New page I banged together

[Brian Young]

Okay, now on to the water thing.
My point is this. A beam travels on until it is blocked by something. If the water was "pitch black," as some of you have mentioned, I'd agree. But that isn't always the case. I've been on 3 cruises to The Bahamas. You can see all the way to the bottom, and it may be a long way. Much farther than it looks. In fact, you can see every rock all the way on the bottom.
The ocean in Atlantis appears very clear on television.
If the beam were a laser, or instance, it would be attenuated more than traveling through the air, but not blocked completely. Only the light absorbed by the water would heat the water. The rest would travel all the way down to Atlantis, just like we saw.
Now, my point about the sunlight is just that. Diffuse sunlight makes it all the way to the bottom.
Sunlight is not coherent. A coherent beam would penetrate much more readily, giving up much less of its energy along the way. *That is why it is coherent, after all.*

See the bottom? I do, clearly. That is because all that diffuse sunlight is shining *right through* that clear water, which you guys are calling "pitch black."

Again, you can clearly see the light on these formations on the bottom of the ocean, to the right and bottom of the images, as well as on Atlantis itself. And to preempt someone saying those lights are from Atlantis, note the formations on the botto of the image are lit on the side opposite the city. Therefore, this light comes from neither Atlantis nor the beam, but from the sunshine.

This image is taken a few minutes later, as Atlantis rises from the ocean, and demonstrates that this is early morning sunlight, and not even bright midday sunshine.

So, again my point is that there is no reason to assume this clear water, which doesn't even shade the sun that much, should absorb huge quantities of a coherent beam.

Taking that a step further, there is no reason to assume this beam has special properties or pseudoscience that prevent us from calculating limits on its firepower. It easily defeated Apollo's shields, but could not easily penetrate a 60 meter asteroid. Therefore, said asteroid is more resilient than said shields. Occam's Razor.

[Brian Young]

Okay, now, long reply to Chris's long reply.
*No, Babtech will drop the curtain and bow before the new year.
*I never said the water was "perfectly transparent." But you call it "pitch black." It may have been some time since you've seen Atlantis, but take a look at the images I just provided. Diffuse sunlight shines all the way to the bottom. This isn't dirty lake water. This is clean ocean water. I haven't been that long removed from a cruise, and in The Bahamas, for instance, I could see very clearly all the way to the bottom. I'd bet a laser pointer would shine just fine too. And I didn't see the first drop of this "pitch black" water to which you refer.
*Yes, it is a coherent beam. That is my point. Coherent beams penetrate more than diffuse light. A laser pointer will shine a lot farther than a lamp with the same power. That is the whole point of making it coherent.
*Maybe the beam has little effect on water, but terrible effect on shields, for whatever reason. Why would this help eliminate Atlantis? The goal was to destroy Atlantis. After this mysterious beam drains the shields, then what? Why not use a beam that simply does what beams normally do? Recall a small asteroid was an effective barrier against this beam.
*Slow down, too fast on all the firepower calculations! I'm getting old! I didn't see any numbers there, but has anyone actually looked at those examples carefully? I note the Hatak vessel is in there, and I have never been impressed by their firepower. In fact, it took several seconds for Anubis's heaviest weapon on his heaviest ship to take out a pyramid. The pyramid is a replica of the Great Pyramid, so we're talking about a skyscraper. The Little Boy bomb dropped on Hiroshima destroyed 60,000 buildings. This was one, albeit large, building. Not nearly as destructive as that one nuke, rated at 15 kilotons, or about 60 terajoules. That ship was much more powerful than a Hatak, and IIRC, powered by naquadria. But in any event, this does not support firepower greater than the Replicators' beam.
*Okay, I can dig the naquadah causing the EMP. It wasn't that severe, and certainly not what you'd expect from a gigaton nuke. So, I'll concede that.
*The fact that Thor used the term terajoules is telling, all by itself. This is, again, on the same order of magnitude as the Replicators' beam. This being the flagship of the "Supreme Commander of the Asgard Fleet" easily places their power generation capabilities below that of most of the other major SciFi races we discuss here. A Minbari Warcruiser, for example, probably outguns any beam weapons powered by those reactors. Certainly, any warship in Star Wars would blow it across the galaxy.
*Destiny can't tap the power from the star's core without reaching said star's core. It barely submerged into the photosphere. The power available at that point would be a few terawatts.
*The missiles and using them against the Ori, Wraith, etc. Well, they tried, and their missiles were routinely shot down.
*Interesting idea about the beams vs the Hive ships, but we have no idea how resilient their hulls are. Being organic in nature, I wouldn't feel comfortable using iron as a base.

