Sometimes to Create, One must First Destroy!

I think the most likely answer is that the engineers use their bioweapons/the xenomorphs to kill off whatever lives there, and then restart. Engineers are most likely a multi-solar system civilization, and planet 4 is likely just a military base and LV 223 and LV-426 were research facilities. It is mentioned in prometheus that they likely had a civil war, so there are likely different ideologies/factions

Certainly think that a Civil War in the Past is Possible.  Before the Prequels we could ASK as to WHY the Space Jockey had those Eggs, and IF they was as Biological Warfare then against WHO?

The Prequels had began to indicate the WHO was US...... ONLY it Evolved to becoming that the Eggs were NOT the Original Bio-Weapon but something that Evolved from the Bio-Weapon..... which Latter again had been Re-written to a Creation of Davids using the Bio-Weapon to Create it.

But we are looking BEYOND and before the Prequels and at the Broader Agenda of the Engineers (not Restricted to Earth).

And so the Engineers (as far as who we been Introduced to and WHO had Created us) are NOT any kind of Super-beings or Magical Gods.  They are merely a MORTAL RACE who have Existed for Millions of Years (Maybe over a Billion) and merely have been AROUND for a Long Time to Evolve and Advance themselves to WHAT we see.

And so we can look to Mankind for Answers.......... if we get to the Alien Franchise lets say ALIENS and so its about 2180, and Mankind has Found New Homes in the Galaxy and Colonized Worlds.  Does this mean that Mankind has NO MORE kinds of Conflicts with each other?   What if in 2500 and we have found say 5 Earth like Worlds that we have Populated and say 25 other Worlds/Moons we have Established Colonies on but they are NOT quite Earth like.

Do we have it were we say OK so CHINA you have that Planet, and AFRICA you have that Planet, and EUROPE you have that Planet and North America you have that Planet etc.

Would this Prevent those Nations from having Conflict with each other?

Even so then a Planet that is Owned by CHINA for Example, who is to say that as Time goes on that this Planet and its Continents do-not get into CONFLICT with each other.

The ONLY way to Maybe Prevent this is ONE GOVERNMENT/WORLD ORDER and so its like say that THIS all Powerful Movement either Take On a Religion and then you FORCE the World (or Galaxy) to FOLLOW this Religion, or Alternatively this NWO  say Accept Atheism and then Eradicate Religion and FORCE everyone to Atheism.

This would Eradicate some Conflict but you will get Rebellion and the Odd Faction form up that would NEED to be Quashed!  Do you take it Further by Eradicating all Races apart from ONE... this may sound a bit HITLER....

But even IF you did all this....... Mankind are Prone to Greed and so Conflicts could STILL break out.... so they LIKELY would Exist.  And so WHAT if we looked at all of this on a LARGER SCALE in Terms of the Engineers!

Has there been Genocide among their OWN KIND? 

IF they Create Life in their Image then IF they deem these Creations are NOT keeping to their RULES or they become Concerned they are a Threat or Potential.....  Or EVEN if they FEEL this Race is NOT so Perfect and they want the Worlds Back to then Create another Race.

Then YES its likely the Engineers would Destroy, and do so for the Benefit of their Greater Agenda.... but INDEED there could be Factions with Different Agendas and so YES we cant RULE-OUT the Engineers having Internal Conflicts, and Especially if they POPULATE many Worlds.

The other THING would be to ASK as to are ALL the Worlds in the Galaxy and Beyond, places that the Engineers Created Life?  Could there be Worlds that have Intelligent Life that is NOT something the Engineers Created?

Would the Engineers feel Threatened by these and having to SHARE the Cosmos with them?  What if the Engineers see this Races Home-world (or other Worlds inhabited by them) and the Engineers are like "This Place is Perfect for us and our Creations"  would the Engineers want to SHARE? or would they Destroy the Civilization on these Worlds and then CLAIM the World for themselves?

Regarding the Worlds we have seen so FAR....

