Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: Kosh on April 25, 2010, 11:28:02 pm
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According to Stephen Hawking (http://news.bbc.co.uk/2/hi/uk_news/8642558.stm)
Aliens almost certainly exist but humans should avoid making contact, Professor Stephen Hawking has warned.
In a series for the Discovery Channel the renowned astrophysicist said it was "perfectly rational" to assume intelligent life exists elsewhere.
But he warned that aliens might simply raid Earth for resources, then move on.
"If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans," he said.
Prof Hawking thinks that, rather than actively trying to communicate with extra-terrestrials, humans should do everything possible to avoid contact.
While I think he does have a point, contact will come sooner or later so we had best be ready......just in case the Zods come and turn out not to be like the Vulcans but rather like the Shivans. That means putting more focus on our space program and scientific and technological development, hopefully leading to the point to where we can start building GTD Orion class destroyers or whatever.
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Man that is some really old news. Those quotes have been on the Science, Discovery, National Geographic, etc channels for years.
He does have a point though but it's way too late. Signals have been going into space for what a century?
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Most of us have probably heard about the "radio signal bubble" or something like that...
I've read conflicting information regarding its influence, though. On one hand, some say that the bubble will simply keep expanding, spreading our transmissions and culture (shudder (?)) to the universe at large. Another stance is that while this bubble does exist, its range is only about 2 ly tops, so nobody else is really going to hear it.
Gut feeling, I'd be inclined to follow the latter stance- day-to-day transmissions probably lack the signal power to be intelligible very far out, but I won't say anything for certain without crunching any numbers...
One thing to really take away is that if its the aliens contacting us, visiting us on Earth, then we've already blown it. A civilization that can pinpoint our planet, possibly identify it as desirable or a haven for life, and send a vessel to our world would be so far ahead in technology and (probably) social advancement that we could only hope for peaceful visitors... Or a swift, painless conquest. :nervous:
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I dislike his view that any aliens that visit us will without question want to conquer us. I do think it would be a good idea to be prepared for hostile alien visitors, but not to assume that every alien who comes along is only interested in conquest.
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I dislike his view that any aliens that visit us will without question want to conquer us.
That's not his view.
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as far as creatures go, humans are just about the most peaceful. when it comes to respecting of other life forms or considering the negative impact benefits to our selves will have on the other more vulnerable animals on the world, we are by far the most benevolent.
I want you to understand what I am saying here, this is not irony, this is fact, as far as animals we know about go, we are without question the nicest to the other animals weaker than us, because if any other animal on the planet were to be given the sort of power we have, just about everything else on the planet would be destroyed within a week. with that track record for life, I would be a bit worried about creatures vastly more powerful than us that don't even have a connection with our planet and don't have to live with the consequences of draining the ocean or something similar.
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Most of us have probably heard about the "radio signal bubble" or something like that...
I've read conflicting information regarding its influence, though. On one hand, some say that the bubble will simply keep expanding, spreading our transmissions and culture (shudder (?)) to the universe at large. Another stance is that while this bubble does exist, its range is only about 2 ly tops, so nobody else is really going to hear it.
Gut feeling, I'd be inclined to follow the latter stance- day-to-day transmissions probably lack the signal power to be intelligible very far out, but I won't say anything for certain without crunching any numbers...
Well, we have heard reflections of our own signals off a couple of nebula that are further than 2 ly away.
But you have a point about the modern transmissions. There was some concern a couple of months back about the Drake Equation (http://science.slashdot.org/story/10/01/30/0650250/Making-It-Hard-For-Extraterrestrials-To-Hear-Us), in that it assumed that once a civilization learns to broadcast they will continue to broadcast as loud as they can forever. Instead we are slowly lowering the power of our broadcasts so that we cause less interference with other transmissions. For example, 50 years ago, super radio stations were all the rage. Broadcast across the entire North American Continent with one omni-directional transmitter. This one transmitter leaked all sorts of radio into space, but now, our radio stations use lower power, directional transmissions (to point them at the ground) so the leakage is almost non-existent.
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why be invaded when we could be doing the invading
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That's not his view.
Okay, looks like I misinterpreted it. :nervous:
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There are so many scenarios that could happen. It's probably a 50/50 chance.
Bad/Good
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Aliens bring incurable disease that wipes out entire human race/Aliens bring cure to all disease
Aliens use us as food/Aliens give us way to eliminate hunger
Aliens are warlike and attack/Aliens are peaceful but have powerful defense that protect us from the bad guys.
Aliens blow up our planet to make interstellar superhighway/Aliens give us on-ramp to interstellar superhighway.
The question comes down to are you willing to risk the survival of the Human race on the flip of a coin?
