How destructive is this?

[kilopi505]

I just got an idea yesterday. How destructive would a solid object or a munition moving at or faster than the speed of light be, if it hits Earth, or a spaceship with sheilds. Say...something as small as a cannonball used by ships in the 1700's? Or a 9 inch shell. Or...the rounds used by battleships in World War I and II? Would they do considerable damage on ships from sci-fi fiction?

I mean, I know that in HALO, the primary anti-ship weapon of the UNSC warships is the MAC, which throws out several hundred meter wide slugs at a considerable percent of the speed of light. If you make it faster, what will happen?

[adam_grif]

Asking for energy transfer for an FTL impactor is very silly, because in order to calculate energy (and thus destructiveness), we need to use equations, and the equations say that going FTL doesn't make sense. Oh sure, you could probably plug Newtonian physics into it, but it's wildly inaccurate for high-fractions of C, so it's basically useless for this.

As far as I can recall, to reach C it needs infinite energy, so um, it would do a lot of damage.

If you want to calculate sub-luminal impact energy, then you can use this. That said, energy in mathematical form is very abstract and isn't good for actually conceptualizing how much damage something will do. I can't help you there.

[Dave]

Atomic Rockets has a rough "boom table" that may help in visualizing the numbers you get out of the aforementioned relativistic kinetic energy calculator. This would assume, of course, that all the kinetic energy of the projectile was converted into, ah, destructive effects.

[GrandMasterTerwynn]

I just got an idea yesterday. How destructive would a solid object or a munition moving at or faster than the speed of light be, if it hits Earth, or a spaceship with sheilds. Say...something as small as a cannonball used by ships in the 1700's? Or a 9 inch shell. Or...the rounds used by battleships in World War I and II? Would they do considerable damage on ships from sci-fi fiction?

As has been mentioned, you can't make a massive object reach the speed of light. And to ask what happens if it goes faster than the speed of light is ludicrous and impossible to answer . . . what happens then relies on whatever hand-waving the story has invented to circumvent Einstein.

I mean, I know that in HALO, the primary anti-ship weapon of the UNSC warships is the MAC, which throws out several hundred meter wide slugs at a considerable percent of the speed of light. If you make it faster, what will happen?

Then it will deliver a quantity of energy determined by the relativistic kinetic energy equation.

[Ford Prefect]

If you make it faster, what will happen?

The slug will probably have distinegrated under the huge forces involved, turning it into a spray of relatavistic stea. On the off chance you geti t out the barrel, Newton is going to give your ship such a massive kick in the teeth that, assuming that the entire ship hasn't just come apart at the seams, it will be no be moving backwards so fast that it will probably take you a year and day to start going forward again. Assuming, for a moment, that the acceleration involved hasn't turned you and your entire crew into a film of proteins streap evenly across the deck plating.

[Ford Prefect]

EDIT: lol jesus, did I just say 'streap'. I mean spread, obviously.

[Caiaphas]

I'm going to first state the obvious--you can't get a projectile to go at the speed of light or faster and expect to be able to accurately calculate how much damage that projectile will do.

Now, then. If we don't ignore the practical aspects of this thought exercise, like where in the hell you're going to get the energy to accelerate this projectile and how you're going to do it, as well as where you're going to launch it from and (provided your launching platform is a ship) your ship and crew are going to survive acceleration, you'll find that it's going to be damn near impossible, given present-day technology, to do something like this. If this is material for a story, set it something like a century or two into the future if you're shooting for realism.

Assuming your projectile does survive acceleration and launching, then you'll find that a ball made of a core of DU about eight inches across with a one-inch thick shell of iron around it (the core will weigh around 35.4 kilograms, the shell about 34.5 kilograms) is going to do a lot of hurt at really, really high velocities. Check out the numbers below (assuming a total mass of 70 kilograms).

0.1 c - 8 MT
0.2 c - 34 MT
0.5 c - 243 MT
0.9 c - 2 GT, or 1929 MT
near-lightspeed - 2.381 e 20 GT or "a helluva lot of bang"

If anyone wants to complain about discrepancies in the numbers, I rounded, okay?

