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Author Topic:   Interstellar Travel - Possibilities and Human Physiology
alaninnont
Member (Idle past 5518 days)
Posts: 107
Joined: 02-27-2009


Message 46 of 63 (504366)
03-27-2009 6:00 PM
Reply to: Message 43 by Sarawak
03-27-2009 9:55 AM


I am sorry you have such a low opinion of your species. I am much more optimistic, but, yes, need may drive the necessary invention.
I have a high opinion of my species (I assume that it is the same as yours) but I think we are going to run out of time. We have to be able to create interstellar travel, make habitable biospheres, and find a planet that could support us soon (in the geological time line). Starting now and working backward it took about 40 years for the human population of the planet to double. Before that it took 60 years, then 150 years, then 700 years and then 1250 years. If this trend continues, the doubling time will become shorter and shorter and we are currently close to 7 billion people. I predict that in another one or two doubling times we will not be able to sustain the population with earth's resources. That would give us about 50 years to accomplish another planet's colonization. I know this seems pessimistic but I don't see major faults with this timeline.

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Taq
Member
Posts: 10158
Joined: 03-06-2009
Member Rating: 4.7


Message 47 of 63 (504403)
03-27-2009 10:18 PM
Reply to: Message 45 by alaninnont
03-27-2009 5:36 PM


For a space station to build another space station would require a vast amount of raw materials which we would have to get from somewhere. If they aren't available from earth, the space station personel would have to find another moon, asteroid, planet, etc. with all the right resources and set up mining and processing facilities. It is possible but we would need some pretty incredible advances in technology to pull it off.
It would seem to me that robotics would work really well for this task. It might be slow at first, but it could really build momentum over time. We might even invent something like a von Neumann machine that can make more copies of itself. This could lead to a exponential increase in resources.
Edited by Taq, : No reason given.

This message is a reply to:
 Message 45 by alaninnont, posted 03-27-2009 5:36 PM alaninnont has replied

Replies to this message:
 Message 48 by alaninnont, posted 03-28-2009 9:33 AM Taq has replied

  
alaninnont
Member (Idle past 5518 days)
Posts: 107
Joined: 02-27-2009


Message 48 of 63 (504436)
03-28-2009 9:33 AM
Reply to: Message 47 by Taq
03-27-2009 10:18 PM


It would seem to me that robotics would work really well for this task. It might be slow at first, but it could really build momentum over time.
I agree that robotics would be a much more practical in space travel. It would be much cheaper to put robots on the moon and they would be able to do practically the same tasks as humans in the current moon missions but it is not so glamorous and exciting. The politicians need the populations financial support so they go for humans because it appeals to our adventurous nature.
We might even invent something like a von Neumann machine that can make more copies of itself. This could lead to a exponential increase in resources.
I don't see how it could increase resources. Please explain.

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 Message 47 by Taq, posted 03-27-2009 10:18 PM Taq has replied

Replies to this message:
 Message 59 by Taq, posted 04-01-2009 12:30 PM alaninnont has replied

  
shalamabobbi
Member (Idle past 2931 days)
Posts: 397
Joined: 01-10-2009


Message 49 of 63 (504453)
03-28-2009 4:00 PM


500 million years left on earth..
There are apparently various estimates of the time left for life on earth due to the changing sun luminosity. Here is a wiki article that summarizes some of the issues. In the first part, not quoted, it gives us 1.5 billion years. But later other estimates are that we have another 500 million years. So the red giant phase will occur long after life has vanished.
quote:
The future of the planet is closely tied to that of the Sun. As a result of the steady accumulation of helium ash at the Sun's core, the star's total luminosity will slowly increase. The luminosity of the Sun will grow by 10 percent over the next 1.1 Gyr (1.1 billion years) and by 40% over the next 3.5 Gyr.[41] Climate models indicate that the rise in radiation reaching the Earth is likely to have dire consequences, including the possible loss of the planet's oceans.[42]
The Earth's increasing surface temperature will accelerate the inorganic CO2 cycle, reducing its concentration to the lethal levels for plants (10 ppm for C4 photosynthesis) in 900 million years. The lack of vegetation will result in the loss of oxygen in the atmosphere, so animal life will become extinct within several million more years.[43] But even if the Sun were eternal and stable, the continued internal cooling of the Earth would have resulted in a loss of much of its atmosphere and oceans due to reduced volcanism.[44] After another billion years all surface water will have disappeared[17] and the mean global temperature will reach 70C.[43] The Earth is expected to be effectively habitable for about another 500 million years.[45]
reference section future

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alaninnont
Member (Idle past 5518 days)
Posts: 107
Joined: 02-27-2009