Oh and I believe the context he answered the question in was if we receive a signal from another planet should we reply. They were talking high powered laser communication.
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while i share the belief that there is other life in the vast universe, i DON'T share the belief that contact is inevitable. the same rediculous numbers of galaxies and stars unfathomable distances away from each other also stack the odds severely AGAINST two civilizations running into each other. contrary to every science fiction movie ever made, there IS a limit on what is physically possible through technology. it is not guaranteed that some super wormhole drive or something is possible to allow one civilization to reach another. and if it is, the odds of happening across one of the inhabited systems in such manner of travel are still insane.
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Re: Is there life elsewhere in the universe?
--> Almost definitely. :)
Re: Radio bubble:
The expanding sphere of our radio transmissions certainly does exist, and furthermore its range (given enough time to expand) is *infinite*. It just requires a larger / more powerful receiver to read the signals at a greater distance.
Re: Contact, good or bad?
I'd argue that any civilization advanced enough to be capable of travelling between star systems is more likely to not be hostile, because I can't fathom how a hostile race would manage to survive long enough to reach that kind of capability. I believe we should do our best (within reason) to find signs of alien life, and if alien life manages to contact us, I think we should answer. Afterall, if we find out that there is life out there, I can't see how our burying our heads in the sand and ignoring it is at all beneficial. They'll probably determine our presence anyway, if they hadn't already done so.
On a related note, last week one of my astronomy professors discussed his views on whether or not it is likely for us (or aliens) to be capable of readily colonizing other star systems. He argued that this is not very likely based on our current observations. The supporting argument goes like this:
First, assume that there is one civilization in our galaxy with the ability to travel to and colonize nearby star systems, and let us assume that they are limited by the speed of light but are capable of traveling at a significant fraction of it – and finally, let us assume that it takes them 500 years to travel to and colonize a new star system.
If this is the case, then by virtue of exponential growth, we would expect that the entire habitable region of the galaxy would be colonized within a tiny fraction of the age of the galaxy. (IIRC my professor gave a value of 30,000 years for this, but I’d like to actually see the math). Anyways, because we do not see evidence of the entire galaxy being colonized, it’s probably a safe assumption that the capability to do so either does not exist, or that we really are the only advanced life in our galaxy. I’m under the belief that the former case is the correct one.
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Re: Contact, good or bad?
I'd argue that any civilization advanced enough to be capable of travelling between star systems is more likely to not be hostile, because I can't fathom how a hostile race would manage to survive long enough to reach that kind of capability.
Well, for some reason the warrior Europeans conquered both Americas and mostly deleted whoever was in their path.
They managed to survive long enough to do that, even though they were advanced enough to be able to travel across oceans and have firearms, which puts them as far ahead of native Americans as anyone travelling across the galaxy and colonizes planets is ahead of us Terrans today.
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That's a good argument. But consider the situation we are in right now. I think that level of aggression you refer to with the warrior Europeans still exists, except now it's more between humanity and the rest of life on earth, rather than conflict between different human cultures. (It's not exactly intentional, but the fact is that our lifestyle is still devestating the planet -- we are an aggressive species, in a manner of speaking.) Do you think that we can become successfully spacefaring on a large scale if we do not drastically change the way we live and treat our fellow lifeforms?
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Thing is, the Native Americans is a good example for another reason. The reason that Native American tribes developed such a deep respect for their environment was because they nearly wiped themselves out by not doing so, in particular, it seems likely that the extinction of the Mammoth in North America was bought about by over-hunting.
Much as I hate to say it, I still think it will take a disaster of global proportions before what is left of humanity gets the message.
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A few things:
#1. Most of our most important technological advancements occurred as a result of war (see: freaking needed it at the time). I have no reason to believe that the opposite would be true, and therefore believe that progress would be slower for 'peaceful' aliens and faster for 'warlike' ones.
#2. The 'peaceful alien' thing only works if they're anything like us (verbal communication, hierarchical social structure, etc.). I.e., If they're formics, well, we're pretty much screwed.
#3. If they were peaceful, why in the Hell would they want to get to know us?
[/mad rambling of a semi-conscious terran]
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look at it this way, we can nuke our own planet, or we can nuke someone else's planet. i dont care so long as were nuking something. start turning keys and pushing buttons!
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If the aliens have any intelligence, they'd avoid giving us any technology. The whole "we can use this to make war/extort our enemies" thing you know.
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as far as creatures go, humans are just about the most peaceful. when it comes to respecting of other life forms or considering the negative impact benefits to our selves will have on the other more vulnerable animals on the world, we are by far the most benevolent.
