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Thread: JTL Physics Completley Off (fun yes, but darn it)
DaveG wrote:
...and the word "laser" and an acronym for "Light Amplitude Stimulated Emission & Radiation".
Message Edited by DaveG on 11-14-2004 03:47 PM
Almost. It's "Light Amplification by Stimulated Emission of Radiation".
You were close though!
Falin
imodi wrote:
...
/applaude. Good post, from one physics graduate to another (presuming you have graudated) I enjoyed reading that.
Frilans wrote:
I'd like to add my 3 cents:
Have you ever felt that cold sweat in your neck when watching any of the SW films you... can actually... SEE THE LASER BOLTS?!?!?!?!
They are moving at a lower speed than a 18th century bullet!You have to point at the heading (predicted future position)of your enemy and you see the "curve" of your laser until it reach its target. In the ground game, some people is able to, not only reflect laser attacks by using his/her lightsaber... but even dodge a laser beam... you know what I mean.
Saying that, anything else seems nothing to me.
Yeah, the only way you could see a laser beam is for there to be enough 'dust' in space to diffuse the beam signficantly. (Shine a laser pointer through steam or hair!)
FalinMor wrote:
Almost. It's "Light Amplification by Stimulated Emission of Radiation".
You were close though!
Falin
Meh, damn typo's. 
Here we go... Laser through hair (NEVER point a laser at someone's face though! Fortunately my target was sleeping!).
DaveG wrote:
Yeah, the only way you could see a laser beam is for there to be enough 'dust' in space to diffuse the beam signficantly. (Shine a laser pointer through steam or hair!)
Starson wrote:
Theytried a little more realistic physics in beta, the outcry of the palyers was so great, themade it this way.
Yeah I found that quite sad really
DaveG wrote:
Ouch, bad use of language on your third point there. You keep refering to the "rate of acceleration", which implies acceration is changing. In the case of David Scott, there is no "rate of accerlation", theacceleration is constant, and that rate is equal to the "acceleration due to gravity" of the moon (on earth, this value is g=9.81 m/s^2).
The only time you would have a "rate of acceleration" is when the force is a function of time, then there isa rate of change of acceleration because acceleration is a function of force. However, in call cases of dynamics with constant force (i.e. not a function of time), then acceleration is constant (for constant mass, typically the norm in non-relativistic models), and thus has no rate of change.
Apart from that, if anyone else is confused, then I suggest the rest of you take "Newton's Laws of motion" as required reading!
/geekmode on
Technically, theacceleration isn't a constant. It'sa function of the square of the distance from the object (falcon feather or hammer in this case) to the gravitational center of the planet/moon you're on, which changes as the object falls. a=MG/R^2. Although for large values of R, this is pretty constant!
imodi wrote:Ok, nice discussion, but i had to jump in with a couple of things as someone who has studied Physics to a high level.for the original post:In theory your assumption that the speed of light limits velocity is correct, what is at is at issue is the acceleration required to get there. Currently we can accelerate particles to within a minute fraction of the speed of light (in a vacuum). but there are many problems surrounding high velocity dynamics.1st mass, as relative velocity increases, so does the mass, untill at the speed of light, the mass of any object is infinite. (this has been agreed by experiment at C.E.R.N.) this then suggests the higher the relative velocity, the more acceleration is required, and acceleration is limited by the energy available to do so.In practice if u were able to accelerate to a speed, you would stay approximately (no noticeable difference) at that speed untill you entered a significant field producing an acceleration (eg gravity)Next point is the "friction" that has been mentioned, no space is not a complete vacuum, but the resistance that will be experienced by any surface will be negligable in comparison to other forces at play, for example, gravitional, electromagnetic and the various forces that exist from the non-inertial state of the universe. Hence the use of Newtonian Physics; "every action has an equal and opposite reaction" (action = force) at best would produce a very rough model.The problem is that relativistic mechanics, if you couple this with the complex nature of the true universe (ie the inertial frame of reference does not exist anywhere) in that everything is in constant acceleration across multiple dimensions at all times, thus introducing rotational