Message 50 of 63 (504454)
03-28-2009 5:00 PM
Reply to: Message 49 by shalamabobbi
03-28-2009 4:00 PM


Re: 500 million years left on earth..
Yes, that is the speculation on the life cycle of the sun but the question is, how long do we as humans have to develop technology for space travel. I propose that it is less than 100 years due to the increasing population, decreasing resources, and economics. By economics, I mean the amount of money that countries are going to have available for huge expenditures like space stations. According to Sir John Glubb Pasha's model of the rise and fall of world empires, the U.S.A. is in the final stage and will steadily or suddenly decline as a world economic power. There are as yet no other countries strong enough economically and politically to replace them so I think we're in for a period of tight fiscal policies. It may be decades before another country can come to the forefront of economic might.

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 Message 51 by subbie, posted 03-28-2009 5:17 PM alaninnont has replied

  
subbie
Member (Idle past 1336 days)
Posts: 3509
Joined: 02-26-2006


Message 51 of 63 (504455)
03-28-2009 5:17 PM
Reply to: Message 50 by alaninnont
03-28-2009 5:00 PM


Re: 500 million years left on earth..
quote:
I propose that it is less than 100 years due to the increasing population, decreasing resources, and economics.
Sounds like more Malthusian shortsightedness to me.
quote:
According to Sir John Glubb Pasha's model....
Are you alluding to this? I haven't read it, but I'm curious. Do you have anything newer than 30 years old, or any other corroborating opinions?

For we know that our patchwork heritage is a strength, not a weakness. We are a nation of Christians and Muslims, Jews and Hindus -- and non-believers. -- Barack Obama
We see monsters where science shows us windmills. -- Phat

This message is a reply to:
 Message 50 by alaninnont, posted 03-28-2009 5:00 PM alaninnont has replied

Replies to this message:
 Message 52 by alaninnont, posted 03-29-2009 9:12 AM subbie has replied
 Message 55 by Taz, posted 03-30-2009 11:24 AM subbie has replied

  
alaninnont
Member (Idle past 5518 days)
Posts: 107
Joined: 02-27-2009


Message 52 of 63 (504471)
03-29-2009 9:12 AM
Reply to: Message 51 by subbie
03-28-2009 5:17 PM


Re: 500 million years left on earth..
Hey, Subbie. Kind of weird meeting you out here.
Sounds like more Malthusian shortsightedness to me.
I'd be happy to be proved wrong. Look at the human population growth curve on this page.
http://users.rcn.com/...anet/BiologyPages/P/Populations.html
(Hope I did that link right) Can you see this being sustainable?
Are you alluding to this? I haven't read it, but I'm curious. Do you have anything newer than 30 years old, or any other corroborating opinions?
Yes. I think it lends more credibility to the model because he couldn't look back at all of the U.S. history and create a model from it. One of the interesting parts is his take on heros. He says that heros are usually associated with the stage. ie. explorers are heros in the pioneer stage, business leaders are heros in the affluence stage, etc. During the last stage which is one of decline he says that people become disenfranchised and their heros become athletes, actors, and musicians.

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 Message 51 by subbie, posted 03-28-2009 5:17 PM subbie has replied

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Sarawak
Member (Idle past 5559 days)
Posts: 47
Joined: 03-07-2009


Message 53 of 63 (504488)
03-29-2009 6:23 PM


Unsustainable growth does not imply extinction of the species.

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alaninnont
Member (Idle past 5518 days)
Posts: 107
Joined: 02-27-2009


Message 54 of 63 (504491)
03-29-2009 7:22 PM
Reply to: Message 53 by Sarawak
03-29-2009 6:23 PM


Unsustainable growth does not imply extinction of the species.
No, absolutely not. I think that the human race will continue for many, many years into the future. The exponential population growth curve along with the depletion in resources would result in difficult fiscal times and a lack of supplies that would make huge endeavors like massive space stations and far reaching space exploration extremely difficult.

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Taz
Member (Idle past 3373 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 55 of 63 (504529)
03-30-2009 11:24 AM
Reply to: Message 51 by subbie
03-28-2009 5:17 PM


Re: 500 million years left on earth..
subbie writes:
Sounds like more Malthusian shortsightedness to me.
Subbie, just because Malthus was wrong the first time doesn't mean he will always be wrong. Malthus was wrong the first time because he didn't put into account the progress we'd make with technology and genetic engineering. That said, food isn't the only resource we'd be fighting each other over. And it won't happen over night either.