I want you to understand what I am saying here, this is not irony, this is fact, as far as animals we know about go, we are without question the nicest to the other animals weaker than us, because if any other animal on the planet were to be given the sort of power we have, just about everything else on the planet would be destroyed within a week. with that track record for life, I would be a bit worried about creatures vastly more powerful than us that don't even have a connection with our planet and don't have to live with the consequences of draining the ocean or something similar.
This is an excellent point.
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I'm kinda in agreement here. It'd be nice to find someone friendly. But...
It's not the chances of someone friendly are necessarily low, it's just the chances of anything positive happening are low. Aliens aren't likely to
A) Have super cures and cool stuff for everything we've always wanted
B) Give it to us for no reason
The most likely chance is anyone that wants to see us in this stage is just some scientist that wants to go check out the primitives. After that the next likely chance is that they want resources or habitable land to settle (there's no guarantee other life breathes the same air as us, BUT, we do know that Earth-type worlds don't grow on trees, at least from what we've seen of the galaxy).
So really, we don't have much to gain from rushing for contact. As people were saying earlier if we show up to first contact with an Orion, some Levis, and a fleet of Faustus, etc, we'll not only be safer off, but it much increases the chance that the race we make contact with will see us as something closer to equals rather than something they can exploit.
If we get a direct signal we may as well reply since they clearly know either our exact location or have some reason to believe someone's in the general area. Not replying indicates we might not have the tech to understand, making us seem even weaker.
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we do know that Earth-type worlds don't grow on trees, at least from what we've seen of the galaxy).
You win the Strangest Use of a Common Saying award, hands down.
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we do know that Earth-type worlds don't grow on trees, at least from what we've seen of the galaxy).
You win the Strangest Use of a Common Saying award, hands down.
I do that a lot. I spend a lot of time trying to figure out whether I'm CHR 6 or 8. Lately i think i've been leaning closer to going with 6 :P
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Re: Contact, good or bad?
I'd argue that any civilization advanced enough to be capable of travelling between star systems is more likely to not be hostile, because I can't fathom how a hostile race would manage to survive long enough to reach that kind of capability.
Well, for some reason the warrior Europeans conquered both Americas and mostly deleted whoever was in their path.
They managed to survive long enough to do that, even though they were advanced enough to be able to travel across oceans and have firearms, which puts them as far ahead of native Americans as anyone travelling across the galaxy and colonizes planets is ahead of us Terrans today.
I think it's a different issue you're talking about. What matters in watsisnames's point is their absolute level of technology, not the level of technology relative to the population they're visiting.
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On a related note, last week one of my astronomy professors discussed his views on whether or not it is likely for us (or aliens) to be capable of readily colonizing other star systems. He argued that this is not very likely based on our current observations. The supporting argument goes like this:
First, assume that there is one civilization in our galaxy with the ability to travel to and colonize nearby star systems, and let us assume that they are limited by the speed of light but are capable of traveling at a significant fraction of it – and finally, let us assume that it takes them 500 years to travel to and colonize a new star system.
If this is the case, then by virtue of exponential growth, we would expect that the entire habitable region of the galaxy would be colonized within a tiny fraction of the age of the galaxy. (IIRC my professor gave a value of 30,000 years for this, but I’d like to actually see the math). Anyways, because we do not see evidence of the entire galaxy being colonized, it’s probably a safe assumption that the capability to do so either does not exist, or that we really are the only advanced life in our galaxy. I’m under the belief that the former case is the correct one.
Well that works only if the species that wants to colonize, breeds.
However, as we can see from hi-tech nations of today (the First World) do we even now see high grow of population?
I would be willing to argue that a space civilizations has the same (if not better) energy technology that would have allowed it to create almost same conditions in wich people don't really want to make that many babies.
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I think it might be a matter of there not being many habitable worlds in the galaxy. Like i said with earth's not growing on trees, most of the extra-solar planets we've identified are down-right inhospitable to life as we know it. Lots of dead rocks and gas giants. Maybe you could terraform them, but even if you have the technology that takes a lot of work, so you wouldn't colonize freely, more on a infrequent basis. You also have the problem of colonization being slowed by contact with other advanced life. And in that example, if you were limited to traveling at a speed less than light, it's going to take a number of years to get there/send later supplies. Which is dwarfed by the amount of time the galaxy has existed for, yes.
But time isn't the only variable. The harder it is to do something, the less willing people are to try unless there's a sweet payoff. And it's sounding like colonization is pretty hard.
Not to mention is that colonization vessels that travel at sub-light would have to be HUGE. Packed with people, supplies, fuel, etc. Exponential growth doesn't work on this since a colonization ship is something that would have to built at a large scale shipyard, something that probably is only at the homeworld and nearby worlds. They're not something that would be built at every colony since building up the industry to create and maintain a shipyard would be a large scale project, and it makes sense to keep things specialized too. Not every city in the US has farmland and factories. We have farming areas of the country along with manufacturing areas.
