Everything is a bomb.

[Firebrand]

Every Vehicle, PA, Fighter, Mecha, Starship, whatever in the setting is a bomb, I just realized. When you combine their sheer mass with the absolutely ludicrous speeds we have (.3c being around average), you see that every PC is flying around in something capable of giving everything a bad day.

Take, for instance, the Mindy M2. Fully loaded, it has a mass of 180 kilograms, and flies around at a speed of .375c. Doing the math to figure out the relativistic Kinetic Energy of the Mindy, It turns out that each and every Mindy at full speed has the kinetic energy of 170 Megatons.

Now, compare this to the Bomb dropped on Hiroshima, which was about 16 Kilotons. With 1 Megaton being 1000 Kilotons, we eventually come out to a Mindy being able to impact with the force of 10625 15 Kiloton Nuclear bombs, the same dropped on Hiroshima.


Have fun with that.

 

[Zack]

Been there, done that

 

[Doshii Jun]

Rude way of putting it, but Zack's right. Could Yamataians go kamikaze and destroy entire planets by ramming them? Yes. But we don't because it's lame.

 

[Soresu]

Rude way of putting it, but Zack's right. Could Yamataians go kamikaze and destroy entire planets by ramming them? Yes. But we don't because it's lame.

Second.

 

[SSharp]

Rude way of putting it, but Zack's right. Could Yamataians go kamikaze and destroy entire planets by ramming them? Yes. But we don't because it's lame.

Second.

Motion passed.

 

[Moogle]

Rude way of putting it, but Zack's right. Could Yamataians go kamikaze and destroy entire planets by ramming them? Yes. But we don't because it's lame.

And isn't awesome things like this what Cluster Flux is for?

 

[tomaszavenger]

I'm not an expert, and please correct me physicists if I'm wrong, but I think he forgot some critical things:

-Terminal velocity (ships on planets): Most of the energy would dissipate into the surrounding atmosphere, assumingly in equal directions, and at the immense height of most atmospheres, the impact wouldn't be too deadly for the people below. That defeats the idea of ships being used as intergalactic ballistic missiles. You'd have to slow down the ship, enter the atmosphere successfully and THEN blow, but that would mean far less kinetic energy

-Momentum (ships on ships) : If we're talking about attacking-ships, let's assume you mean small against large ship (as a small against small will obviously blow both ships). If a fast, small ship hits a stationary large ship, the large ship wouldn't be affected so much. Why? Well, the coefficiant of restitution between the colliders isn't exactly 100%, maybe we can take a value closer to 70%; in this case, 30% of the energy will be returned to the small ship, obliterating it (obvious). But the 70% of the momentum being transferred to the large ship wouldn't matter, the mass of the large ship will be WAY larger than the small ship, and with the materials used (which will probably distribute the shock wave like modern materials, but probably better than we can), will only be sufficient enough to knock it off course AT MOST.

-FTL (very 'fast' ships): If we're talking about FTL, ships that travel at these 'speeds' actually travel very slowly. If you think I'm being stupid, think about how the technology works: spatial folds; the energy being used by FTL drives is sent into 4th Spatial Dimension, not our perspective 3rd dimension, and is being used to create the folds (gateways) which the ship travels through: only a small amount of energy is required to cross a fold once it's made! (It's like a folded piece of paper, at the beginning, to get from the top to bottom you have to travel the whole distance of the paper, afterwards, you just have to travel the width of the fold (trans-dimensionally)). In other words, FTL isn't a problem, unless somebody travels the fold directly INSIDE another space-ship; not only is this VERY unlikely (practically neglegible), but even if you tried it on purpose you're unlikely to succeed due to the chaotic mechanics that are likely to be present in a spatial dimension we cannot see!

In other words, no, it cannot be used as an effective bomb, except maybe on an asteroid, and that is why spaceships generally use precision weapons like lasers rather than blunt, massive rounds.

Just my input...

 

[MissingNo]

http://riventree.com/jeff/humor/ravioli.txt

As we pass Cerenkov 1.0 in the target, we get a new phenomenon -- Cerenkov
radiation. This is that distinctive blue glow seen around water-cooled
reactors. It's just (relatively) harmless light (harmless compared to
the other blast effects, that is). I mention it only because it's so
nifty...

