85 réponses à ce sujet

[AlanC9]

ME lore doesn't make sense. Quelle surprise!

Now that we've settled that..... what happens?

[Vazgen]

Good thing we have technology that can manipulate object mass, huh?

You may want to reread the last section of my comment. I didn't say nukes are ineffective, I said that they are not very effective against the Reapers, something you mentioned yourself in the original post. I also said that nukes are still used in ME3 on different occasions. And I also said that those countermeasures are not explained in lore. So... what are we arguing about?

[SuperJogi]

ME lore doesn't make sense. Quelle surprise!

Now that we've settled that..... what happens?

 

Nothing. Nitpicking about scientific inaccuraties in a fictional universe on an internet forum is entirely pointless. But it's fun.

 

Good thing we have technology that can manipulate object mass, huh?

 

Yes and the more mass you have the begger of an eezo core you need. Wich means that there are limitations on how massive a ship can be. That makes a hull out of thick, highly dense material impossible, or at least highly undisirable. The reapers might be able to pull that off though.

 

Anyway I think we can both agree that MEU does not deliver a good explanation on how ships are shielded against gamma radiation.

I go even further and say that there isn't one possible because physics.

 

I think that concludes this argument.

[AlanC9]

Nothing. Nitpicking about scientific inaccuraties in a fictional universe on an internet forum is entirely pointless. But it's fun.

I can hardly deny that. I'm here, right?
 

Yes and the more mass you have the begger of an eezo core you need. Wich means that there are limitations on how massive a ship can be. That makes a hull out of thick, highly dense material impossible, or at least highly undisirable. The reapers might be able to pull that off though.

Wait a second. If the extra mass to defend against gamma rays comes from mass effect field manipulation rather than actual mass, then it doesn't impact the ship's maneuverability while the defense is off. Though this means there's a tactical problem since defending against nukes makes you easier to target with conventional weapons.

[Vazgen]

Wait a second. If the extra mass to defend against gamma rays comes from mass effect field manipulation rather than actual mass, then it doesn't impact the ship's maneuverability while the defense is off. Though this means there's a tactical problem since defending against nukes makes you easier to target with conventional weapons.

It comes from the making materials more dense with mass effect fields in the process of construction. That results in heavier ships and mass effect field manipulation is required to make that extra mass irrelevant. However, as SuperJogi pointed out, "the amount of element zero and power required for a drive increases exponentially to the mass being moved and the degree it is being lightened. Very massive ships or very high speeds are prohibitively expensive." Link

[sH0tgUn jUliA]

So that's why we didn't use nukes. Because if we did use nukes, then the Reapers might have been able to be defeated conventionally.

[Vazgen]

So that's why we didn't use nukes. Because if we did use nukes, then the Reapers might have been able to be defeated conventionally.

That's assuming radiation is problematic for them.

[SuperJogi]

Since I was bored i decided to make some quick calculations to see if my nitpicking is even correct.

I couldn't find any good technical data on any ME ship so I decided to take the kodiak shuttle as an example since it's size is quite easy to guess.

 

The kodiak is about 15m long, ignoring the engine stuff at the back the crew compartment is about 10m long, 3m high and 5m wide. (rough estimate)

That gives us a surface area of about 190m² (rough estimate)

 

An effective gamma shield needs about 10cm of lead in order to reduce the intensety of the rays to about 0.1%.

1m² of 10cm thick lead has a mass of 1134kg.

That makes about 215 tonnes of lead to shield the entire crew compartment of the kodiak.

Now you can improve the efficency of that by about 50% by alloys of different materials with different atomic numbers.

That still leaves you with about 143t of extra mass. Thats probably a lot more than the entire shuttle weighs in the first place.

And that is a low estimate. Considering what amounts of high intensety gamma rays we are talking about here, reducing the intensety to 0.1% might not be enough.

You're gonna end up with millions of tonnes of armour in order to shield an entire dreadnought.

 

Edit: Improving likelyhood of absorption through high atomic number only works for low energy gamma were absorption happens through the photoelectric effect. Not relevant here.

