Why would we need Earthlike planets?

In terms of colonizing other star systems, wouldn't small objects like asteroids, moons, and dwarf planets make more sense to develop, as their low escape velocities mean it would be easier to extract and launch resources in space to be used on-orbit?

A colony ship immediately investing all of their resources into trying to build a self sustaining civilization at the bottom of a deep gravity well would make progress difficult, as they'd have to spend much more effort trying to synthesize fuels in order to shuttle mass back and forth from surface to orbit and vice versa, as well as requiring much more complex and difficult to build rocket systems. By contrast, a colony ship using several asteroids or moons to gather resources would be able to use relatively simple propulsion technology and wouldn't have to spend much time producing propellant as not much would be needed by comparison.

We already know that every element we use on Earth can be found in much greater concentrations and in much larger quantities than here on Earth, so why wouldn't the case be the same for other solar systems?

Maybe trying to find and study Earthlike planets has little or nothing to do with eventual colonization efforts. Finding asteroid belts and other small objects is probably far more important.

Earth-like planets provide atmospheric pressure, radiation shielding, and would have water. Colonizing is about sending supplies for eventual self-sustain, not so much about launching supplies back.

I'm talking about supplies the colony ship would use in space. If a colony ship is large and industrially capable enough to last through the several hundred year transit, it would be silly to abandon it once you arrived in your target solar system. Such a generation ship would have radiation shielding built in so it wouldn't be an issue unless you went too close to a Jupiter-like planet's magnetic field or something. It makes way more sense to continue living on the ship, using it's industrial capability along with resources from small objects to build new habitats and machinery etc.

Eventually you would be able to set up a new industrial base on one of the planets or moons of the system, but until then you'd want to spend your limited time and energy to increase your ship's habitable area and resource stocks so that if something goes wrong on one of your surface colonies you aren't fucked.

Also water is one of the most common substances in the solar system, and is probably just as common elsewhere. Small icy moons in our own solar system easily have more water than the entire planet Earth.

Yes, small icy moons in our own solar system easily have more liquid water than the entire planet Earth. No additional energy is required to obtain that water. It is immediately safe to consume, too. We also have the R&D, currency, technology, industry, and cooperative ability to build and maintain such a generational ship to operate. It's not as if developing more robust launch systems would pave the way for more feasible, efficient means of transit from surface to orbit, let alone provide new techniques through said innovation.

I'm sure there are no good reasons you would want to take advantage of a planet with its own magnetic field, atmosphere, hydrosphere, solar cycle, and potential deposits of more fuel, and mineral resources, than you would know what to do with. It makes more sense to take the time to build habitable mega-structures using those resources, and fly them out some odd hundred light years away, just to build more.

Are you reading what I'm writing?

First of all, we're going to filter any water we come across either way. Secondly, solid water ice is pretty close to as pure as water can get in a natural form, since water ice crystals exclude salt and other impurities as they form.

Obviously we currently can't build a generational ship. My question is in the hypothetical case of interstellar colonization, which strategy makes more sense, immediately cutting yourself off from the available resources of the asteroids comets and other small objects in that system by dumping all of your efforts into colonizing a world that is somewhat more habitable than Mars, OR is it better to remain a mostly space-based civilization until the material resources and industrial capability become available to allow large scale colonization of planets with high gravity?

Easier means of getting into orbit are a meme. Space elevators are possible on worlds with lower gravity, on worlds with Earthlike gravity it may be impossible and is certainly infeasible. There is only so much energy that can be released per unit mass of reactants in a chemical rocket, and with NTRs you can't achieve the same level of thrust as a chemical rocket, which means you can't reach a TWR of greater than 1. Better chemical engines compared to modern tech are possible, but they're more complex and you probably wouldn't want to rely on them 100% if the outcome of them failing is possibly going to result in the eventual ending of your colonization effort and the eventual death of every colonist. That's why I mentioned simpler propulsion technology, like pressure fed engines, that are not only extremely reliable but can easily be used to build SSTO vehicles that work on small objects. It's all about risk-reward here.