Planet 4 does-not look like a Military Place to me, it may seem Strange that those Engineers seem to Populate that ONE CITY, but its as i said in another Thread this is Quite like what Paradise was like, Paradise being Planet 4 and therefor that City being like the Garden of Eden.

LV-426 seems to be the PLACE that the Derelict and its Cargo had ENDED UP being on.  It seems this is just a BARON MOON (Prior to ALIENS).

LV-223 is a Interesting One, it could be Purely a Military Outpost, but then its WHY would some of them or HOW/WHY was it that Clues to this Place had been shown to Mankind on Earth for at least 30'000 Years?

*Come to this Place when you can! (Ha Ha those Humans will DIE when they do).  AKA TRAP!

*Dont go to this Place its Dangerous! AKA WARNING!

But then IF there Intentions was to Destroy us all that Time ago then WHY do they NOT go and do it?  It seems ONLY about 2000 Years ago they Attempted this and it went to POT!

I believe that LV-223 is a Outpost to Experiment and Create Life, to then Assess this Creation and WHEN you are Pleased you can TAKE IT or Seed it down to Worlds.  But at some point this Place  had Became or was Turned into something else.... and the Horrors began.

The Juggernaught to me does-not make a Good War Machine.... well ONLY if your Targets are a Race who are NOT in anyway Advanced to Protect themselves and also the SACRIFICIAL GOO is the Perfect Weapon as it it.....

RAIN DOWN URNS of that Stuff and what Happened to the Sacrificial Engineer would Happen to the Life on this World.... you have RESET the World.

Sacrifice fellow Engineers in a way to Collect the Broken Down Material and STORE it into URNS and then RAIN them down on a World and you have a more Efficient and Diverse way to SEED a World than to DROP OFF a Engineer........................ and THUS this is WHAT i think the Juggernauts were they are a UPGRADED version of Seeding Worlds. (The Original Drafts there was NO Pebble Ship but Juggernauts).

However this does-not mean the Engineers have or NEVER had any Military as surely there would be Conflicts the ONLY WAY they would NOT really Need more than the Juggernaught is IF all the other Worlds that have Intelligent Life are KEPT in Check and Technologically Ancient.... and that any Threats have been ERADICATED many many Years ago.

But the Galaxy is HUGE and the Engineers likely have been to other Galaxies and so the Potential for Conflict both Current and in Past and Future is HIGH and you would Expect the Engineers to have some WAY to deal with this.

"It is mentioned in prometheus that they likely had a civil war."

I don't believe anything like this was mentioned. The captain of the Prometheus did pass an opinion that the pyramid was a military installation where a weapon of mass destruction had got out of control, but no mention of a civil war.

I've mentioned my thoughts before, but - based on known behavioural evidence - it strikes me that the ancient race of the Engineers have long since roamed the Galaxy and heavily steered the development of life. As Ridley Scott put it: "gardeners".

As to whether they tend the garden or plant it outright, that's an open question. I'd like to think that life has evolved independently millions of times throughout the Galaxy, without Engineers needing to light the blue touch paper.

But it is evidently clear that if the Engineers don't like what they see, they are more than happy to wipe the slate clean. And - rather disturbingly - they seem keen to mould life in their own image. Echoes of Christianity there, where Man has dominion over all creatures on the Earth, but taken one level further to embrace the entire cosmos.

With a virtually limitless supply of alien civilisations facing the prospect of annihilation, that could lead to some very interesting storylines.

@BigDave, you mention that the Juggernaut is not a good war machine. I agree. But it's good enough, and I am happy to entertain the thought that its design / technology may hark back to an earlier period. The Alien universe is weird enough that the Juggernauts could in a sense be alive, and are grown. Maybe they came from a race that preceded the Engineers.

"As Ridley Scott put it: "gardeners"

Exactly i think that was the Main Objective of the Engineers, and its likely they have been Gardening in a LOT of Places.

