If we'd had another habitable world in our system...

[Udat]

^ Such an interesting point, but I highly doubt an alien planet virus would hold any threat to us a-little like animal diseases hold little or no threat to humans. Granted there would be exceptions.

As for food, surely proteins and carbohydrates etc are going to be the same from planet to planet? I suppose that all depends on the planets atomsphere!

Loving this thread.

 

[STR]

The practicalities involved will probably mean that it will have to be a joint venture between nations.

Space travel isn't that much more expensive than some large scale private projects such as aircraft manufacturing or mining. The reason why governments have to join up to build a space station is because no individual country is willing to spend the money on its own for something that may or may not EVER provide ANYTHING of enough useful value to offset the cost of the thing. Same with other speculative research ventures like ITER.

Now, add an actual NEED to go someplace in space, and you'll quickly see private industry do what it does best: supply a demand. What would be the primary demand of a habitable Venus? Freedom. Economic, or political, being 20 million miles from earth gives you liberties you don't have here. The liberty to build an empire, or just a home where you're not underfoot. We're talking about the Wild West x100,000. Being habitable and having resources just lowers the cost of that freedom.

Therefore, the primary cargo of a dual-planet economy would be people, and until they could be manufactured locally, complex equipment and tooling.

So you have a demand (get the @#$^ off this rock) and and ability to supply it (space travel). You then need ten billion dollars (the cost of the 787 R&D program, or a new world-clase mine, or a silicon fab) to seed your project. The first one to launch probably would get government assistance, either in the form of direct investment or loan guarantees, but once you have one successful firm, others will follow.

Don't mistake government lack of will for human lack of ability. $1trillion worth of investments change hands daily. Once space manages to sustain itself, it will get access to that vast system.

 

[Nerys Ghemor]

I was thinking about the idea of exploring another habitable world when I saw this thread title and without suits its impossible/highly dangerous even if any such planet is Earth like. Our immune systems for example would probably be torn to shreads by alien bacteria/viruses.

Could we adpat and if so how long would a colony of people need to live there for ?

Perhaps it would take alien diseases awhile to adapt to us. In a case like that, we might even be able to find the most likely diseases and come up with preventive immunizations. Samples could perhaps be brought back either to Earth in a quarantined area, or to a space station that could be used as a quarantined area for analysis.

 

[Finn]

How close would it be to Earth? I always wondered what it would be like if Earth had a huge moon that was inhabitable.

 

[Nerys Ghemor]

How close would it be to Earth? I always wondered what it would be like if Earth had a huge moon that was inhabitable.

That part I don't know. The story I am writing does not necessarily involve our solar system, so all options are open. Just the stages of technological development are what I'm looking at--whether humans or aliens of the week do it.

 

[Myasishchev]

I was thinking about the idea of exploring another habitable world when I saw this thread title and without suits its impossible/highly dangerous even if any such planet is Earth like. Our immune systems for example would probably be torn to shreads by alien bacteria/viruses.

Could we adpat and if so how long would a colony of people need to live there for ?

Perhaps it would take alien diseases awhile to adapt to us.

Yes. Alien viruses are less of a threat to human habitation than, say, archaea viruses. Bacteria may be problematic, but perhaps less so than the strains already subject to a systematic campaign of destruction carried out by a scientific, intelligent eukaryote.

All this assuming identical chirality, as Great Mambo Chicken mentioned, which would make us both immune and the biosphere in question worthless. I don't know where he's getting the idea that obligate, species-tuned parasites like viruses are capable of rapidly jumping domains* like a New York subway turnstile. Maybe I'm wrong about that, but it seems unlikely.

As for technology that could detect life? Equipment capable of determining the chemical composition of a nearby planet's atmosphere would work. O2 content equals life, because there is no significant mechanism (that I am aware of) to sustain a molecular oxygen atmosphere except photosynthesis. Likewise, aerobic life will also probably exist where there's photosynthesis, because of the O2 toxicity problem.

F2 and Cl2-heavy atmospheres would lend themselves to the same analysis, but they're unlikely for a number of reasons, and you wouldn't want to visit anyway.