Earthlike does not mean Earth-clone. Those things you mention would be useful but their effect would already be supplied by the ship, and ALL resources are more common in space than on Earth, as stated.

>Are you reading
Well...
>water is one of the most common substances in the solar system
>Small icy moons in our own solar system easily have more water than the entire planet Earth

No mention of how the water would be processed, regardless of what state it would be in.

>we're going to filter any water we come across either way
>solid water ice is pretty close to as pure as water can get in a natural form
I mean, you did just type that. Just exactly a few moments ago.

>what makes more sense
I feel like by the time we are capable of constructing the kinds of facilities, vehicles, and structures to be a space-based civilization, we will be more than capable of colonizing worlds that are on par with Earth, or less than equivalent to Earth. Just saying.

If you've developed a way of creating super-materials to make sure your super-habitat doesn't tear itself apart while it spins to simulate gravity, assuming it doesn't generate its own gravity somehow, then you probably have taken the long and hard road of creating a colony, plus learned the feats of engineering, physics, chemistry, aspects of biology necessary... which means you more than likely have the technology and know-how to set up shop on just about any planet, anyways. Hypothetically, sure. Bring on the space habitat. It does make sense.

And I know Earth-like does not mean Earth-clone, but since an Earth-like planet could or could not have anything an Earth-clone definitely does, it makes sense to suggest that we would aim for the most Earth-clone-like planet, if we had the luxury to do so. That probably means it at least has a hydrosphere, and a magnetic field equivalent to Earth's own magnetic field. Otherwise, why go?

And why not harvest asteroids? I never said you couldn't. I'm just suggesting that, all in all, the hypothetical super-habitat is an entirely different means for an entirely different end.

Yea it's likely not important to find earth like planets once you are offplanet & have mass industries building space habitats

Reaching orbit from Earth is not at all "hard", nor is the energy cost particularly massive. So thats not the problem.

It just makes more sense to take advantage of what already exists, than striving to fine-tune something of that scale, for that many people, to deal with things like the gene pool, psychological health, and other avenues of social behavior that can lead to "space-crazy". That is the extant risk and reward we face, probably for the next hundred years or so. Hypothetically, that can all be done.

If you try to approach it with the finest touch of realism, then it gets increasingly complex from our current point in time. Those are all tall orders. And, I doubt we'll be reaching a solar system 40 light years away in less than a hundred million years, let alone 70.

I mean.

An user said it before. The intent is not to be ferrying between two points. It is to stay there, explore, understand, and develop a foothold for further development. The risk and reward comes with having a large canvas of a surface area to develop upon, with said canvas being a raw deposit of resources already. Free gravity. Free shielding, maybe. Maybe a free atmosphere. Maybe a free climate. No real need to climb back to orbit once you've settled- again, if we're doing anything outside our solar system, we will probably have the technology to build a proto-super-habitat. That probably means the majority of things we think are problematic today, will be trivial "tomorrow".

We could definitely do it your way, with the habitat. It's a definite option. But it just seems unnecessary. It's a different solution for a different problem, prompted by the same question that people answer with "live on (insert planet here). I bet privatized companies will mine asteroids and ship them to Earth or another colony, but I doubt anyone will mine on a planet and decide to ship it somewhere else, than distribute it amongst the colony so it can prosper.

Doing stuff in bulk is easy
3d printing large habitats from raw materials will be easy
Shipping around large objects in space is far easier than on a planets surface

People might CHOOSE to live on a earthlike planet in other Solar Systems, but its unlikely that that would be the first thing you do when arriving there

If people are choosing to live on an Earth-like planet, aren't they making the decision to live there, already? If they aren't choosing to go, then they don't go. If you are sending someone far, far away, they know they may as well not be coming back. They might intend to research the planet- but they can also end up dying there. They may as well get comfortable, and have a place to poop, eat, and sleep.