Again, looking at the basics, this beam kicked Apollo's ass, with those fancy Asgard shields and all. It was gonna take out Atlantis in the 8th round. But it couldn't content with an asteroid the size of Serenity.
This is the only instance of a natural object being directly compared to Apollo's shields that I can think of.
Thus, all those beams that can't defeat Apollo are less powerful.
I see no reason to inject an unknown variable just because the seawater didn't stop the beam or cover the area with steam, because even diffuse sunlight penetrated to the bottom easily.
Beam > shields. Asteroid > beam. Asteroid > shields. Occam's Razor.

[Brian Young]

The US Navy has been working on laserlink communications with submerged submarines for a long time and to my knowledge hasn't made much in the way of headway due to the water absorbing most of the signal.

The fact they tried at all is telling enough.
And, as you said, "for a long time." Obviously the US Navy feels a laser can travel through that pitch-black-but-looks-clear-to-me water. And they were confident enough to keep trying it.
And being for communications, we are talking about long distances. Atlantis was probably a few hundred meters under water, to my eyeballing.
Again, yes this beam was cool, but I see no reason to assume it is anything more than a typical SciFi beam weapon.

Now here is a cool idea though. Being a coherent beam, and it did cause some steam, what if it IS vaporizing water, maintaining a column of super-heated steam from Atlantis up to the surface?
As water pours in to the column, it is vaporized.
Now that is a cool concept.

[adam_grif]

I'm going to watch the episode with Camulus' ZPM again, because from memory that ZPM was expected to cause far more damage than any calcs you did would lead us to believe is possible.

I've always had a theory about ZPM power, which is to say that there is an "optimal" level of power draw, and when you try to draw more, you start reducing the overall power capacity of the artificial region of subspace. This would explain why sometimes ZPM's power cities for 10,000 years holding off the water above them, and sometimes they are depleted overnight from bombardment. It would also explain why getting the city to fly with 1 ZPM ruined that ZPM, whereas with 3 of them they are expected to fly around no worries.

[adam_grif]

Watched the episode, it was a bit disappointing really. All we got was a rough guesstimate, a statement that "I can't even imagine the magnitude of the explosion, it could take out the entire planet".

Then right at the end Carter said she thinks he underestimated it, and it might have "destroyed the solar system". Not really sure how we can take this, but I think it's safe to say that total ZPM output in the Megaton range is frankly ridiculous given what we know.

[Xon]

Then you get the Arcturus reactor was outputing 12-24 ZPMs of worth of power, and it destroyed 3/4ths - 5/6ths of a solar system when the system overloaded due to power buildup in a matter of minutes.

[adam_grif]

I don't think Arcturus is useful for calculating much of anything. If it's throughput was equal to 24 ZPM's, that doesn't imply that it's total reserve of energy was equal to 24 ZPM's. It may have orders of magnitude more energy capable of being extracted compared to 24 ZPM's, which was presumably what gets unleashed when they explode.

If project Arcturus was a hard drive, we know its read speed but we have no idea of its capacity.

[Brian Young]

But since a ZPM doesn't use discernible fuel, we can't really base power calculations on an explosion. Drawing zero point energy, the explosion might involve some kind of pseudoscience involving part of the universe collapsing in on itself.
Note these facts:
*You can hold a ZPM in your hand. It is small, light, and doesn't produce a lot of heat.
*Even the chamber that holds Atlantis' 3 ZPMs is not sealed. You can walk right up to the ZPM, eject one, and carry it in your hand, immediately after it has been used.
*McKay said powering the Replicators' beam would require "a black hole, or an unlimited number of ZPMs." This places the power of a black hole orders of magnitude above the power of a ZPM.
*That beam (powered by unlimited ZPMs) had only to power the stargate, power the shield, cut through a small asteroid, and defeat crippled Atlantis. No amount of debate over the nature of the beam changes that. It was quite an episode and an interesting situation. But when contrasting with other SciFi technologies, it simply wasn't impressive firepower.
Given McKay's report, its effect on the Apollo, and Atlantis, this is simply the most powerful beam weapon the involved personnel had faced. We can talk about explosions all day, but it won't change that. And that same beam could not drill through an asteroid the size of Serenity.
A single turbolaser bolt would vaporize that asteroid in a fraction of a second.
A single photon torpedo would fragment that asteroid in a fraction of a second.
Excalibur's main weapons would fragment that asteroid in a couple seconds.
Therefore, those weapons, all beam weapons, are more powerful.

