PDA

View Full Version : About the colonizer craze: when should I pack my bags for Mars? Etc.


krystof
06-01-08, 04:52 PM
The last two documentaries I have watched, Hyperspace and The Universe, seem to take it for granted that 'we must' colonize the solar system and 'hopefully' the galaxy. And perhaps if I took more notes I would be more clear about this. But from what facts I can remember, I am rather fuzzy and skeptical.

1. In about 3 or 4 billion years (or is it 3 or 4 hundred thousand years) the sun will expand. (Although it will first contract...?)

2. Therefore, supposedly there will be a time period of perhaps 100,000 years during which the earth is too hot, but with a bit of terraforming, Mars or perhaps Europa can be made habitable.

3. But, the reason Mars has no atmosphere is because it has a weak magnetic field to deflect solar winds. So, I really don't see how we might terraform its atmosphere back with CO2 generators, as suggested by Hyperspace. Unless maybe the damage of solar winds is very gradual?

4. In any case, if after 1 billion years of human civilization, we have not been able to leave the solar system, it does not seem worthwhile to gain a such a relatively brief reprieve with such a huge effort.

5. Currently, the human race is unable to plan sensibly for the self-evident extinction of fossil fuels in the next 50 years. Yet we are ready to plan to colonize Mars to escape the sun's demise? At the very least, we should first solve problem no. 1, if only as a test to prove our intelligence is high enough to make our survival worthwhile.

6. I might be mistaken, but I understand that in about 2 billion years, the Andomeda galaxy is scheduled to collide with the Milky Way? Is this not sooner as well as a bigger problem than our sun's demise?

7. The discovery of life is often repeated as a central reason for space exploration. Bacteria on Mars or Europa supposedly will greatly increase the chances that the universe is teeming with life. But will the disproof of life there thus reduce the chances? I think not. Also, meteors from Mars have reached Earth. How will we know whether some bacteria on Mars or perhaps even Europa did not originate from Earth?

8. Long-lasting fuel for an interstellar voyage, likely to take thousands of years, is a problem. As the sun decays, might some of its power be captured for such fuel?

9. The documentary Hyperspace claims that creating 'wormholes' is a serious possibilty for interstellar travel. But makes no mention how. Is this really so 'serious'? If so, how? (References welcome.)

(My time scales might be wrong and I hope someone can please correct me.)

My current tentative conclusions on the colonizing of space.

a.) Our best hope under current technology is to discover possible young worlds and shoot out bacteria to those worlds. Possibly along with a plaque or something that records what we did. However hopefully to be careful that instead of creating life on a barren planet, our bacteria could wipe out life on that planet.

b.) Also possibly to look for such a plaque already existing on the earth.

c.) More ideal perhaps would be for us to create a race of space-gypsy humanoids, designed to survive in space forever. If and when they ever come to another green planet would be highly unlikely. In any case, this would take so long that it is better not to plan for this as an expectation!

d.) Rather than colonizing Mars, a much more promising cost/benefit ratio would be gained by building a huge radio telescope on the Moon. Thus to assume that intelligent life exists, and to optimize the chance of communicating with them--whether or not 'worm holes' or other inventions might ever make space travel more feasible--and also optimizing our chances of learning such an advanced technology.

e.) It must be noted that currently, the following ideas have an equal chance of ever being successful as space travel, and for all we know, may well prove to be much more feasible.

... life after death
... travel to alternate dimensions
... time travel

Oli
06-01-08, 04:56 PM
e.) It must be noted that currently, the following ideas have an equal chance of ever being successful as space travel, and for all we know, may well prove to be much more feasible.

... life after death
... travel to alternate dimensions
... time travel

Really?
Space travel is a question of funding and technology, the three given above aren't.

Roman
06-01-08, 07:18 PM
What good is space travel when every planet we reach is dead?

cosmictraveler
06-01-08, 08:40 PM
when should I pack my bags for Mars?