>3d printing large habitats from raw materials will be easy
So, how are we powering these habitats? How are we powering these printers? Who's overseeing all of the logistics here? Quality control? Margin of error? How are we assembling these fabricated parts? Structural integrity? Materials used? Technologies involved? Contingency plans for certain failure scenarios, like venting atmosphere, loss of pressure, radiation leaks, faulty parts, etc? Stress tests?

User error?

I don't doubt that it would be easier to construct things in space. I don't doubt that shipping large objects in space is easier, too. But that would both go for the habitat, and the colony ship meant to put colonists on another planet. Both can be large objects, both could be assembled in space.

In all likelihood, we will have mined what is closest to us, and then sent a colony ship to some destination, with everything we would have thought it needed. That probably includes the means to mine celestial bodies that are not planets or stars, after arriving at their destination.

But I don't see us building a truly permanent space habitat before we attempt to colonize a planet. I really only see the permanent aspect of that habitat coming from trying to build on a terrestrial surface that isn't at all welcoming- because it is easier, for example, to have gravity generated by a relatively large mass, than attempt to carry out R&D with more moving parts that can all fail in varying ways.

How are you doing any of that stuff on a planets surface?
An atmosphere & a planet blocks most of the light coming from a sun, making solar power worse
An atmosphere causes stuff to rust/oxidize/wear away

Planets can be dangerous in regards to extreme weather, earth quakes, poisons, floods, etc
Easier to understand what extremes can occur in a space habitat, where all the problems will be known rather than unknown.

People also need to live where the work is. There is no magical need to live on a planet.

>How are you doing any of that stuff on a planets surface?
The same way you do most of that stuff on Earth.

>solar power
Okay, but that is solar power.

>An atmosphere causes stuff to rust/oxidize/wear away
Yep.

>extreme weather, earth quakes, poisons, floods
If we are flying outside of our solar system, then we will most likely know how to build habitats that can deal with the majority of those things. And, don't forget, we already live on Earth.

Earthquakes happen. Floods happen. Extreme weather happens. Poisons are present.

It may be easier to understand what extremes can occur in a space habitat, but the fact that you have to construct a space habitat adds new variables that you would need to control for. If this is still the hypothetical scenario, then it is no wonder you can build the habitat and have no problems.

It is hypothetical.

>There is no magical need
Yeah. I mean, I agree with you. We don't need to live on a planet. But, again... what is the goal here? To create a colony, or to live in a space habitat and travel for an untold amount of time?

Depends how solvable these low gravity health problems turn out to be.

IF it is a mirror of Earth, where you can immediately start growing food, mining deposits, accessing fresh water, living in the open, breathing the air, etc

Then yea they might go land there first thing.

But I think you'd be an idiot to imagine that any planet we find is going to be anything other than a sterile rock.
It was life that turned Earth into being habital for humans, so you are not going to find ANY empty world which has a 20% oxygen atmosphere.

>but the fact that you have to construct a space habitat adds new variables that you would need to control for.
It's simple variables like, find usable materials then produce habitats.
This is kinda what I mean, producing large habitats out of metals or carbon composites or w/e future material will be very low cost.
Basically a totally automated process.

Look at the low cost of manufacturing stuff today, that'll only get cheaper.

Uh...

>an idiot to imagine that any planet we find
>is going to be anything other than a sterile rock
Any planet? You mean, 100%, all other planets we could find are going to be sterile rocks? No phosphorous, no carbon deposits, nothing? Not even seas of methane? Just, sterile rocks? Just iron? No geological activity, no water deposits... nothing?

100%, no chances of anything else? Just sterile rocks, huh.

>you are not going to find ANY empty world which has a 20% oxygen atmosphere
If they're all sterile, that'd be the case. But, if you can build a super-habitat, why would you need to set foot on a planet with/out oxygen? Could you not just establish a base on the oxygen-less planet, introduce hydroponic plant life to the environment, or synthesize some oxygen from local compounds on the planet/excess resources from launch?