I love Stargate too, but this isn't a popularity contest. I think I like Stargate now more than B5. But these forums are for applying logic to determine who has superior military prowess.
That beam could be some kind of exotic thing. But it sounds more like how desperate Trekkies use pseudoscience to elevate their figures. And why would the Replicators use an exotic weapon that was so easily blocked by a mundane asteroid?
The answer is that this was all they could muster.

We could talk about the uses of pseudoscience in the series to elevate the figures, like taking out a planet, etc. But this example pits the Replicators' best shot against an asteroid. That places this example above all the others in reliability. This is the kind of thing we look for to allow a comparison.
When you get dow to it, this is onscreen demonstration, while the other things were just talk.

[Brian Young]

Then you get the Arcturus reactor was outputing 12-24 ZPMs of worth of power, and it destroyed 3/4ths - 5/6ths of a solar system when the system overloaded due to power buildup in a matter of minutes.

What episode was this? I'd like to take a look.

[Brian Young]

Watched the episode, it was a bit disappointing really. All we got was a rough guesstimate, a statement that "I can't even imagine the magnitude of the explosion, it could take out the entire planet".

Then right at the end Carter said she thinks he underestimated it, and it might have "destroyed the solar system". Not really sure how we can take this, but I think it's safe to say that total ZPM output in the Megaton range is frankly ridiculous given what we know.

But then why can't "an unlimited number of ZPMs" blast through an asteroid that would fit in my back yard?

[Brian Young]

I've always had a theory about ZPM power, which is to say that there is an "optimal" level of power draw, and when you try to draw more, you start reducing the overall power capacity of the artificial region of subspace. This would explain why sometimes ZPM's power cities for 10,000 years holding off the water above them, and sometimes they are depleted overnight from bombardment. It would also explain why getting the city to fly with 1 ZPM ruined that ZPM, whereas with 3 of them they are expected to fly around no worries.

Makes sense to me.
My impression of the ZPM is that, compared to other SciFi technologies, it isn't all that powerful, but it is probably the most efficient I can think of. It uses no fuel! It produces no significant heat. It is small and portable.
Quite a feat of technology!

[Brian Young]

LOL! Okay, a photon torpedo is not a beam weapon. Anyway, pass the ham!

[Batman]

The US Navy has been working on laserlink communications with submerged submarines for a long time and to my knowledge hasn't made much in the way of headway due to the water absorbing most of the signal.

The fact they tried at all is telling enough.
And, as you said, "for a long time." Obviously the US Navy feels a laser can travel through that pitch-black-but-looks-clear-to-me water.
And they were confident enough to keep trying it.

Which doesn't mean much. Apparently the US military still hasn't given up on the Osprey either

And being for communications, we are talking about long distances.

Err no we're not. Maximum service depth for US submarines is 450m and they so far can't do it because the water absorbs too much of the signal. We're talking aerial relay/satellite to sub comms, not sub-to-sub. So far, they can't make it work without the sub coming up to pretty much periscope depth which rather defeats the whole purpose of the idea.

Atlantis was probably a few hundred meters under water, to my eyeballing.

It has to be that far down as the tips of the towers don't poke above the surface. From the light levels I'd actually call it less.

Again, yes this beam was cool, but I see no reason to assume it is anything more than a typical SciFi beam weapon.
Now here is a cool idea though. Being a coherent beam, and it did cause some steam, what if it IS vaporizing water, maintaining a column of super-heated steam from Atlantis up to the surface?
As water pours in to the column, it is vaporized.
Now that is a cool concept.

Small problem-there isn't one. Even accepting the unusual clarity of the ocean water (I don't think you'd get that much ambient light at a depth of a couple hundred metres anywhere in Earth's oceans) there should have been a lot more noticeable interaction between the beam and the seawater in its path.
The beam is pretty much instantly and continuously vapourizing a couple hundred cubic metres of water. I'd expect something decidedly more noticeable than what we saw in the episode.

[Xon]

I'm trying to find the exact quote, but Carter or Mckay definitely state at some stage that keeping the Stargate open past the 38 minute mark requires exponentially more power.

