Average Seperation

[Dr. Anomaly]

Re: Average Seperation

 

BTW' date=' could you tell me where you read that Sol was moving at the same speed as the spiral arm? I think the shock-wave is faster, and in fact Sol has been in and out of spiral arms a number of times in its 4.5 billion years of existance.[/quote']

I didn't, and I didn't mean to imply that...if my earlier post sounded that way, I apologize. I just meant it to say that the stars that currently make up an arm are moving in an orbit around the center of the galaxy, because I didn't want to give the impression the stars were standing still as the wave moved past/through them. And yes, I'm sure the compression waves are moving faster than the stars are.

[Dr. Anomaly]

Re: Average Seperation

 

So the gaps are called "lanes" huh? Interesting. So all I need to do if create a number of additional populated worlds that' date=' like Earth, escape the compression waves. I'm figuring this won't be too accurate, scientifically, but it'll work for a game and seem at least remotely plausable. At least I think it will. I hope so anyway. One of my players knows a LOT more about this stuff than I do, and another's actually taking classes.[/quote']

Sol and Earth haven't "escaped" the compression waves; as a matter of fact, we're in one of the spiral arms right now...the Orion Arm. As Basil pointed out, the real concern in that case would be "is the world too close to a star that has gone (or will go) supernova?"

 

If you're looking for something to "restrict the territory" that spacefaring races have available to them, or to put gaps of "star desert" between inhabited systems, see my earlier post about the "oasis" suggestion.

[Dust Raven]

Re: Average Seperation

 

I didn't' date=' and I didn't mean to imply that...if my earlier post sounded that way, I apologize. I just meant it to say that the stars that currently make up an arm [i']are[/i] moving in an orbit around the center of the galaxy, because I didn't want to give the impression the stars were standing still as the wave moved past/through them. And yes, I'm sure the compression waves are moving faster than the stars are.

It was me that said that.

 

I don't recal exactly where I saw it, it was one of the things I came across through the links above. I don't know what page I finally got to that said that though, sorry.

 

In any case, if I'm wrong, then the source I read was wrong, or else I inferred something from it that I shouldn't have.

[Dust Raven]

Re: Average Seperation

 

Sol and Earth haven't "escaped" the compression waves; as a matter of fact' date=' we're [i']in[/i] one of the spiral arms right now...the Orion Arm. As Basil pointed out, the real concern in that case would be "is the world too close to a star that has gone (or will go) supernova?"

 

If you're looking for something to "restrict the territory" that spacefaring races have available to them, or to put gaps of "star desert" between inhabited systems, see my earlier post about the "oasis" suggestion.

One thing I don't like about the oasis idea is that it would make one race for each oasis highly dominant due to having more time to evolve compared to any others nearby. In the time it would take a rock flung off of one planet as life was forming to reach the nearest star, that's one planet's life might already have developed a technological civilization. By the time that civilization reaches the other worlds the life there is still fighting to create a stable ecosystem. Even if it only takes a thousand years or so for the liferock to seed other worlds, that puts whatever life is there a thousand years behind where life originated.

 

The other thing is that if I wanted to keep the campaign inside one of these bubbles, all the life would have to be really, really similar (at least as similar as life on Earth is). While I subscribe to the idea that there will be many evolutionary constants among sapient races, I don't want the races in my campaign to be that similar.

 

I don't mean to put down your idea, I acutally like it. I just don't think it will work for the campaign I want to run.

[Dust Raven]

Re: Average Seperation

 

Okay, so other than the occasional Supernova, which aren't much more common anyway, stars in the galactic arms aren't any less likely to develope life, theoretically speaking. Does that include intelligent life? I suppose we have no way of knowing... but would it be plausable to assume so? Sure, there would be a number of worlds in the arms that have intelligent life, but not nearly as many as in the lanes. Just as many worlds capable of having life, and just as many worlds with life, just not nearly as many worlds that developed intelligent life. Due to the occasional nearby supernova or being in an area with too much background radiation.

 

If this is even remotely plausable, I'm happy. It's space opera, and all I need to "remotely plausable" to make my players happy. Maybe even the astronomer.

