HW2 Physics

[Agent_Worm]

I'm not gonna nit pick about the game because I love it and everything about it makes it awesome.

However, I'm taking a physics course and I began to wonder; "what were to happen if real physics were to play into the game..."

Here's a neato link that talks about physics in movies. But it can relate to games too.

Notice specifically what it says about the explosions, "...observing an exploding spacecraft in outerspace would be quite dangerous compared to observing one on Earth. The shrapnel and debris from exploding spacecraft would attain very high initial velocities just like they do on Earth. However, with no gravity to pull them to the ground and no air drag to slow them down, the debris would travel outward in straight lines virtually forever until they hit something.

Distance from the explosion would reduce the number of projectiles striking a spaceship. However, impacting pieces would have the same kinetic energy they had right next to the blast. A spacecraft would have to use the time afforded by distance from the explosion to raise its shields or risk annihilation. Being in a desperate battle surrounded by exploding ships and having no shields would be certain death."

If this were to hold true for HW2 dogfights with corvettes and fighters (as far as I know they don't have shields), then the attacking squandrons would eventually annihilate themselves because of the ship debri. Cruiser and frigate fights would be a different story. It would depend on the distance and how they exploded.

Physics... ruins movies, and soon games too

SAW

ps. I really don't care for the game being too "realistic" it's one hell of a game, but it's fun to think of this kind of stuff.

[Nerath]

Well, there's the old action/reaction that ion cannons would shove ships backwards, and more fuel would have to be expended to counteract that. But cap ships don't have fuel, so I guess more energy?

Then there's the fact that it would probably take less damage to kill a ship than it does - scout projectiles would punch holes in cap ships, drain out the oxygen, kill the crew, and that would be the end of it.

Flames would never burn in space, so you wouldn't see the flames from damaged ships.

Splash damage would apply, because flying debris would gut nearby ships. The debris wouldn't just sit there. Also, ships would make no sound in space. I'm sure there's more...

[FallenSoloSLS]

If there ever is space combat, it will likely be very quite, very distant, and as far as movies and games are concerned, very boring.

In any event, the explosions would not necessarily send debris in a spherical shape away from the location of the ship when it exploded. The motion of the spacecraft at the time of explosion would have to be taken into account.

When you consider the motion of the exploding ship, the assymmetry of some debris and local gravitational influences (like local planets), some pieces might well be flying off in a parabolic trajectory.

[Adm_Ackbar]

well, considering that ships right next to the explosion don't get damaged anyway in hw2, It's atleast consistant.
In addition, i would like to add that homeworld and space sims all have this notion that different ships have different maximum velocities in space. The maximum velocity of any ship should be the speed of light and as long as their engines are burning, they should be accelerating. The only difference should be how fast they accelerate. plus, atleast in hw 1 and 2, ships seem to decelerate much faster than they accelerate even though their main engines are in the back of the ship.

[FallenSoloSLS]

I don't think that's entirely true.

I think, that according to relativity, the closer to the speed of light an object gets, the more mass the object has - at some point, there would be an equilibrium that the object's source of thrust could not overcome.

If the thrust from an object is not sufficient to overcome the inertia, then accelleration should stop, right?

[Adm_Ackbar]

No that is not correct. as a object approach the speed of light the mass does not change. It only becomes more resistant to acceleration. so the classical f=ma become f=ma/sqrt(1-v^2/c^2). Also no matter how close v approaches c, there will always be some accleration. the only time acceleration is not possible is if v=c but to accelerate to that speed will take an infinite amout of time (since infinite energy is required) for a classical particle.

[Pyromonger]

I wouldn't say it's incorrect so much as an alternative interpretation to the equations.

Words are just words, after all.

[TechnoTorgo]

basic sum up: in space, things fire. when they fire, nothing slows it down, becuase there is no outside force to slow it down. Unless it's an enemy ship. Hw2 is not a physics simulator. We just want to play, not make this a physics lesson.

[Agent_Worm]

Originally posted by TechnoTorgo
basic sum up: in space, things fire. when they fire, nothing slows it down, becuase there is no outside force to slow it down. Unless it's an enemy ship. Hw2 is not a physics simulator. We just want to play, not make this a physics lesson.

You basically said what stated at the beginning and at the end of my post, but it's still fun to think about this kind of stuff...

But to get back to the physics argument...

basically, if a ship is flying at a certain velocity and it blows up, those pieces are still gonig to be spreading out in a sphere shape, that is assuming that's how they blow up. Regardless of how it blows up (meaning the direction, spherical, angled), the explosion will give the debri enough acceleration to over come it's initial velocity, those debris will keep that velocity since there is nothing in space to stop them (like air resistance). A planet and star with a gravitational field would be negligible unless they were really close, and it wouldn't have a noticable affect on the object.