So you'd really have colonization speed decreasing with each world, as the worlds you try to travel to become farther away from the homeworld, which makes it longer to travel,more costly (need more supplies), and higher risk. Additionally, all of these things make people less enthusiastic to go in the first place.
EDIT: Just to add on, your astronomy professor's argument assumes that each colony would become a copy of the homeworld, matching it in population and industry. Which just isn't going to happen unless breeding rates are out of control, and you're REALLY good at quickly building up all the infrastructure to support that expanding population.
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I think it might be a matter of there not being many habitable worlds in the galaxy. Like i said with earth's not growing on trees, most of the extra-solar planets we've identified are down-right inhospitable to life as we know it. Lots of dead rocks and gas giants.
That's in no small part because these planets are easiest to identify. Once we have better search techniques, I'm betting garden worlds will turn out to be fairly common.
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Doesn't Prof. Hawking know that the first aliens we meet will look just like us, only with pointy ears? :nervous:
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In my opinion, unless there is some amazingly cheap form of FTL to be discovered, most civilizations will find that interstellar colonization offers no tangible benefit to the home system. Any resources you could hope to obtain from another star system would be much more easily obtained from the home system (i.e., asteroids, moons, gas giants, local sun(s), an Oort Cloud, etc). And if you are hurting for additional living space... look at it this way. If you have the technology and the resources to build a colony ship capable of surviving the decades (or more likely centuries) of travel to another star system, then why bother? Why not just use those technologies and resources to build local habitats that can be put to immediate use? Colonization is a gamble you will not hope to see any payoff from for centuries.
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Which is more likely:
a) The human race ended when one asteroid impacts one planet, killing all humans.
b) The human race ended when ten asteroids impacted ten planets within a short timeframe, killing all humans.
gotta get all of our eggs out of this one basket, even if it is a really nice basket.
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There are a lot more planets than just the Earth in this solar system.
And I'm not limiting us to living on planets. You shouldn't either. From the perspective of a space-faring civilization, planets are about the worst places to live. Assuming some basic biological hurdles are cleared (space radiation, bone and muscle degradation due to living in free-fall, etc.), the biggest attraction of planets is going to be nostalgia. You cannot move a planet out of harm's way. And planets are subject to some nasty misbehavior of their own, a la the Haitian earthquake, the Sumatran tsunami, and the Icelandic volcano just for some more recent examples.
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But a planet like Earth is also a self-correcting biological machine.
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Do you have massive orbital stations and space metropolises in mind? Like Nar Shaddaa from Star Wars?
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Nar Shadda was still a moon. At one point, at least. I think he had some thing more probably like the Citadel from Mass Effect.
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Small moons / asteroids are the most obvious places to start. There are any number of NEAs that would be ideal. Eros comes to mind. There have been quite a few science fiction stories involving that particular asteroid. The moons of Jupiter and Saturn are of particular interest to me just because that would provide so much variety in a relatively small area. The biggest problem there is going to be radiation. Jupiter's magnetic field is truly frightening. I'm given to understand that Saturn's is more benign, but I am not sure how much more benign.
We have been able to enjoy trips into space thus far with relative impunity because we have (almost) always been traveling no further out than low-earth orbit, well inside the van Allen Belts. In other words, all human beings except those on the Apollo moon missions have been safely protected by the earth's magnetic field from the freakish vagaries of charged particle radiation sleeting through space, both from the sun and from elsewhere. As of yet, I have not heard any good plan to protect humans from this radiation during long periods of exposure.
But, assuming you can harden your ships against this radiation, small moons and asteroid can give you protection so long as you build your colonies underground. Also has the benefit of giving you a source for raw materials for your bioplants.
If you are really interested in this sort of thing, I recommend Paul McAuley's "The Quiet War" and "Gardens of the Sun." I was a bit disappointed by the stories themselves, but the biologist's perspective on intrasystem colonization was very interesting and very practical. The books highlighted a lot of the problems we're going to have to overcome, and some of how to do it.
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Which is more likely:
a) The human race ended when one asteroid impacts one planet, killing all humans.
b) The human race ended when ten asteroids impacted ten planets within a short timeframe, killing all humans.
gotta get all of our eggs out of this one basket, even if it is a really nice basket.
It's not just about the eggs, man. It's about the sperm too! :lol:
Until First Contact is made, we won't know anything about the technology of an alien race. So who the **** knows if they'll obliterate us or not.
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Well that works only if the species that wants to colonize, breeds.
However, as we can see from hi-tech nations of today (the First World) do we even now see high grow of population?