>large habitats of metals or carbon composites or w/e future material
Big things don't/can't move fast, just saying. That, and a totally automated process, while possible, is a little out of our reaches for the near future. Even if the cost of manufacturing goes down, it does not change that you are going to, or are trying to, build a super-structure. Again, by the time we even approach that stage... it will be more cost effective to simply live on the planet. It's what I'm trying to put across; going from today, to living in a super-habitat is absurd, it's skipping a lot of steps. Unless, of course, we're content with staying on Earth for however long it would take to get to the super-habitat stage, right?

Think about how expensive the ISS is right now to operate. Think cheaper means of this- assuming the cost doesn't actually go up for reasons like politics or economy. Now think about the hypothetical super-habitat meant to travel interstellar distances. A really big thing. Meant to keep a lot of people alive. Meant to be self-sufficient, to be self-correcting, to be foolproof enough that a mere mishap won't kill everyone.

>ster·ile
>2. free from bacteria or other living microorganisms; totally clean.
>"a sterile needle and syringes"

>That, and a totally automated process, while possible, is a little out of our reaches for the near future.
Meanwhile we're talking about colony ships being launched to other solar systems before anyone has even left this planet
Look at how much shit has changed over the last 100 years, how the % of people involved in primary & secondary industries has collapsed. Expect that to continue.

>it will be more cost effective to simply live on the planet.
But where is the WORK in the solar system being done? Where are the industries? Still in the ship you travelled with?
So how can these people go live on the planet, when they are needed to do work throughout the solar system.

Yes, user. Sterile. You are saying that, 100%, all other planets we will find, will be sterile. Correct?

>Meanwhile we're talking about colony ships
Woah, slow down there. Do you mind showing me exactly where I've said that we can, are, could, or should send colony ships right now, today? I don't remember that.

>Look at how much shit has changed
Things may have changed in the last 100 years, but you better be a trend analyst, because otherwise that claim doesn't mean much. Just as things have changed in the last 100 years, so changes the things that we deal with, day by day, involving those things that have changed. For example, assembly lines and manual labor. There used to be no assembly lines, and tons of manual labor. Now, there are assembly lines, and sometimes little manual labor. Still, now, there exists a demand for specialist to better operate those assembly lines.

>But where is the WORK in the solar system being done?
Probably in the asteroid belt. Or, in a lunar orbit. Maybe on Mars. Maybe, on Earth. There are industries on Earth, already, remember that. If you're constructing something with the intent of staying at another location, it would make more sense to access what you can easily access, and then take that with you.

It would be the same as building the habitat. You're putting everything into this super-structure, people included, and seeing it off. With respect to a colony ship, this structure probably isn't meant to be disassembled, land, or become several other modules. A colony ship, however, is most likely intended to land on the planet, or deliver the cargo and personnel to the planet. Seeing as how you might be going with what you take with you, and that alone, under the sentiment of self-sufficiency, I imagine you would want to put as much raw materials on that cargo list as possible, and then salvage the entire ship once you are on the planet- permanently.

The work is done first. The people are sent with the finished/fabricated products, later. It all goes in one- there is no constructing more landers, pods, or anything else mid-flight. Industry is established using what has already been given to you- remember how you mentioned that you could 3d print parts of the habitat out in space?

I imagine you would be traveling with the machines capable of mining, processing, and fabricating anything you expected you could, on the planet, after you settle. The industry would be established once you establish a basic habitat on the surface. They go to work, because when they arrive, they have the tools on them already. The tools to make more tools, too.

>Woah, slow down there. Do you mind showing me exactly where I've said that we can, are, could, or should send colony ships right now, today?

The very first sentence of the first post in this thread

>You are saying that, 100%, all other planets we will find, will be sterile.
I'd say, unless there is bacteria or some form of life found on other worlds in this solar system, you can safely assume there will be none found in any nearby systems.

