Spaceships like X3 and EVE actually can reach lightspeed

[HCGxKaLiBeR]

I was watching the Alien movies, and I saw a spaceship was boosting its engine to start in motion, then it turned it off for cruising/drifting, the crews went to hypersleep after till the ship reached its destination.

So it comes to my mind that under a perfect space circumstance, it should has no friction nor gravity.

Spaceships only need to boost a little power to keep it in motion and the right direction. The ships like X3 and EVE could reach light speed if they keep firing their engines like that.

maybe someone could make a mod that make X3 ships have unlimited acceleration, and for balance purpose, higher the speed, more time needed to stop the ship.

[Samuel Creshal]

maybe someone could make a mod that make X3 ships have unlimited acceleration, and for balance purpose, higher the speed, more time needed to stop the ship.

Have fun making the AI work with that.

This proposal isn't new, and the engine theoretically allows for it perfectly fine. The only problem is the AI – it's rare enough when the AI manages to not slam into stations/asteroids/each other/planets now, but with the changed physics? No way.

[HCGxKaLiBeR]

back to thinking, u r prob right.

1. AI problem
2. control problem, the physics of the ship will be a mess when u r on high speed.

tho my point was, the ships in game are totally unrealistic.

so far imo, the most physics realistic space game is Jupiter Incident.

[Morkonan]

I was watching the Alien movies, and I saw a spaceship was boosting its engine to start in motion, then it turned it off for cruising/drifting, the crews went to hypersleep after till the ship reached its destination.

So it comes to my mind that under a perfect space circumstance, it should has no friction nor gravity.

Spaceships only need to boost a little power to keep it in motion and the right direction. The ships like X3 and EVE could reach light speed if they keep firing their engines like that....

Errr... no.

The Laws of the Universe don't work how you describe. There is little friction in space, a few electrons and particles here and there in deep space don't matter very much. But, gravity is eternal - It extends infinitely, only reducing in strength at a rate inversely proportional to its distance or, in other words, the Inverse Square Law of gravity - ie: The gravity experienced by one mass due to the influence of another would be - F = G Ma Mb / r2

The unique thing about this is that a very tiny portion of the gravity you are experiencing right now, this very moment, originated from something within the light cone of Earth.. (That which we can exchange information with as dictated by the speed of light, separation velocities dictated by expansion, etc..)

IOW, an imperceptible tug on one of your hairs could have come from halfway across the galaxy due to a small mote of rock orbiting a distant sun... despite being the "weakest" of all the Fundamental Forces. The influence of gravity extends infinitely in all directions and "infinitely" is a very long way... the longest! (It is, however, limited to the speed of light.)

However, neither friction or gravity have anything to do with why you can't travel at the speed of light.

I will attempt to explain why the ship can never attain lightspeed:



You've heard of Einstein's E=mc^2, right? Well, we are going to build on that in order to explain why a mass bearing particle, spaceship or towel can not reach the speed of light, which is denoted as "c."

A mass bearing object (m) traveling at a constant velocity (v) has momentum, which is a product of m*v and is noted as "P." Therefore - (We'll skip the applicable units.)

P=mv

(Momentum = the object's mass multiplied by its velocity, also its inertial mass.)

Now, remember Newton and the whole "An object at rest.." set of laws? Well, the object that is in motion will remain in motion until acted upon by another force, so to speak. That force has to overcome the object's inertia, or its tendency to keep going wherever it is going. The amount of force necessary to move an object with inertia is directly proportional to its mass times its acceleration. In short, as the wiki describes, it requires an increasing amount of force to move larger objects at a faster rate. Now, things get interesting...

(Bear with me, it's almost 6am here and I have yet to go to bed. )

Whenever you add force (F) to an object to increase its velocity (v), you are also adding energy to it. The energy is expressed as an increase in velocity, but is also its "kinetic energy." ie:

E=(m)((v^2)/2) or, it's kinetic energy is equal to it's mass times it's velocity squared, divided by two. This is applicable to spaceships, bullets, rocks, falling leaves, dead rabbits.. whatever. If it has mass, it works.

But, only with Newton... In the matter of Special Relativity, which deals at the fundamental level of all things moving really really fast (or are very tiny), things are different and certain rules apply. One of these are Lorentz equations which govern how space and time contract in the direction of motion.

And, now, we come to the defining formula that easily demonstrates why you can not accelerate to lightspeed. Once you understand how the formula works, you can rattle it off at parties to impress the girls...

E= mc^2/ sqrt (I- v^2/c^2) (Hmm, I think my hierarchy is right, there.) Here's a graphic, just in case:

[ external image ]

Or, the amount of energy required to accelerate the object is equal to its mass times the speed of light, squared, divided by the square root of one minus the product of its velocity, squared, divided by the speed of light, squared.