In about 40 years or so if we are lucky.

Xelios
06-02-08, 05:03 PM
The biggest problem with space travel is propulsion. If we can figure out how to get up to 99.999% the speed of light and slow down again there's no problem. Time dilation at that speed means people on board a ship could reach the other side of the galaxy in a few years of their time. They could cross the known universe in 50 years of their time.

I don't think it'll take millions of years for us to figure out how to do that.

Ophiolite
06-03-08, 08:48 AM
1. In about 3 or 4 billion years (or is it 3 or 4 hundred thousand years) the sun will expand. (Although it will first contract...?)
Long before that the steadily increasing solar temperature will have rendered complex life on Earth untenable. We have about 500 million years left, at best. Still, time for several more Indiana Jones movies.;)
2. Therefore, supposedly there will be a time period of perhaps 100,000 years during which the earth is too hot, but with a bit of terraforming, Mars or perhaps Europa can be made habitable.
I'm not at all clear where you came up with this 100,000 year figure. Mars could be terraformed now, and the increased solar output over the next 500 million years would simply make the process easier, the further we were along that time line.
3. But, the reason Mars has no atmosphere is because it has a weak magnetic field to deflect solar winds. So, I really don't see how we might terraform its atmosphere back with CO2 generators, as suggested by Hyperspace. Unless maybe the damage of solar winds is very gradual?It would take at least fifty thousand years for serious depletion of the atmosphere to occur. That is ten times the length of written history. I'm sure we could figure out a solution in that time frame. By the way, I would favour enriching the atmosphere with cometary impacts, which would have the advantage of bringing in lots of water and organics and nitrogen.
4. In any case, if after 1 billion years of human civilization, we have not been able to leave the solar system, it does not seem worthwhile to gain a such a relatively brief reprieve with such a huge effort.We should have the technology to leave the system this century and certainly within one thousand years. The political will is more important than the technology, since the technology (light sails, von Neumann probes, and cryogenic embryos) is comparatively simple in late 21st century terms.
5. Currently, the human race is unable to plan sensibly for the self-evident extinction of fossil fuels in the next 50 years. Yet we are ready to plan to colonize Mars to escape the sun's demise? At the very least, we should first solve problem no. 1, if only as a test to prove our intelligence is high enough to make our survival worthwhile.
With women leading the planet we can engage in multitasking and do both at the same time.
6. I might be mistaken, but I understand that in about 2 billion years, the Andomeda galaxy is scheduled to collide with the Milky Way? Is this not sooner as well as a bigger problem than our sun's demise?As noted above the rise in temperature of the sun will be a problem long before then. The collision of the two galaxies may not be a problem for the Earth. Stars are a long way apart - we could well escape any close encounter. However, by then we should have populated the galaxy anyway and a have a collision plan in place.:)
7. The discovery of life is often repeated as a central reason for space exploration. Bacteria on Mars or Europa supposedly will greatly increase the chances that the universe is teeming with life. But will the disproof of life there thus reduce the chances? I think not. Either instance will alter our estimate of the probabilities.
Also, meteors from Mars have reached Earth. How will we know whether some bacteria on Mars or perhaps even Europa did not originate from Earth? Examination of the DNA.
8. Long-lasting fuel for an interstellar voyage, likely to take thousands of years, is a problem. As the sun decays, might some of its power be captured for such fuel?
You don't need fuel with a light sail. Frank Tipler estimated that by such means the galaxy could be populated in less than one million years.
9. The documentary Hyperspace claims that creating 'wormholes' is a serious possibilty for interstellar travel. But makes no mention how. Is this really so 'serious'? If so, how? (References welcome.)
It is a serious speculation, rather than a serious possibility.
It often makes good sense to start with wikipedia, though in this case there is not much there.
http://en.wikipedia.org/wiki/Interstellar_travel#Wormholes