What episode was this? I'd like to take a look.

Stargate Atlantis 2x06 Trinity.

Makes sense to me.
My impression of the ZPM is that, compared to other SciFi technologies, it isn't all that powerful, but it is probably the most efficient I can think of. It uses no fuel! It produces no significant heat. It is small and portable.
Quite a feat of technology!

The damn things are also capable of effectively instantaneous variable power output and the ZPM itself can auto-sense superconductive links to compatable technology.

[Brian Young]

Trinity. Okay, thanks, I'll take a look at it. Maybe tomorrow after work, before football.

Yes, keeping the stargate open beyond 38 minutes requires a lot of power. So does dialing another galaxy. But that works against the idea that the beam is some unusual shield-draining thing that causes little damage. McKay said it would take "a black hole, or an unlimited number of ZPMs" to do what the Replicators were doing. Atlantis had only 1 ZPM. It is only capable of using three. Which scenario makes more sense:

1. The Replicators want to destroy Atlantis. So they rig up a stargate to fire a beam that is so weak, it can't melt through an asteroid the size of my back yard. This beam will take a full day to defeat Atlantis's shields, because it is also so weak it can't vaporize water. However, it defeated Apollo's shields, because this weak beam is actually specially made to drain shields, even though it doesn't do much physical damage to asteroids, or even water. Because it is a special beam. One made to penetrate water, but not asteroids, and drain shields. This will require them to keep the stargate open for the full day, using up all that energy they could have been firing at the target instead. But they need this weak, but special beam to have a full day dwell time on the target. You know, because it is a special shield-draining thing. It won't do much damage to the city, kind of like the asteroid, but they won't have shields anymore. But they actually wield firepower that rivals a supernova. They were just holding back.

2. The Replicators want to destroy Atlantis. So they rig up a stargate to fire a beam at the city. The stargate itself will use up most of their power to stay open for more than 38 minutes. They can't use that power to actually fire at Atlantis, because, you know, they need to power the stargate instead, so they can send a weak beam through for a full day. This is a special beam, designed to cause little physical damage to objects as mundane as asteroids, so it will take a long time to destroy the city itself, and they'll need to keep the gate open even longer when they penetrate the shields. So they better hold back even more firepower, so they can power the gate even longer, rather than just firing all this energy at the city. This beam has to be a special, but weak one, because it has to slowly drain the shields for a full day and it has to be designed to penetrate water, in case the personnel decide to submerge the city during this full day the special shield-draining beam will need to drain the shields.

3. The Replicators want to destroy Atlantis. So they rig up a stargate to fire a beam as powerful as they can muster. This beam easily defeats Apollo's shields, but takes longer to defeat Atlantis' superior shields, being also powered by a ZPM. This beam is so powerful, it allows the stargate to stay open as long as the beam is firing. However, this beam has trouble dealing with a small asteroid, calling into question the firepower of the Replicators, and by extrapolation, the Ori and Asgard as well.

Third time's the charm. Occam's Razor.

[adam_grif]

Penetrating water well but not asteroids can be accounted for by them assuming that they would sink the city to dissipate the beam (that's a very logical course of action and they no doubt anticipated it). The beam physics either do not allow them to ignore asteroids so easily, or they did not anticipate it. Either way, drilling through the asteroid only bought them a minimal amount of time in the scheme of things, and the slow, inevitable collapse of the shield pressed on until they planned their daring escape. The gating in prevented them from gating out, and the plan had no major problems except not anticipating a third act asspull to get the stardrive working. Remember, as far as the Asurans were aware, there was no way for them to escape and they had to MacGuyver that shit to get it going.

You want Occam's Razor? How about this:

The Asurans gate in, and they send an extremely small remote piloted ship with a beaming device and nothing else. It beams 5 zero point modules rigged to blow a few hundred meters above Atlantis, before anybody can react, and then detonates them. The city is obliterated. Or, the same thing, but with a Naquadah bomb which we know canonically are orders of magnitude more powerful than regular nuclear devices, up to the strength of a low-end Nova in extreme cases, and Gigatonne range at the low end.

So instead of your 3 scenarios, how about we have this one:

The Asurans gate in, they are firing a beam specifically designed to drain shields so they can deplete the power of the shields. This takes tremendous energy, but the beam weakly interacts with ordinary matter. Only a tiny portion gets absorbed by the water, but the dense asteroid scatters the beam shield draining component/gets broken up by the smaller physical component.