All that may seem sort of complicated, but it's not. When you see how beautiful it is, you'll poop yourself...

Note that the object's velocity squared is divided by the speed of light, squared. All those squares help keep pesky negative numbers out, btw. But, here's the important part -

What happens in the formula as the object nears the speed of light???

If we input ever increasing velocities into the formula, as they approach the speed of light, the product of the object's velocity divided by the speed of light will approach 1. Yet, in the formula, that product must then be subtracted from 1, the square root derived and then that must divide the object's mass times the speed of light, squared. What happens? Go ahead, add in some numbers for that part of the formula. What you will find is that the end result is that it takes an ever increasing amount of energy to accelerate any mass bearing object.

But, what's really important is that it becomes quite clear that you can not accelerate a mass bearing object to the speed of light. Why? Because, if the velocity of the object is the speed of light, c, then you will have the speed of light, squared, divided by the speed of light, squared, and that equals 1, which then has to be subtracted from 1, which would yield... zero. And, you can't divide by zero! Well, you can, but what you get is an infinite number.

So, as the velocity approaches the speed of light, the amount of energy required begins to approach the infinite until, finally, you reach a required amount of energy for acceleration that is simply not available in this universe!

And that is, in simple terms, why you can not travel at the speed of light. It's also the sign that I need to go to bed and get some sleep, now.

(In terms of the game, this rule applies as well. A computer could not accelerate a spaceship, even if it is fake, to "the speed of light" because it uses tiny masses and a heck of a lot of heat to generate information and that information simply could not travel fast enough.*)

Edit - Add - However, I do know of one way and one way only that could be used to "fake" a simulation of a ship actually traveling at the speed of light across a computer screen... But, I am not going to share that information. Unless someone asks...

[Skillzfire]

damn Morkonan you outdid yourself that time

you a teacher of some sort? it takes skill to make a think guy like me understand sciance

[brucewarren]

What about that strange force at the very edges where gravity
appears to be working in reverse and the galaxies are accelerating away
from each other?

I know that was a bit mean on my part, but someone brought up the
Lorentz transformation and that makes my head hurt

[Lanky]

Don't forget that if you are in that spaceship getting ever nearer to the speed of light you also experience time dilation i.e. the closer you are to light speed the slower your relative time is to the outside (or the faster outside time appears to pass for you).

For an example of this listen to the lyrics of the (very old) Queen record "39" -
"In the year of '39 came a ship in from the blue
The volunteers came home that day
And they bring good news of a world so newly born
Though their hearts so heavily weigh
For the earth is old and grey, little darling we'll away
But my love this cannot be
Oh so many years have gone though I'm older but a year
Your mother's eyes from your eyes cry to me"

[HCGxKaLiBeR]

damn, nice explanation up there though i have trouble understand half of it.

im not a native english speaker, i dont even bother to put them in google translate(it will be worse... ), but i c ur point...

[red assassin]

Nitpickery:

That force has to overcome the object's inertia, or its tendency to keep going wherever it is going. The amount of force necessary to move an object with inertia is directly proportional to its mass times its acceleration.

The wording is a little misleading here - any force will accelerate the object, no matter how large its mass; the F=ma formula gives the force required to achieve a given acceleration.

But, only with Newton... In the matter of Special Relativity, which deals at the fundamental level of all things moving really really fast (or are very tiny), things are different and certain rules apply. One of these are Lorentz equations which govern how space and time contract in the direction of motion.

This is also slightly misleadingly worded - special relativity applies in any inertial reference frame to any system, regardless of velocity or size. It reduces to Newtonian mechanics for speeds << c. Size is only relevant in that very small particles tend to move at speeds close to c.

And, now, we come to the defining formula that easily demonstrates why you can not accelerate to lightspeed. Once you understand how the formula works, you can rattle it off at parties to impress the girls...

E= mc^2/ sqrt (I- v^2/c^2) (Hmm, I think my hierarchy is right, there.) Here's a graphic, just in case:

[ external image ]

Or, the amount of energy required to accelerate the object is equal to its mass times the speed of light, squared, divided by the square root of one minus the product of its velocity, squared, divided by the speed of light, squared.

This is actually wrong - the formula you have there, often expressed as E = γmc² (γ being the Lorentz factor) gives the total energy of the system, including the rest mass (since γ = 1 when v = 0, giving rise to the common but misleading formula E = mc², which only applies for a stationary object). The kinetic energy component would be given by E_k = (γ-1)mc².

Obviously, this doesn't affect the conclusion.


I'm also not convinced about the flow of your discussion, as it implies F=ma is valid for a relativistic system, which it's not since the apparent mass changes as well. (Sidenote: The apparent or relativistic mass here is a deprecated concept as it's not especially useful and can be confusing, but you never explicitly mentioned it.)