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 Message 51 by subbie, posted 03-28-2009 5:17 PM subbie has replied

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RAZD
Member (Idle past 1487 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 56 of 63 (504629)
03-31-2009 7:29 PM
Reply to: Message 45 by alaninnont
03-27-2009 5:36 PM


another concept
We would probably have to use centripital force to simulate gravity since artificial gravity doesn't seem to be anywhere near possible in the foreseeable future.
If one puts aside the need to visit planets, then one does not need to keep a gravity style organism, and you could evolve to be better adapted to space travel - small for less consumption requirements, able to hibernate, for long trips with minimal use of resources. You would want to re-invent the species for a new environment.
I could see how a space station once built could be self sustaining but it would take an incredible amount of resources to build and people on earth are doing a good job of using up the resources we have.
The resources needed for life are on the surface of the planet, and the only real raw input is solar energy to drive vegetation growth. Again, what you need is to adapt to the environment, use energy for plant growth and recycle the systems effluents. We've had small success because the environments created were small in comparison to the population loading. With robotics for mundane tasks the number of individuals necessary becomes an issue of long term species survival. See if you can find an old film "Silent Running" if you haven't already seen it (it's a classic SF film).
For a space station to build another space station would require a vast amount of raw materials which we would have to get from somewhere.
Asteroids can have higher metal content than found on the surface of planets, making harvesting of these resources easier from space than from a planet.
Think of a space station complex that can use solar sails to minimize energy consumption, and that travels to new star systems for raw materials to make another station complex -- it's like the station hunts for resources and reproduces when it has sufficient "nutrients," similar to bacteria.
Enjoy.

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This message is a reply to:
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subbie
Member (Idle past 1336 days)
Posts: 3509
Joined: 02-26-2006


Message 57 of 63 (504638)
03-31-2009 11:55 PM
Reply to: Message 52 by alaninnont
03-29-2009 9:12 AM


Re: 500 million years left on earth..
quote:
I'd be happy to be proved wrong. Look at the human population growth curve on this page
Well, I actually looked beyond the graph, to this language at the bottom of the page:
A consensus?
The several agencies that try to predict future population seem to be moving closer to a consensus that:
* the world population will continue to grow until after the middle of this century
* reaching a peak of some 9 billion (up from today's 6.6 billion) and then
* perhaps declining in the waning years of this century.
If I'm reading this right (and I'd like to think that I am), it seems to be at odds with your prediction. You talk about the doubling time getting shorter and shorter, and predict that after two more doublings we'll lack sufficient resources to put together a space-directed solution. However, the (unnamed) experts don't think there will be even one more doubling. I have no idea how accurate this consensus is, but it's most curious for you to cite to a webpage that actually contradicts what you say.

For we know that our patchwork heritage is a strength, not a weakness. We are a nation of Christians and Muslims, Jews and Hindus -- and non-believers. -- Barack Obama
We see monsters where science shows us windmills. -- Phat

This message is a reply to:
 Message 52 by alaninnont, posted 03-29-2009 9:12 AM alaninnont has not replied

  
subbie
Member (Idle past 1336 days)
Posts: 3509
Joined: 02-26-2006


Message 58 of 63 (504639)
03-31-2009 11:57 PM
Reply to: Message 55 by Taz
03-30-2009 11:24 AM


Re: 500 million years left on earth..
quote:
Malthus was wrong the first time because he didn't put into account the progress we'd make with technology and genetic engineering.
And as far as I can tell, alaninnont did the exact same thing. All he did was predict an increasing rate of population growth (which incidentally is contradicted by the webpage he cites) with no discussion whatsoever about potential increases in productivity.

For we know that our patchwork heritage is a strength, not a weakness. We are a nation of Christians and Muslims, Jews and Hindus -- and non-believers. -- Barack Obama
We see monsters where science shows us windmills. -- Phat

This message is a reply to:
 Message 55 by Taz, posted 03-30-2009 11:24 AM Taz has not replied

  
Taq
Member
Posts: 10158
Joined: 03-06-2009
Member Rating: 4.7


Message 59 of 63 (504677)
04-01-2009 12:30 PM
Reply to: Message 48 by alaninnont
03-28-2009 9:33 AM


I don't see how it could increase resources. Please explain.
If your manufacturing robots double in number every year your resources will grow exponentially.

This message is a reply to:
 Message 48 by alaninnont, posted 03-28-2009 9:33 AM alaninnont has replied

Replies to this message:
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alaninnont
Member (Idle past 5518 days)
Posts: 107
Joined: 02-27-2009


Message 60 of 63 (504703)
04-01-2009 7:36 PM
Reply to: Message 59 by Taq
04-01-2009 12:30 PM


If your manufacturing robots double in number every year your resources will grow exponentially.
Resources would include minerals, metals, and fuel.

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Replies to this message:
 Message 61 by Taz, posted 04-26-2009 4:53 PM alaninnont has not replied

  
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