a.) Our best hope under current technology is to discover possible young worlds and shoot out bacteria to those worlds. Possibly along with a plaque or something that records what we did. However hopefully to be careful that instead of creating life on a barren planet, our bacteria could wipe out life on that planet.
Probably irresponsible; possibly considered a hostile act by more advanced civilisations, which would then carry out a disinfection of the Earth.
b.) Also possibly to look for such a plaque already existing on the earth. An interesting idea. Even more interesting is to specualte on the form the 'plaque' might take.
d.) Rather than colonizing Mars, a much more promising cost/benefit ratio would be gained by building a huge radio telescope on the Moon. Thus to assume that intelligent life exists, and to optimize the chance of communicating with them--whether or not 'worm holes' or other inventions might ever make space travel more feasible--and also optimizing our chances of learning such an advanced technology.
As above, do both and more besides.
e.) It must be noted that currently, the following ideas have an equal chance of ever being successful as space travel, and for all we know, may well prove to be much more feasible.
... life after death
... travel to alternate dimensions
... time travelI echo Oli's comments on this one.

MetaKron
06-03-08, 09:18 AM
Before we can drive around the city, we have to be able to take that first step out the door. Colonizing Mars may turn out to be a good first step. That rock may have all the resources that a million people need to build the next generation of spacecraft, and it takes a lot less energy to lift off from Mars than from Earth.

Humans will probably engineer life that can bring materials for an atmosphere up from deep within the crust. The most likely cause of the lack of atmosphere in Mars is the lack of vulcanism. This could be substituted for by any system that goes under the crust and brings up materials.

Letticia
06-04-08, 11:01 AM
Here is a very very long Web page which basically pours cold water onto "space colonization" dream: The High Frontier, Redux (http://www.antipope.org/charlie/blog-static/2007/06/the_high_frontier_redux.html).

Warning A: If you are gung-ho about space colonization, this page will upset or anger you. A lot.

Warning B: If you read it carefully, you will realize that Charles Stross does not claim space colonization and interstellar travel will never happen; he just claims they will not happen without major breakthroughs such as conscious AI, mind uploading, radical genetic engineering, or completely new physics. Merely piling on energy, as in anti-matter rocket, won't cut it.

Best line in the entire dialog, IMO: "If interstellar colonization does happen, it will be as an afterthought of some eccentric post-humans."

Enmos
06-04-08, 11:39 AM
While there is still hope for the world, I support colonizing dead planets.
When all hope is gone and the world is dead, humans should die with it.

hypewaders
06-04-08, 03:21 PM
Thank you Letticia for sharing the link to Charles Stross (http://www.antipope.org/charlie/). I've long neglected to read contemporary scifi, and had never discovered his work.

I didn't find Stoss' reality-check disheartening at all. I understand that living 1000 years back, it was similarly out of reach for individuals to experience or predictively imagine the planned colonization of continents. The interstellar ocean doesn't only dwarf our present dreams and lifetimes of today. It's tugging on them. It's pulling so hard that I expect it really will extend what we consider human life far out of present sight in space and time.

I can only abide plausible scifi, and because Stross is a thinking present-day realist, I'm a more content passenger following his dreams beyond the now. Accelerando (http://www.accelerando.org/_static/accelerando.html) is quite a ride. Thanks for your unexpected introduction to new worlds.

Letticia
06-04-08, 03:28 PM
I can only abide plausible scifi, and because Stross is a thinking present-day realist, I'm a more content passenger following his dreams beyond the now. Accelerando (http://www.accelerando.org/_static/accelerando.html) is quite a ride. Thanks for your unexpected introduction to new worlds.

You are welcome, but... you managed to read "Accelerando" in four hours?? That's how long ago I posted the link.

hypewaders
06-04-08, 03:50 PM
I've only traveled out as far as Jupiter, in Part 2 (http://www.accelerando.org/_static/accelerando.html#PART2) so far.

sly1
06-04-08, 05:12 PM
what i want to know is what the hell makes us think our extinction is NOT inevitable?

all things transform from their origional form to something else eventually right?

