooded B deck, and the closest ship is 3 months away.

Quick! wheres the closest planet in teleporter range!?

it's a place called earth sir!

Oh pancake, we're doomed. tell the crew to transmit their last will to the federation and prepare to go down with the ship. For the safety of the citizens of the federation we will have to disintegrate the ship to leave no traces for the earthlings to follow, the lives of the many outweigh the lives of the few.

[Vee]

Holy Hell, that's the second draft?

[Biz]

Holy Hell, that's the second draft?

Maybe if he someday reveals his theory, the knowledge and tech that comes of it will allow us to travel to whatever reality he lives in?

[Joshex]

Holy Hell, that's the second draft?

I aimed to please :D

[ivanhedgehog]

I lost points of IQ from reading that.

[Victoria Victrix]

...then that night I had to prepare a powerpoint for a lecture this morning....

Amway?  Herbalife?