Once the shields were fully drained, they were intending to switch to a different kind of beam that would destroy the city quickly, or they were going to turn the beam away from the city, Quarantine it by blowing up any ship attempting to leave, all the while still trapping them inside thanks to the active gate. Another Asuran ship was going to show up at this stage, and they would take the city. Since the shields are down they can beam personnel out into space at will, or if they want they could employ some kind of enhanced radiation bomb to wipe everyone out or a BC weapon, whatever, it doesn't matter how.

Even if they did not want to take the city intact, we can explain away their not using naquadah bombs / their simple means of instantly destroying the city via ZPM's as not wanting to destroy a perfectly viable planet and ecosystem just to take the Atlantis crew out.

You no doubt think this is just mental gymnastics, and it is to an extent, but we have canon examples of Atlantis tanking firepower far higher than should be possible according to you in The Siege, Part 3 where it eats a day of fire from a gajillion Wraith ships, and then detonates an MT range nuke on top of it's shield when it's in danger of being depleted already, and still has enough juice to switch to a cloak until the Wraith leave after that. It was running on one ZPM. This is in addition to the boom capabilities of the ZPM we have seen before, where Camulus' half depleted ZPM was expected to easily destroy all life on Earth (even if we don't believe the hyperbole about the whole solar system).

Now, you'll say something like "blah blah chain reaction blah they aren't that powerful in normal operation", but we know how they operate. They extract energy from an artificial region of sub-spacetime until it reaches maximum entropy, paraphrased from Zelenka. The subspace region can't release more energy than it contains, and if they are reaching the point where no more energy can be extracted then that implies they should be getting approximately equivelant energy out of the slow, controlled release than they do out of the big boom, just over a longer timescale.

I'm willing to buy inefficiencies to explain some discrepancies, but what you're proposing is that although ZPM's have enough juice for an extinction level event that might even split the planet open entirely (i.e. possibly death star blast level or higher, given what we know about Arcturus this might actually be the case), when used in a slow, controlled release the ZPM is only good for a few Megatonnes. It's frankly a little ridiculous, and this is the entire reason why the "shield draining beam" was proposed in the first place.

[seanrobertson]

*snip*

I'm willing to buy inefficiencies to explain some discrepancies, but what you're proposing is that although ZPM's have enough juice for an extinction level event that might even split the planet open entirely (i.e. possibly death star blast level or higher, given what we know about Arcturus this might actually be the case), when used in a slow, controlled release the ZPM is only good for a few Megatonnes. It's frankly a little ridiculous, and this is the entire reason why the "shield draining beam" was proposed in the first place.

Overlooking the ass-backward nature of your methodology, the most ridiculous thing in the thread's how you've blithely ignored the fact that the Replicator beam had to be powered by "a black hole or an unlimited number of ZPMs."

Kindly explain that. You've ignored it at least three or four times now. And if you continue to appeal to your understanding of how ZPMs work, I'll also thank you to substantiate that with quotations. Brian's backed his shit up with quotes and vidcaps; it's only fair that the rest of you do the same.

On a similar note, could we try a bit -- and by a bit, I mean a shitload -- harder to use more precise numbers? In your last post alone, Adam, I found essentially useless references to, among other things, a "gajillion," "megaton-ranged" and "on top of their shields." Had someone even alluded to such things in a pro-Trek argument, you'd have an angry mob with pitchforks and torches on your ass.

[seanrobertson]

Again, yes this beam was cool, but I see no reason to assume it is anything more than a typical SciFi beam weapon.
Now here is a cool idea though. Being a coherent beam, and it did cause some steam, what if it IS vaporizing water, maintaining a column of super-heated steam from Atlantis up to the surface?
As water pours in to the column, it is vaporized.
Now that is a cool concept.

Small problem-there isn't one. Even accepting the unusual clarity of the ocean water (I don't think you'd get that much ambient light at a depth of a couple hundred metres anywhere in Earth's oceans) there should have been a lot more noticeable interaction between the beam and the seawater in its path.
The beam is pretty much instantly and continuously vapourizing a couple hundred cubic metres of water. I'd expect something decidedly more noticeable than what we saw in the episode.

How do you frequently put it? Ah, yes: "As per your say-so"?

I couldn't resist

As briefly as we see that beam interacting with the ocean, I think it's hasty to say not enough seawater was vaporized, especially based on unquantifiables like "I think we should see more steam."