Are we suggesting we will outlive/surive the planet earth? our sun/solar sytem? our galaxy? the universe itself?

When I really think about our time in existance in comparrison to the existance of time.....I belive our extenction or transformation to be inevitable......

nietzschefan
06-04-08, 05:38 PM
We are advanceing very rapidly right now, I really doubt anyone can predict a timeline for colonization outside earth. Mostly political reasons will hold it back.

What I am saying is, it all depends on the social and political advancement in the next 40 years. If we can learn to play nice together globally, we can move on to bigger and better things. I believe this is a requirement even for interplanetary settlement, even if we had the techology/knowledge for interstellar travel(the means of which no one can see right now).

eburacum45
06-05-08, 10:30 AM
Stross points out that for each metric tonne of payload sent to Proxima Centauri orbit you need at least 10e18 joules. This is equivalent to the output of all our power stations on Earth for two and a half days.
Sounds a lot; but if instead you consider the total amount of sunlight falling on the Earth, that represents only eleven seconds worth of sunlight.

Given a large scale energy economy in the future, going to the stars would be acheivable. Note that living in a very large scale energy economy might be a precarious existence; given such vast amounts of energy available for apparently trivial tasks such as spaceflight, the energy required to boil a city would be readily available.

Here are a couple of links from the bottom of that page, supplied by the remarkable Jonathan vos Post
http://magicdragon.com/EmeraldCity/Nonfiction/STL.html
http://magicdragon.com/ComputerFutures/SpacePublications/STAR.html

and a bit of nonsense (by me) from OA (actually derived from a post on this forum, a few years ago)
http://www.orionsarm.com/ships/Colony_Ships.html

D H
06-05-08, 11:34 AM
Stross points out that for each metric tonne of payload sent to Proxima Centauri orbit you need at least 10e18 joules.
NB: This assumes that the propulsion system in use is 100% efficient at converting energy into momentum and that the propulsion source is external — that is, there's no need to take reaction mass along en route.
We don't know how to do that. What we do know how to do is to carry the reaction mass with the vehicle -- i.e., a rocket. The energy required with a rocket is a tad bid more than 1018 joules. For example, suppose we develop a large-scale VASIMR engine (specific impulse=290000 meters/sec, 65 times that of the best chemical rocket). The propellant mass required to accelerate a 1 metric ton payload to 0.1c with such a rocket is 4*1017 solar masses (http://www.google.com/search?q=exp%28%280.1c%29%2F%28290000m%2Fs%29%29*1 e3kg%2F%28solar+mass%29). This is just getting up to 0.1c. The rocket has to slow down as well. The only way to make the trip take 1018 joules is to magically pull the energy out of space.

Letticia
06-05-08, 12:41 PM
When I really think about our time in existance in comparrison to the existance of time.....I belive our extenction or transformation to be inevitable......

There is a huge difference between extinction and transformation. One means we are gone, poof. The other means our children (perhaps speaking loosely) will continue -- even if they no longer look like us.

sly1
06-05-08, 03:08 PM
There is a huge difference between extinction and transformation. One means we are gone, poof. The other means our children (perhaps speaking loosely) will continue -- even if they no longer look like us.


nothing goes extinct for all things are either mass or energy and neither can be destroyed. so by extinction I ment transofrmation.

draqon
06-05-08, 03:18 PM
The earliest the better. It is time for us to realize that Mars is our new home.

MetaKron
06-05-08, 07:39 PM
While there is still hope for the world, I support colonizing dead planets.
When all hope is gone and the world is dead, humans should die with it.

Jerk.

Engulfed_Door
06-06-08, 04:24 AM
We are advanceing very rapidly right now, I really doubt anyone can predict a timeline for colonization outside earth. Mostly political reasons will hold it back.