Back to the science. If you're not going to worry about how the damn things get up to speed, just at what speed they're going, I wouldn't recommend near-lightspeed projectiles, unless the story is a Cold War-type thing. They tend to end conflicts far too quickly.

For effects on planets, you're going to have to ask other people.

[kilopi505]

I'm going to first state the obvious--you can't get a projectile to go at the speed of light or faster and expect to be able to accurately calculate how much damage that projectile will do.

Now, then. If we don't ignore the practical aspects of this thought exercise, like where in the hell you're going to get the energy to accelerate this projectile and how you're going to do it, as well as where you're going to launch it from and (provided your launching platform is a ship) your ship and crew are going to survive acceleration, you'll find that it's going to be damn near impossible, given present-day technology, to do something like this. If this is material for a story, set it something like a century or two into the future if you're shooting for realism.

Assuming your projectile does survive acceleration and launching, then you'll find that a ball made of a core of DU about eight inches across with a one-inch thick shell of iron around it (the core will weigh around 35.4 kilograms, the shell about 34.5 kilograms) is going to do a lot of hurt at really, really high velocities. Check out the numbers below (assuming a total mass of 70 kilograms).

0.1 c - 8 MT
0.2 c - 34 MT
0.5 c - 243 MT
0.9 c - 2 GT, or 1929 MT
near-lightspeed - 2.381 e 20 GT or "a helluva lot of bang"

If anyone wants to complain about discrepancies in the numbers, I rounded, okay?

Back to the science. If you're not going to worry about how the damn things get up to speed, just at what speed they're going, I wouldn't recommend near-lightspeed projectiles, unless the story is a Cold War-type thing. They tend to end conflicts far too quickly.

For effects on planets, you're going to have to ask other people.

Actually, the idea I got is attaching a FTL engine (how does Star Trek warp engines work?) to an object, and then arming ships, or even fighters with these FTL torpedoes.

And as for where this is gonna get used on, how would sheilds from the various sci-fi universes fare against such a contraption?

[kilopi505]

I'm going to first state the obvious--you can't get a projectile to go at the speed of light or faster and expect to be able to accurately calculate how much damage that projectile will do.

Now, then. If we don't ignore the practical aspects of this thought exercise, like where in the hell you're going to get the energy to accelerate this projectile and how you're going to do it, as well as where you're going to launch it from and (provided your launching platform is a ship) your ship and crew are going to survive acceleration, you'll find that it's going to be damn near impossible, given present-day technology, to do something like this. If this is material for a story, set it something like a century or two into the future if you're shooting for realism.

Assuming your projectile does survive acceleration and launching, then you'll find that a ball made of a core of DU about eight inches across with a one-inch thick shell of iron around it (the core will weigh around 35.4 kilograms, the shell about 34.5 kilograms) is going to do a lot of hurt at really, really high velocities. Check out the numbers below (assuming a total mass of 70 kilograms).

0.1 c - 8 MT
0.2 c - 34 MT
0.5 c - 243 MT
0.9 c - 2 GT, or 1929 MT
near-lightspeed - 2.381 e 20 GT or "a helluva lot of bang"

If anyone wants to complain about discrepancies in the numbers, I rounded, okay?

Back to the science. If you're not going to worry about how the damn things get up to speed, just at what speed they're going, I wouldn't recommend near-lightspeed projectiles, unless the story is a Cold War-type thing. They tend to end conflicts far too quickly.

For effects on planets, you're going to have to ask other people.

Actually, the idea I got is attaching a FTL engine (how does Star Trek warp engines work?) to an object, and then arming ships, or even fighters with these FTL torpedoes.

And as for where this is gonna get used on, how would sheilds from the various sci-fi universes fare against such a contraption?

P.S.
I wanna assume that these FTL torpedoes would be as fast as Star Trek ships. Or at least as fast as Race Starships in Turtledove' WorldWar series.