At around .9 c (Cerenkov 1.1) , the ravioli starts to perceptibly weigh
more. It's just a relativistic mass increase -- all the additional weight
is actually energy, available to do compressive heating upon impact. The
extra weight is converted to heat energy according to the equation E=mc^2;
it looks like compressive heating but it's not.

[Here's where I'm a little hazy on the numbers; I'm at work and
don't have time to rederive the Lorentz transformations.]

At around .985 c (Cerenkov 1.2 or so), the ravioli now weighs twice what
it used to weigh. For a one pound can, that's two pounds... or about sixty
megatons of excess energy. All of it turns to heat on impact. Probably
very little is left of the space-cruiser.

At around .998 c, the impacting ravioli begins to behave less like ravioli
and more like an extremely intense radiation beam. Protons in the water
of the ravioli begin to successfully penetrate the nuclei of the hull
metal. Thermonuclear interactions, such as hydrogen fusion, may take
place in the tomato sauce.

At around .9998 c, the ravioli radiation beam is still wimpy as far as
nuclear accellerator energy is concerned, but because there is so much of
it, we can expect a truly powerful blast of mixed radiation coming out of
the impact site. Radiation, not mechanical blast, may become the largest
hazard to any surviving crew members.

At around .9999999 c, the ravioli radiation may begin to produce
"interesting" nuclear particles and events (heavy, short-lived particles).

At around .999999999999 c, the ravioli impact site may begin to resemble
conditions in the original "big bang"; equilibrium between matter and
energy; free pair production; antimatter and matter coexisting in
equilibrium with a very intense gamma-ray flux, etc.[1]

Past that, who knows? It may be possible to generate quantum black holes
given a sufficiently high velocity can of ravioli.

So the danger isn't from FTL travel. It's from sufficiently advanced STL velocity that you may blow up a planet with a can of ravioli.

 

[Zack]

Warning: Math
With a little help from this site

Let us assume that the power armor or shuttle weighs about 150 pounds (in 1 g). This is a decent approximation of the weight of the human pilot but in virtually any circumstance the mass is going to be greater so this is a low ball estimate.

I’m going to use 0.3c (or 89937737.4 meters per second) for speed because things in this setting go about that fast on average.

This comes out to about 65 megatons or four Tunguska events. This is more energy than even the largest nuclear device ever detonated. It is also very likely the blast will occur fairly low to the ground (perhaps within 50km at the start of the denser stratosphere) and cause considerable damage to the surface just like the Tunguska event.



Terminal velocity doesn’t really apply here, yes the atmosphere will slow down the incoming object but this will be in the form of intense heat and light as the object plows through the atmosphere. When the atmosphere finally gets dense enough to produce enough heat to break apart an object moving this fast it is very likely that a Tunguska style air blast will occur which will only increase the devastation.


High energy collisions leave some wiggle room for speculation but basically there are two possible results with the momentum. The ship being hit can be penetrated entirely through by the object, due to the speeds involved the object will break up on impact and act like a jet of water squirting through the ship leaving most of the energy to keep on going. In this case the ship has enough momentum to resist the effects somewhat. The other possibility is that the object simply explodes on impact due to armor or whatever. This means most of the energy gets transferred into the other ship and it gets knocked off course and exploded (though in which order is up to you).


FTL systems have been house ruled to not actually impart any acceleration. This solves a bunch of physics problems like infinite damage weapons. The ‘ships used as bombs’ thing only really applies to STL systems and the ship’s own power sources which provide more than enough oomph to cause damage.

 

[Gabriel]

Guys, you all miss a crucial point: (Physics WILL be involved)

YES, if you wanted to a kamikaze into a ship then you could destroy the entire ship and anything around it. At the same time, NO, you cannot do this to a planet, for a very simple reason. It's called terminal velocity. Assuming that your 150lbs power armor at .3c entered the atmosphere, it would not be accelerating, simply going at a constant speed of .3c, correct? So soon it will start to incur air resistance.

Resistive force is equal to -.5*Coefficient of Drag*Density of Air (1.2)*Surface Area*Current Velocity (89937737.4).

So therefore, R=-.5*D*1.2*A*89937737.4.