Edit 2: Actually is relevant to reduce electron scattering and secondary gamma and X-ray radiation caused by compton effect. But too difficult to calculate for me. I'm no expert on quantum electro dynamics.

Modifié par SuperJogi, 08 mai 2015 - 11:10 .

[AlanC9]

So that's why we didn't use nukes. Because if we did use nukes, then the Reapers might have been able to be defeated conventionally.

Heh. Cute, but no. If nukes worked against Reapers, they wouldn't be designed to engage in close-in combat. Since Reapers are organized as a fleet of space battleships, space battleships have to be viable in the MEU.

[MrFob]

Since I was bored i decided to make some quick calculations to see if my nitpicking is even correct.

I couldn't find any good technical data on any ME ship so I decided to take the kodiak shuttle as an example since it's size is quite easy to guess.

 

The kodiak is about 15m long, ignoring the engine stuff at the back the crew compartment is about 10m long, 3m high and 5m wide. (rough estimate)

That gives us a surface area of about 190m² (rough estimate)

 

An effective gamma shield needs about 10cm of lead in order to reduce the intensety of the rays to about 0.1%.

1m² of 10cm thick lead has a mass of 1134kg.

That makes about 215 tonnes of lead to shield the entire crew compartment of the kodiak.

Now you can improve the efficency of that by about 50% by alloys of different materials with different atomic numbers.

That still leaves you with about 143t of extra mass. Thats probably a lot more than the entire shuttle weighs in the first place.

And that is a low estimate. Considering what amounts of high intensety gamma rays we are talking about here, reducing the intensety to 0.1% might not be enough.

You're gonna end up with millions of tonnes of armour in order to shield an entire dreadnought.

 

A lot of weight for sure but we don't really know what standards here are and how efficient eezo really is with it's ME fields. Given that it is powerful enough to accelerate a ship that is usually flying at moderate sub-light speeds with fusion torches to almost 5000 times the speed of light, I wouldn't count out the possibility that it can lighten the mass of the armor required here.

Correct me if I am wrong but I am not aware of any reference points in terms of ship's mass. Do we know how heavy the Normandy is?

 

EDIT: BTW, as I typed the last sentence, I imagined EDI giving me an icy stare and asking "Are you saying I'm fat?"

[SuperJogi]

A lot of weight for sure but we don't really know what standards here are and how efficient eezo really is with it's ME fields. Given that it is powerful enough to accelerate a ship that is usually flying at moderate sub-light speeds with fusion torches to almost 5000 times the speed of light, I wouldn't count out the possibility that it can lighten the mass of the armor required here.

Correct me if I am wrong but I am not aware of any reference points in terms of ship's mass. Do we know how heavy the Normandy is?

 

I'm not aware of detailed technical specification for any ME vessel. Bioware probably purposely left that open so that people like me don't start calculating.

[MrFob]

I'm not aware of detailed technical specification for any ME vessel. Bioware probably purposely left that open so that people like me don't start calculating.

 

Yea ... that worked well.

[AlanC9]

It kind of did. All they need to do is add something a codex entry about Vazgen's super-dense radiation shielding being present on every warship and call it a day.

[SuperJogi]

It kind of did. All they need to do is add something a codex entry about Vazgen's super-dense radiation shielding being present on every warship and call it a day.

 

Yeah, since we don't know how effective ME fields are at reducing mass they could theoreticly do that. But considering how important the limitation of the size of an eezo core is supposed to be for ship building, I find it hard to believe that over 75% of a ships mass is supposed to be it's radiation shielding.

It makes much more sense to say that ships are not shielded against that because nuclear weapons are outlawed and not used in conventional warfare.

That still leaves nukes as a very effective WMD and especially powers at odds with the council would have great interest to invest in a nuclear deterrent to keep the overwhelming council fleets at bay. That of course is a great dampener to the councils military influence. Turians wouldn't like that.

[AlanC9]

But that's exactly the problem -- would the council races really cripple their ship designs relative to non-council races? Would that situation be stable?

[Laughing_Man]

But that's exactly the problem -- would the council races really cripple their ship designs relative to non-council races? Would that situation be stable?