[Starglider]

Amusingly using the standard Stark Trek version of 'warp drive' (i.e. one that works purely by changing the topology of space around the body, using magical plasma-absorbing 'warp coils') the projectile will have no real-space velocity at all, and will do no damage on impact (save for perhaps some fracturing and twisting of structures around the impact point due to the residual warp 'field'). Attempts to design physically plausible 'warp drives' probably would do a lot of damage if they hit something, because they involve ludicrous amounts of energy and huge masses of exotic matter, but none of those designs are anything close to buildable.

[Teleros]

Actually, the idea I got is attaching a FTL engine (how does Star Trek warp engines work?) to an object, and then arming ships, or even fighters with these FTL torpedoes.

And as for where this is gonna get used on, how would sheilds from the various sci-fi universes fare against such a contraption?

I've only heard of 2 sci-fi settings in which you can reach FTL velocities in normal space (and not hyperspace, bubbles of space like Star Trek, etc): the Lensmen & the Skylark series, both by Doc Smith...

Skylark FTL
Throw Einstein out the window and stick to Newton for dead simple accelerations to FTL velocities. A rather... extreme way to make FTL work in a setting mind you, because you're pissing over a hell of a lot of very fundamental physics (just how do black holes work now, for example?). On the other hand, you can now have ships that move so fast that even with the very best collision-avoidance systems and energy shields, they'll eventually blow themselves up when they hit a stray hydrogen atom.

Lensmen FTL
Objects become inertialess - that is, they instantly achieve the speed at which the thrust from their exhausts equals the "air resistance" provided by the medium they're travelling through (be it interstellar dust or Earth's atmosphere). However, because inertia is suspended, such ships cannot be used as FTL kinetic missiles, because once they hit the target they'll come to a dead stop, instantly. Note that your pre-inertialess velocity is "remembered": if you're moving at 2km/s along the X-axis of your galactic map, become inertialess, and fly off along the y-axis, once you restore inertia you will instantly revert to travelling at 2km/s along the x-axis. Conservation of momentum was thus preserved, after a fashion.

It should also be noted that in real life, becoming inertialess would do Bad Things to everything from biological systems to photons and the hull of your ship.

When they found a way of making an inert object travel at FTL speeds (from a foreign universe where ordinary matter could & regularly did achieve such velocities), they had to take precautions with lots of god-tech to avoid the entire universe collapsing due to the nonsensical mass of the missile.



If you still want to make an FTL missile like this, probably the best thing to do is say that it is fired, accelerates to the speed of light via never-explained-technobabble, and then at the moment of achieving this becomes a black hole, because otherwise you're going to run into the problems mentioned above.

[Uncluttered]

If you still want to make an FTL missile like this, probably the best thing to do is say that it is fired, accelerates to the speed of light via never-explained-technobabble, and then at the moment of achieving this becomes a black hole, because otherwise you're going to run into the problems mentioned above.

I was listening to an episode of astronomy cast, and this is a possibility.
here's a link to the transcript and shownotes.
http://www.astronomycast.com/listeners/ ... #shownotes

[Ghost Rider]

If you still want to make an FTL missile like this, probably the best thing to do is say that it is fired, accelerates to the speed of light via never-explained-technobabble, and then at the moment of achieving this becomes a black hole, because otherwise you're going to run into the problems mentioned above.

Not only one of the better ways because it avoids the Doc Smith problems to say nothing of how do you use a weapon that doesn't really reach the target if a stray piece of matter gets between it.

The other problem is it's a tad bit expensive for something that if you have that level of technobabble, you'd have much easier ways of achieveing far more destructive weaponry.

[justicar5]

If your wanting to throw FTL weapons about, you have access to anti-matter in decent amounts, use AM instead, far simpler. For instance case an AM payload in a magnetic containemt field insidce a railgun round, fire the railgun at 'techno-babble but still sane C' and wait for the kabooom.

[Teleros]

If your wanting to throw FTL weapons about, you have access to anti-matter in decent amounts, use AM instead, far simpler. For instance case an AM payload in a magnetic containemt field insidce a railgun round, fire the railgun at 'techno-babble but still sane C' and wait for the kabooom.

I'm assuming you mean "still sane fraction of C" there, because I don't think anyone on the receiving end of a missile travelling at twice the speed of light will either care or notice what it's made of .

