Well, the entire basic premise of how starships actually work is based on that assumption, so it's not a personal opinion such much as it is a direct observation.
It's kind of like when Spock says "I am a Vulcan. I am incapable of lying" when we know for a fact Vulcans lie about shit whenever they have a logical reason to do so. We just conclude that Spock, knowing the reputation for Vulcan truthfulness, has a logical reason to lie about being incapable of lying (e.g. Klaa will probably believe him).
Vulcans generally don't lie unless very specific set of circumstances compel them to do so... but its not the same as saying 'replicators convert energy to matter, except that they don't.'
Not even remotely the same... and I'm sorry, but I'd rather go with the characters and their canonical statement that replicators convert energy into matter (incidentally, these are feats that WE are experimenting with right now).
Or... you could be wrong.
No offense, but you don't hold the authority on what is possible or plausible in Trek (let alone what could be acomplished with hundreds of years of exponential advancements - in this line of thinking, the Federation should have actually been portrayed as hyper more advanced than what we saw in the 24th century).
Yes, it occurs in vacuum fluctuations via pair production, and also occurs in every endothermic nuclear fission, fusion or chemical reaction.
To be clear: it is the conversion of energy into mass, not matter. Mass and energy are equivalent. Matter is the set of all things that possess both mass and energy. Energy isn't a "thing" unto itself, it's a quality -- like mass -- that matter happens to have. A given amount of matter can trade mass for energy or it can trade energy for mass but energy cannot be "converted" into matter anymore than temperature can be converted into coolant.
To quote Picard:
In the year in which we live, humans have discovered that energy and matter are interchangeable. In the holodeck, energy is converted to matter. Thus you have substance. But only here.
To quote Data:
DATA:
Perhaps we should consider the transporter system. It uses many of the same principles as the holodeck. Both, for example, are capable of converting energy into matter.
Janeway says the same thing about holodecks as Data (who also mentioned at one point that they lost the ability to replicate complex elements due to energy loss).
What Picard is essentially stating here (and Data confirming) that Humans simply built upon the process by changing one state (also known as energy) into another state (known as matter).
Now, if you wish to argue this, by all means.
But don't forget that we are also engaging in experiments of converting light (energy) into matter TODAY.
Obviously, in science, 'energy' and 'matter' may be interchangeable, but they still describe two different states for differentiation purposes.
They don't. It's just a colloquialism. Probably exactly the kind of thing Spock would pedantically correct if he happened to be there.
A 'colloquialism' which apparently manifests itself across TNG, DS9 and VOY repeatedly, and was also repeated by AI known as Data (who is known for not making such simple mistakes).
So, either they and their whole technology is wrong... or you might be wrong.
I'm gonna go with the premise that you might be/are wrong.
So buy TWO fusion reactors instead of one. You've accomplished the same goal at an infinitesimal fraction of the cost of building a dyson swarm. TEN fusion reactors would be massively excessive, but would still be far cheaper and less time consuming.
By that same definition, why bother building a gigantic starbase (like Starbase 1 or better yet the Yorktown) or two in the middle of nowhere for starship construction?
Wouldn't a simple shipyard suffice? Far less resources, personnel and material involved.
A self-replicating dyson swarm can easily serve as a multi-functional array of facilities that would provide massive energy for current and future projects.
Just 1 massive solar collector the size of 10 km would be equivalent or better than a Federation starbase for example - and it could still have fusion power generators in case they are needed.
You can easily replace most starbases like that, as its likely you can simply replicate whole ships and massive superstructures into existence from the ridiculous amount of energy a star provides continuously than bother with replicating ships in stages and then assembling them (which is still pretty fast, but wouldn't inherently beat 5 to 10 seconds of materialization).
Engineers seek to solve problems that someone actually has. A theoretical problem that nobody calls for a theoretical solution. A dyson swarm is such a solution.
Depends on whom you ask.
The Federation focuses more on exploration, discovery and furthering its own scientific understanding of the universe.
Building a Dyson Swarm might easily provide them with the necessary baseline to massively accelerate construction, scan areas of the galaxy that would otherwise require starships years to get to, improve their understanding of energy accumulation, storage, conversion, etc.
We're talking about a combination of societies that was able to accomplish deliberate time travel by warping around a star in the 23rd century.
I mean, they already have a bunch of historians from the future studying the past.
What purpose did the Federation have pursuing development of time travel technology and allowing historians to study the past if it's just running a too dangerous risk of changing the timeline?
No, because nearly every race in the galaxy uses the annihilation of matter and antimatter to produce energy despite the inherent dangers involved (antimatter containment failures, etc). If it were possible to convert mass into energy WITHOUT using antimatter, there are literally hundreds of situations where their ability to do this would have been useful ("Peak Performance" being the most obvious). The only race that doesn't seem to use antimatter are the Romulans, and they convert energy by dumping mass into an artificial black hole and collecting the radiation that spills out of its collapse (basically fusion on steroids).
Peak Performance? The Hathaway was stripped to it's bare bones intentionally and didn't even have warp capability.
The ship was crippled by intent... and it took Wesley's m/am experiment to just give the ship enough of a 'jolt' to activate Warp briefly.
Besides, that was a Constellation class star-ship which didn't even have replicators... all of the technology in the ship was based on 23rd century (including console interfaces).
The Hathaway didn't have a functional warp core... the ship was likely running on fusion generators, and I would imagine that fusion reactors do not provide sufficient energy on starships to run replicator (unless you are on a starbase like DS9 - which btw had 3 massive fusion reactors - which begs the question: why didn't the Cardassians simply use 3 large warp cores instead... or automation for mining and processing as opposed to using Bajorans that are by definition slow and inefficient by comparison?
