Picard wrote:Battlestar Wiki put Galactica's nukes at 5 - 150 kilotons each. And I don't remember seeing anything close to teratons...
I honestly wonder where they got their numbers from.
Mr Oragahn wrote: (yes, they were using nukes against ships where a single conventional bunker buster type would have already been overkill).
Nukes in space are not very effective...
Depends how they're used. Weapon grade nuclear fuels provide so much energy for their mass, compared to chemical reactants, that the gain is very obvious.
Even if only quarter of the energy goes into the hull close to the point of impact, it's still far more than any chemical system can deliver.
What it lacks is momentum, but evens it up by producing a shockwave through the material that is heated up around the very close proximity to the point of impact.
However, against a thick hull, it's not going to do wonders, but no weapons will as a matter of fact.
People forget that while the nuke fired by the Cylon raider was indeed small, the nukes fired by Basestars were big, and that means they would logically be heavy. That mass can be a result of a heavier casing. A heavy casing means that the nuclear device will produce its own momentum. Nukes can hit hulls at speeds of high several hundreds of meters per second (
video of a nuke hitting Pegasus), which means that there will already be a significant momentum upon impact. Then, the casing itself that surrounds the nuke will most likely be built as to produce a blast of vaporized metal in the hole.
Although I can't find the reference there, there was an US nuclear test around a few megatons which produced a massive crater on some atoll I think, after a ground detonation. It was said that the crater was so vast because the nuke casing turned the EM energy into a kinetic one.
Perhaps it was Ivy, Mike or a Castle Bravo.
And, of course, there's also the
power. Fractions of microseconds being far better than chemical reactions and even superior to say, in a vs, super long laser bolts which still completely get into their target in only a 25th of a second.
remember, we have no evidence that they are shaped charge,...
Indeed, but they don't really need to be. The sheer fraction that will go into the hull at the point of impact will always be greater than anything that could be produced by a chemical reaction.
Is there any way to calculate energy required to melt 1m3 of Galactica's hull?
You can go with the idea that it's plain iron.
It's very hard to know what is the real thickness of your average armour plate.
I could look at Galactica and estimate the thickness of the plates that cover the ridges. I have pictures which allow me to make precise measurements of the ridges' width for one. I'd go with half a meter.
It is probably stronger than their transparent materials. In one episode, there were two people including Caly who got stuck in some storage room. There was an observation booth isolated from the room by windows. Admiral Adama was in that booth while something suggested to place charges, but he or someone else said that the glass is so tough that the charges needed to blast them would also kill the two persons on the other side, and the room in question wasn't exactly small to begin with and contained many crates and other things.
In terms of thermal capacity, we have the beaten up Galactica's free fall through low atmosphere for 40 seconds. Without factoring the friction, at the end the ship would have been falling at a speed of nearly 400 m/s. With that mass, I guess we could safely claim a speed of 300 m/s, based on the loss of speed observed in the results from this excellent
impact calculator. I use values for an atmospheric entry of a loose piece of ice at 300 m/s, 90°.
It's interesting to see what we get with an object already 100 meters wide and dense like ice entering at a speed of 300 m/s (
result).
Your Inputs:
Distance from Impact: 1.00 meters ( = 3.28 feet )
Projectile diameter: 100.00 meters ( = 328.00 feet )
Projectile Density: 1000 kg/m^3
Impact Velocity: 300.00 meters per second ( = 984.00 feet per second )
Impact Angle: 90 degrees
Target Density: 2500 kg/m^3
Target Type: Sedimentary Rock
Energy:
Energy before atmospheric entry: 2.36 x 10^13 Joules = 0.56 x 10^-2 MegaTons TNT
The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 2.2 x 10^3years
Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundreths of a degree).
The impact does not shift the Earth's orbit noticeably.
Atmospheric Entry:
The projectile begins to breakup at an altitude of 15900 meters = 52300 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 0.112 km/s = 0.0695 miles/s
The impact energy is 3.28 x 10^12 Joules = 0.78 x 10^-3MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.462 km by 0.462 km