Oh and the ships could blow up with flames, flames just need fuel and energy. How do you think the rockets in space work? There's no oxygen?

SAW

[The5thElephant]

Agent_Worm there is oxygen in liquid form in rockets, most fuels need oxygen in some form to ignite and burn. But ships in space COULD burn because they obviously have oxygen on the inside to keep the crew alive. Eventually it would run out and the fire would go out but still it could happen. Also a planet or star would not be negligible. It may not cause the object to impact the planet or star but the trajectory would definitely change. The amount of the change depends on the distance but it would still change. Also think of how fast and large comets are and those get tunred around by stars, so a piece of debris will definitely be turned around by a star eventually (if within a certain distance of a star).

[Agent_Worm]

Originally posted by The5thElephant
Agent_Worm there is oxygen in liquid form in rockets, most fuels need oxygen in some form to ignite and burn. But ships in space COULD burn because they obviously have oxygen on the inside to keep the crew alive. Eventually it would run out and the fire would go out but still it could happen. Also a planet or star would not be negligible. It may not cause the object to impact the planet or star but the trajectory would definitely change. The amount of the change depends on the distance but it would still change. Also think of how fast and large comets are and those get tunred around by stars, so a piece of debris will definitely be turned around by a star eventually (if within a certain distance of a star).

good point... now re-read this:

]Originally posted by The5thElephant Also think of how fast and large comets are and those get tunred around by stars, so a piece of debris will definitely be turned around by a star eventually (if within a certain distance of a star).

The force for gravity is proportional to it's distance (r) squared.

F = G (M1 * m2)/r^2
not that the gravitation constant (G) is really small about 6.67 x 10-11 N(m2/kg2)

You wouldn't want to be to close to a star because it'll destory the ships with radiation depending on the size star. You also have a small tiny, lets say a baseball sized piece of debri. The mass of the debri isn't going to matter much in the equation, and if you have that large distance, it's going to cut down the amount of force exerted on it by the star. Now, if they were close to a planet, then there may be a noticable change in it's direction, after a while, you may see it change.

Remember all of this will depend on the distance, larger distance, less force, closer distance, more force.

I love physics (and I should be doing my homework rather than figuring out this other stuff ). Don't take this all to serious, I mean, it's fun to think about, but it's still a fun game.

SAW


[edit] Okay, I just noticed that you, 5thElephant essentially said what I said...that's what happens when you're a nerd...

[Tel'Quessir]

Maximum speed explaination:

HW ships do indeed fly in actual orbital physics - but only the flagship takes that into account. Fleet components maneuver using the flagship's velocity as a reference point, and the "maximum velocity deviation" used solely for the purpose of ease of command/control. Sure - you can fly things at unlimited "relative speed" and do lightning-fast firing passes, but it's not going to be practical in most cases. Exceptions do exist but not in the current military fleet engagement doctrine that specifies holding and securing critical volumes of space with force is the prime agenda...

Hmm, that doesn't sound very cohesive, does it?

A little essay on why HW2 weapons produce muzzle flashes and tracer is much better, but I'll save it for a later post. It's easy to explain, really.

[hint: Coating rounds with phosphorous won't work in the vacuum of space, but plasma does glow and charged plasma delivered into magnetic containment then projected as a weapon does work, no?

And you can't practically have massdriver rounds that span over 3 stories high - each turret would only have 1 or 2 ready rounds at most, making this thing totally useless in more than a single salvo. Don't talk about passing ammo that size through the turret base - it's not even big enough to fit the rounds in.]

[AntaresSITH]

i got a deja vu of a deja vu...

this discussion pops up every month either here or in the GD forum.
what about making a forum just to tackle this problem?

neat idea isnt it?

[FallenSoloSLS]

spreading out in a sphere shape

I believe that if a moving ship explodes, the shape of the explosion would be more egg shaped, considering the velocity of the object that explodes.

If an object is not in motion, relatively, like a satellite in stationary orbit. Then the explosion would be roughly spherical.

An interceptor that is blasted in mid turn would throw more debris toward the outer part of the arc of it's turn than toward the inside of the arc.

[Agent_Worm]

Originally posted by FallenSoloSLS


I believe that if a moving ship explodes, the shape of the explosion would be more egg shaped, considering the velocity of the object that explodes.

If an object is not in motion, relatively, like a satellite in stationary orbit. Then the explosion would be roughly spherical.

An interceptor that is blasted in mid turn would throw more debris toward the outer part of the arc of it's turn than toward the inside of the arc.

I believe your right.

SAW

[Ta_erog]

FallenSoloSLS

Not correct,
All explosions that would create a sphere at rest would create a sphere at ANY speed! Baring out side forces (like gravity or friction. . It is all relative . . as long as you are in the same frame of reference and no external forces are at play, a spherical explosion will always be a spherical explosion.

