A nonserious "Situation" of mayhem

[The Dude]

To fight the 'Nids, they need numbers (that they probably don't have) and a higher tech base. The Imperium with it's level wins as much as it loses it seems, so frankly with ST I'd say build a generation fleet and run the hell away to another galaxy/dimension.

[Mr. Oragahn]

You're not shooting a device at "inert" matter. You're shooting a device that will pump massive amounts of energy into bugs which, in packed swarms, can absorb energy. I suppose it would work though, but you better be sure that no pack of blocks will survive.

Well if the bugs are immune couldn't you simply convert the planet(s) into a star or something and fry the buggers that way?

I'm not sure how you can convert the planet into a star. Perhaps one of the groups of this scenario can. You better be sure that the bugs have not started spreading though, otherwise you just pissed them off. When Replicators realize that you're a menace of considerable power, they attack fiercely.

The bomb turned a nebula into a star, and planet with breathable atmosphere and plant life, so radical alchemistic transformations are not completly impossible.

In this case we're clearly dealing with the transformation of a planet. I'm sure the odds are favourable to the Genesis device -but again can they even build one?- but I don't recall the device affecting an entire planeteary mass, just the crust.
It was effective with a large amount of gases, managing to draw its particles into one single spot, and probably the rest of the newly created mass finishing sucking the rest via newly made gravitational forces, but when it comes to hitting a solid rock ball, it seems that the mass of the planet itself partially acts as a shield, like if the inertia to overcome in the initial stages of the chain reaction was too much.
So the question is how deep the Replicator crust was, and how deep the Genesis effect can reach. It's hard to know how deep the bug crust ran, but we know that Halla was an Earth-like planet. The city where the new O'neill was built was stuck between an ocean and mountains. The Replicators completely flattened the planet's surface. Whether you say they filled the oceans with bugs and ate the mountains, or leveled all the surface nearly down to the deepest chiasm in the ocean, that doesn't make much difference. When you consider the list of high altitude mountains (1), there can be up to a difference of 10~13 km between an ocean's floor and a mountain's apex.

That is also assuming they wouldn't erect a shield. What a bug can do, bigger and more of them can as well, and better.

That is assuming an erected shield would be of any use, they felt the need to generate it as opposed to trying to assimulate the new hunk of tech just dropped on them etc.

If it's a missile, chances that it will be considered like a menace more than a curiosity.

A medusa-like ship can produce battle shields, and the power production increase of the bugs multiply their numbers is not exactly linear I'd say.

What is the differnce between a "battle shield" and a regular shield? I don't remember any distiction being made.

That's the terminology I use to make a difference between shields which can protect from powerful attacks, and generally turn visible when doing so, in opposition to the shields which cover small Goa'uld crafts like the Al'keshes and Tel'taks, but which don't protect ships against even the weapons of Death Gliders, don't reveal themselves when the ships are hit, and seem just good enough to protect from particles.

Also, Carter said in reaction to the plan about overloading Prometheus' naqahdria-fed hyperdrive (in order to destroy a building encased in a neutronium shell), that the Replicators would much likely be powered by the blast.

Well if its Unnatural selections, season 6, we're talking about the planet was at that point MADE of replicator, at least the outer layer, so it isn't surprising a nuclear blast couldn't wipe them all out. Please keep in mind that rentry heat fried a ship full of the critters, thier tough but are killable.

Yes, chiefly because they were all isolated as single bugs. They had not even formed the larger beetle-like bugs. As a point of comparison, the medusa ship, unshielded at that time, was blasted by seven camping O'neills using weapons built specifically to fight the Replicators, but it still managed to rain Replicators down onto the surface of Orilla (2). Although they were not isolated bugs, the fragments would manage to guarantee that a sufficient amount of bugs could invade a planet.
The Replicator planetoid... the sheer mass of them, that's way tougher. The Asgards stuck the bugs in a time dilation field, turned Halla's star into a blackhole and tried to destroy them all that way, but even that proved insufficient.
That's why you really need to be very well prepared to fight them, and I think that contrary to JMS' suggestion, a Death Star would actually be more than welcomed!

As for the supernova, Replicators have FTL sensors. They'll have plenty of time to detect the supernova, erect a shield if they can or need to, or leave, before the supernova reaches them.
Besides, the use of time dilation and spacetime raping device may not work so well against the Replicators.

Unless I'm mistaken they'd only have minutes. Even they would have trouble with a mass evacuation in such a time scale. The odd stray can be dealt with later with ships or if needed ground troops. The other option is generating a shield strong enough to withstand a star going nova which I find skeptical.

The Asgards went for a blackhole + time dilation combo. A supernova, even the Tok'ra and SG-1 managed that with a single stargate and a blackhole. You can be sure that the supernova is not sufficient, since it's easily within the Asgards' capacity.
That, and a supernova would cook the exposed surface, but the dark side of the planetoid would be protected.

So what's your proposal to weather the aformentioned threats? from Protoss to replicators, to Tyranids?