(In terms of the game, this rule applies as well. A computer could not accelerate a spaceship, even if it is fake, to "the speed of light" because it uses tiny masses and a heck of a lot of heat to generate information and that information simply could not travel fast enough.*)

I'm going to attribute this to tiredness on account of not actually making any sense.

Don't forget that if you are in that spaceship getting ever nearer to the speed of light you also experience time dilation i.e. the closer you are to light speed the slower your relative time is to the outside (or the faster outside time appears to pass for you).

Not true - while the Universe observes time aboard your ship to be passing slower than for the Universe, from the ship's frame of reference it is still and the Universe is moving, and thus it observes that the Universe's time is passing slower than its own! Reconciling these two apparently contradictory statements requires also considering length contraction. This is also the source of the "Twins Paradox", which is resolved by noting that the ship accelerates when it turns around, and general rather than special relativity is required to consider the ship's frame of reference.

[milytar]

When Morkonan writed about that FTL are never be possible and explained it in his own way i was so unhappy,but when red assassin wroted that Morkonan explains might be not so true then my day wasnt ruined anymore,cos -WE STILL HAVE A HOPE(humankind)
PS!Im stupid about that E=ymc 2 stuff so i want belive that we can still reach to FTL

[pjknibbs]

You should read red assassin's comment again, milytar--he quite clearly says:

Obviously, this doesn't affect the conclusion.

So he agrees with Morkonan's conclusion (that it is impossible for an object with mass to ever reach lightspeed), he merely disagrees with some of the detail.

[milytar]

Damn me...and again my day is ruined

[Morkonan]

Nitpickery:...This is actually wrong - the formula you have there, often expressed as E = γmc² (γ being the Lorentz factor) gives the total energy of the system, including the rest mass (since γ = 1 when v = 0, giving rise to the common but misleading formula E = mc², which only applies for a stationary object). The kinetic energy component would be given by E_k = (γ-1)mc².... Obviously, this doesn't affect the conclusion...I'm also not convinced about the flow of your discussion,...

Yes, I was tired and flubbed a great deal of the "nitpicky" things, especially concerning the flow of the example. And, I am not a physicist, mathematician nor formally trained. The above was a simple explanation that I have seen used and demonstrated as an understandable example of accelerating a mass and the problems caused as one approaches a velocity equal to the speed of light. By changing some of the variables, like keeping v constant and increasing energy, we can also reduce it to E=mc^2, implying E=mc^2, energy=mass=energy, etc.. No?

However, can you help a layman correct it, in you opinion, so that it is still "basically" a faithful representation of the concepts that can be easily understood? I would hate to give this example again, in error and ignorance.

..I'm going to attribute this to tiredness on account of not actually making any sense.

Partly. But, what I meant was that you could make something "appear" to travel at the speed of light, or greater. Of course, pixels are not a spaceship. But, if, for instance, you constructed a computer in such a way as each pixel on a screen was controlled by a separate clock, and then just set the timing for a series of pixel's activation so that the series of pixels lighting up would give the impression of a game object traveling at the speed of light, it could be done. Not that you could track such a thing on even a large monitor or that it would be of much use, otherwise.

It's a "runway light" sort of demonstration. Get a string of lights, each controlled by a separate timer to light a specified time and then as each light becomes visible, it appears as one light moving along a line. When, as anyone knows, that is not what a string of runway lights actually is. It just appears that way because of how we interpret our surroundings.

[Morkonan]

Damn me...and again my day is ruined

Not at all.

All that is true is that an object with mass can not travel through normal space at the speed of light.

Change some of those conditions and you can still effectively travel at or greater than the speed of light. For instance, if you could drag space along with you, then you wouldn't be violating any rules, would you? If you didn't actually have to travel "through" space, but could somehow go around it and emerge at your destination, you wouldn't violate any speed limit laws.

But, AFAIK, all of those methods require either enormous amounts of energy, likely more than we can handle, or strange matter or technology that is far beyond us, etc... So, today, we don't know how to accomplish such things. But, that does not mean we won't ever be able to accomplish them.

[brucewarren]

Hyperspace Jump.

Isaac Asimov got there first

Now all we need is a ludicrously powerful computer to calculate the jump.

[milytar]

"Eppur si muove”

[fiksal]

did anyone mention yet, that both X3 and EVE dont model what happens when you move close to speed of light, they also dont fully model Newtonian physics?



so....
yeah

[red assassin]

Yes, I was tired and flubbed a great deal of the "nitpicky" things, especially concerning the flow of the example. And, I am not a physicist, mathematician nor formally trained. The above was a simple explanation that I have seen used and demonstrated as an understandable example of accelerating a mass and the problems caused as one approaches a velocity equal to the speed of light. By changing some of the variables, like keeping v constant and increasing energy, we can also reduce it to E=mc^2, implying E=mc^2, energy=mass=energy, etc.. No?

