Mars or venus?

[HebaruSan]

5 hours ago, mikegarrison said:

Science has taught us that no complex organism we have any evidence of has ever had a species lifetime of billions of years.

Science has also taught us that biological reproduction can continue in an unbroken chain for billions of years; speciation happens, but why should that make us care less about our descendants than we would if they remained indistinguishable from us?

[kerbiloid]

2 hours ago, HebaruSan said:

if they remained indistinguishable from us

Unlikely, unless they degenerate into monocellulars.

P.S.
Also, can you imagine TV series a billion years long?

Edited October 13, 2017 by kerbiloid

[Green Baron]

7 hours ago, HebaruSan said:

Science has also taught us that biological reproduction can continue in an unbroken chain for billions of years; speciation happens, but why should that make us care less about our descendants than we would if they remained indistinguishable from us?

Only a few species last longer than a few 10s or hundred thousands of years under ideal circumstances, in principle they (we) are under constant change. Our problem is our attention span. And the (culturally induced) imagination that a development has a direction that leads to something better than before, which is not the case.

Edited October 13, 2017 by Green Baron

[Green Baron]

11 hours ago, mikegarrison said:

There is a difference between "space" and "fantasy".

Fantasies have their place, but it's useful to keep science and fantasy distinct. Science has taught us that no complex organism we have any evidence of has ever had a species lifetime of billions of years.

I only have one like per post :-)

The oldest individuals we found so far are several sub-species of trees with an exceptionally slow metabolism, and they have thousands of years (<10.000). Clonal colonies might get older, but they don't "develop".

Edited October 13, 2017 by Green Baron

[mikegarrison]

Unless they get it slammed in their face (through illness, danger, or old age), most humans don't like to really think that they themselves will die. And many of them are convinced that some part of them will live forever, or be reincarnated, or some such thing. We *really* don't like to imagine that someday all humans will be gone. And most likely it won't be because we evolved to some "higher form", but because of either just bad luck and/or environmental changes. If you think of all the dinosaur species that roamed the Earth, how many of them left direct descendants? Probably only one, really -- whichever one was the parent to all the birds.

Every other hominid species died out already. Humanity has made a pretty spectacular mark on the planet, but all-in-all we haven't lived a long time yet as a species. And I'm not entirely sure we can survive the global climate change we seem to be driving right now. Most of the mass extinctions in the Earth's past have been driven by climate changes not much bigger than the one we are in the middle of creating.

So yeah, maybe 1000 years from now there will be humans living on a terraformed Mars or even in other solar systems. Or maybe there will be no humans at all.

[kerbiloid]

1 hour ago, mikegarrison said:

environmental changes

A sapient species changes the environment, rather than changes itself. Caves, houses, fire, tools, skins, synthetic fertilizers, hydroponics, computers, nuclear energy, so on.

Self-sufficient colonies spreaded around would require a really intergalactic catastrophe to shut them down at once.
And such catastrophes look more or less rare and far. Even the closest big galaxy to collide we have to wait for several hundred million years.

1 hour ago, mikegarrison said:

If you think of all the dinosaur species that roamed the Earth, how many of them left direct descendants? Probably only one, really -- whichever one was the parent to all the birds.

Humans are that one for monkeys. And rather than dinos they have much more survival tools.

1 hour ago, mikegarrison said:

Every other hominid species died out already.

Yeah, we helped them a little.
Also those losers poor things were weak in cognitive aspects.

1 hour ago, mikegarrison said:

Humanity has made a pretty spectacular mark on the planet

7 000 000 000 units ~70 kg each is not just a spectacular mark.
It's a natural final form of organic matter self-organization, a precursor for non-biological form of mind.

[magnemoe]

On 11.10.2017 at 7:10 PM, MatterBeam said:

Orbital habitats are the simplest. They provide the best living conditions. However, they cost the most to produce and need to import everything they consume. 
The Moon is the easiest to develop and build on due to its proximity to Earth. It lacks many vital resources, such as large quantities of water or carbon, and the 1/6th gravity can mean very bad things for long term health of adults and the development of children. 
Mars fares better in terms of living conditions. A bit less than half gravity might not be so bad, and it has a lot of water and CO2 that is just a bit difficult to extract or collect. Bonus points for lots of iron and minerals in the soil to grow plants on. Energy will be expensive however.
Venus provides excellent living conditions at much lower cost than orbital habitats, but still needs to import a lot of resources. Energy from sunlight is more available and a thick atmosphere makes importing resources slightly cheaper. 