"that the Juggernaut is not a good war machine"

It depends on what you mean by a War Machine, it Certainly can be USED to bring about DEATH.  Just Dawns to me that if this went up against say the Galactic Empires Destroyers then it would NOT stand a Chance... i would even say W-Y Military Ships of the 23rd Century would Dispatch a Juggernaught.

And so this seems Counter Productive to the TOPIC..... in Part as FAR as Conflict and HOW they Deal with it. By that i mean.....

*It seems the Juggernauts have NO MEANS to Take Out other Ships, not from what we have seen.

*It seems Planet 4 had NO MEANS to Take Out the Juggernaught (unless it was Too Late by the Time they Realized what was going to Happen).

These MAKE Sense IF the Engineers know or FEEL there are NO THREATS as FAR as Worlds that have Advanced Technology because they KEEP EYE on their Creations and other Threats and Eradicate them before they can become Technologically Advanced to POSE any Threat or be able to DEFEND against a Juggernaught and its Cargo.

Then the Juggernauts are FIT for the Purpose to Destroy...... i think the Sacrificial Goo is GOOD ENOUGH as a means to Destroy as in Destroying it will Create and it SHOULD go and Create like the Sacrificial Scene so that MAKES more Sense as a CLEAN THE SLATE kind of Option.

I see the Juggernaught as a Seeding/Evolving Tool.... go and Capture some Tigers and Lions and Subject them to the Sacrificial Goo and Collect the Result (after the Felines have Broken Down) and Store this in the URNS and then RAIN this Down onto a City of Humanoids.... and well we can Assume they would MUTATE into Thundercats or Eventually something Similar will Evolve.

But we Never Saw something like this in Alien Covenant, those Engineers appeared to Suffer from a Poisoning (Pathogen) of Sorts and the Goo Started to Replicate inside and Swarm to other Engineers..... but  in the END what we had was like Statues, they became like Mummified!

The Result of the Black Goo and a WAY the Bio-Weapon was Activated or Programed?

Or maybe the Engineers had some Device that would RELEASE a Energy Blast or something that would KILL ALL LIFE within a Radius, by Turning the Molecules of Life into like Stone (well cause the Engineers to Dry Out).

I am NOT sure those  Working on the Movie had a Explanation or thought that ONE was Needed. (As Far as WHY the Engineers remained like Stone/Mummified).

So YES the Juggernaught can Bring Death, but also Life, i would NOT go and RULE out it as having Multiple Uses.....

But WHEN/IF the Engineers are Faced at Conflict with another Faction who are on Equal Technological Level or against other Races who are Technologically Advanced even as FAR as say Mankind in the Year 2100-2000, then YES the Engineers would NEED to have other Forms of Attack and Defense you would THINK?

If NOT then this Lack of Military Might would become their Undoing...but then to Attempt to Create Horrors on LV-223 seemed to become their Undoing in PART.

Looking at the SCOPE of the Plot that Expands Beyond our Galaxy then i think its UNLIKELY the Engineers have gone around for Millions and Millions of Years without any Conflict with each other...... or maybe we CANT go and Assume there are NO OTHER (Races) or that other Races are ALL at Technological Levels that are NO-WHERE as Advanced as even Earth at Present (2021).

"Juggernauts could in a sense be alive, and are grown"

You could get that Impression with the Derelict, and HR Giger even said he thought the Ships would be Grown!

The Juggernauts however seem WAY MORE like Mechanical/Synthetic, there seems to NOT be a lot of Organic Aesthetic to them.  But while the Derelict looks Truly Bio-Mechanical and we have YET to see HOW the Derelict got to LV-426 then YES it could be OPEN to Explore the Derelict as being Different and that the Engineers had Reverse Engineered, or Based their Designs from SOMETHING ELSE..... that is maybe Created/Grown by some OTHER Race?

It was of Wayne Haags Opinion (and it could be just that) that he FELT the Engineers Technology was STOLEN from someone else.  This could be Explored.

“the Engineers would NEED to have other Forms of Attack and Defense you would THINK?”