“If an object is not in motion, relatively, like a satellite in stationary orbit. Then the explosion would be roughly spherical.”
Again depending on your frame of reference all objects can be considered at rest. . independently, . . . so it is entirely up to the differences in your frame of reference that determine relative speed.
There IS real difference between a satellite in a “stationary” orbit or a interceptor that is blasted in mid turn but one thin in common is that they are both are moving in relation to something (ie you! if they are seeming to move) and both ARE in a state of changing vector . . (ie turning)
The interceptor is using engines to change vector and as soon as they stop the craft and (all debris stops changing vector) So if it gets hit and destroyed . . . that resulting explosion at “rest”, “motion”, or during a vector change does not matter! it will be the same shape and it will move in a strait line/vector (barring external forces) and expand normally.
The satellite has a force acting on it all of the time making it “fall” at the planet, but it keeps missing because of its tangential speed.
There is NOTHING special about a “stationary” orbit . . it just happens to be the orbit that matches the rotation of the planet it is only called stationary because the people calling it stationary are on the surface of the planet and the two are matching movements . .
If the satellite explodes, it would do so in a sphere also and that sphere would “fall” at the same rate and orbit the planet . . . BUT since the very fact that it is in orbit (being effected by an outside force to change it vector) the sphere will change shape . . . the parts now have different velocities and vectors and depending on the magnitude they will all move into different orbits . . some at which will intersect the planets atmosphere and some may move out of orbit and other just stay in highter or lower orbits.

Got it?? Common sense CAN NOT be used in explaining motion in space because our earthly experiences have little barring on them and the magnitudes are not in or normal realm of thought.

Hence all of the confusion people have and why a higher level physics understanding is really required.

[Pyromonger]

Heh.... it would kidna suck if HW2 was more realistic... you could just send a probe over, find enemy, then start shooting from your MS. As long as there's no asteroids or anything in the way.... LONG RANGE BOMBARDMENT!!!

[Adm_Ackbar]

Pyromonger: no i believe being more resistant to acceleration is different from being more massive. because being more massive implies matter is gained. Most physicists will say that the object becomes more resistant to acceleration, not mass increases.
Tel'Quessir: i agree with most of your explanation but there is one huge problem. I don't know about you but if i'm screwed and want to get out of a bad situation, i think i would put my engines to max and get out of there as soon as possible. same thing goes if i would like to chase down the enemy

[Steppe]

lets do a project. lets float the space with oxygen, so if there ever is a space battle it will have nice sound and explosions and stuff like that

[FallenSoloSLS]

Ta_erog,

I think we're in general agreement.

All explosions that would create a sphere at rest would create a sphere at ANY speed! Baring out side forces (like gravity or friction. . It is all relative . . as long as you are in the same frame of reference and no external forces are at play, a spherical explosion will always be a spherical explosion.

My point is that even in space, there are forces that can affect an object. The outside forces I'm referring to are inertial and centripetal forces, which are still present in a <roughly> gravity free environment if the object is in the midst of accelleration or a tight turning maneuvre.

I still contend that if an interceptor is in the midst of a turning maneuvre, the explosion of said interceptor would create a debris dispersion that is influenced by the inertia and centripetal forces of the exploding object.

Likewise, if an object, say a rocket, is in the midst of accelleration when being fired, the explosion would not look unlike the Space Shuttle Challenger explosion back in the 80s. In that situation, the explosion was elongated in the direction of the movement of the exploding object.

However, if a ship is in constant motion in a gravity free vacuum - say the space ship Discovery from 2001 while en-route to Jupiter (or was it Saturn?) after the initial firing of the rockets. If that space ship blew up, I agree that the explosion would be spherical since there would be no forces acting upon the object.

[Ta_erog]

No, I don’t agree exactly
Any forces that a ship accelerating either in a straight line or not (turning) will make no difference on the explosion since at the point of destruction all non explosion based acceleration stops (the engine that is expelling matter to accelerate the ship in the opposite direction no longer exists so is no longer a factor) So every particle of the ship will have the SAME vector at the instant of parting ways and since there are no other OUTSIDE forces acting on the particles (no drag or gravity etc.) every particle will keep its vector . . . Ie the original vector at the INSTANT of separation plus the vector of the explosion . . since every bit of the ship has the same vector in that instant the only variable is the explosion (and we already stated it was a spherical one, so it will remain so)