 

No they wouldn't. That would be a new level of pathetic wishful thinking.

 

The simple truth is that any space faring civilization has to solve at least to some degree the problem of radiation in space if they ever hope to to do more than travel inside their own solar system.

 

And the idea that one sufficiently powerful nuke or EMP device can disable an entire fleet, is rather unlikely, because the danger is too obvious.

Saying "It's against the law, so there is no point in defending against it, because surely no one will use it ever, right?"

Sounds to me like an unplausible level of stupidity, even for the council.

 

In a Sci-Fi universe that has the mind boggling space magic of Synthesis, I have no problem believing that there are methods to block or reduce certain types of radiation.

 

Personally, If anyone is looking for anti-Reaper weapons, I would recommend:

 

A. Trying to find a way to upscale the idea of SMG's to space combat, meaning a constant barrage of lesser impacts instead of one heavy impact in order to deal with barriers. A Dreadnought would expand the same amount of energy on a burst of smaller rounds - that it would otherwise use for one big chunk of metal.

 

B. Shoot a large penetrator round containing an anti-matter warhead through the main gun of a dreadnaought. It should make a dent in just about anything.

[SuperJogi]

A. Trying to find a way to upscale the idea of SMG's to space combat, meaning a constant barrage of lesser impacts instead of one heavy impact in order to deal with barriers. A Dreadnought would expand the same amount of energy on a burst of smaller rounds - that it would otherwise use for one big chunk of metal.

 

Your right, since kinetic energy is the only relevant factor to penetrating a kinetic barrier, it make much more sense to use many small and fast projectiles to optimise accuracy, instead of one slow and heavy one which has a smaller effective range.

 

B. Shoot a large penetrator round containing an anti-matter warhead through the main gun of a dreadnaought. It should make a dent in just about anything.

 

Antimatter is actually not the all destroying substance that scifi often makes it out to be, it's much more complex than that. But let's go through with it.

 

Assuming that in the MEU they have the capability to create large quantities of antimatter in reasonable time, which considering how advanced their magnetic accelerators are, is not so far fetched, you are left with the problem of storing it. Since antimatter can only be safely contained by suspending it in magnetic fields, it means that the antimatter you want to use is both stable and electricly charged. That leaves you with positrons and anti protons as a realistic choice. Since matter/antimatter annihilation releases huge amounts of energy, that in space would be transmitted via radiation, you are basicly looking at a radiation weapon again. In order to maximise the efficency against ME ships, you want radiation that is not blocked by kinetic barriers, and penetrates very far into matter while doing large amounts of damage to both hardware and "software" (organics). The easiest way to do that is low energy electron-positron annihilation, since that produces pure gamma.

 

Let's make some calculations to see how effective an electron-positron warhead would be:

A ME dreadnought can fire a 20kg projectile at 4000km/s. Let's say for our warhead that 19kg would make the casing, trigger mechanism, and electro-magnetic equipment to keep our payload safe. That means we have a 1kg payload consisting of 500g of electrons and 500g of positrons. Thats about 5.5x10²⁹ electrons and the same amount of positrons, meaning 5.5x10²⁹ annihilations will occur. A single electron-positron annihilation at rest creates 2 photons with an energy of 0.511 MeV. Since the energy gain for a single particle by accelerating the warhead it to 1.3% c is extremely small, i will just ignore it here. With 5.5x10²⁹ annihilations happening (in optimal conditions) thats 1.1x10³⁰ gamma photons with an energy of 0.511 MeV each beeing released. That's a total of 90 quadrillion joules of pure gamma, or 21.5 Megatons of TNT equivalent.

This radiation blast would cause photo emission and compton scattering on such a magnitude that it would obliterate atoms in it's path. I don't care what kind of magical thin and light gamma absorber you could come up with. The relativistic photoelectrons ejected from your now obliterated radiation shield would be enough to kill you and destroy every computer. That 10cm lead shield I was talking about looks really attractive now. And that's of course just the addition to the kinetic energy of the original warhead.

 

Of course you could also build an antimatter warhead that works by emitting massive particles and therefore helps destroying the kinetic barrier.