If they were to encounter a plucky race – or a belligerent faction of their own – willing to put up a fight, then certainly they ought to have technology to deal with that threat. The juggernaut on LV-223 wasn’t any good at dealing with the Prometheus, for example. So there has to be something better for that purpose tucked in the garage.

I could easily imagine Engineer battle fleets using technology we haven’t seen yet, which would be fun to see.

Another possibility might be that if you’ve been gardening the Galaxy for a very long time, you kind of know what you’re doing, and opposition might be extremely rare. In a worst case scenario, you might have – let’s say – a green crystal on a stone plinth that, when pressed, can detonate a star dozens of light years away.

A contemporary parallel to this might be the Tory Party in the UK. They are very good at clinging on to power, and crush all opposition, despite being fundamentally self-serving and morally corrupt ;-)

Gardeners!? More like psychopaths. Control freaks to the nth degree.

I now think it was a mistake keeping the Engineers alive.  I think the real threat was Weyland industries obtaining the mutagen and bringing it back to Earth ( and the highest bidder ). Humans are very capable of 'weeding' themselves without the help of a juggernaut loaded with the stuff.

The timescale for this gardening is unfathomable, how long would this stuff take? Seems more like a hobby than a defense ( or offense ) strategy.

Well i think you RAISE a Exceptional Question!

"let’s say – a green crystal on a stone plinth that, when pressed, can detonate a star dozens of light years away"

If we are talking a Advanced Race that have been what more Advanced than maybe we will be by the Year 3000 but these have been at least as Advanced as maybe we could get then, but for Hundreds of Millions of Years then we REALLY dont know the LIMITS of the Technology as FAR as the Ability to Destroy.

And as Genetic Gardeners you would think they have ways to have a KILL-SWITCH.  And the Juggernauts and Especially if they USE the Sacrificial Goo are Perfect for RESET SWITCH of a World.

But do they have Technology to Protect Ships/Worlds some kind of ATTACK as IF the Juggernaught had such Weapons it could have Destroyed the Prometheus and then gone to Earth.  IF we saw Planet 4 have these maybe they could have Destroy the Juggernaught... but it seemed by the TIME they Realized what was Happening it was TOO LATE.  You really want to be Destroying a Ship like that before it gets into the Atmosphere.

If they have such Weapons then maybe they have NUKES or similar that they can USE on Worlds, maybe they can EVEN go and Destroy Worlds (HR Giger Death Star anyone) but YEAH if they had such Weapons and Wanted to Destroy Mankind then WHY NOT go and USE them?

Makes No Sense to Create a Weapon to Drop like the Black Goo to Mutate them into Horrors unless this is WHAT they want to Turn us into.... as to SIMPLY go and KILL US then maybe there are Better Ways and to RESET the WORLD then the Sacrificial Goo via Bombardment is PERFECT.

I think as FAR as Exploring a Ancient Alien Race as a Race who ONLY have the Juggernauts to go around and DROP DRUMS of Pathogen on Folk... i think thats Very Limiting.

"a green crystal on a stone plinth that, when pressed"

So again back to this.... could they Install like Underground Explosives or Something Near the CORE of a World that when it is Activated/Detonated will Cause the Planet to either EXPLODE or Cause like a MASS of Earthquakes and Volcanic Eruptions which will RESET a WORLD where it may NEVER be the same Again... or would take Millions of Years to be back to Normal.

Could this have Happened to LV-426?  Could the Star Map had been showing us to LV-426 and it was a Different Place like Many Thousands of Years ago?  Who knows... they could Explore that... or NOT.

Something like this could be the Ultimate Plot Device to Explain the Pursuit of the Xenomorph in the Franchise, instead of going to LV-223...  If there is a KILL SWITCH on LV-223 or the Engineers have a Technology they can Unleash from Space that would DESTROY the Moon... or Render It so that it has NOTHING to be Gained from it.

But back to the Question about WHY those Horrors?

Maybe ONE thing we overlook could be FEAR!