I would be willing to argue that a space civilizations has the same (if not better) energy technology that would have allowed it to create almost same conditions in wich people don't really want to make that many babies.
Notice though that all observations so far indicate that a population grows exponentially for as long as space and resources are available. The reason humanity is reaching the point of diminishing growth is because we no longer have the space/resources to sustain such growth. I’d think that if a civilization has better technology, then its growth rate would actually be increased as long as it has the space to do so. In short, exponential growth appears to be inevitable as long as the means for continuing it exists.
To further clarify my above example considering a hypothetical space-faring civilization with the capability to colonize new star systems, we can assume it has nearly limitless space and resources (the entire galaxy), therefore it will have a tendency to grow exponentially, and continue to grow for as long as new habitable planets can be found. The question is how long would it take for this growth to reach out over the entire galaxy, and the answer is that even if you allot 100,000 years for the population to double, then it’d take only 3,000,000 years to colonize a billion planets (230 iterations). It’s doubtful that there are even a billion habitable planets within our galaxy, and the galaxy has been around for a *lot* longer than three million years, so therefore it is unlikely that such capability actually exists. (Or there isn’t other advanced life in the galaxy, but I don’t believe that).
Battuta: “That's in no small part because these planets are easiest to identify. Once we have better search techniques, I'm betting garden worlds will turn out to be fairly common.”
Indeed. We can’t even detect earth-size worlds yet, though we are getting extremely close. :)
Castor: “I think it's a different issue you're talking about. What matters in watsisnames's point is their absolute level of technology, not the level of technology relative to the population they're visiting.”
Well I think he’s comparing interstellar travel to overseas travel, and pointing out how that culture was able to accomplish such travel and yet was very much violent and aggressive against the technologically inferior Americans. Therefore we can’t expect the same to not be true of space-faring races. To be fair, it’s possible that the morality point I brought up isn’t all that valid… perhaps it is inevitable that in the search for growth and riches, better morality is often tossed aside, like what the movie Avatar hints at.
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Well that works only if the species that wants to colonize, breeds.
However, as we can see from hi-tech nations of today (the First World) do we even now see high grow of population?
I would be willing to argue that a space civilizations has the same (if not better) energy technology that would have allowed it to create almost same conditions in wich people don't really want to make that many babies.
Notice though that all observations so far indicate that a population grows exponentially for as long as space and resources are available. The reason humanity is reaching the point of diminishing growth is because we no longer have the space/resources to sustain such growth. I’d think that if a civilization has better technology, then its growth rate would actually be increased as long as it has the space to do so. In short, exponential growth appears to be inevitable as long as the means for continuing it exists.
To further clarify my above example considering a hypothetical space-faring civilization with the capability to colonize new star systems, we can assume it has nearly limitless space and resources (the entire galaxy), therefore it will have a tendency to grow exponentially, and continue to grow for as long as new habitable planets can be found. The question is how long would it take for this growth to reach out over the entire galaxy, and the answer is that even if you allot 100,000 years for the population to double, then it’d take only 3,000,000 years to colonize a billion planets (230 iterations). It’s doubtful that there are even a billion habitable planets within our galaxy, and the galaxy has been around for a *lot* longer than three million years, so therefore it is unlikely that such capability actually exists. (Or there isn’t other advanced life in the galaxy, but I don’t believe that).
Battuta: “That's in no small part because these planets are easiest to identify. Once we have better search techniques, I'm betting garden worlds will turn out to be fairly common.”
Indeed. We can’t even detect earth-size worlds yet, though we are getting extremely close. :)
Castor: “I think it's a different issue you're talking about. What matters in watsisnames's point is their absolute level of technology, not the level of technology relative to the population they're visiting.”
Well I think he’s comparing interstellar travel to overseas travel, and pointing out how that culture was able to accomplish such travel and yet was very much violent and aggressive against the technologically inferior Americans. Therefore we can’t expect the same to not be true of space-faring races. To be fair, it’s possible that the morality point I brought up isn’t all that valid… perhaps it is inevitable that in the search for growth and riches, better morality is often tossed aside, like what the movie Avatar hints at.
When we are reliably able to identify far-off planets, we'll find out if there actually are aliens. :P There's something like 100 billion stars in the galaxy. Say that 1/10th have a planet, 1/10th of those have multiple planets, and 1/10th of those have an earth-sized planet. That's .1% that have an earth-sized planet. Even saying that 1/10th have water and 1/10th of those have liquid water and 1/10th of those have a nitrogen/oxygen atmosphere. That's about 100,000 earth-like planets spread around the galaxy. The diameter of the galaxy is about 100,000 ly and it's about 1,000 ly thick. Assuming it's a cylinder, that's 100,000 earth-like planets in ~6 billion ly3 of space (taking away about 1/4 of the volume of a cylinder; probably should be closer to half). Even in the best case scenario, that's 400,000 earthy planets in ~4 billion ly3 space, or nothing habitable for at least 13 ly in each direction. Even worse odds if there's two or more earth-like bodies in the same system.