Note to change direction of motion and "turning" are not necessarily the same thing (like a “strafing” turn, and a spin, one changes direction of movement but not faceing and one does not changes direction of movement but changes faceing) to change direction of motion you must accelerate in a in a different vector then the one you are in. and the act of changing the vector is a exerting a force over time (acceleration). . at any instant you can take a snapshot and plot the vector (vectors are ALWAYS strait lines) and if that acceleration stops that very instant, the object would move strait down that vector at a constant speed.
IE a curved path = a constantly changing vector = force/acceleration being constantly exerted . . since a destroyed ship can’t exert any additional forces on its own and if there are no external forces the result is ALWAYS the same . . (note a funky explosion, can easily make a non spherical "particle" dispersion but the prior “movement” of the exploded object has no bearing on the shape of the explosion)

“Space Shuttle Challenger explosion back in the 80s”
For one it was in the atmosphere of a planet (lots of “extra” forces here) and two it was only a partial and slow explosion. . Ie parts of the ship where still intact and accelerating/decelerating while the explosion was happening (notice I say instant above). So some parts were still accelerating and thus still under there own power and others slowing due to gravitiy and friction. So, of course! it got elongated along those acceleration vectors?!? . . really a very bad example.

Take your Discovery example . . it would not matter if it blew up during the firing of the rockets or after as long as the engine’s acceleration stops at the moment of destruction. If it does not . . well anything could happen then and not really any use discussing since that action would define the shape (ie the rockets take off at a random angle?!?)

Also note that the centripetal force from the changing direction acts on the ship as a WHOLE and would, as seen above, stop acceraration when the ship stopped thrusting due to the explosion.
BUT there is second centripetal force that also happens if the ship is spinning (like a top) and this would be the same whether or not the ship was moving or not since this is just effected by just the speed and axis of rotation regardless of movement.
Also note Centrifugal force does not exist . . Any time the word Centrifugal Force is used, what is really being described is a Lack-of-Centripetal Force

So again, unless the explosion is very drawn out over time AND the part that is still “exploding” is still accelerating over this time . . . the shape does not change no matter the prior movement. . if some parts are still accelerating on there own then they have not "really" exploded and thus really don’t apply to the discussion. .

[Pooed Unit]

Then there is the problem with visibility. You would not be able to see the ships because space is dark.....very dark and only the lights from the ships would illuminate them.

[Ishaar Niirfa]

Visibility isn't really a problem. Light reflects off ships as well. The ship would have to absorb light to be invisible. That is not so. Metal reflects light, most of the light that hits it in fact.

[FallenSoloSLS]

In general, I think you're right.

since every bit of the ship has the same vector in that instant the only variable is the explosion (and we already stated it was a spherical one, so it will remain so)

While the ship as a whole may have the same vector, as it breaks apart, the vectors and forces acting on all the individual parts that become detached from the whole during the explosion will have their own vectors. Explosions, while pretty fast, are not instantaneous - especially over an entire ship. I believe that an explosion is different from an exploding inteceptor. In my turning interceptor example, the entire strike craft does not have thrust, there is torque on the ship as a whole induced from the thrusters. The thrust is not coming from the entire object, but it is affecting the entire object. Inside the object the parts are experiencing their own centripetal forces, resisting a change in vector, just like the interceptor as a whole (inertial dampers come to mind). As a ship like that breaks apart in an explosion while in a turning maneuvre, there are bound to be some funky things happening, because there will be LOTS of things flying off in their own vectors. Likely creating something not exactly sphere like.


Consider a sphere that is on a string in a vaccuum and a gravity free environment. Suppose the spere is made up of a device that is mostly hydrogen and oxygen and something that would set off the explosion. Now swing that string around you so that it's flying around your head (assume the string is long enough so that when it blows up it won't hurt you and assume you're able to fix your location in space). If you spin that string at a given velocity, and then the sphere explodes, then, given there is nothing but the centripetal vector that the object is moving at the time it explodes, then sphere would blow up in a spherical manner. But that's not an interceptor.

Also, while the explosion looks spherical, I would contend though in this example, the object would explode and look spherical that is not to say that the sphere's front end and the back end are travelling at the same speeds. I would think that the vectoral speed would be subtracted from items flying the opposite dirction of the vector, but that would likely be negligible. So while the it looks like a sphere, it is expanding with a continually changing center.


Also, I believe the space shuttle is actually a good example of an complex object exploding while accellerating. But you're talking about a "pure" explosion, not the explosion and breakup of complex objects, which is what would happen in the real world. The seconds after the shuttle explosion show how an complex object's inertia and many parts play havoc.

[Agent_Worm]

I think we've covered the explosion part real well, whether it would expand in a sphere etc.

I think we've failed to think about the true question at hand. If the explosion caused the debri to fly out at some high velocity, wouldn't it tear the other ships that were nearby apart?

SAW

[FluxX]

Yes.

Thats what happens to all our satalites.. and the Mir station.

If they drop a spanner when on a space walk, they need to make shure it don't meet up with them after a days orbit.