Make sense for what? Supporting a population or making money? Requiring the least amount of money to explore or having the best long term prospects. It is also dangerous to mix up terraforming with colonization. People who moved into the Siberian tundra adapted their equipment, homes and lifestyle instead of not bothering with the land because melting all the ice is very difficult. 

You need an reason to go, science is an obvious one, economic is another, economic does not require earning money but can simply imply getting more science for the amount of money used. 
Now you might also want to colonize to mark the land as yours, this might be relevant for Shackleton crater rim on Mooon south pole, you might also want an base for prestige. 

Take an permanent Mars base, if you could use this for exploring Mars it would be far more efficient than doing many short term Mars missions. 
I don't see an city on Mars as very realistic an research station on the other hand is, its mostly an cost issue. 

An Moon base has much of the same benefits, add that you can probably export resources to Earth orbit and its easy to resupply or evacuate in an emergency. 
Downside is weaker gravity, less resources and less interesting. 

An habitat in Earth orbit has to get everything however it would also be in the most economical useful position for space based operations. 

Venus, yes it has the benefit of an shielding atmosphere and almost 1g, however you could get this in an simple orbital station also and way less complicated. 
Main weakness with an floating colony is getting back into orbit, this require almost the same as on earth, however from an floating platform without earth infrastructure. 
Just trying to launch and recover an rocket larger than falcon heavy on top of an balloon is interesting, more so with the strong winds. 
Testing this on Earth would be fun, 
 

[Green Baron]

8 minutes ago, kerbiloid said:

A sapient species changes the environment, rather than changes itself. Caves, houses, fire, tools, skins, synthetic fertilizers, hydroponics, computers, nuclear energy, so on.

It changes first and foremost itself e. g. through self-domestication or avoiding natural selection through technology. Global/endangering environmental changes are secondary effects, in our case they became clearly visible some 20 years ago.

8 minutes ago, kerbiloid said:

Self-sufficient colonies spreaded around would require a really intergalactic catastrophe to shut them down at once.

An "intergalactic catastrophe" ? What would that be ? Even if we colonize Mars or whatever we were still under the same astronomic risks than we are on earth. With the difference that our natural environment is missing, which doesn't exactly sound reassuring. There is no retreat if something goes wrong. Self sufficient colonies are fantasies.

8 minutes ago, kerbiloid said:

And such catastrophes look more or less rare and far. Even the closest big galaxy to collide we have to wait for several hundred million years.

If you refer to the "imminent" collision between Milky Way and Andromeda that is not a cataclysm of sorts. It's more like gases mixing.

8 minutes ago, kerbiloid said:

Humans are that one for monkeys. And rather than dinos they have much more survival tools.

I fear our tools are just an illusion and many can only exist (and be affordable) because we have a worldwide economic network. Set us back to e.g. late medieval times and things already look much different. The earth would not be able to support 7 billion people then and plagues or wars over resources would decimate us (did decimate them).

 

8 minutes ago, kerbiloid said:

7 000 000 000 units ~70 kg each is not just a spectacular mark.
It's a natural final form of organic matter self-organization, a precursor for non-biological form of mind.

May i ask what you mean with that ?

[kerbiloid]

56 minutes ago, Green Baron said:

It changes first and foremost itself e. g. through self-domestication or avoiding natural selection through technology.

A non-sapient being grows an additional fur or a thicker skin.
A sapient being covers itself with those from the previous one.
Polar and equatorial people are more or less the same, rather than deers or elephants. Fur coats and cotton shirts make them more or less interchangeable.
Humans have "appeared" with small teeth, without fur, but with an axe and spear in hands, sitting near the fire, wearing skin or grass coats. Just because all these things were invented much earlier than the human species became enough sapient to know itself.

56 minutes ago, Green Baron said:

An "intergalactic catastrophe" ? What would that be ? Even if we colonize Mars or whatever we were still under the same astronomic risks than we are on earth.

If/when a lifetime/velocity allow to spread around even in a thousand ly radius, even a hypernova can't take them out. Something more serious will be required.
Especially if they also spread inside the planets/asteroids/DeathStars, not just outside. Not much things can penetrate even 1 km thick cap.
Of course, this is impossible for nowadays natural biohumans, but this is not a question of the closest century.