Now say 10% of those planets develop life, 10% of those lively planets develop intelligent life, and 10% of those intelligent planets survive to explore the cosmos? That's less than 400 civilizations that could be like us, not counting those destroyed after making it to space... spread over an area in excess of 4 billion cubic lightyears. And at our current rate, we'll sooner settle Mars than even explore Alpha Centauri, by hundreds of years margin.
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While I like the base logic there, how do you figure that 1/10 have a planet, etc.? If the ratio is much smaller, we may never find another one.
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It's an arbitrary number to be sure, but it illustrates the already huge odds against finding a space-faring species in anything resembling adjacent space.
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Not 1/10 having a planet. 1/10th having a habitable planet. :)
edit: whoops, I totally misread what you were quoting -- nevermind :X
edit2: Actually, based on our current data, it appears that the rate of planet formation is higher than 10%. It's possible that more than half of [population II] stars actually form planets, and the rates are higher for stars with higher metallicity (which makes sense because that means more metals/dust were incorporated into the accretion disk as well). So using a 10% figure is actually pretty good in that it's probably lower than the true value.
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Small moons / asteroids are the most obvious places to start. There are any number of NEAs that would be ideal. Eros comes to mind. There have been quite a few science fiction stories involving that particular asteroid. The moons of Jupiter and Saturn are of particular interest to me just because that would provide so much variety in a relatively small area. The biggest problem there is going to be radiation. Jupiter's magnetic field is truly frightening. I'm given to understand that Saturn's is more benign, but I am not sure how much more benign.
We have been able to enjoy trips into space thus far with relative impunity because we have (almost) always been traveling no further out than low-earth orbit, well inside the van Allen Belts. In other words, all human beings except those on the Apollo moon missions have been safely protected by the earth's magnetic field from the freakish vagaries of charged particle radiation sleeting through space, both from the sun and from elsewhere. As of yet, I have not heard any good plan to protect humans from this radiation during long periods of exposure.
But, assuming you can harden your ships against this radiation, small moons and asteroid can give you protection so long as you build your colonies underground. Also has the benefit of giving you a source for raw materials for your bioplants.
If you are really interested in this sort of thing, I recommend Paul McAuley's "The Quiet War" and "Gardens of the Sun." I was a bit disappointed by the stories themselves, but the biologist's perspective on intrasystem colonization was very interesting and very practical. The books highlighted a lot of the problems we're going to have to overcome, and some of how to do it.
charged particle radiation is not hard to sheild for. betas, the most penetrating, only need a few cm of relatively dense material. heavy ions are stopped by a sheet of paper.
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Not 1/10 having a planet. 1/10th having a habitable planet. :)
Not every system will have a planet, and not ever planet will be habitable. In just our solar system, 1/8th of the planets are habitable. Look outside, we've not even identified a single planet that is habitable as-is (or with some plant growth; we should probably be looking for a nitrogen&carbon dioxide planet with water and ~earth gravity, as that'd be easiest to grow know plants and crops in and could quickly provide a source of oxygen. Besides, calling it 1/10th may be a bit more accurate as there are a lot of systems that have already gone (super)nova or are in a multiple-star system. You don't necessarily want to give a binary or trinary star system double or triple (or more) the number of planets; if anything, there'll probably be less planets, as more material is going into the stars or split among cooler stars (Alpha Centauri AB-C is a binary system but star C is a dwarf; the material in that Dwarf is probably as much as our entire solar system has). As far as I know, other than location relative to a volatile star, there's nothing stopping a habitable planet from appearing in a binary+ system. Though almost surely, the planet itself will either orbit one star or will orbit the central point of multiple close stars.
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Another interesting thing to note is that we observe many systems with some truly bizarre planetary orbits, and it's unlikely that habitable worlds could exist in such systems.
We don't yet know how common star systems that "look like ours" (terrestrial worlds close in, gas giants farther out, orbits with low eccentricity) really are in the universe, but hopefully the Kepler mission will help answer that question.
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Not every system will have a planet, and not ever planet will be habitable. In just our solar system, 1/9th of the planets are habitable.
fixed :) pluto will always be a planet!
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fixed :) pluto will always be a planet!
Only to people who don't understand science. :p
Feel free to carry on going on about phlogiston instead of oxygen and mentioning how if we could push the aether out of the way we could get faster than light travel while you're at it though. :p
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charged particle radiation is not hard to sheild for. betas, the most penetrating, only need a few cm of relatively dense material. heavy ions are stopped by a sheet of paper.