>Now, there are assembly lines, and sometimes little manual labor.
There is still large amounts of manual labor involved which looks like it will disappear in the next 20 years
Deep learning AI's will change a lot, automated forklifts/truck driving/taxi's/etc will change a lot.
When we finally have machines that can replicate human hand motions, and in real time "see" things, most human labor needed will disappear. This is something that we can anticipate in 50~ years.

>I imagine you would want to put as much raw materials on that cargo list as possible, and then salvage the entire ship once you are on the planet- permanently.

I can't imagine why you would do it that way, you are going to want to bring as much machinery/computing power as possible, not raw materials.
Then you would be mining easily accessed resources, which ISN'T going to be on a planet.

>The very first
That wasn't my post, though.

>I can't imagine
Well, if you're operating a colony ship in the near future, and you suggest that autonomous systems will increase in their capacity exponentially by then, then it should be assumed that on such a ship, there is already a large presence of machinery and computing power.

>The people are sent with the finished/fabricated products, later
>I imagine you would be traveling with the machines capable of mining, processing, and fabricating anything you expected you could
>because when they arrive, they have the tools on them already
That is what I have outlined in this post. You go with those things- not just stockpiles of raw material, but with stockpiles of raw material.

Besides, if a planet is sterile, why wouldn't there be surface deposits of resources on the planet to begin with? Nobody is saying that you cannot mine the asteroid belt before you send your colonists on your way. But, I don't see why you're so against accessing resources that might exist on or within the planet/s, besides the fact that it is easier to build in space, or that you can just scoop asteroids up for processing. Resource deposits on planets? They can be there, and truth be told, if they are there, they would require less effort to mine if you are at the technological point where mass fabrication and reactive systems are the norm.

Seriously. If there's a planet with no microbial life, but deposits of oxygen, the oxygen is either going to be in its bodies of water, or exist as a rust/oxide of some element. Most likely, iron oxide. If that's the case, then it also means that there exists iron exposed somewhere on the surface.

And you could identify that in an instant.

I don't see your objections to the thought of a large habitat ship capable of housing its own industry and life support etc. as valid because in the original post I posit those factors are hypothetical, as things to be taken for granted as already existing in this thought experiment. We are exploring what it would mean for colonization given X factors, not debating whether those given factors exist.

No generation ship would be capable of landing on the surface of a planet, that's absurd. We're talking something that is a minimum of several kilometers in length, with massive and complex propulsion systems and huge enclosed spaces meant to mimic nature. Such a vehicle would probably not be able to even orbit close (within several thousand kilometers) to large planets, as the tidal forces alone could be enough to cause undue stresses.

My argument is that in a scenario in which humanity can design, build, and operate these massive generation ships, and use them to colonize other star systems, it would be both far easier and more sensible to utilize the massive amounts of resources that can be found on asteroids, comets, and other small objects, in order to expand the finger-hold in that target star system into a handhold. That would take the form of mining ices, metals, and carbon compounds from various asteroids and other objects, refining those materials and using the products to produce more large space habitats and vehicles. Those vehicles would then be able to use the generation ship as a home base while shuttling back and forth between many colonies on many worlds.

Thus, the entire system would be colonized at once, producing a large space-based civilization from the beginning, rather than focusing 100% of the effort on several colonies on one planet at the bottom of a deep gravity well, hampering the ability of that civilization to spread beyond that one planet into the star system at large.

Note, they key words of this post are;

"Why would we ***NEED*** Earthlike planets?"

That is to say, DO we need Earthlike planets in order to colonize a different star system, would Earthlike planets even be a benefit beyond living space, why would a space based civilization limit itself to just one planet upon attempting to colonize an entire new star system, etc?

The point of a colony is that it's permanent. You can't permanently live on an astroid because of the lack of gravity and resources. However I do agree that we should start by colonizing smaller objects like the moon. Because of the lower gravity, studies show that a space elevator could be possible with current technology. This would greatly aid in colonization efforts.

nothing is permanent tho

Some things are more permanent than others.