[Gil Hamilton]

Out of curiousity, in your analysis of the asteroid, why'd you pick a sphere 60 meters across, when none of the dimensions that you marked out were 60 meters? You could have picked a sphere 54m across, which was the largest dimension, and still have been generous. After all, the beam cut through the edge of the thing in your image.

[seanrobertson]

Out of curiousity, in your analysis of the asteroid, why'd you pick a sphere 60 meters across, when none of the dimensions that you marked out were 60 meters? You could have picked a sphere 54m across, which was the largest dimension, and still have been generous. After all, the beam cut through the edge of the thing in your image.

Hiya Gil. Hope you're well -- been ages.

Brian's page said he just rounded up. But you're right: it is most generous.

[adam_grif]

And if you continue to appeal to your understanding of how ZPMs work, I'll also thank you to substantiate that with quotations.

I already nearly-directly quoted Zelenka on that but if you insist on doing this the anal way that requires me digging through transcripts I can oblige.

"It extracts vacuum energy from [an] artificial region of subspace-time until it reaches maximum entropy."

Overlooking the ass-backward nature of your methodology, the most ridiculous thing in the thread's how you've blithely ignored the fact that the Replicator beam had to be powered by "a black hole or an unlimited number of ZPMs."

It's stated that such energy is required to indefinitely maintain a wormhole. It is NOT stated that the beam is being powered by "an indefinite number of ZPM's", because those ZPM's / a singularity may simply be hooked up to the gate on the other end to provide power in the same way that the ZPM's are normally interfaced to provide power boosts to the gate.

We also know that a non-trivial amount of power from the beam is being drawn by the satellite itself to maintain shields that are potent enough to resist any and all weapons that the 304 can throw at it.

(In space, Apollo sends out three missiles towards the satellite. They impact harmlessly against a shield surrounding it.)

ELLIS: It’s protected by a shield. Give me some options, McKay.

McKAY: The shield’s taking its power from the beam. Look, I registered a slight drop in output when you fired on it.

ELLIS: Could I get a nuke past its shield?

McKAY: No, probably not.

SHEPPARD: I’ll get in the Chair and give it everything we’ve got. Maybe that’ll collapse the shield.

(He turns to run for the Chair Room but stops as Rodney speaks.)

McKAY: I said “slight” -- as in point zero zero two. Look, I doubt any amount of firepower is gonna collapse it while that beam is active.

From this we can infer that:

- The 304 still has nukes
- The only way they feel it is possible to destroy is by getting said nuclear devices past the shields (i.e. the shields could take a hit from the 1200 MT warheads that come on 304's standard).

From these two things, we can further infer that, therefore, the beam's power output must be sufficient to counter a significant portion of a 1.2 GT device detonating in close proximity. It's guaranteed that more than half of a detonation will be wasted because it's a spherical burst, but assuming 1/5 of the energy was delivered (a very close explosion, but easily doable since there is zero point defense and is not moving erratically). This puts the durability at ~240 MT assuming it "barely survives" that.

If even 1/10 of that value was devoted to the beam's strength, it would have sliced the asteroid in twane without a moment's hesitation and slaughtered Atlantis in seconds.... unless the beam was NOT a pure DET weapon.

On a similar note, could we try a bit -- and by a bit, I mean a shitload -- harder to use more precise numbers? In your last post alone, Adam, I found essentially useless references to, among other things, a "gajillion," "megaton-ranged" and "on top of their shields." Had someone even alluded to such things in a pro-Trek argument, you'd have an angry mob with pitchforks and torches on your ass.

The number of hive ships is largely irrelevant since we have no firepower calculations for them. The ZPM was expected to last "days" against them, and did last for about a day before their plan was put into action. The best we can draw from this is that they ate 1/7th of the ZPM's remaining reserve capcity, and even that number is highly shaky.

If you must know, it was 12 hive ships but they destroyed 2 of them. Miscellaneous smaller vessels escorted them.

"Megatonne range" is an estimate based on the height of the mushroom cloud, but this estimate can vary from "hundreds of kilotonnes" to "single digit megatonnes" based on the scaling of Atlantis you use.

This is the chart used to roughly approximate the expected yield:



I have no idea what you're talking about with "on top of the shield"? How is that a vague allusion? They literally beam the device a tiny distance above the shield and detonate it.