[Dr. Anomaly]

Re: Average Seperation

 

One thing I don't like about the oasis idea is that it would make one race for each oasis highly dominant due to having more time to evolve compared to any others nearby. In the time it would take a rock flung off of one planet as life was forming to reach the nearest star' date=' that's one planet's life might already have developed a technological civilization. By the time that civilization reaches the other worlds the life there is still fighting to create a stable ecosystem. Even if it only takes a thousand years or so for the liferock to seed other worlds, that puts whatever life is there a thousand years behind where life originated.[/quote']

Not necessarily. First, planets themselves vary so widely in their individual make-up and circumstances, there's no way put a "standard benchmark" on how long evolution will take to produce an ecosystem or intelligent life. For example, the Earth has had a series of major extinction events every 60 - 200 million years, and at least one of those wiped out over 90% of the species on Earth, and most of those that survived were ocean-going. Where would life (and intelligent life) on Earth be now if those extinction events hadn't happened? Millions or billions of years ahead of where we are now.

 

I'm not trying to 'force' you to use my idea or anything, just point out there are so many different environmental factors for each individual world that there is no way to say that "worlds on the rim of the bubble will be xxx many years behind worlds near the center of the bubble" -- after all, if worlds near the center of the bubble keep getting hit with the 'cosmic reset button' and some worlds near the 'rim' don't, they could well be on equal footing.

 

For that matter, the kind of impact that would be necessary to toss "lifeboat" rocks out of the gravity well of a planet like Earth probably would be large enough to cause an extinction event...meaning that the world(s) that served as the source of the "seeds" likely wouldn't be all that far ahead of the worlds that got seeded.

 

Plus, with evolution being the hit-or-miss thing it is, one world might have an ecosystem 20 billion years old that never evolved intelligent life, and another world might get intelligent life in only a billion years. There's simply no way to predict.

 

Like I said, please don't take this as "brow-beating" -- more just playing Devil's Advocate for your ideas/assumptions.

 

The other thing is that if I wanted to keep the campaign inside one of these bubbles' date=' all the life would have to be really, really similar (at least as similar as life on Earth is). While I subscribe to the idea that there will be many evolutionary constants among sapient races, I don't want the races in my campaign to be that similar.[/quote']

 

Again, not necessarily; it really depends on what you mean by "similar". If you mean on the dna / ammino acid level -- then yes, probably. But keep in mind that if your various aliens and ecosystems aren't compatible at that level, they won't be eating each other's foods, drinking each other's beverages, and so on, as they'd at best be indigestible and at worst be poisonous. That also means that it would be nearly impossible to colonize other worlds, because you'd have to bring your entire ecosystem, from the microbes on up, with you, and you'd have to completely wipe out the native ecosystem of the place you're trying to colonize. That doesn't make colonization a very attractive option, since basically what you'd be doing is terraforming with the added hassle of trying to make sure you permanently stomped out the indiginous ecosystem without doing so much damage in the process that your transplanted ecosystem won't be able to survive.

 

This would also cut down on the reasons for warfare. One of the most popular reasons for war between planets is resources. Well, if you're just talking mineral-type resources, those are available far more abundantly on airless, rocky bodies (from asteroids up to Mercury or Mars -size planets) and you don't have to fight anyone for them. If you're going to go to the bother of invading/warring with an already-inhabited world, it won't be mineral material resources you'd be after...it'd be something that doesn't occur "naturally" (that is, things not on the periodic table or things that are not minerals that form naturally from elements on the periodic table). That usually means something from the biosphere/ecosphere...and if your alien races are so different from each othere that there's not some kind of compatibility on the dna/ammino acid level, there's probably not a reason for conflict.

 

If it's a conflict over living space (both races need planets that orbit the same type of stars at the same approximate distance from those suns) then you've got the "terraforming" problem again. Since you'd have to completely wipe out the native life forms before you could transplant your own, you'd be far better off finding a world in the right general place, but that never formed a biosphere (like Venus) and terraforming it...you don't have the extra "expense" of wiping out the native (possibly intelligent and able to defend itself with weapons) life.

 

If you think, then, that your various alien races will be compatible at the dna/ammino acid level, then why are you worried about "seeded" planets having life that's "too similar" to that of the "parent" planet? Just look at the huge variety of life here on Earth. Now take some microbes from Earth, put them on another potentially life-bearing world, and let them grown and evolve. Since evolution is hit-or-miss (it doesn't go with the best solution, it goes with the first solution that works [ie doesn't die]) there's no reason at all to believe that a world seeded with Earth microbes would develop life forms that looked anything at all like those of Earth. Earth itself is justification for having any amount of difference you like between your aliens, and Earth is just one planet...can you imagine the variety that would ensue if the same kind of evolutionary chain was run on a dozen different planets, with their individual varying factors? It boggle the imagination!

 

If you didn't mean either of those two things by "too similar", I guess I missed your point and will ask you to clear up for me what you do mean by "similar".