56 minutes ago, Green Baron said:

Self sufficient colonies are fantasies.

We are living in one of them (natural). Size Scale matters.

56 minutes ago, Green Baron said:

If you refer to the "imminent" collision between Milky Way and Andromeda that is not a cataclysm of sorts. It's more like gases mixing.

I wouldn't be so sure about Milky and Andromeda collision harmlessness, though, as we are sitting in the most safe place of the Galaxy, far from natural radiation sources, and the galactic collision will shuffle the cards.
Of course, unlikely something will collide with the Sun or the Earth, but we easily can get a stray bullet giant or pulsar passing by somewhere beyond the Pluto. This could be enough for the Earth life, too.
(Of, course, this is a joke. The Earth will become a dead _literally end even earlier, due to the Sun extension.)

56 minutes ago, Green Baron said:

The earth would not be able to support 7 billion people then and plagues or wars over resources would decimate us (did decimate them).

If put 7 bln into water or fire things will be even worse, but why do this.
Can you name another macroorganism species (tens kg or bigger) whose amount is 7 bln pieces?
I can remember only sheeps+goats together. (20 or so).
Can you name species of this size living for ~70 years? Elephants, chimps, humans, rare turtles. If not of this size - also some fishes and parrots.

Compare total human biomass to the total biomass of the Earth (say,  https://en.wikipedia.org/wiki/Biomass_(ecology) ). Earthworms, fishes and cyanobacteria weight more.
By the time the terrestrial biomass originally represented only by microscopic algae and bacteria, has been concentrated into multicellular bodies as long-lasting, stable, and self-reproducing systems where it has best chances to keep intact and self-reproduce. And the human bodies are most numerous, lomg-lasting and stable between them, weighting ~0.5 billion t in total.

As probably (I'm sure, inevitably) the human society will keep evolving into an animal-technology symbiosis, while the wild nature will keep being supressed by humans more and more, unlikely there will appear another sapient species on the Earth before the human-technology symbiosis achieves the full indivisibility when the second ("artificial") component will get prevailing.

 

Edited October 13, 2017 by kerbiloid

[tater]

Self-sufficient colonies are not a fantasy, they are just a very distant prospect. Self-sufficient being defined solely as not requiring input from Earth. Orbital habitats could harvest objects for required materials (asteroids, comets, etc). When something like this could happen is another matter---put it way out there, time wise, well past any reasonable prediction horizon.

[Green Baron]

 

1 hour ago, tater said:

When something like this could happen is another matter---put it way out there, time wise, well past any reasonable prediction horizon.

I'd call that a fantasy :-)

Though i doubt it'll ever happen. Too many unsolved problems here on earth.

[tater]

5 minutes ago, Green Baron said:

 

I'd call that a fantasy :-)

Though i doubt it'll ever happen. Too many unsolved problems here on earth.

I'd define fantasy as impossible. Magical elves are fantasy. Anything not forbidden by physics is possible.

[Green Baron]

I'm looking forward to the first crew who made it to Mars, stayed there a while and made it home again not being half dead.

Though i might not live up to see it, being a little older than half a century ;-)

[magnemoe]

2 hours ago, tater said:

Self-sufficient colonies are not a fantasy, they are just a very distant prospect. Self-sufficient being defined solely as not requiring input from Earth. Orbital habitats could harvest objects for required materials (asteroids, comets, etc). When something like this could happen is another matter---put it way out there, time wise, well past any reasonable prediction horizon.

How do you define self sufficient? producing +90% of their own food? that one is pretty doable and pretty necessary on an large permanent Mars base. 
Don't need any supplies from Earth to  survive long term, forget it, you would need so many specialized parts just for space suits and without them you can not go outside to repair base. 
And no 3d printers will not help you much here. 

[tater]

6 minutes ago, magnemoe said:

How do you define self sufficient? producing +90% of their own food? that one is pretty doable and pretty necessary on an large permanent Mars base. 

Don't need any supplies from Earth to  survive long term, forget it, you would need so many specialized parts just for space suits and without them you can not go outside to repair base. 
And no 3d printers will not help you much here. 

Self-sufficient means they require nothing from Earth at all. Ever. That seems self-evident.