D (Coefficient of Drag) is equal to (2mg)/(V^2*Density of Air*A), Terminal Velocity is 43m/s on which means:

D=(2*9.8*(150*2.2))/[(43^2)*1.2A] = 6468/1849A = 3.498/A

By means of substitution we know that:

R=-[.5*3.498*1.2*A*89937737.4]/A

Both Surface Areas cancel, meaning:

Resistive Force=-.5*3.498*1.2*89937737.4 = -188767101.8399N

Now, if you take into account that the resistive force will decrease as the power armor slows, you have the basic equation:

R=-.5*.3.498*1.2*V; R=-2.0988V, and with the starting Force of -188761323.25512N, we have the final linear equation of:

R=-2.0988V+188767101.8399

Now, if F=ma, and mass is 150*2.2 (1lbs=2.2kg), which means that Force is equal to 330a. As a result, a=F/330.

Now, if F=-2.0988V+188767101.8399, and a=F/330, substitution says:

acceleration=(-2.0988V+188767101.8399)\330

so acceleration=-.00636V+572021.5207 where V is the current velocity

-----------------------

Now, the goal of this entire physics rant is to discover the true final speed of the PA upon hitting the ground. Most air resistance begins in the Mesosphere, approximately 80,000m (80km) above the earth's surface, which is something we will need to know.

We know that a2^2=a1^2+2jv where j is jerk (rate of change of acceleration). So since our starting resistive acceleration is -572004.009864 and that at terminal velocity, our resistive acceleration would be -9.8 (equal and opposite to gravity) we can now plug in and solve for our jerk.

-9.8^2=-572004.009864^2+2j(89937737.4-43)

So jerk=1818.9736m/s^3

By integration we can show that a=-1818.973t+C where C is the starting acceleration, and through further integration we show that v=-909.4868t^2-572004.00986t+D where D is the staring velocity. By integrating once more we finally get:

x=-303.16227t^3-286002.00493t^2+89937737.4t+E where E is the starting distance of 80000. (Please keep in mind that the equation has negatives because both the jerk and starting acceleration are negative, but the starting velocity and starting height are positive (For the sake of this, down is positive and up is negative))

So, when x=0 (when the power armor hits the ground) our equation will look like this...

-80000=t(-303.16227t^2-286002.00493t+89937737.4) and by using the quadratic formula we discover that:

t=248.82502, 0, or -1192.191914413193 when the PA hits the ground. Based on common sense, we can infer that the time is neither negative or 0, so therefor our time is 248.82502.

So now that we have our time, we can plug this back into our equation of x=-303.16227t^3-286002.00493t^2+89937737.4, plugging in 248.82502 for my time.


SO v=-909.4868*(248.82502)^2-572004.00986*(248.82502)+89937737.4 (Remember, the second two terms are negative because starting acceleration and starting velocity are in the negative direction). Solving across, after all that physics work, i get a final velocity of.... *DRUM ROLL*

108701038.01083-89937737.4 = 18,763,300.61083m/s, which is still very high, but is about 2/15 that of the original speed.

 

[Zack]

Except the energy doesn't just disappear, it gets transfered to the atmosphere in the form of heat and light. Regardless of what happens to the object it still is packing 65 megatons of force and that force has to go somewhere. For something this small atmospheric friction is likely going to cause it to explode long before it hits the ground.

So if a power armor were to hit a planet at full speed the resulting blast would likely look like this.

 

[Nashoba]

Terminal Velocity does not apply, a ship or even a power armor is not "free falling" into the atmosphere. It has a propulsion systems and will travel at speeds sufficient to wreak havoc.

A skydiver in a belly to earth free-fall position is about 195 km/h (122 mph or 55 m/s).

The earth has been hit by objects just as meteorites traveling many times faster, and the atmosphere does heat it up, but it doesn't slow it to terminal velocity.

 

[Gabriel]

I didn't think of propulsion, but my point wasn't that it would slow to terminal velocity, because that would require several thousand kilometers of space to slow something down that much, the point was that it wouldn't be as fast as people are claiming, but still quite fast.

Also, I feel like something moving that fast would be desintegrated entering the atmosphere. Yes, it would cause massive heat like Uso suggests, although I have a funny feeling it would never actually reach the ground, because resistive forces as high as the ones I have shown would rip any power armor to shreds, even if it is a power armor. Although, on that note, we can assume that no power armor could still be using propulsion after entering the atmosphere, because there would be nothing left to propel.

 

[MissingNo]

That's what I've been wondering. Materials have to be very strong to resist being burned up, it's why most meteorites never reach surface. The more speed something has, yeah, it'll have more energy on impact, but more of it will be consumed before reaching the ground. It's why launching a can of ravioli wouldn't actually do anything, and why railguns are only a good idea in space (where atmosphere won't slow or burn up the projectile before it hits the target).