I think with the explosions in space, its easyier to explain the opposite, IE explosions on Earth.

The only things that effect the shape of an explosion would be atmospheric drag (absent in space) and resistence from the ship/hull itself.

So you would get debris in a sperical vector (or whatever) but some debris may be stoped, or deflected of other parts of the ship. This would probably be minimal though.

[Tel'Quessir]

Tel'Quessir: i agree with most of your explanation but there is one huge problem. I don't know about you but if i'm screwed and want to get out of a bad situation, i think i would put my engines to max and get out of there as soon as possible. same thing goes if i would like to chase down the enemy

You got it - if HW2 had the option of speed boosting as a special ability I would have integrated something like this to override fleet velocity reference, however, there is none.

Ta-erog's Fleet Engagement does indeed have capital vessels having a common "max velocity", with mass [acceleration] being the deciding factor. Might want to take a look there.

Now on to space debris - yes, since there is no atmospheric friction to slow down the spread of fragments they remain deadly for as far as they can "move", relatively.

However, as mentioned above, fragmentation can be irregular, although there are manufacturing practises to make warheads generate a set number of fragments evenly across a sphere.

So yes, in a HW2 PDS - esque massed skirmish there would be a whole lot of debris flying about "in reality".

However, since the time of HW1+, most spacecraft operating in the Fleet are designed with survivability in mind, look at the old HW manual on multilayered armour protection and the like - they're very far off from current space technology, and not really worried of those little bits of shrapnel and space debris floating about.

I made proximity burst weapons create a measure of surpression, but removed the magical disappearances of strikecraft caused by stock-game FFEs.

For example, given like velocities, a 50lb solid metallic massdriver round will undoubtedly have far superior penetration power than say, a 250 gram piece of shrapnel [quite large already]

But a proximity burst nearby will have greater chances of knocking out unprotected external systems on a hull.

It is of course unwise to let ships take constant damage whist flying though debris fields for the interest of gameplay - HW:C's requiring management of Strikecraft just because explosions of capital ships doing blast damage is bad enough.

Many factors present "in reality" cannot be simulated in the current level of software. This includes individual evasive maneuvers, survivability measures and techniques, ECM capabilty of individual ships non-beneficial to allies,etc m, all these are taken into account on those percentage hit chances for almost any weapon. [at least in my work] Except in obvious cases where 100% hit chance is gauranteed - as in the case of attacking massive targets like BCs, MS, etc.

Lack of the above factoring is the sole culprit of insanely low Strikecraft survivability in the stock game. It takes months to convert a mathematical-based hitpoint system to something resembling a simulation of sci-fi naval warfare.

And that actual crews are present in those vessels we blatently throw about into combat situations, abeit in simulated form - no sane pilot would willingly fly straight and level into batteries of anti-fighter weaponry, nor would a Frigate helm crew decide to stand still under fire, except where their assignment is Fleet fire support in the rear echelon of a capital formation.

Not to mention it's silly to waste primary weapon charges on tiny Frigates where DDs and BCs are inbound

Reworking targetingpriorities cure almost all of these non-logical factors.

Finally, actual space warfare [would be] fought at ranges way beyond visual ranges, if progression of naval warfare from surface gun engagement to over the horizon ASM firings today using airborne platforms for target designation and missile course guidance would be any indication.

The combat system in HW2 does indeed consist of visual range engagements, for obviously no one would like staring at obscure arrays of electronic displays in a futuristic CIC

Detection methods like stellar occlusion, magnetic field analysis, emissions detection, exhaust stream spotting using out-of-visual-spectrum illumination, can provide a ton of data regarding what is incoming even without the use of active sensors. Or even years before an opposing fleet might close the range enough on conventional drives in order to take up planatery bombardment positions on some planet. Moot with sci-fi hyperspace, of course.

Conclusion - only so far can we go and make HW2 resemble a simulation of sci-fi naval warfare, but it is convincing enough if we knock out enough "realistic" factors

[Ta_erog]

“Explosions, while pretty fast, are not instantaneous - especially over an entire ship. I believe that an explosion is different from an exploding interceptor”
Granted Explosions are not instantaneous but, you said an Explosion (A single catastrophic event) not a lengthy break up or even multiple Explosions with parts of the ship still under there own power??. . .
“I believe that if a moving ship explodes, the shape of the explosion would be more egg shaped, considering the velocity of the object that explodes.” –FallenSoloSLS
And
“An interceptor that is blasted in mid turn would throw more debris toward the outer part of the arc of it's turn than toward the inside of the arc.” –FallenSoloSLS
That is what you said and what I responded to . . and which at stated are wrong. And the correct answers are NOT intuitive! And MUST be figured out mathematically!