Anything short of that is not self-sufficient. 

Any attempt at anything short of that is not really colonization, IMO. That's why I say it's possible, but very distant in time.

[daniel l.]

Well.

If I want to live in the clouds on a giant pool floaty. Then Venus.

If I want solid ground beneath my feet and not have to worry about falling out the window to a terrible death. Then Mars.

[DAL59]

The self-sufficiency(on Mars, at least) could actually be achieved in a few years, especially considering advances in 3-d printing and robotics.  Water is easily obtained through underground glaciers, oxygen through water, the soil has been proven to grow food, the soil could be made into bricks, and if there were missing metals, there are 2 asteroid moons.  

Venus would likely never become self sufficient, though it would be good for agriculture.       

[DAL59]

n:

	Earth (equatorial)	Mars (median /  Curiosity)	Moon (equatorial)	Small solar system bodies	Venus (54.5km, 70° latitude)
Gravity (g)	1	0.38	0.17	Very low	0.9
Air pressure (atm)	1	0.006	0	0	0.5
Day temp. (avg., °C)	25	-40	-25	Usually low	25
Diurnal variation (°C)	8-15	90	300	Very high	15
Day length (h)	24	24.5	336	Widely varied	48
Local mobility	Moderate	Low	Low	High	High
Radiation shielding, meters of water mass equivalent	10.3	0.06	0	0	5.3
Magnetic field	25-65 μT, intrinsic	Weak, induced; 20-40 nT MPR, 5-20nT magnetosheath	None	None	Weak, induced; 40-80 nT MPR, 10-40nT magnetosheath
Health hazards	Those which humans evolved to	Fine, abrasive dust / silicosis; perchlorates; chromium(VI)	Highly abrasive dust /  silicosis	Highly abrasive dust / silicosis	Corrosive acid mists; numerous known and theorized chemicals
Other local hazards	Those which humans evolved to	Marsquakes; landslides; dust storms; solar storms. Others?	Moonquakes; landslides; solar storms. Others?	Solar storms. Outgassing? Landslides? Poorly quantified.	Lightning? Gusts / shear? Icing? Storms? Limited data.
Planetary protection	Not applicable	Category IV	Category II	Category I to II	Category II
Delta-V to destination, from LEO (km/s)	0	4.5	6.1	As low as 3.8, but usually well more	3.5
Delta-V to LEO (km/s)	10.1	5.9	5.6	Low to extremely low	11.8
Transit time (mo)	0	9	0.1	Widely varied	5
Launch window frequency (mo)	0	25	Several days per month	Widely varied	19
Aerobraking	Available	Available	Absent	Absent	Available
Parachute decel.	Significant	Limited	Absent	Absent	Significant
Surface hazards	Present	Present	Present	Present	Not approached
Peak solar energy (29% triple junction W/m²)	290	~50, up to 129; sometimes almost none	400 (but two weeks w/o light)	Widely varied	500
Wind energy resources	Moderate	Effectively none	None	None	High (tethered turbine)
Diversity of resources	Baseline	Probably moderate to low	Probably low	Low	Probably high, but arid
Valuable resources	Moderate	Probably moderate to low	Moderate to low	High	Probably high
Accessibility of resources	Moderate	Moderate	Moderate	High but hindered by microgravity	High atmospheric, low surface

Details of the above graphic can be found in Rethinking Our Sister Planet: A Handbook For The Development Of Venus, ch. 1.

[magnemoe]

We can sum Mars, Moon, asteroids up to: Launch BFR or system of similar capability cheaply from Earth,  refuel in orbit, have ISRU on location and return to Earth.  

Venus add an complication: you have to launch BFR and the full stack not only upper stage, and land both first and upper stage on top of an balloon. The balloon would also need facilities for maintaining the first stage. You also have to launch refueling missions. 

Scaling the return system down would require disposable cargo missions, who would drive cost up a lot. 
Can some Venus fans give data for the balloon needed? 

[kerbiloid]

8 hours ago, DAL59 said:

48

Venus day length is 48 h long?

[Bill Phil]

18 minutes ago, kerbiloid said:

Venus day length is 48 h long?

At a specific altitude and latitude. The winds on Venus are pretty quick, and so you could presumably circumnavigate the planet in a dirigible in 48 hours, maybe even less.