Wraith ships shouldn't explode.

[Aer'ki]

Aer'ki, are your assumptions based upon RL nukes or the dozens-of-gigatons SG nukes, + the insanely powerfull reactors of the ship. for a ship that size, probably gigatons aswell.

Both, but I was mainly referring to present day nukes. Most people simply see a nuke as a super bomb that will annihilate anything and don't have an understanding of the physics involved.

On earth, a nuke's destructive power comes mostly from the concussion wave it produces in the atmosphere. In space there is no concussion wave, which is why nukes are as powerful when hitting the hull of a ship in space. Their destruction is very short range, not proximity.

The original comment made was 'vaporize anything at 25 miles'. If you run through the calculations of the energy it takes to vaporize a square meter of anything, then factor in the blockage caused by that vaporized material(it's going to shield other things somewhat), then factor in how many metric cubes of hull space a Hive ship contains...the numbers add up to so great a number that there is no possible way a Hive ship can be destroyed in a single explosion. It's just too big with too much mass to destroy.

A nuke would make a nasty hole in the thing and bend and distort the surrounding decks, seriously wounding a Hive, but that's the end of it.

The Ancient satellite energy weapon had to vaporize only a small amount of mass to cut the ship in two, making it far more effective than a spherical distribution of energy. The two halves of the Hive are still intact, but their control lines, power lines, etc have been severed, rendering most of the hive inoperable. Possibly some weapons in the section with an intact reactor could still function, so it wouldn't be 'completely' dead.

This is also why I think the drones shouldn't kill a hive ship the way we've seen. Again, too much mass to deal with.

And I'll remind you, the writers have never explained how the Wraith defeated the Ancients in terms of space combat. Cloning a vast army of wraith does no good when fighting in space. You need ships for that.

If you take a realistic look at what the Wraith technology is capable of and the mass of the Hive ships...them defeating the ignorant Laneans is much more feasible.

[Aer'ki]

According to my calculations if only one face is facing the explosion and all the energy that hits the cube it's transformed in heat and distributed uniformely it would take 474 megatons at 1 mile. At 25 miles it would take 625 times more (296 gigatons).

Are you assuming that all the energy from the nuke is directed onto that one meter square area? Vaporizing iron in under a second requires a vast amount of energy. Vaporizing a full square meter of the stuff is nearly undoable at a mile's distance. The US Military tested nukes against old naval vessels and I don't believe that they were vaporized in the blast.

[Character]

Whats the problem with nukes? They dont vaporize the hive themselves, they only cause internal explosions. If your such an expert on energy effects, tell me how much energy would be needed to accelerate the many tens of millions of tons of hive mass to atleast interplanetary speeds, power multi GT weapons and enter hyperspace? then tell me what would that energy do to a hive if released inside, with more or less even distribution?The energy that hive ships use are several orders of magnitde above our petty multi GT nukes, so its reasonable to think that that energy vaporizes the hive when released uncontrolably.

Where did you get the 25 miles figure? i can only remember michells qoute of 100 miles radius, although i'd take his "vaporize" as "burn to a crisp". Also the wraith could build a hive ship in about two weaks wothout any special power, after getting some zpms, i'd think they could make several a day, the only problem would probably be crew for so many ships, which they solved with cloning, no wonder ancients couldnt keep up.

[Aer'ki]

Whats the problem with nukes? They dont vaporize the hive themselves, they only cause internal explosions. If your such an expert on energy effects, tell me how much energy would be needed to accelerate the many tens of millions of tons of hive mass to atleast interplanetary speeds, power multi GT weapons and enter hyperspace? then tell me what would that energy do to a hive if released inside, with more or less even distribution?The energy that hive ships use are several orders of magnitde above our petty multi GT nukes, so its reasonable to think that that energy vaporizes the hive when released uncontrolably.

Where did you get the 25 miles figure? i can only remember michells qoute of 100 miles radius, although i'd take his "vaporize" as "burn to a crisp". Also the wraith could build a hive ship in about two weaks wothout any special power, after getting some zpms, i'd think they could make several a day, the only problem would probably be crew for so many ships, which they solved with cloning, no wonder ancients couldnt keep up.

The 25 miles was from a post in this thread, I don't know where he got it from. As for ships 'accelerating' before they enter hyperspace...that's a whole other discussion.
And the wraith can't make a hive ship in one day. Biomatter has to grow, and that takes time, not to mention available resources.