Only if those ions etc. have a relatively low energy level. If you are referring to the alpha and beta particles kicked off by radioactive decay, then typical kinetic energy is only going to be on the order of 5 MeV or less most of the time. The minimal shielding you describe would be adequate.
However, a significant portion of the charged particle radiation in space is cracking along at relativistic and ultrarelativistic velocities. I'm seeing 40 MeV being quoted by Wikipedia as a threshold beyond which damage is likely to occur. The Sun can whip out particles with KE in the GeV range. Galactic cosmic rays have been observed with energies of as much as 1020eV. And the real kicker is that unless your shield is a veritable sponge for low AND high energy radiation, the thicker it is, the more secondary radiation you are going to create from spallation.
I do not think it is an unsolvable problem, but it is not a trivial one. Many solutions have been considered. The ones that are most likely to be effective are some of the most difficult to implement because of our extremely limited surface-to-orbit lifting capacity.
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fixed :) pluto will always be a planet!
Only to people who don't understand science. :p
Feel free to carry on going on about phlogiston instead of oxygen and mentioning how if we could push the aether out of the way we could get faster than light travel while you're at it though. :p
Are you telling me my ether plow isn't going to work?
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fixed :) pluto will always be a planet!
Only to people who don't understand science. :p
Only to people who underestimate Macgyver (http://macgyverpluto.ytmnd.com/):P
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fixed :) pluto will always be a planet!
Only to people who don't feel like following pointless arbitrary rules that have no bearing on reality. :p
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Well I think he’s comparing interstellar travel to overseas travel, and pointing out how that culture was able to accomplish such travel and yet was very much violent and aggressive against the technologically inferior Americans. Therefore we can’t expect the same to not be true of space-faring races. To be fair, it’s possible that the morality point I brought up isn’t all that valid… perhaps it is inevitable that in the search for growth and riches, better morality is often tossed aside, like what the movie Avatar hints at.
Oh, I thought your were talking about the probability of a civilization to extinct/near-extinct itself half accidentally (catastrophic failure in controlling the use of power). Among a number of civilizations with the same "level of moral", the most technologically advanced is the most capable (probable) to pull that off, I'd think? In long run, that should favor the more pacifistic civilizations to grow more advanced.
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I find it hard to believe that we're closer to extraterrestrial contact than technological singularity (http://en.wikipedia.org/wiki/Technological_singularity).
And if tech singularity radically changes everything we currently understand about society, humanity, and Earth, all current hypotheses about extraterrestrial contact are meaningless.
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We are of course assuming that said race doesn't have awesome technology that allows them to defy physics and travel between solar systems in a few weeks with low energy costs, making FTL travel highly accessible.
If we humans ever get something like that, say, subspace drives, you bet we're going to be competing amongst ourselves for territory and resources with mass drivers and fusion warheads.
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That would be a very fast conflict.
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charged particle radiation is not hard to sheild for. betas, the most penetrating, only need a few cm of relatively dense material. heavy ions are stopped by a sheet of paper.
Only if those ions etc. have a relatively low energy level. If you are referring to the alpha and beta particles kicked off by radioactive decay, then typical kinetic energy is only going to be on the order of 5 MeV or less most of the time. The minimal shielding you describe would be adequate.
However, a significant portion of the charged particle radiation in space is cracking along at relativistic and ultrarelativistic velocities. I'm seeing 40 MeV being quoted by Wikipedia as a threshold beyond which damage is likely to occur. The Sun can whip out particles with KE in the GeV range. Galactic cosmic rays have been observed with energies of as much as 1020eV. And the real kicker is that unless your shield is a veritable sponge for low AND high energy radiation, the thicker it is, the more secondary radiation you are going to create from spallation.
I do not think it is an unsolvable problem, but it is not a trivial one. Many solutions have been considered. The ones that are most likely to be effective are some of the most difficult to implement because of our extremely limited surface-to-orbit lifting capacity.
i hadn't considered the higher energies, no. but how much exposure from those is there when you aren't right next to a star? radiation intensity falls off as 1/r^2. heavy ions of huge energies would still have relatively short ranges (i.e., not requiring feet of material), but would do a ****load more damage. cosmic rays would be rather penetrating, but if i'm correct in my understanding, the earth's atmosphere does not sheild those and we are already subject to them as part of our natural background radiation, and that component shouldn't change in space.
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We are of course assuming that said race doesn't have awesome technology that allows them to defy physics and travel between solar systems in a few weeks with low energy costs, making FTL travel highly accessible.
If we humans ever get something like that, say, subspace drives, you bet we're going to be competing amongst ourselves for territory and resources with mass drivers and fusion warheads.