But proton-antiproton collisions are quite complex and beyond my ability to calculate.

[KrrKs]

I'm just going to point out that, according to the codex, military ships employ antiproton-hydrogen* annihilation thrusters, so a viable radiation shielding really should be present.

 

*Yes, the codex only mentions hydrogen, not ionized hydrogen/protons.

[SuperJogi]

I'm just going to point out that, according to the codex, military ships employ antiproton-hydrogen* annihilation thrusters,

 

*Yes, the codex only mentions hydrogen, not ionized hydrogen/protons.

 

Haha, I can just imagine the Bioware writer typing that into the codex going: "Whatever, sounds cool."

 

I initially didn't want to talk about proton-antiproton annihilation because they do not simply destroy each other like electrons and positrons. Instead, their quarks start interacting with each other creating different kinds of mesons (like pions and kaons), which then decay into other kinds of mesons, which eventually decay into photons, electrons, positrons and neutrinos. The entire process is ridiculously complex and requires to dive deep into quantum chromo dynamics (and I already mentioned my pretty shoddy knowlegde of that). So don't ask me about the details (atleast not right now, maybe when Im more familiar with it).

How this reaction is supposed to create any kind of thrust to move a spaceship, I have no idea. Ask the BW writer who put that in there, although he probably has even less of a clue.

 

so a viable radiation shielding really should be present.

 

Yes, on the inside of the engine, not on the entire outside of the ship. Big difference.

[The Gman707]

Perhaps there is a story there to be told. The discovery of a new material that resists nuclear attacks for use on vessels.

[SuperJogi]

Perhaps there is a story there to be told. The discovery of a new material that resists nuclear attacks for use on vessels.

 

No. Because the fact that there is no such thing as a light and thin shield against gamma rays is not a technical limitation. It's embedded into quantum electro dynamics. Any solution would equate to space magic.

[Laughing_Man]

No. Because the fact that there is no such thing as a light and thin shield against gamma rays is not a technical limitation. It's embedded into quantum electro dynamics. Any solution would equate to space magic.

 

Space Magic, which even as it is, already exists in the ME universe, so it's not much of a stretch...

 

Besides, you can always imagine that some genious scientist had a eureka moment and found a way to circumvent a certain problem by using the: *insert techno babble here*, to solve the problem of *insert scientific problem here*.

 

Meaning, necessity is the mother of invention, and innovation can go a long way even in the face of supposedly un-solvable problems.

[KrrKs]

[About radiation shielding]

Yes, on the inside of the engine, not on the entire outside of the ship. Big difference.

The supposed engine placements (at the end of the 'wings') don't seem to leave all that much place for any sort of shielding though.

 

If an effective protection can be applied there, it can also be applied in at the regular hull (not necessarily in full strength though).

If it can't be applied directly at the engine, that's even more of a reason to shield the main living compartments.

[SuperJogi]

The supposed engine placements (at the end of the 'wings') don't seem to leave all that much place for any sort of shielding though.

 

If an effective protection can be applied there, it can also be applied in at the regular hull (not necessarily in full strength though).

If it can't be applied directly at the engine, that's even more of a reason to shield the main living compartments.

 

 

I just had a look at the codex entry you were talking about  and now it makes much more sense. Instead of using the proton-antiproton reaction to generate thrust they use it to quickly generate enough energy to heat the hydrogen gas to high temperatures and then release the pressurised gas through a nozzle. So in effect pretty much like a normal rocket engine. Since exhaust gases from these engines and normal fusion torches are supposed to be millions of kelvin hot, it is reasonable to assume that the inside wall of the reaction chamber and nozzle are build out of fairly dense metals, which might already be enough to reduce and filter out most of the gamma rays to non harmful levels. You have to factor in that the reactions we are talking about here are much lower in intensity than the electron-positron annihilation discribed above and that there are several walls between the crew and the reaction inside the engine, which is outside of the main ship.

[Iakus]

That's assuming radiation is problematic for them.

They have organic components.  I'd say radiation is an issue.  

 

Not to mention, you know, nuclear explosion...