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SDR 5 in Megatons?

CadetNewb

CadetNewb

Well-Known Member
I'm beginning to get curious - how many Megatons of TNT would an explosion or impact need to be rated at in order to register at SDR 5? Thinking about it, this would actually be a much more accurate measure of how powerful our weapons are, especially considering the mental imagery we have with the Megaton. It's still not as accurate as something like using petajoules, but it's something. The biggest nuke humanity's ever set off in real life had a fireball with a diameter of about 8 kilometers, or 5 miles, and that was only somewhere between 50 and 58 Megatons of TNT.

What does it take in Megatons of TNT to be rated as SDR 5?
 
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The Damage System does not really work as a measure of Megatons. Its a measure of how powerful the destructive energy is of a given weapon.

For example the Ke-Z2 bomb is a SDR 4 and it is listed as 50 MT. blast obliterates almost anything within 50 kilometers But the Ge-Z1 anti-matter warhead is also SDR 4 but has an effective destructive area of 1.6 km.
 
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I'm well aware that the DR system doesn't work as a measure of Megatons of TNT, and I'm sorry if I wasn't clear. I initially didn't phrase the question well, and edited it in my post. I was asking how many Megatons of TNT, in terms of energy involved, would it take to reach the category of SDR 5. I'm working on some ship weapons, and I'd like them to be more detailed than they normally are, rather than being vague. Megatons of TNT aren't necessarily just the rating of bombs however, but is really the measure of energy involved. Asteroids impacts, like the one that caused the mass extinction several million years ago was, in terms of energy, 100,000,000 Megatons of TNT.

I'm asking this to better put SDR 5 weapons into perspective, besides trying to have the science of some things I'm working on be harder.
 
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We used to have some of those measurements on the old weapons around here (Yottawatts, anyone? How about gigajoules?). It's great that you're looking to quantify a weapon's destructive power, but the very thing you seek is partly what led to the DR system.

We're science fiction, mixed with an RPG. We can't quantify the explosive, energetic or ballistic impact of weapons we cannot replicate in the real world. Our system is arbitrary and vague by design — it allows the GM and players flexibility to describe how it works within a certain parameter.
 
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Yeah, that's true, but I asked this because I want to avoid yottawatts you see. That is, to make sure whatever I'm working on is not only fitting for an SDR 5 weapon, but also not powerful to the point of absurd silliness. I'm guessing that I should simply describe the projectile diameter, omit length, say that it's going very fast, and not specify its mass?
 
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Huh. I thought that projectile weapons with large masses and velocities approaching anywhere close to the speed of light were taboo? I think, and just assuming that shell is steel, that Mass Driver Gun is a planet splatter-er. To get around this problem, and the taboo that I thought that was in place, I was trying to carefully figure out the amount of energy involved on impact using proper mass and velocity figures. I wanted to know the Megatons of TNT worth of energy involved with an SDR 5 weapon so I could adjust mass and projectile velocity accordingly.

So that I didn't end up in yottawatts territory, but was still 100% competitive in the setting.
 
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Lol At least yours gives a velocity - the Plumeria's Positron Cannons don't even say how fast they go. That's pretty important in space combat since it's a little like sniping some guy a kilometer away while he's running with a Barret. Gotta lead, and it'll still take a second or two. XD
 
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If that's the case, the article really needs to be cleared up. The terminology used is the kind found in projectile weapons. Rather than 'shell', it should likely be 'bolt'. The fact that it uses the word 'railgun' also strongly suggests a projectile weapon too - if the article opened up by saying it was a directed energy weapon using magnetic rails to project the stuff, that'd help to clarify it a lot.
 
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Think of the Positron Rifle from Evangelion. It's practically the same weapon (just on a slightly smaller scale?). The "Shell" is an electromagnetic bottle containing a High energy positron package. At least thats the way I understand it. I would guess it goes at between 0.8c and o.9c
 
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Yeah if we're talking railguns, anything a fraction of light-speed is equivalent to nuclear weapons in the kiloton range. The Positron Shell thing, I question, but whatever. I'd say roughly half of its damage wouldn't be coming from the impact, but the anti-matter striking matter (And remember, we're in a vaccuum, so not all of that energy is striking a singular point, or at all). While Positrons do have mass, it is relatively minuet in comparison to something like a brick of steel. So when you think about two-thousand KILOGRAMS of this stuff striking a ship. We're talking enough energy to power IRL Earth for centuries (I think. I'm no Physicist.) just from the energy release. One gram antimatter equals to a forty-three kiloton bomb. There are one thousand grams to a kilogram. Two thousand Kilograms per shell. One thousand Kilotons to a Megaton. The math here is staggering in how much damage just one shot from that gun can cause.
 
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Yeah. Even a ridiculously small mass, such as a baseball, can have a lot of punch to it. And that's just 0.9c - the closer things get to the actual speed of light, with more 9's tacked onto the end, the stranger things get. With just a few 9's tacked on, the earth would be gone for an example, and the nearby planets would be scorched.

And out there, somewhere, would be a Neko on monitoring duty, wondering what just happened as she looks at her station's volumetric screen.

But yeah. I really wanted to figure out how many mengatons of TNT energy wise was worth SDR 5 so I didn't accidentally reach that point. I'll just go with Doshii and be extra vague.
 
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Well, I may have fudged my math on the Positron Shells, but, it'd be in the order of equivalency to 86 Gigatons of TnT. And that's only SDR 3-4. So it'd have to be like an order of magnitude higher. Which is ridiculous already with a weapon can could crack a planet with one shot (Positron Cannons.)
 
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I'd like to note that ADR 5 is listed as equivalent of a tactical nuke, which have been ranged between 1 kiloton to 80 kilotons. Given how absurdly powerful some SDR 5 weapons are, we can be sure that the Damage Rating system is similar to an exponential increase in power rather than a multiplicative increase. Though similar does not mean exactly, so I'd just follow Arieg's suggestion for ease of design.
 
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