[ggf31416]

To vaporize something it's needed: Energy to melt + energy to vaporize once melted:

((Tf -T0) * c + DHf) + ((Tb - Tf) * c + DHb)

Where Tf = 1811K Melting point
T0 Temperature of the environment (to simplify 0K rather than 3K as some kelvins won't change the results)
c = Specific heat capacity of iron = 25.10 J·mol^-1·K^-1. That's the amount of energy that it takes to increase the temperature of 1 mol of iron by 1K or 1ºC
DHf = Heat of Fusion: required to pass from solid at the melting point to liquid = 13.81 kJ·mol^-1
Tb = Ebullition point = 3134 K at 1 atm (it's should be lower in vacuum)
DHb = Heat of Vaporization: to pass from liquid at the ebullition point to gas = 340 kJ·mol^-1

That can be simplified to
(Tb - T0) * c + DHf + DHb
If we assume T0 = 0K
Tb * c + DHf + DHb

so
3134 K * 25.10 J/mol/K + 13.81 KJ/mol + 340 KJ/mol = (78.66 + 13.81 + 340) KJ/mol = 432 KJ/mol

1m^3= 100cm * 100cm * 100cm = 1000000 cm^3
density of iron is 7.874 g/cm^3 so 1m^3 = 7.874*10^6 g
1 mol iron = 55.845 g so 1 m^3 = 141000 mol

141000 mol * 432 KJ/mol = 6.09 * 10^7 KJ = 60.9 GJ to vaporize 1 m^3 of iron.

The area of a 1 mile radius sphere is 4 * pi * radius^2 = 4 * pi * (1609 m)^2 = 3.255*10^7 m^2

Assuming that the energy that reaches the iron cube is distributed uniformely in the cube and converted into heat we can calculate the energy required as:
Area of a sphere centered in the bomb * energy required to vaporize 1 m^3 of iron / area in the cube exposed to the explosion

If we assume that 1 face is facing the explosion:
3.255*10^7 m^2 * 60.9 GJ / 1m^2 = 1.98 * 10^18 J
That is equivalent to 474 MT.

For a 15MT explosion the radius is about 290m
For a 20 KT explosion the radius is only 10 meters.

[thekillman]

why does everyone think hives are vapourised?

mostly the effects show a big internal explosion which cuts it in half with secondary explosions mostly shredding it. something totally possible with dozens of GT's being blasted in every direction creating powerfull jets of solid, liquid, gaseous and plasma matter in many directions. ever seen how a shaped charge works? well seeing as hives probably have some internal support structure, this would have a similar effect: jets of matter are converted and cut the hive to shreds in every direction.

force goes the way of least resistance. seeing the amount of hallways, and the air that is inside with minimal resistance, i'd say the effects are pretty bad. besides, the superheated matter has a kinetic force. vapourising isnt the only factor. a powerfull shockwave goes through the ship, causing even more damage, and the above jets would destroy the ship.

[Aer'ki]

To vaporize something it's needed: Energy to melt + energy to vaporize once melted:

((Tf -T0) * c + DHf) + ((Tb - Tf) * c + DHb)

Where Tf = 1811K Melting point
T0 Temperature of the environment (to simplify 0K rather than 3K as some kelvins won't change the results)
c = Specific heat capacity of iron = 25.10 J·mol^-1·K^-1. That's the amount of energy that it takes to increase the temperature of 1 mol of iron by 1K or 1ºC
DHf = Heat of Fusion: required to pass from solid at the melting point to liquid = 13.81 kJ·mol^-1
Tb = Ebullition point = 3134 K at 1 atm (it's should be lower in vacuum)
DHb = Heat of Vaporization: to pass from liquid at the ebullition point to gas = 340 kJ·mol^-1

That can be simplified to
(Tb - T0) * c + DHf + DHb
If we assume T0 = 0K
Tb * c + DHf + DHb

so
3134 K * 25.10 J/mol/K + 13.81 KJ/mol + 340 KJ/mol = (78.66 + 13.81 + 340) KJ/mol = 432 KJ/mol

1m^3= 100cm * 100cm * 100cm = 1000000 cm^3
density of iron is 7.874 g/cm^3 so 1m^3 = 7.874*10^6 g
1 mol iron = 55.845 g so 1 m^3 = 141000 mol

141000 mol * 432 KJ/mol = 6.09 * 10^7 KJ = 60.9 GJ to vaporize 1 m^3 of iron.

The area of a 1 mile radius sphere is 4 * pi * radius^2 = 4 * pi * (1609 m)^2 = 3.255*10^7 m^2

Assuming that the energy that reaches the iron cube is distributed uniformely in the cube and converted into heat we can calculate the energy required as:
Area of a sphere centered in the bomb * energy required to vaporize 1 m^3 of iron / area in the cube exposed to the explosionIf we assume that 1 face is facing the explosion:
3.255*10^7 m^2 * 60.9 GJ / 1m^2 = 1.98 * 10^18 J
That is equivalent to 474 MT.