If the Engineers have Creations who become Rebellious or do-not Behave or they have Races they wish to CONTROL then FEAR is a Method of Control.

If on Earth you wanted to Control a Population by Forcing them to your View or Religion and those who DO-NOT go and Follow will be KILLED... then it depends on HOW you Kill them that can Effect the likely-hood of HOW they would GET IN LINE.

A Slow Death a Horrific Death, a Death in Front of the Public a more Barbaric Ways would cause more FEAR.

So maybe those Horrors are Created as a way to Strike FEAR into those you wish to Control.... you show them on SMALL SCALE of WHAT can Happen... you then PUT the FEAR OF GOD into them.... Job Done..

But you NEED to TEST this Horror... this Weapon of Fear!

Not saying this is WHAT is the Reason... just Speculating that its a more Logical Reason.

I think the Juggernaut is what it appears to be - a cargo ship. There is no reason to suppose there aren't Engineer warships, they just weren't present on LV-223 because humanity was so primitive 2000 years ago they weren't needed for whatever it was they were going to do with Earth, and the base has been nonfuctional since then. 

My guess about the Engineers and the humanoids they create is that since the Engineers are heavily into bio-engineering, they create species of guinea pigs who are similar enough to them that they can substitute for Engineers in experiments, but are reduced enough in intelligence relative to Engineers that they don't have the ability to catch up and become a potential threat. 

That can make Sense.... as far as WHY they would Create us.

It depends on HOW DEEP you go with the Engineers Plot as far as them Needing any Weapons...  IF they are the FIRST MAIN Species of their Kind so other Worlds are Primitive and without their Interaction they do-not even get to the Level of say Ancient Rome....  then there would be NO THREATS.

And then even the Worlds you Visit you can KEEP a Curb on HOW FAR they would Advance, and so if these are allowed to get as Advanced as Ancient Rome then they POSE no THREAT.

Because with Worlds like this then you would ONLY need the Juggernauts to DROP down the Urns of Goo to RESET/EVOLVE or Destroy the Life on that World.

And so in this Context the Engineers Fate becomes a Consequence of their Naivety in which they would ASSUME if they Abandon a World of Creations then they would NEVER be able to Advance themselves to be a THREAT... and well they were VERY WRONG!

But this would LIMIT the Plot and well HOW you can Explore the Engineers, and at the Very Least you have to think they may have had Conflicts with Each-other at some Point in the Past and so i THINK they could have other more Military Ships.

The Juggernauts make NO SENSE as a Purely Military Ship unless its against Primitive Worlds.  They do HOWEVER make Perfect Sense as a Seeding Ship!

Especially if we look at HOW the Goo Worked in Prometheus and HOW it was Envisioned from Earlier Drafts/Concept.

You want to Evolve say the People of South America into Hybrid Human/Cats, then you USE the Sacrificial Goo on a Jaguar and Collect the Result into Urns and then you DROP a Few Urns on a Few Ancient Settlements in South America and those who are Infected would take on FELINE Traits and we have some Thundercats who would Appear from South America.

Want to Completely Reset the World then you MASS BOMBARD the World with the Sacrificial Goo and you RESET the World to like the Sacrificial Scene.

Want to take some Humans and other Creations from where they are to say LV-223 to First Experiment with WHAT you want to Evolve/Change them too, then this makes SENSE.  And so in Context to all that then the Juggernauts make Perfect Sense.

For them to be a Ship that is Created to Carry Eggs to Bomb Down, makes Little Sense, to Create Horrors on LV-223 to DESTROY a World makes Little Sense.

To have a Sub-Creation become Displeased at its Role, Jealous of its Creators and maybe their other Creations, to then have Bitterness and Hatred and want to CAUSE TERROR and Create something Horrific.... and USE the Existing Creation Technology to Create such Horrors....  That makes Sense!

so too look at that, and then look at the LV-223 Engineers and David to FIT that Role and thus be like Satan/Fallen Angels and have this Agenda to Corrupt/Taint and Destroy the Wonder of Creation then this Makes Sense.