dynamics etc. it becomes far too complicated to accurately reproduce by a home pc, (how ever much it cost) N.A.S.A themselves use both galileon and Newtonian physics for plotting courses etc as the approximations are accurate enough for the missions.To make my point, limiting velocity (|speed|) by energy required to accelerate to that point is accurate, the maximum possible speed of any particle is the speed of light in a vacuum (that is what Einstein told us!) for relativistic reasons. the effect of matter in space is so minimal that its really not worth mentioning, you would come into close proximity to a large gravitational field or large collision before your navigational equipment could detect a change in velocity.Oh and the use of very basic physics to explain this, without actually explaining anything is irritating. (wrathbelli) i only mension this as i find the use of reudimentory and irrelavent physics to explain phenomona that were explained by einstein after 10 years of re-writing the laws of physics, frankly i found it insulting.sry for the rant, and i don't intend to flame, i just get very pationate about what i have devoted my life to studying.imodi
nice explanation, though as an engineer i am not so insulted by having to simplify things for people... difference in profession. there is one other thing that was not mentioned though, the effects on the occupants of a vehicle as it accelerates.
yes, yes i know star wars vehicles have inertial compinsaters but all devices have operational limits. these limits would dictate the maximum acceleration that the ship can have because to exceed these would put the occupants at risk of physical injury. the arguments about maximum acceleration need to be put into the context of what the body can sustain, for example the acceleration of a bullet can range from 2 x 10^5 m/s^2 up to 1.7 x 10^6 m/s^2 (accerating a person at this rate would kill them); where as the space shuttle only has an acceleration at lift off of 29.4 m/s^2.
as we all probably know as the body accelerates the heart must force blood to the brain, if you increase the acceleration you reach a point where the heart can no longer overcome and blood flow to the brain slows and will eventually stop (worse things can happen if you continue to increase the acceleration but i don't really want to mention that). for air force training the centrifuges that are used typically go from 15 to 20 times the acceleration due to gravity (therefore max would be about 184 m/s^2 though i don't know if the pilots are ever exposed to the maximum setting on these centrifuges).
so your acceleration would then be limited to the compinsater’s ability to shield the occupants from the force accelerating the vehicle, you could exceed this by some but not much as you would like the occupants to remain conscious. btw this would also affect the negative accleration of the vehicle (slowing it down) as you would not be able to stop on a dime from a high speed (it wouldn't be a good thing to be ejected from your starship when you stop).
Lilleth wrote:
Second thing: space is not a vacuum. There is no real vacuum in the universe. You have billions and more billions of particles of different sizes. So you have also the problem that colliding with some of the particles can do severe damage to your ship (Apollo 13 is a good example for this).
Sorry Lilleth, Apollo 13 was a TERRIBLE example of this. Apollo 13's mishap was a result of a faulty component creating a spark which triggered an explosion inside the vehicle. This explosion caused great damage and ruptured the service module's hull. It had nothing to to with damage caused by particles floating in space. Even the movie touched on this as the cause. Unless you are trying touse the debris itself ejected by Apollo 13 as an example of how space is not empty...in which case you are correct.
To date, there have been no documented catastrophic failures of a manned spacefight due to collision with "space particles" (Columbia almost being an exception, but the debris strike was from a part of the shuttle's own external fuel tank).There has been evidence of micrometeorite and "space junk" impacts on the US shuttle and other craft, most notably small dings in the various shuttle's forward viewports (is it okay to call them windscreens? They are really there to keep the air in and the burning re-entry gases out not just block the wind :smileywink
but none resulted in catastrophic failure.
Besides,most of the "drag" on a spacecraft in space isdue to the influence of nearby gravitational fields(which is pretty powerful) and the powerful streams of energy released by stars (which is negligible).
And now back to our regularly scheduled fiction...
Message Edited by Guamarhea on 11-15-2004 02:28 PM