McKAY: Which is why we fake a self-destruct. Have the Daedalus beam a nuke right above the city's shield, and then detonate it. While their sensors are blinded, we cloak the city; when the smoke clears ...

... and later on in the episode they do exactly that.

As briefly as we see that beam interacting with the ocean, I think it's hasty to say not enough seawater was vaporized, especially based on unquantifiables like "I think we should see more steam."

His calc puts it on "kilotonnes per second" based on the asteroid melt, and this is what happens when you blow up a 23 KT device underwater:



Naturally there are significant differences between a coherent beam and a spherical detonation, but this should give you an idea of the magnitude involved. What we see on screen is not exactly inspiring for even his estimate of KT/s.

Also, as a note, this weapon obviously isn't a laser since we see it quite clearly in space with no atmosphere to diffract off. Would not questions of wavelength penetration thus be redundant?

[Brian Young]

Guys,

No reason to get hostile with each other.
I think it was...Batman...who brought up the great images of nukes exploding. Good job.
But it doesn't really relate to the use of a beam, which has different effects than an explosion. Quite right about the amount of energy involved. But *for whatever reason*, the water didn't absorb much of the beam. Therefore, we don't have a lot of steam.

We could debate about the specific nature of the beam all week, but I'm willing to concede that it is some form of superphysics, because it obviously isn't a laser, like most other SciFi beam weapons.

But the nature of the beam isn't really relevant.

!
Why? We know the Replicators intended to destroy Atlantis. This requires large scale physical damage. It therefore must be their best shot.

If the beam were designed to just drain shields, and was not DET, as you said, what would they do once the shields are down? How would they know when the shields were down? Why would a beam that drains shields NOT affect the asteroid more?

I'm sorry, but I really see no valid reason to assume the beam was NOT intended to destroy Atlantis, as the Replicators said. That requires a weapon that does physical damage. Period.

This was the Replicators' best shot, and it was great. But not compared to other SciFi beam weapons we've seen. Assuming the beam was not DET, simply because we don't see much steam is a stretch. It just is.

[Xon]

!
Why? We know the Replicators intended to destroy Atlantis. This requires large scale physical damage. It therefore must be their best shot.

Except the Replicators do not want to destroy Atlantis. We see how the Replicator's weapon satellite is aimed very close to the command tower, but isn't directly hitting it. The satellite tracks them as they submerge, this isn't rocket science to hit a non-moving target with a weapons which isn't effected by wind conditions. In Stargate Atlantis 3x11 the replicators go as far as to cannibalizes thier starship to repair Atlantis in less than a day after the command tower had a bomb destroy the command levels. They went as far to hunt down and kill every Ancient left rather than destroy Atlantis.

The Asurans replicators are utterly pissed over humanity's prefered status as a child race to the Ancients, it comes up time and again that they are quite jealous about this.

[Brian Young]

The Replicators made it quite clear they intended to destroy Atlantis. Watch the episode.

[Brian Young]

Okay guys, those of you claiming this beam wasn't a threat, because it was just not their best shot, or some kind of special beam designed to not be dangerous, listen up.
For that argument to hold water, you must address my questions.
*Why would the Replicators use a weak beam to destroy Atlantis, if they have all this "supernova" firepower in reserve?
*If ZPMs have this "supernova" power, why was it *not sufficient* to make the ship lift off the planet? They had to tap the power from an adjacent installation. And don't even start with saying it was weak from powering the shields. That one ZPM was holding off that beam for HOURS, calling the firepower of the beam even further into question. This means it takes more power to lift off than to defend from that beam.
*If ZPMs have "supernova" power, why could "an unlimited number" of them not blast through an asteroid?
*Why would the Replicators use a beam specially designed to drain the shields *that can't drain the shields*? It was going to take 19 hours!
*If the beam can't take out a small asteroid, how was it supposed to destroy the city? Was it going to take another 19 hours after the shields failed? They were trying to eliminate the Atlantis personnel, because they were now a threat! That is an awful lot of time in which to get away in the Apollo.

This is basically the same argument fanatical "Fivers" used to use by claiming, no matter what the Vorlons or Shadows did, they were "holding back." That their true capabilities were hidden from us onscreen.

The Replicators made it clear they intended to destroy Atlantis and kill the personnel stationed there. They had become a threat. If this beam is not their best shot, you really must answer the above questions logically. Otherwise, you have no workable hypothesis.