Mind you, if you want to shoot anti-matter at someone via a railgun (which at least implies unguided munitions), that means you've got masses of cheap anti-matter... so why not just make the railgun slugs out of anti-iron?

[lordofchange13]

well me not reading the other comments and not knowing every thing about science. im pretty shore a cannon ball moving faster then light and it hit earth there would be a big bomb, earth would lose a lot of air and a big ass hole will go though the planet

[thegreatpl]

That makes me wonder; what would be the smallest size of an object traveling at just less than the speed of light hitting to earth to destroy it?

Frankly, i have to wonder whether or not the thread question is even necessary, since you can pretty much destroy a planet with projectiles at less than the speed of light.

[Eddie Van Helsing]

I just got an idea yesterday. How destructive would a solid object or a munition moving at or faster than the speed of light be, if it hits Earth, or a spaceship with sheilds. Say...something as small as a cannonball used by ships in the 1700's? Or a 9 inch shell. Or...the rounds used by battleships in World War I and II? Would they do considerable damage on ships from sci-fi fiction?

Why would you need your projectile to travel at the speed of light, or at greater than light speed? The energy required to accelerate a projectile to that velocity could be better used elsewhere, don't you think?

[Sea Skimmer]

That makes me wonder; what would be the smallest size of an object traveling at just less than the speed of light hitting to earth to destroy it?

Depends, what do you mean by destroying the earth? A relatively small object hitting at that speed might easily kill all life on earth, but it’s going to punch a hole through one side and out the other before it physically blows the earth away. The hole would then be violently crushed closed by the earth’s gravity, a process which would probably kill most life on earth on its own through massive earthquakes and volcanic eruptions.

Physically destroying earth like a Death Star blast is very troublesome to pull off, even with unlimited energy. You need some way of making the energy spread out in multiple directions in such a way that it pushes all the pieces apart at escape velocity.

[Eddie Van Helsing]

Physically destroying earth like a Death Star blast is very troublesome to pull off, even with unlimited energy. You need some way of making the energy spread out in multiple directions in such a way that it pushes all the pieces apart at escape velocity.

I don't think you could do it with an energy beam. I think you would first have to burn your way to the earth's core, somehow keep the contents of the earth's mantle from filling in the hole, and then initiate a nuclear device with a multi-zettaton yield at the freshly hollowed-out center of the planet.

[Sea Skimmer]

I don't think you could do it with an energy beam. I think you would first have to burn your way to the earth's core, somehow keep the contents of the earth's mantle from filling in the hole, and then initiate a nuclear device with a multi-zettaton yield at the freshly hollowed-out center of the planet.

Well, a big enough energy bolt going through the planet would eventually be able impart enough force to blow the whole planet apart, like a bullet through an apple, it would just be preposterously uneconomical in terms of energy use. Exploding something in the center would certainly be better, and simply breaking apart the planet into tiny bits and ejecting them into space one by one with giant construction equipment better still.

[Eddie Van Helsing]

Exploding something in the center would certainly be better, and simply breaking apart the planet into tiny bits and ejecting them into space one by one with giant construction equipment better still.

Or, you could just drop a shitload of rocks on the planet, wait for the environment to settle down, and then exploit the living hell out of the planet's mineral wealth. Blowing it up seems like a waste, even if it does look awesome in the movies.

[Sea Skimmer]

It would be a waste most of the time, but I could see two basic scenarios in which it could make sense. The first is some kind of total war in which a planet has a strong symbolic or religious value. Physically destroying it could be just the kind of shock you need to end the war, or at least seriously erode enemy moral. Hopefully this will avoid the need for victory through interplanetary genocide.

The other situation would be extremely deep fortifications. In the modern day bunkers are usually small things buried under a few thousand feet of rock at most. But designs for depths as great 8,000-12,000 feet have been studied and deemed feasible. Mines in South Africa have reached depths like this already. An advanced civilization, instead improving and expanding its bunkers for hundreds or even thousands of years could create absolutely colossal deep underground facilities. With a robot based economy, expansion might go on perpetually and requiring nothing more a supply of raw materials for tunnel liners and piping. The feasible depths might also increase considerably, especially if everyone’s favorite sci tech neutrino radiator could be perfected. Getting rid of heat is the largest barrier to deeper tunneling depths.