Really? Assuming the Defiant is aware of the invasion schedule, trying to convince major SW powers, including Rebels and the Empire, that the whole galaxy is at risk. Disclose the arrival list, and wait for the first arrival (Defiant counts as "zero"), five years later, as a proof.
Eventually the best thing that can happen is a fragile alliance of all sensible and reasonable humanoids to band against the successive arrival of Replicators, Tyranids and the Borgdom. Show to the new waves that their arrival was entirely predicted. The Terran Confederacy shouldn't be too hard to convince. The Terran Empire, that's a bit more difficult, but even them can realize the benefits of an alliance with the Empire. You can be sure that they will scheme, plot and not engage all their forces, but the second arival alone would be a major support in favour of the "prophecy". Apophis won't be too difficult to convince, in a way, since at that time, he's not powerful enough and fairly isolated, and is more concerned about his butt than total power if push comes to shove. His forces are minor, but the addition he can bring are in the form of Goa'uld technologies. It's unknown if he'd disclose the various healing, resurrecting, hyperdrive and nano-fold tech. The lack of naqahdah in the galaxy may severely limit the usefulness of some of them. Apophis would have to modify the tech to be powered by whatever is available.
That said, being the third wave, he woud unwittingly be the proof that the arrival list is correct.
Of course the OP doesn't say if the list explains what each enemy is capable of though. It better has.
If all goes well, 20 years later, the Protoss arrive and should be convinced that the rather bizarre alliance seeks the protection of all present life as much as possible, and is not a threat to the Protoss and their vow.
By that time, they should have prepared enough hyperlanes, ships and outposts, and merged enough technologies to fight in the Outer Rim with maximum response capability when the Replicator planetoid manifests itself.
Then dealing with the Borg will be the second biggest problem, since they have many ships. The control of the wormhole is most important. If the Borg manage to escape and build a beachhead somewhere, they better use maximum firepower. There won't be enough overkill. Thankfully, the Borg will first send one Cube, then perhaps another one, then two, etc. They won't really unleash the armada until they really think there's a big force here, and thus something really tasty to assimilate, if only for the scope of the buffet.

Comparatively, at this point the Tyranid fleet may be a piece of cake.


Sidenote: Apophis wasn't at the height of his power during SG-1. He's largely been making desperate gambles, using only the few ships he had left and right, and several times running away. It's nothing like the time he took control of Sokar's forces, or his power millenia ago, when he banded with Ra to kick Sokar out of the throne of Supreme System Lord on Earth.
So in this scenario he is a very negligible addition safe for his knowledge on Goa'uld technologies.

[Khas]

I've been giving this scenario some thought, and these are some of the things I came up with:

A) Reverse-engineer and combine technologies. Begin with combining AQ and Imperial tech, and continue this until Apophis shows up. Once he does, start reverse-engineering the tech of any Goa'uld ships that haven't been completely destroyed. Equipping ships with this tech is a must. After five years, convince the Protoss that there are more dire threats coming, and begin tech exchange. Begin building massive fleets with Federation, Klingon, Romulan, Imperial, Goa'uld, and Protoss technologies all put together. At this point, I'd start doing research into transphasic torpedoes. Genesis devices should also be of use.

B) When the Replicators show up, a red matter bomb straight to their homeworld should do the trick, and start blasting any that don't get omnomnomed by the black hole. Begin studying ways to reverse-engineer them, like in "Ark of Truth". Also equip ships with mass-drivers in case energy weapons fail.

C) Borg show up. Start lobbing transphasic torpedoes at them like nobody's business, and hope they don't adapt. Mass drivers should also come in handy. Reverse-engineering Borg tech is a must.

D) When the 'nids arrive, I'm going to increase my industrial capacity to the point of near-insanity. Start slave-circuiting starships, and possibly give them AIs. With all the tech advances I've made, my fleet MIGHT be able to hold them off.

[Mr. Oragahn]

B) When the Replicators show up, a red matter bomb straight to their homeworld should do the trick, and start blasting any that don't get omnomnomed by the black hole. Begin studying ways to reverse-engineer them, like in "Ark of Truth". Also equip ships with mass-drivers in case energy weapons fail.

Red matter should fail. First you need to get close to the planet, and Replicator had some ships scanning intruders down to their atoms. Sort of.
Secondly, the red matter itself, even assuming it manages to hit the planet (again there's the question of a shield, or even the structure of Replicators blocking the beam), the Replicators have proved to handle a black hole to some extent by fiddling with time dilation. That said it's not totally desperate since that trick "only" allowed them to secure enough block for a large ship, on their first try. Still, such a ship can have shields, it's fully FTL capable, can beam stuff around, and fire shield penetrating mini-ships. It's not guaranteed that the projectile would get through the shields of the alliance's ships, but if this ever happens, you better have a plan to get rid of them before they take control of the ship.

D) When the 'nids arrive, I'm going to increase my industrial capacity to the point of near-insanity. Start slave-circuiting starships, and possibly give them AIs. With all the tech advances I've made, my fleet MIGHT be able to hold them off.