For a 15MT explosion the radius is about 290m
For a 20 KT explosion the radius is only 10 meters.

Area of the spherical blast radius at one mile times the energy required to vaporize the cube is correct...but I don't see why you divide by the face of the cube. Since the blast is not continuous, and occurs within a very short period of time, the full energy required to vaporize the cube must be delivered instantaneously to that one meter square face. That amount of energy times the total blast radius area at a 1 mile radius equals the needed energy of the bomb...I don't understand the division at the end of your equation.

[Mister Oragahn]

why does everyone think hives are vapourised?

mostly the effects show a big internal explosion which cuts it in half with secondary explosions mostly shredding it. something totally possible with dozens of GT's being blasted in every direction creating powerfull jets of solid, liquid, gaseous and plasma matter in many directions. ever seen how a shaped charge works? well seeing as hives probably have some internal support structure, this would have a similar effect: jets of matter are converted and cut the hive to shreds in every direction.

force goes the way of least resistance. seeing the amount of hallways, and the air that is inside with minimal resistance, i'd say the effects are pretty bad. besides, the superheated matter has a kinetic force. vapourising isnt the only factor. a powerfull shockwave goes through the ship, causing even more damage, and the above jets would destroy the ship.

Most of the superstructure is vapourized. It's not not unprecedented. We've seen Ha'taks be almost completely, or purely entirely vapourized before, leaving behind them nothing more than a whisper of energy.

Hiveships are largely vapourized because in many ways, that's just what happens. Instead of having large sections of the ship blocking the light and ejecta coming from the inside, you have entire superstructures turning white, into growing giant balls of bright hurt.

Explosions like in Siege part I and III show features such cases, like Pegasus Project, which can be contrasted with other mode moderate explosions such as in The Hive or the one where Carter sacrifices the 304.

[adam4evelyn]

are u talking about the large blue rings that explode from hive ships ? if its that they dont always go that way i think its an overloading ftl drive. in season one when the ancient satellite sent a shot through a hive i remember that hive breaking up . as well as the last man hive battle where micheal drops out of hyperspace above to battling hives . while it doesn exactly focus on the hives they look a hell of a lot lyk there breaking apart

[Mister Oragahn]

are u talking about the large blue rings that explode from hive ships ? if its that they dont always go that way i think its an overloading ftl drive. in season one when the ancient satellite sent a shot through a hive i remember that hive breaking up . as well as the last man hive battle where micheal drops out of hyperspace above to battling hives . while it doesn exactly focus on the hives they look a hell of a lot lyk there breaking apart

In some cases, they're more of the break apart flavour, but in the case of the Lantian satellite, after the hiveship was cut in two halves, they drift a while and then self vapourize themselves into clouds or fire.

[Todd The Wraith]

yea your right about that. and theoreticly it wouldnt, but its not like the show ran over wriath ship scematics with us. And if one single power supply is powering a ship of that size, its bound to be a gigantic explosion if it comes in contact with intense heat and preasure. Allthough the ships are organic, there is still some sort of gass/chemical fusion going on for power which would be unstable. Im a wraith so i should know.

[Aer'ki]

I'll give you an example of one scene that has it about right.

Season 3 opener, when the Daelalus fires a nuke and hits the hive ship from the outside. Big, blue explosion, significant damage, but the ship still lives and still fights on from its non damaged areas.

Also, the Orion jumps in and launches drones at the other hive. (the drones are way too big compared to the ship's size, by the way)

Several hundred drones pour into the ship, burrow their way through, come out the top and split up to hit secondary targets. The hive is seen to have numerous internal explosions, but the superstructure stays intact. Little fire spouts are seen all over the ship, but while the ship is essentially toast, there is too much mass to 'blow up' because the ship is so frickin huge.

I don't know if they showed the derelict in the background later or not, but that shot of the drones killing the hive is probably the most legitimate in the entire series.

[thekillman]

only again have you not answered the one question: can the powersource be responsible? you've seen what small amounts of naquahdah do to nukes. you probably know the energy needed to move such a massive structure around. wouldnt an internal explosion set the powercore off and the powercore is what annihilates the craft, not the nuke?

[Phantom6]

Maybe it (Destructive force/catastrophic damage) just causes a massive feedback in the Hives power supply, BOOM.

[thekillman]

i said that