IF you could make 2 identical “complex” explosions it would not make a difference whether or not the ship was moving and broke apart while accelerating (and some parts like the engine decide to keep going) or if it was not accelerating and that same engine started up exactly during the explosion . . the only thing different in these scenarios is that part of the ship accelerates on its own from the explosion. The parts that detach will not accelerate in either case.

“Consider a sphere that is on a string in a vacuum . . . . . . But that's not an interceptor”
They follow the same physics . . . again, you need to really specify that the interceptor in question will explode slowly, and have a runaway engine and secondary explosions. If it is one event then there is no difference.

“So while the it looks like a sphere, it is expanding with a continually changing center”
Now you got it . . a moving expanding sphere and a stationary expanding sphere are the same when you subtract the common vector. . . .if you are moving in the same direction and speed as the moving expanding sphere it is not moving in your frame of reference it is only expanding. . if you are not, the center of the explosion would be moving and ALL of the particles would have the apparent vector of the expansion from a point plus the overall common movement vector . . Ie your “changing” center really means a moving epicenter and all particles have the same added vector as the epicenter.

“I would think that the vectoral speed would be subtracted from items flying the opposite dirction of the vector, but that would likely be negligible”
I think this is where you are missing it . . the “vectoral speed” of the expanding sphere is the explosion element (vectors in all directions) and the total movement vector is added to all of the explosion vectors, but it make more sense saying the epicenter=interceptor and the interceptor’s vector=the explosion’s INITIAL vector . .so all particles resulting of the explosion already have the interceptor’s vector added in. That is why the speed or even the acceleration does not matter because acceleration stops at dissociation and the speed can be taken out of the equation entirely.

“Also, I believe the space shuttle is actually a good example of an complex object exploding while accelerating”
Yes and No, you stared talking about the physics of a object in space doing a simple action (exploding) this is none of the above . . it is like saying throwing a object earth orbit will behave like X and then discounting that behave is true because you throw a ball on earth and it does not appear to behave that way . . ?? you go from one external force to quite allot . .

As, you may notice I am not guessing at these conclusions. These are mid level physics problems. . even ones that may be on collage tests. (and I am not surprised people get messed up with these, because that is why they are on collage level tests!) (that is also why I am trying to set things strait to help people out)
But, it seems like you may have to find this out your self, If I didn’t explain it well above or if you didn’t understand it. I can’t really easily show you the equations with these fonts here. But I may be able to show you a graphic sim if you are really interested.
(sorry for being so long winded)

[Ta_erog]

Tel'Quessir

Ya, good post! I aggree!

[Tel'Quessir]

Ok, lets have a simulated scene of a Vagyr Battlecruiser emitting some debris.

VMS Warspite was disabled in combat operations as part of TF53, 13th Fleet. [insert location here]

Cause of loss: Hyperspace inhibitor support was disabled, leading to Hiigaran units having free reign on hit and run operations. Warspite was ambushed by the Hiigaran battlewagon Prince of Hiigara and support strikecraft wing.

Technical details on hull breakup for Engineering analysis are as follows:

Internal pressure doors functioned adequately as hull breaches were detected, maintaining atmospheric pressure in critical areas. All personnel were at action stations, and hence under protection of the tiertiary armour belt. No breaches reported therin.

Early in the surprise attack, the dorsal heavy missile battery was hit by primary weapons fire and bomber strike from the PoH, leading to an ammunition explosion. The vessel was spared the brunt of the detonation energy as failsafes vented the blast upwards and discharged plasma mass of the ready missiles as well, then isolating the battery.

This explosion would be directed generally upwards due to the warhead positioning and angle of attack.

Your debris trajectory would be in a irregular, wide conical fashion projecting "upwards" relative to the VBC

Secondary massdriver fire from the PoH then targeted the dorsal fire control station, which is external to the hull armour system ahead of the heavy missile battery.

[b] Here, we're talking about total penetration of the station's structure - no way can that thing stand up to the HBC's Arbiter cannon slugs

Your debris propagation would be like spalling in armour plate of armoured vehicles. Conical fashion with the centre of it the path of the massdriver rounds, which would penetrate cleanly [/i]

Primary weapons fire from the hostile capital vessel then shifted to the main engine exhaust ports as Warspite attempted to turn about on attitude control thrusters to bring main guns to bear.

The main fusion chambers were armoured enough to withstand the attack [no loss of power capacity], but the thrust vectoring vanes were dislodged from their mountings and swept away by the exhaust stream.

Easy one - the TVC vanes are blown away by the fusion exhaust "backwards"

Ok, you get the idea so far

Conclusion

Aforementioned debris are emitted on a vector originating from the parent vessel, the VBC, if you take that as the zero velocity reference.

Lets say the ship was in orbit when the attack occured. The debris would then appear to spread out while maintaining orbital track with a deviation proportional to the velocity they are "thrown out" from their source.