However, can you help a layman correct it, in you opinion, so that it is still "basically" a faithful representation of the concepts that can be easily understood? I would hate to give this example again, in error and ignorance.

E=γmc² is the formula for the *total* energy, which is the energy due to the object's mass plus the energy due to the object's motion, i.e. the kinetic energy. At rest, obviously, there's no kinetic energy. But to accelerate it to some velocity, you only need to add the kinetic energy - it has the mass already. Since when v = 0, γ = 1, the formula for the energy required to accelerate to some velocity is (γ-1)mc².

The point about E=mc² is just that, while it's entirely true for an object at rest, because γ has been simplified out it tends to get forgotten when you start considering objects which are not at rest, and hides the fact that the formula you gave for the energy of a moving object is exactly the same formula as the famous E=mc². This is mostly an issue when you start doing actual calculations with it; it's just something to keep in mind.

Partly. But, what I meant was that you could make something "appear" to travel at the speed of light, or greater. Of course, pixels are not a spaceship. But, if, for instance, you constructed a computer in such a way as each pixel on a screen was controlled by a separate clock, and then just set the timing for a series of pixel's activation so that the series of pixels lighting up would give the impression of a game object traveling at the speed of light, it could be done. Not that you could track such a thing on even a large monitor or that it would be of much use, otherwise.

It's a "runway light" sort of demonstration. Get a string of lights, each controlled by a separate timer to light a specified time and then as each light becomes visible, it appears as one light moving along a line. When, as anyone knows, that is not what a string of runway lights actually is. It just appears that way because of how we interpret our surroundings.

It's a computer. Nothing represented in its memory is actually going anywhere or otherwise subject to relativity in any sense. You don't need to do anything special or different to draw an object on the screen travelling at greater than the speed of light rather than less than it, although as you say you wouldn't be able to refresh the screen or the observer's eye fast enough to actually see anything. What you've described is effectively how anything is drawn on a screen.

[Morkonan]

...It's a computer. Nothing represented in its memory is actually going anywhere or otherwise subject to relativity in any sense.

I think I understand the spirit of your comment. That's why I wrote "appear" and "simulate."

But, as far as "nothing going anywhere or otherwise subject to relativity in an sense" I'd have to say you were wrong, there. For one thing, your not going to be able to get electrons in a computer chip to travel faster than light or any signal in a computer communicate faster than that. That processing may occur at obscenely fast speeds doesn't negate the fact that it can't move faster than light, no matter how small the chip is.

You don't need to do anything special or different to draw an object on the screen travelling at greater than the speed of light rather than less than it,..

You couldn't do it because the computer is not fast enough to send a single sequence of signals to the monitor at that rate. But, you could fake it by using multiple, independent, inputs and give the appearance of something traveling across the screen at that rate.. if you could detect it, that is.

[red assassin]

...It's a computer. Nothing represented in its memory is actually going anywhere or otherwise subject to relativity in any sense.

I think I understand the spirit of your comment. That's why I wrote "appear" and "simulate."

But, as far as "nothing going anywhere or otherwise subject to relativity in an sense" I'd have to say you were wrong, there. For one thing, your not going to be able to get electrons in a computer chip to travel faster than light or any signal in a computer communicate faster than that. That processing may occur at obscenely fast speeds doesn't negate the fact that it can't move faster than light, no matter how small the chip is.

You don't need to do anything special or different to draw an object on the screen travelling at greater than the speed of light rather than less than it,..

You couldn't do it because the computer is not fast enough to send a single sequence of signals to the monitor at that rate. But, you could fake it by using multiple, independent, inputs and give the appearance of something traveling across the screen at that rate.. if you could detect it, that is.

I said represented in its memory. The physical components of the chip have no bearing on the mathematical constructs it executes, and you don't need to move electrons around any faster to increase an entirely arbitrary number in the memory which happens to represent the position of an object at a rate of c rather than any other equally arbitrary rate.

Actually, with a clockspeed of something in the order of 3GHz, an ordinary desktop processor is pretty close to the tick speed required. Light travels approximately 30cm every nanosecond, meaning the system 'ticks' once about every 10cm travelled by a passing photon. When compared to a monitor which, at best, has a response time in the order of a millisecond, a million times slower than the system clock, you are barking up entirely the wrong tree trying to improve the speed of the processor in order to display an object moving across the screen at what happens to be lightspeed.

At any rate, the original point was "(In terms of the game, this rule applies as well. A computer could not accelerate a spaceship, even if it is fake, to "the speed of light" because it uses tiny masses and a heck of a lot of heat to generate information and that information simply could not travel fast enough.*)" which is, as I have said above, entirely and completely false.