Also, in the case of an Earthlike world, you could just have a sufficiently powerful telescope and look at the clouds and oceans and vegetation deposits (possibly green, maybe black or red, iirc green has more to do with our sun's specific emission curve).

*Domains isn't really the right word. I looked this up the other I couldn't find anything relating to an astrobiological taxonomical system, that would have a classification to differentiate between life from two separate planets and no phylogenetic relationship. I personally like "oikumene."

 

[Myasishchev]

I was thinking about the idea of exploring another habitable world when I saw this thread title and without suits its impossible/highly dangerous even if any such planet is Earth like. Our immune systems for example would probably be torn to shreads by alien bacteria/viruses.

Could we adpat and if so how long would a colony of people need to live there for ?

Perhaps it would take alien diseases awhile to adapt to us.

Yes. Alien viruses are less of a threat to human habitation than, say, archaea viruses. Bacteria may be problematic, but perhaps less so than the strains subject to a systematic campaign of destruction carried out by a scientific, intelligent eukaryote.

All this assuming identical chirality, as Great Mambo Chicken mentioned. I don't know where they're getting the idea that obligate, species-tuned parasites like viruses are capable of rapidly jumping domains* like a New York subway turnstile. Maybe I'm wrong about that, but it seems unlikely to me.

As for food, surely proteins and carbohydrates etc are going to be the same from planet to planet?

Nope, unless there's a particular adaptive reason we use right (or is it left?) handed proteins. Which there may be. From the Mighty Wiki:

The origin of this homochirality in biology is the subject of much debate.[10] Most scientists believe that Earth life's "choice" of chirality was purely random, and that if carbon-based life forms exist elsewhere in the universe, their chemistry could theoretically have opposite chirality. However, there is some suggestion that early amino acids could have formed in comet dust. In this case, circularly polarised radiation (which makes up 17% of stellar radiation) could have caused the selective destruction of one chirality of amino acids, leading to a selection bias which ultimately resulted in all life on Earth being homochiral.[11]

So maybe two biospheres in the same planetary system would still have a high likelihood of being homochiral. Neat.

Anyway, as for technology that could detect life? Equipment capable of determining the chemical composition of a nearby planet's atmosphere would work. O2 content equals life, because there is no significant mechanism (that I am aware of) to sustain a molecular oxygen atmosphere except photosynthesis. Likewise, aerobic life will also probably exist where there's photosynthesis, because of the O2 toxicity problem.

F2 and Cl2-heavy atmospheres would lend themselves to the same analysis, but they're unlikely for a number of reasons, and you wouldn't want to visit anyway.

Also, in the case of an Earthlike world, you could just have a sufficiently powerful telescope and look at the clouds and oceans and vegetation deposits (possibly green, maybe black or red, iirc green has more to do with our sun's specific emission curve).

*Domains isn't really the right word. I looked this up the other day and I couldn't find anything relating to an astrobiological taxonomical system, that would have a classification to differentiate between life systems from two separate planets and no phylogenetic relationship. I personally like "oikumene."

 

[Kain]

There might be some other habitable worlds in our Solar system. Europa has a very high possibility of harbouring life underwater, and there could also be some kind of life on Titan.

So I suppose that we refer to a celestial body closer to us, like Venus or Mars.

My guess is that if there was another habitable planet close to us, we would have proved it by the 50's-60's with our telescopes, and we would have gone there after the Apollo missions. Since we would have known there is a very high possibility of life there, and the planet was very close to us, we would probably be extremely interested in it, and even the governments would not resist to send people there. Because of that, our technology might also have been a bit more advanced by now, since we would have forced our scientists to develop it sooner to go to this planet.

 

[JarodRussell]

Even Galileo would have already been able to see that there's green and blue on Mars.

 

[Nerys Ghemor]

Does anyone have any images that show what Galileo could've seen in his time? I'd be very interested to see that.

I'm not totally sure that even a habitable planet would necessarily have green plants or be quite far enough along for our kind of plants. Could another kind of lifeform photosynthesize or even create oxygen, like bacteria or fungi? If we saw something like that--blue and...something else, instead of something exactly like our world, how long would it take to figure out what we were looking at, that the atmosphere could be breathable and that temperatures might be within range?