If the ship took enough damage to be totally disintegrated later on, it won't just "explode", but break up over a period of time as structural integrity is lost. This will of course lead to even more debris, or none at all - it might just break in half along the midsection as the HBC focuses fire on that area. Then your "debris" would be relatively mild - two halves of a ship floating apart.

Or in the former case, lots of secondary explosions like what is seen in HW2. Each explosion generates its own cone of debris pointed whereever the blast vector is in an irregular fashion like the heavy missile battery example above.

If somehow the fusion reactors would lead to a catastropic explosion [unlikely] then that final blast would again have an effect of all other debris generated.

The hull might already be in pieces and floating apart when something causes that huge outburst of plasma, then those pieces would be of course pushed away by the final explosion, perhaps spawning even more breakups and secondaries.

So you see, debris analysis isn't that easy, but the basic rules of relative velocity [magnitude and direction] still applies.

And of course ships don't get disabled or "Bismarcked" in the stock game

[Agent_Worm]

That was awesome... good explanation and detail. You should write some fanfiction

SAW

[VPR]

Have any of you played the sequels to Elite, Frontier Elite 2 or Frontier First Encounters?

Both these games have realistic physics in space. Combat is quite interesting. The smaller ships have more powerful engines while the larger ships do not due to their larger mass. Engine power is measured in thrust acceleration of Earth G's. For example most fighter craft have main thrust values of 16G's to 30G's. Ships also have retro-thrusters (i.e. reverse thrusters) which are normally around half the power of main thrusters. The ships also have thrusters for each axis to allow them to roll/pitch and turn. The games limit you from going over a certain velocity but all ships can reach this maximum value.

Combat happens around 6km distance or below due to the pulse/beam laser systems you can use having short range and the fact that missiles self destruct after 60-90 seconds but they have really powerful engines (67G's thrust). Fights are quite interesting and it does take a while to get the hang of it. You usually travel to planets from your hyperspace point where you get up to several thousand km/s in velocity. Pirates intercept you while you begin to slow down (they just begin to slow down later so they can intercept you). I've tried this myself and it takes practice to get right. Other smart thing are you can do is use planets and stars gravity to do sling-shot manoeuvres.

Ships fight with their engines off and only use them to manoeuvre and counteract intertia during the fight. Fights involve ignoring your true speed as you continue towards the planet at so many km/s. It's the speed difference between you and your target which you only take note of. Combat usually ends up as a joust with ships running in on each other and then thrusting as they move away from each other counteracting inertia until they begin to move back towards each other again. Fighting bigger ships with a smaller craft can be quite testing as they are usually better armed but you can get on their tail by matching speed as they can't accelerate as quickly. It's fairly easy to hit other objects though once you get good but you do have to beef your ship up with shield generators and use more powerful weapons to outclass your opponents. Some battles can last for a while though if both opponents are equally matched. When you start the game your ship is pretty rubbish so you have to avoid fights until you've traded enough to buy a better ship and equipment.

This webpage from one of the main Elite community sites explains it better though I think

It's all relative!

[Hakone]

Originally posted by Adm_Ackbar
No that is not correct. as a object approach the speed of light the mass does not change. It only becomes more resistant to acceleration. so the classical f=ma become f=ma/sqrt(1-v^2/c^2). Also no matter how close v approaches c, there will always be some accleration. the only time acceleration is not possible is if v=c but to accelerate to that speed will take an infinite amout of time (since infinite energy is required) for a classical particle.

:jaw: wow.............:jaw: :werd:

[Hakone]

my turn....

A ship that blows up WILL create a sphere, BUT, if the ship is moving, the sphere will move, not just stay in place.

For example, ship explodes while moving
the slashes wont go where I put them so please try to imagine the second set of slashes over and under the second set of dashes.

\ | /

\|/
- - -----------------------------------> - -
/|\
/ | \


Now a ship standing still will do this...





\|/
- -
/|\



\ | /

- -

/ | \


I know that the projectiles aren't right, but that's the best that I can do without making something on paint.

[Ta_erog]

Hakone
that’s what I was trying to get across in a rather longwinded manor . . but people seem to have problems detaching them selves from "common knowledge” physics . .

[Hakone]

glad I could help.

[Tel'Quessir]

A ship that blows up WILL create a sphere, BUT, if the ship is moving, the sphere will move, not just stay in place.

Erm, both ships and debris would be "moving", just that we are taking the ship as the zero-velocity point, or the "fleet reference velocity" in HW fare.

If a ship is accelerating and emits debris, the debris would of course maintain their eject velocity, and appears to be left behind as the ship continues accelerating.