>I don't see your objections to
>as valid because
>I posit those factors are hypothetical
>as things to be taken for granted

Okay. Can we take for granted that 9/10 things on a planet are Earth-like? Can we explore what that would mean for colonization given those factors?

If we're not debating whether those factors exist:
>I think you'd be an idiot to imagine that any planet we find is going to be anything other than a sterile rock
The previously established hypothetical nature of the topic suddenly wasn't so hypothetical here.
>w/e future material will be very low cost
Here.
>totally automated process
Here.
>Look at the low cost of manufacturing stuff today
Here.
>Look at how much shit has changed over the last 100 years
>Expect that to continue
Here.
>unless there is bacteria or some form of life found on other worlds in this solar system
>you can safely assume there will be none found in any nearby systems
Here.

This is why I replied in kind with regards to whether factors existed or not.

I know we're talking about a very large craft:
>make sure your super-habitat doesn't tear itself apart while it spins to
>Bring on the space habitat
>Hypothetically, that can all be done
>Hypothetically
>that can all be done

>It's all about risk-reward here.

So let's break it down. This is a hypothetical scenario. Since it is hypothetical, and things are being taken for granted, where is the risk? There's only reward.

Everything works. Everything is solved in a hypothetical scenario where only the most ideal things occur. What does it matter that we can't build a generational ship, unless we're going to get into the practicality of building one, not taking the possible risks and rewards for granted?
>Obviously we currently can't build a generational ship
>Easier means of getting into orbit are a meme

The fairly unregistrable sarcasm in my first reply was an attempt to show my disdain with discussing a hypothetical scenario that asks for answers to questions that involve factors which are pertinent to us.

I played along, but now this is absurd. Your argument, is that in a scenario in which humanity has the capacity to bring forth these generation ships with the intent for colonization, it would be easier and sensible to use the abundant resources floating freely in space- it would be easier to secure all the material in the local solar system before focusing on planetary footholds, keeping the generation ship as a primary base of operations, a hub of sorts, a home base. That is what you are telling me.

And I agree. It would be. And that's the end of it. That is exactly the case, given the above. It makes sense. It works.

But given
where it says
>Why would we need Earthlike planets
it asks for the answer to the question
>Why would we need Earthlike planets
full stop. Given the comment
>Maybe trying to find and study Earthlike planets has little or nothing to do with eventual colonization efforts
>colonization efforts
>Earthlike planets
>find and study
it is now asking the question
>Why would we need to study, find, or colonize Earthlike planets
and, you know what?

I have provided ample enough responses as to why we would need to colonize Earth-like planets, both hypothetically, and realistically. Hypothetically, it is being said that we now magically have the capacity to build megastructures, have full details of a hypothetical solar system, have ideal conditions for operation of the megastructure, have relatively complex technology to power it, abundant resources, top-notch logistics efforts, everything is a given. Even building a base not of the megastructure, perhaps on an asteroid or even a planet, is a given.

Realistically? Even slightly, assuming everything else? We are not going to go from a rock to a laser. We can not afford to make mistakes, and mistakes are a possibility. We do not currently have the technology, and if we did, we would need to test it somewhere. And then there exists more potential for mistakes.

And all of this costs us resources and currency, because of our state of affairs regarding nations, economy, and society. Politics killed space exploration once before. Plainly, the answer to the question
>Why would we need Earthlike planets
as it pertains to
>trying to find and study Earthlike planets
is because it is more efficient, perhaps not necessarily effective, to take advantage of what is already there, than construct everything from scratch. Actual small steps.

Otherwise, the answer to that question is whatever you would like it to be.

we're not going to need earthlike planets until this one is about to kick the bucket. That's exactly how we handle shit.

I don't think we'd need an Earth-like planet at all.

Either we will be someday capable of building large space habitats (because there is no other realistic way of traversing the massive amount of space between stars) and thus not require an earth-like planet to survive OR we will simply never traverse to other star systems at all.