Simpler answer might be that cardassian replicators on DS9 actually manipulate matter and not energy (unlike the Federation), and were just plain idiots who did nothing but hurt themselves if they realistically expected manual labor to deliver same efficiency as automation.
I know they conquered the Bajorans and wanted to subdue them through slavery, but come on, anyone with a basic understanding would know that running workers into exhaustion and stripping the planet to nothing only hurts so-called 'productivity' when the needed minerals and resources are likely found in far more abundant supplies in asteroids.
So this is a constraint in real world physics as much as it is in Star Trek: mass and energy cannot be DIRECTLY exchanged without annihilation or particle/antiparticle pair production. They can reorganize and transport matter relatively easily using transporters and replicators, and THAT does not require pair production of matter and antimatter, but it also doesn't provide you with a source of energy, which is why warp cores are still a thing.
Starships use a combination of Bussard collectors (which accumulate matter from space), Fusion and M/AM reactions to generate energy.
We have seen time and again that replicators on board Federation ships tend to require M/AM reactors to work.
The Enterprise-D did supply the Uxbridges in 'The Survivors' with a matter replicator that was fairly limited. So it was likely this less sophisticated version can run on a fusion reactor to generate basics.
You still haven't explained why their reliance on primary reactors wouldn't be preferable in the first place. EITHER system still has to actually be built before you can benefit from it. A series of redundant reactors, however, would take a couple of weeks to assemble while a dyson swarm would take years and would be a million times more expensive.
The town I live in doesn't have its own powerplant and my house doesn't have its own generator... is there a reason why we would need either of those things when the municipal state-wide power grid is 99% reliable?
Let's see, fusion reactors and even M/AM reactors end up running out of 'juice' eventually.
Using the star to power your primary systems and rely on actual power generators as a backup is a much more sensible approach because the star is much less likely to run out of power soon.
Also, in the case of the Whale probe which used dampening fields to strip away starships power generation, Starfleet ended up resorting to Solar power in order to power subspace communications.
That way, you'd only end up using the reactors a fraction of the time and would last virtually indefinitely - and their energy storage options are far superior, suggesting they can store massive amounts of power for later use.
The question remains: what exactly can you accomplish with a dyson swarm that could not be more easily accomplished with a couple of warp cores?
I already provided plausible answers to that one... but fundamentally speaking, you won't know until you actually make one and see what kind of paths it enables from that point on.
People tend to be limited in perceptions and ways of thinking until they end up doing something bigger that opens up ways of thinking for other ideas.
Is it more than they could accomplish by simply giving every one of their researchers a 500GW fusion reactor?
That's a serious question, by the way. How much energy do they actually NEED, and what makes you think the dyson swarm is the most efficient way of meeting those needs?
Please provide me with a reference that says any number of Warp cores can equate the energy output of a single star like our own.
And to answer your question, yes, it IS more than they can accomplish by giving researchers a 500GW fusion reactor.
These people manipulate subspace and scan tens, hundreds, or even thousands of lightyears, they bend the fabric of space-time.
Look at how much power an upgraded Large Hadron Collector uses vs the non-upgraded one.
Plus, the size of LHC is what also enables researchers to conduct much better experiments.
A similar thing could be extrapolated with a self-replicating solar collector that houses other technologies.
The underlying scientific research that could be done from say a fully done Dyson Swarm would likely dwarf anything in the Federation by orders of magnitude on a much larger scale than before.
Really, this is the "High Frontier" nonsense all over again, where Gerard O'Neill tried to convince NASA that his orbital powersat idea was the wave of the future and then utterly failed, after 10 years of trying, to convince anyone to seriously invest in it. It became clear that almost everything O'Neill had proposed could be done at one tenth the cost just by NOT launching all of that hardware into space and simply building it slightly larger on the ground, which is what they ended up doing.
That has more to do with human short-sightedness and living in a ridiculously outdated socio-economic system that is based on money and cost efficiency and has nothing to do with our ability to actually make something from a resource and technology point of view.
Those structures could have been built back then, and I have to wonder how much more we could have learned and advanced if we had done so.
Same with the dyson swarm. If you've got the resources to build ten thousand gigantic solar power satellites, you might as well just build a million fusion reactors instead. The dyson swarm won't do anything that a million fusion reactors won't do; if it's living space you're after, then reduce it to ten thousand fusion reactors and put them on space stations instead (which you can now put anywhere you like, even in the outer solar system near gas giants for hydrogen collection, since they have fusion reactors and don't have to be in a swarm).
10 000 gigantic solar power satellites that house plethora of technologies which can be used for scientific and technical advancement and are self-contained cities in space.
And most likely, those 10 000 gigantic solar power satellites would produce more energy than a million fusion reactors could (which would run for a set amount of time and then you need to make new ones).
Because they have other technologies that accomplish the same job more efficiently and less expensively.
Expense is hardly what concerns the Federation.
If they have the technical, scientific and resource capability to make something, and it could result in massive breakthroughs, they probably will do it.
Several things in Trek that Federation made didn't make particular sense to people who watched it... doesn't mean such things would have 0 intrinsic value to society and civilization at large though.
Without people who think big, people that think small will likely end up dragging others down.
Besides, you don't have to stop constructing existing energy sources which can be used on starships and other stations.
For something as large as the Federation, even without replicators, they can easily scrounge up enough matter from nearby asteroids in massive quantities to do the trick.