As long as there's free space, the only conflicts going on would be those of planets/star systems etc trying to get independant from Earth (or later on other planets).
Either that or fighting with aliens.
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i hadn't considered the higher energies, no. but how much exposure from those is there when you aren't right next to a star? radiation intensity falls off as 1/r^2. heavy ions of huge energies would still have relatively short ranges (i.e., not requiring feet of material), but would do a ****load more damage. cosmic rays would be rather penetrating, but if i'm correct in my understanding, the earth's atmosphere does not sheild those and we are already subject to them as part of our natural background radiation, and that component shouldn't change in space.
Potentially, expose could be pretty severe. If the Apollo astronauts had been unlucky enough to be half-way between the Earth and the Moon during a solar flare, they would have been exposed to enough radiation to kill them in a matter of hours.
Even under nominal levels of solar activity, the cumulative radiation exposure is sufficient that health problems are inevitable unless some kind of protection can be implemented. Either biological hardening (augmenting our bodies' ability to cope with higher ambient levels of radiation) or physical shielding, or some combination of the two.
Radiation intensity does fall off as the inverse square of distance, yes. But we're dealing with individual particles here with sufficient energy to do damage just on their own. The effect is cumulative. The Earth's atmosphere and magnetic field do a pretty good job of protecting us from all but the most extremely energetic particles down here on the surface. Outside of that protective envelope, there's an entire spectrum of charged particle radiation we are not normally exposed to (unless you happen to sleep in a cardboard box huddled under a nuclear reactor to keep warm). Mostly, we're talking about very fast moving protons (hydrogen ions), but there is some helium and heavier ions in the spectrum. It's worth reading up on if you are really interested. Next to our pitiful surface-to-orbit capacity, space radiation is probably the biggest hurdle we need to overcome before we can really start living in space.
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So here's an interesting question that even Hawking didn't seem to touch on.
What if the dominant form of life in the universe isn't remotely organic or even sentient? What if the von Neumanns have taken over?
Most biomass here on Earth is bacterial or insectoid. Neumanns would be the analogous tactic on the galactic level, except their advantages over 'standard' aliens would be even more pronounced.
I did a story once in which the galactic ecosystem was dominated by berserker-style Neumanns that were attracted by radio activity (a relic of their original programming as weapons in an early-universe war.) Our solar system seemed to have some kind of mysterious immunity, and the thrust of the story was figuring out why. Cookie for anybody who gets it.
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So here's an interesting question that even Hawking didn't seem to touch on.
What if the dominant form of life in the universe isn't remotely organic or even sentient? What if the von Neumanns have taken over?
Most biomass here on Earth is bacterial or insectoid. Neumanns would be the analogous tactic on the galactic level, except their advantages over 'standard' aliens would be even more pronounced.
I did a story once in which the galactic ecosystem was dominated by berserker-style Neumanns that were attracted by radio activity (a relic of their original programming as weapons in an early-universe war.) Our solar system seemed to have some kind of mysterious immunity, and the thrust of the story was figuring out why. Cookie for anybody who gets it.
Because they were programmed to ignore their system of origin? They are what is left from the first time life evolved on Earth; all life currently on Earth, including us, is a result of a second "genesis" after a mass extinction event.
:nervous:
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Good guess...but not the direction I took.
Imagine a Neumann ecology. Presumably they'd start preying on each other.
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They saw what a fantastic job we humans have done of killing each other over the millennia and figured they didn't want to stick around to be offed themselves? :p
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I just remembered I had this...
[attachment deleted by admin]
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Good guess...but not the direction I took.
Imagine a Neumann ecology. Presumably they'd start preying on each other.
Tomato in the mirror? (http://tvtropes.org/pmwiki/pmwiki.php/Main/TomatoInTheMirror)
Or is that too cliché?
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Good guess...but not the direction I took.
Imagine a Neumann ecology. Presumably they'd start preying on each other.
Tomato in the mirror? (http://tvtropes.org/pmwiki/pmwiki.php/Main/TomatoInTheMirror)
Or is that too cliché?
If...I'm understanding the trope right...I think it's a step in the right direction?
(This guessing game makes me feel incredibly self-important. :nervous:)
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I just remembered I had this...
That's pretty cool.
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I just remembered I had this...
That's pretty cool.
Concur, it was a very interesting read.
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It was pretty good. Reminded me a bit of Vernor Vinge's best work.
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Enjoyable little read, that.
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Although it's worth pointing out it was clearly written by an amateur, and the punch line's a bit tired. But it's a fun role reversal of sorts.
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I just remembered I had this...
cool story bro!
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I just remembered I had this...
Nice, I like it.
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I just remembered I had this...
Would be better if it were in actual text format, though.