Anyway even the known feasible facilities would be able to withstand several hundred megaton direct hits, actual resistance depends heavily on the rock structure (its possible for only 3,500ft depth to withstand a 350 megaton surface burst in ideal rock conditions). If they spanned whole continents, and had plenty of space and resources for the tunnel dwellers to dig out after an attack then even super massive orbital or rock bombardments might well fail to wipe the facilities out. At this point even melting the planet crust could not be certain of sealing them in, since a super tech nuclear powered TBM might just be able to tunnel through the lava.

So as a solution, and for situations when you cannot afford to just blockade the planet for years on end you would want massive overkill solutions, like dropping a moon sized rock on the planet, or hitting it with a massive fractional speed of light hit, or blowing it apart, all depending on what your technology makes most feasible would be the only way to assure destruction. This is pretty well assuming both high tech, and large interplanetary civilizations, but then when else would you consider planet killing weapons?

[Uncluttered]

This is something I've been thinking about.

Say the startrek federation has access to some binary neutron stars, preferably a pulsar. Rotating black holes will do as well. This should make it "cheap" to accelerate projectiles to high relativity.

Procedure: You drop the projectile on close flyby, catch it with warp drive, and drop it again and again until it has the energy you need.
Each time it does a flyby, it is going to gain momentum.
Actually one star/hole will do if you use warp. With warp technology, you can keep "dragging" and dropping the projectile around the stars until you have the kinetic energy you want.

It should be easy to scale up production.

Once the projectile is up to high relativity speeds, Put it in a warp bubble "treadmill" torpedo.
Since warp 1, is lightspeed, this should be no problem for any trek power. The nice thing about warping space, is that the treadmill should be able to orient the projectile in any direction without actually touching it. You can also clear out the space in the warp bubble with perfect vacuum. so there is little cherenkov radiation from dust wasting your energy, and giving away your weapon.
Mass of the projectile might be a problem in a warp field. Maybe someone can elaborate on this.

Lets make the target an ISD. They are near invincible. You need 1e19j minimum to get through the shields. But,IIRC with a relativistic projectile, there is no upper limit on the amount of smash you can carry. (At some point your projectile might resemble a black hole to an outside reference frame.)

The hard part as always, is going to be to hit the ISD. (The ISD has FTL wank even faster than warp. It has FTL sensors to detect you.
What is not known, is if it can effectively shoot an evading target at warp.)

The best use of these could be as planetary defense.

You won't actually want hit the target at warp speed. Due to a quirk in warp tech. Hitting the target at warp will hurt it much less. Instead, the treadmill will drop out of warp just a few meters from the target. The projectile will travel the last few meters at the speed of light.

If the projectile is a black hole to outside reference frames, it's harder to damage.
A turbo laser shot that smashes the treadmill torpedo case, will release the projectile sooner. Any energy or matter will be effectively absorbed by the singularity. Of course, the projectile at this point would only be moving at light speed, giving the target a nonzero chance to evade.


Damage.
Most likely, it will breach the shields.
Also, Most likely, it will just bore a hole right on through unless it's made to fragment.

Arguably, your projectile could be a warp capable spacecraft itself. I choose to put the projectile in a "treadmill" because the treadmill needs to be on 24/7/365 to contain the projectile. Having the "treadmill" warp field inside a container allows for external power sources to contain it.

The big IFs.
1. Can you put a warp bubble around an object traveling at high relativistic speeds?
2. Can you make a warp "treadmill" perpetually moving space inside a container at light speed.
3. Can you move this container around at FTL once you've made it.

Still. There you go. A new VS weapon for the mice. Keeps the cat entertained longer.

[Ghost Rider]

To answer the stupidity of new weapon for versus. Does this happen before or after the day they find Earth and threaten to turn Vulcan and the Federation into slag?

The other parts of why the weapon is silly are handled elsewhere.