Their fleets are generally big swarms. Not only the strength of their main ships is largely overblown, but due to their fleet formation, if you have a big enough WMD, you can get rid of an entire swarm in one shot.

[Khas]

B) When the Replicators show up, a red matter bomb straight to their homeworld should do the trick, and start blasting any that don't get omnomnomed by the black hole. Begin studying ways to reverse-engineer them, like in "Ark of Truth". Also equip ships with mass-drivers in case energy weapons fail.

Red matter should fail. First you need to get close to the planet, and Replicator had some ships scanning intruders down to their atoms. Sort of.
Secondly, the red matter itself, even assuming it manages to hit the planet (again there's the question of a shield, or even the structure of Replicators blocking the beam), the Replicators have proved to handle a black hole to some extent by fiddling with time dilation. That said it's not totally desperate since that trick "only" allowed them to secure enough block for a large ship, on their first try. Still, such a ship can have shields, it's fully FTL capable, can beam stuff around, and fire shield penetrating mini-ships. It's not guaranteed that the projectile would get through the shields of the alliance's ships, but if this ever happens, you better have a plan to get rid of them before they take control of the ship.

So I guess my best bet is to maybe pull a Dakara?

D) When the 'nids arrive, I'm going to increase my industrial capacity to the point of near-insanity. Start slave-circuiting starships, and possibly give them AIs. With all the tech advances I've made, my fleet MIGHT be able to hold them off.

Their fleets are generally big swarms. Not only the strength of their main ships is largely overblown, but due to their fleet formation, if you have a big enough WMD, you can get rid of an entire swarm in one shot.

Maybe a Borg Multi-Kinetic Neutronic Mine, with a yield in the millions of isotons? Or an omni-directional thalaron wave device?

[Mr. Oragahn]

For the Replicator planet, it's hard to tell, but surely your best bet is either a Dakara weapon, but no one in the group in question knows about it, or red matter and the largest fleet ever assembled, assuming you won't mind fighting in an environment where funky black holes and time dilation takes care, or something.
That said, the black hole created by the Asgards used the mass of a star, which makes the mass of a planet like Halla simply all too negligible. On the other hand, the black hole in question was obviously located were the star was, but it did rip the planet apart and disintegrated a Goa'uld scout ship pushing its engines on max in order to get away from it.
Teal'c and Carter were aboard, and beamed to Thor's new ship.

For the Tyranid swarm, well you need something big, for sure. Actually many ships would suffice, in that their abilities don't really grow exponentially the more of them there are. But anything that can bring the power of an exploding planet will surely be far more than enough if detonated close enough.

[Sunburst]

I'm not an expert by any means and I believe Wars weapons to be superior to Trek so I'll just move on to something specific.

Red Matter:
It doesn't have to be used as a "battering ram" against a planet directly. It can be used to change the gravity and planetary orbit effectively flinging entire planets to their doom ie into the sun for example.

Of course trilithium torpedoes could be used against stars as well to destroy a star system.

[Mike DiCenso]

I'm not an expert by any means and I believe Wars weapons to be superior to Trek so I'll just move on to something specific.

Been watching the CGI Clone Wars series? You should, it'll disabuse you of the notion that SW weapons are superior to Trek ones.
-Mike

[Sunburst]

I'm not an expert by any means and I believe Wars weapons to be superior to Trek so I'll just move on to something specific.

Been watching the CGI Clone Wars series? You should, it'll disabuse you of the notion that SW weapons are superior to Trek ones.
-Mike

I tried watching the CGI movie when we rented it...and I couldn't make it through. Although I was happy to hear the power levels obliterated the cross-section numbers.

My personal canon doesn't really include much of the EU or the prequels...but that's a topic for another thread.

[Mr. Oragahn]

I'm not an expert by any means and I believe Wars weapons to be superior to Trek so I'll just move on to something specific.

Red Matter:
It doesn't have to be used as a "battering ram" against a planet directly. It can be used to change the gravity and planetary orbit effectively flinging entire planets to their doom ie into the sun for example.

The problem is, the planet in question is, at the very least, covered by things which can move on their own and form starships in little to no time. Technically, on theory, the mass of Replicators could very well move itself, both via STL and FTL means.

[sonofccn]

Forgive me if I'm not understanding something but, assuming you had sufficent "red matter", couldn't you simply "activate" it inside say a cloaked ship parked next to the planet and form a blackhole to consume the planet or am I missing something?

[sonofccn]

D) When the 'nids arrive, I'm going to increase my industrial capacity to the point of near-insanity. Start slave-circuiting starships, and possibly give them AIs. With all the tech advances I've made, my fleet MIGHT be able to hold them off.

I'd suggest Thalaron radiation, from a weapon chassie of your choice, which an area of effect that is highly controllable, including planet bathing, and even minute dosages is fatal to organic life. Which the 'nids just happen to be. Of course if they adapt than a few billion photon torpedoes could come in handy as well.