But we're trying to explain that if a ship "blows up" and is moving at a rate of say, 600m/s towards your mothership, the debris would be "moving towards you at the about same rate as the former ship" as there is nothing affecting the velocity of the debris - until they hit something or influenced by nearby "environmental factors" like seconaries, etc.

So yes, we all are correct in our own sense - just a different manner of presentation

Fanfiction

Did dabble in that, and although the technical aspect is fine, character generation is not. Thanks for the encouragement

[nickersonm]

I believe that FallenSolo's problem with the "simple explosion" explanation is that, during a turn, different parts of the ship may have different velocity vectors. So if the ship is in the middle of a turn when it explodes, the front part may have a velocity vector one way, and the rear part another. This would not create a nice sphere. The large distribution of velocity vectors could create a "smearing out" effect.

- nickersonm

[Tel'Quessir]

Thats right - different velocities between parts of a rotating vessel will have the effect of smearing out the debris sphere.

For a more natural effect, look at the shape of a spiral galaxy.

[Ta_erog]

That is right, centripetal force will have an effect on the explosion but this effect is from the “spinning” of the ship not its movement though space . (so, that same ship at “rest” spinning at the same rate would effect the explosion the SAME way that a “moving” ship spinning at the same rate would effect the explosion . . . the movement vector has no effect) . . .Look in one of my previous posts for a larger explication.
So, these two motions . . can be separated freely and do not effect each other. . . also a turn can only be so violent with a human pilot and you still have to accelerate the rotation and cancel it out and you would have to do that very quickly to make any real centripetal force, remember we are talking centripetal force not the change in “movement” vector.
So, in the end this will only have a VERY minor effect on the shape of an explosion expanding at many 1000 m/s2 (>then 8000m/s2 really).
Essentially, this centripetal force is the same as the force you would feel if you where sitting on a marry-go-round that started up . . rotated 90 deg (or whatever the “turn” was) that then stopped with in X seconds. The longer and more massive the craft the more it will resist a quick rotation. (yes, a “shorter” stubby craft of the same mass, and mass distribution, would take less energy to spin at the same speed as a “longer” craft)

Again note that this is NOT the Gs felt by a fighter pilot during a turn!! In fact, since the pilot in a normal modern fighter sits in front of the center of axis in most all planes that centripetal force would push him FORWARD not back. (this seems rather strange but it is true). The force that he feels turning is the craft pushing him into a new vector . . IE going 300 knots in one vector then being pushed to go 300 knots in another vector . . Rotation is not needed, it is just common because the way most craft in the atmosphere work.

So, remember it is not the “TURN” that can change the shape of the explosion! It is ANY rotation can change the shape of the explosion.

Also note there is NO reason for any “space” ship to move like a aircraft . . In fact a change in heading with your thrusters ON while you are rotating your ship to orient the engines for that new vector would be very wasteful. Since they would still be accelerating you in the old vector until you are oriented perpendicular to that old vector . . . . rather sloppy for anything <90deg and downright counterproductive in anything >90 deg. (people really have to stop thinking aircraft :naughty: )

[Tel'Quessir]

(people really have to stop thinking aircraft )

LOL, nicely done, enjoyed reading that post

[Ta_erog]

Thanks, I try . . .

The amount at which Hollywood and “common knowledge” distorts what we think is reality, is rather amazing . . I have argued with some rather smart people over things that SEEM common sense in general physics but are in reality totally wrong . . or at least very misunderstood . .
The trick is that allot of it is hard to visualize and is not apparent in everyday life experience due to scale and well, our limited frame of reference on this planet . . .but the math does not lie, and sometimes seems to contradict some of our common understandings (from our limited frame of reference) that we have. Some people, however smart, do not like giving them up to something that sounds at first all wrong and other people really do not have the schooling to fully understand some aspects making it even harder . .

That’s why I try to help when I can . . even though it seems long winded (I am very good with physics and not necessarily English) and some of these concepts are rather hard to get across in plain text.

I really appreciate the comment!

[Tel'Quessir]

Some people, however smart, do not like giving them up to something that sounds at first all wrong and other people really do not have the schooling to fully understand some aspects making it even harder . .

Like the best way of mine to teach virtural pilots fresh from the more arcadish games that energy fighting with you maintaining a tactical advantage over prey is preferable to getting into some 5G 2-dimensional continuous turning fight -

Duel them and fly high speed, gradually tightening spiral climbs in Bf109 [where it has a lot of advantage over most Allied fighters] after luring them to pull their nose towards me, and the result is that the "Trainee" badly stalls out trying to do an unrealistic pursuit course while I piourette gracefully, flip down into the vertical, and give him a precise burst of MG151 fire. [IL-2 online]

Sometimes people need practical demonstrations of what works and what not before they understand something. Can't blame ourselves, it's human nature

[Starblade]

My head hurts from reading this.