 

[tomaszavenger]

(Contains more math and physics :-D)

Firstly Gabriel, I already mentioned terminal velocity, this is not something you came up with alone (look up).

Secondly, I assumed the propulsion drive would stop on impact with the atmosphere for my calculation.

Thirdly, Wes, the force has to go somewhere, but assuming it explodes at height will mean that most of its energy will dissipate:

KE = 1/2mv^2

Using Gabriel's values (rounded):

0.5 * 68 (kh, I use the SI units) * 19 000 000 = 646 million joules of kinetic energy.

Let's assume it hits the Earth, and the energy is distributed over 1/20th of the Earth

The Earth's atmosphere is 4.2 billion cubic kilometres, so dividing this by twenty gives us 0.21 billion cubic kilometres which will be affected.

Now, assuming energy is distributed equally over that volume.

646 million joules / 210 million = 3.076 joules per cubic kilometre = 3.076 x 10^-9 joules per cubic metre = 3.076x10^-18 joules per cubic centimetre, in other words, no real noticeable temperature change (since to heat 1 cm^3 of water by 1 celsius you need 4.196 joules). Of course, distribution will NOT be equal and most of it will hit the upper atmosphere, but we're mainly concerned with surface dwellers. Simply looking at numbers, you can travel very, very fast and not do much.

You'd need a big ship with a big speed as a weapon, and nobody is going to throw that kind of power away, as a kamikaze weapon!

No, you cannot make a bomb out of a ship.

If we did assume it was propelling its way down to the surface, surely it could be stopped with any futuristic surface to air weapon, which will then allow the previous calculation to apply.

Thank you for being kind to me as a new member.

 

[Zack]

Keep in mind this isn't a binary thing, some objects don't have enough energy and do burn up in the atmosphere while others can have enough mass to make it to the surface.

For example the can of ravioli would just burn up harmlessly if dropped from the international space station, but fired at a planet moving at .9999999c it has enough energy to not only destroy earth but knock the pieces out of the solar system.

---

I can't math out the exact height the object would explode at but I would say the most likely distance is 5-10km (based on the tunguska event). In this case we're not talking about hundreds of millions of miles to be affected but only a few hundred with the blast focused entirely in the center of the area.

646 million joules / 200 km = 2,153,333 J/km. Consider that this will also be much more powerful towards the center of the blast. Easily enough to take out the downtown area of a city.

The boom table, for comparisons

 

[tomaszavenger]

Okay, that makes sense, I was just trying to disambiguate the fact it's not capable to devestate on an interplanetary scale, and if it was shot down at high distance by surface to air weapons, the energy distribution wouldn't be very effective as a bomb.

Do we have surface to air weapons in common use?

 

[Zack]

Nepleslia has a few different vehicles for surface to air duty like the K4 and K1 but those are the only things I know off the top of my head that act like a modern day air defense network.

The NMX have an anti-starship battery which is more surface to orbit, and I think a few other factions do have similar systems but you'd have to search for those on the wiki if you want more information.

 

[topsecret221]

Well, as far as I can tell, most of you are only looking at planets with atmospheric properties. But what about planets with little to no atmosphere, or colonized asteroids (if, for whatever insane reason, someone attempted to colonize an asteroid).

Lets take, for example, a [theoretical] valuable and significant weapons development "colony". It is more like a space station on a planet; no access to the outside with the exception of docking ports, hidden far from the front lines. If an enemy faction's munitions are primarily produced on that planet, then accelerating 150 lb power armor at .3c and then subsequently ramming it into this atmosphereless planet would be able to annihilate a lot of stuff (depending on the planet's size, of course). Then that would be a crippling loss to the oppossing military's forces and weaponry.

This is without math, unfortunately (still a sophmore, just turned 16... at our school physics is a junior class), but just based on what I know and what I've read (and all you guys' hard work ^^) I think that it can be a viable tactic in the right (or damn near perfect) situation.

Or am I wrong?

 

[Zack]

Well if we have no atmosphere to worry about....

http://www.stardestroyer.net/Empire/Sci ... roids.html


.... This calculator is pretty self-explanatory (or at least the explanation is on the same page). Naturally a moon is probably going to be a little different in composition than a nickel-iron asteroid or ice comet but you should be able to get a good idea of how much energy it takes to blow something up with this.