What I am saying is, it all depends on the social and political advancement in the next 40 years. If we can learn to play nice together globally, we can move on to bigger and better things. I believe this is a requirement even for interplanetary settlement, even if we had the techology/knowledge for interstellar travel(the means of which no one can see right now).

yes

eburacum45
06-06-08, 08:17 AM
We don't know how to do that. What we do know how to do is to carry the reaction mass with the vehicle -- i.e., a rocket. The energy required with a rocket is a tad bid more than 1018 joules. For example, suppose we develop a large-scale VASIMR engine (specific impulse=290000 meters/sec, 65 times that of the best chemical rocket). The propellant mass required to accelerate a 1 metric ton payload to 0.1c with such a rocket is 4*1017 solar masses (http://www.google.com/search?q=exp%28%280.1c%29%2F%28290000m%2Fs%29%29*1 e3kg%2F%28solar+mass%29). This is just getting up to 0.1c. The rocket has to slow down as well. The only way to make the trip take 1018 joules is to magically pull the energy out of space.
Nobody would use VASIMR drive to get to another star, especially not at 0.1c.
Only certain types of highly speculative antimatter-powered drive could get a ship to a nearby star in a reasonable time. Alternatively, some form of beamed propulsion could be used- this would remove the requirement for accelerating vast amounts of fuel and propellant with you (except, of course, you would need enough fuel to decelerate at the destination).

One design for a craft that would get to the stars in a semi-reasonable time is the Daedalus concept:
http://en.wikipedia.org/wiki/Project_Daedalus
this used fusion rather than antimatter, and would reach 0.12c on a fuel/payload ratio of about 100/1. Unfortunately this would only allow the craft to reach a nearby star, not slow down; to slow down the ratio would be 10000/1. Large, but not impossibly large.

D H
06-06-08, 09:58 AM
Nobody would use VASIMR drive to get to another star, especially not at 0.1c.
Of course not. I picked VASIMR because we don't know how to do any better in terms of specific impulse.
Only certain types of highly speculative antimatter-powered drive could get a ship to a nearby star in a reasonable time. Alternatively, some form of beamed propulsion could be used- this would remove the requirement for accelerating vast amounts of fuel and propellant with you (except, of course, you would need enough fuel to decelerate at the destination).
I would put this as even more speculative than matter-antimatter.

One design for a craft that would get to the stars in a semi-reasonable time is the Daedalus concept ...
We don't know how to build a fusion rocket. Scientists and engineers have slightly different concept of what is feasible.

... this used fusion rather than antimatter, and would reach 0.12c on a fuel/payload ratio of about 100/1. Unfortunately this would only allow the craft to reach a nearby star, not slow down; to slow down the ratio would be 10000/1. Large, but not impossibly large.
Unfortunately, things don't necessarily scale up that way. Structures are 3D, surfaces are 2D. Look at the kinds of things evolution has done with insects versus elephants. There are some things evolution can do on a small scale that simply do not scale up. The same goes for scientists and engineers. Some things simply do not scale up the way we want them to. Rockets are one of those things.

eburacum45
06-07-08, 10:00 AM
Alternatively, some form of beamed propulsion could be used- this would remove the requirement for accelerating vast amounts of fuel and propellant with you (except, of course, you would need enough fuel to decelerate at the destination).
I would put this as even more speculative than matter-antimatter. Yes; a lot of things are speculative, but far less outlandish than faster-than-light warp drive. Here is a beamed power concept by the late Robert Forward,
http://en.wikipedia.org/wiki/Starwisp which interestingly enough, Stross himself used in his SF novel Accelerando.

eburacum45
06-07-08, 10:05 AM
My own image of a starwisp can be found here
http://www.flickr.com/photos/25577499@N07/2410264072/in/set-72157604502272263/

eburacum45
06-07-08, 10:33 AM
Here's Forward's original paper- note the use of a zone plate, a useful bit of kit that might make all sorts of things possible at very long range.
http://www.transorbital.net/Library/D001_AxA.html