 

[Christopher]

There's no reason alien plants would have to be green. In fact, it's kind of odd that Earthly plant life is green, because it's reflecting away the brightest part of the Sun's spectrum. (We think of it as a yellow star because of the way our eyes process color, but technically Sol's peak wavelength is in the green part of the spectrum.) The thing is, the first photosynthetic algae that evolved were red or purple, meaning they absorbed yellow and green, the brightest part of the Solar spectrum, while reflecting red and violet. The algae living beneath them in ponds were stuck with the leftover red and violet light that passed through those other algae, and so they developed a green pigment to absorb it. And somehow, the green plants managed to outcompete the red/purple plants and take over the planet. But it could've gone differently. We could've just as easily evolved on a planet where the vegetation was purple. And you could find a wide range of plant colors on other planets.

 

[Allyn Gibson]

I wonder, if we had determined in 1970 say that Venus or Mars was habitable, would it have made a difference to the space programmes of various nations?

Harry Turtledove's novel A World of Difference explores that premise. The Viking probes land on Mars in 1976, and a native Martian is photographed on the surface. This leads to a manned mission to Mars (in Turtledove's book, it's called Minerva) within the next fifteen years.

 

[sojourner]

^yea, I still remember his tagline inside the book. "Mars is just too damn small."

 

[Corwwyn]

Does anyone have any images that show what Galileo could've seen in his time? I'd be very interested to see that.

Mars though a Galilean Telescope

 

[JarodRussell]

There's no reason alien plants would have to be green. In fact, it's kind of odd that Earthly plant life is green, because it's reflecting away the brightest part of the Sun's spectrum. (We think of it as a yellow star because of the way our eyes process color, but technically Sol's peak wavelength is in the green part of the spectrum.) The thing is, the first photosynthetic algae that evolved were red or purple, meaning they absorbed yellow and green, the brightest part of the Solar spectrum, while reflecting red and violet. The algae living beneath them in ponds were stuck with the leftover red and violet light that passed through those other algae, and so they developed a green pigment to absorb it. And somehow, the green plants managed to outcompete the red/purple plants and take over the planet. But it could've gone differently. We could've just as easily evolved on a planet where the vegetation was purple. And you could find a wide range of plant colors on other planets.

The question is if the plants are stupid or if there is a valid reason for it.

Life on this planet is so complex and all factors coming together are so instable (take one thing away and the entire card house falls) that I think "It could have gone differently" is much easier to say than it would have been to realize.

 

[Deckerd]

Life on this planet is so complex and all factors coming together are so instable (take one thing away and the entire card house falls) that I think "It could have gone differently" is much easier to say than it would have been to realize.

Indeed. Statistically the chances of finding life anywhere in the galaxy, let alone our solar system, are not good, even if you had some way to observe them at great distance.

 

[Goliath]

Does anyone have any images that show what Galileo could've seen in his time? I'd be very interested to see that.

The Moon:

Saturn, Jupiter, Mars, Venus--the phases of Venus provided important empirical support for the heliocentric model of the universe:

The moons of Jupiter:

Apparently, Galileo also observed Neptune in 1612 and 1613, but thought it was a fixed star.

 

[Starscape]

We'd be able to determine the constituents of a planetary atmosphere using absorption spectroscopy (molecules absorb certain frequencies of light, so sun-light reflected off an atmosphere would be deficient in those frequencies).

Here's a timeline of various molecular/atmospheric discoveries within the solar system:
http://www-mpl.sri.com/inserts/ast-aero-history.html

And some dates lifted from that website, which might be of use:

1932 Adams - Planetary Spectroscopy: CO2 absorption by Venus atmosphere
1952 Kuiper - CO2 absorption by Mars atmosphere
1972 Carleton - O2 absorption by Mars atmosphere

 

[Meredith]

The space race between the Soviet Union and the United States would still be going on, this time to colonize the other world before the other one does......


It might have even meant WW-III...

 

[ALF]

Totally.

And guess who would be the first to bring Christianity and Democracy and TEH FREEDOM to the new planet????