 

I don't mean to put down your idea' date=' I acutally like it. I just don't think it will work for the campaign I want to run.[/quote']

No offense taken, etc. And as I said, please don't take the above as trying to "force" you to use my idea.

[Dust Raven]

Re: Average Seperation

 

No offense taken' date=' etc. And as I said, please don't take the above as trying to "force" you to use my idea. [/quote']

No problem. I'm just looking for other options. Thanks for working on this with me. You've got some brilliant ideas. I'm actually kinda sorry I don't want to use any of them (though I might latter on, dunno yet).

[Dr. Anomaly]

Re: Average Seperation

 

No problem. I'm just looking for other options. Thanks for working on this with me. You've got some brilliant ideas. I'm actually kinda sorry I don't want to use any of them (though I might latter on' date=' dunno yet).[/quote']

Help yourself; use whatever you want to, including nothing at all. Besides the fact that this is a community of like-minded individuals in which we make an effort to help each other...well, my close friends would all tell you that I love to "help" this way. (They'd mean, "He loves to talk and to pontificate." )

[Basil]

Re: Average Seperation

 

I didn't' date=' and I didn't mean to imply that...if my earlier post sounded that way, I apologize. I just meant it to say that the stars that currently make up an arm [i']are[/i] moving in an orbit around the center of the galaxy, because I didn't want to give the impression the stars were standing still as the wave moved past/through them. And yes, I'm sure the compression waves are moving faster than the stars are.

It was me that said that.

 

I don't recal exactly where I saw it, it was one of the things I came across through the links above. I don't know what page I finally got to that said that though, sorry.

 

In any case, if I'm wrong, then the source I read was wrong, or else I inferred something from it that I shouldn't have.

 

Ah, OK. No harm done.

 

Help yourself; use whatever you want to, including nothing at all. Besides the fact that this is a community of like-minded individuals in which we make an effort to help each other...well, my close friends would all tell you that I love to "help" this way. (They'd mean, "He loves to talk and to pontificate." )

Hmmm... I believe I have that disease too.

 

Thanks for covering matters in more detail than I would've thought to.

[Dr. Anomaly]

Re: Average Seperation

 

Hmmm... I believe I have that disease too.

 

Thanks for covering matters in more detail than I would've thought to.

You're welcome. Anything for a fellow sufferer of AD!

[Michael Hopcroft]

Re: Average Seperation

 

It wouldn't be that great a stretch to psotulate a galaxy in which intelligence evolved only on Earth. After all, from the perspective on a species survival it isn;t all that valuable a characteristic and there is no reason it should be selected for more readily than any other. If one doesn;t want to go that far, it is more reasonable to think that the sort of tehcnolgocial stepping-stones required to reach the stars were only reached or survived on earth, and that by the skin of our teeth -- we very nearly didn;t survive learning how to split the atom, after all, and still mgiht not.

 

The result would be a cosmos in which humans would explore as much of their spiral arm as they can reach for thousands of years and still nto meet an alien species. natural genetic variation would result in humans changign as they settle in different environments, so that in, say, 3,000 years we might encoutner human sub-species that are alien in msot of the areas that matter but that are still descended from Earth's gene pool.

 

This, of course, assumes interstellar travel is possible at all, which all the evidence indicates is not true in the real world. any trip to another solar system will likely be essentially one-way, with no future contact with home at all.

[Nyrath]

Re: Average Seperation

 

The result would be a cosmos in which humans would explore as much of their spiral arm as they can reach for thousands of years and still not meet an alien species. natural genetic variation would result in humans changign as they settle in different environments' date=' so that in, say, 3,000 years we might encoutner human sub-species that are alien in most of the areas that matter but that are still descended from Earth's gene pool.[/quote']

Offhand I'd say you need more than 3,000 years for that to happen. 3,000 years ago from right now was ancient Egypt, and nobody believes that they were a different species from us.

 

The current human species arose about 30,000 years ago.

[Dr. Anomaly]

Re: Average Seperation

 

Offhand I'd say you need more than 3,000 years for that to happen. 3,000 years ago from right now was ancient Egypt, and nobody believes that they were a different species from us.

 

The current human species arose about 30,000 years ago.

Given current advances in genetics, I'd lay money on colonists using genetic manipulation to make themselves better suited for survival on the world they've chosen. With that, 3,000 years becomes a snap for species variations.

[Basil]

Re: Average Seperation

 

It wouldn't be that great a stretch to psotulate a galaxy in which intelligence evolved only on Earth.

Isaac Asimov's Foundation Trilogy had this as an underlying assumption.

 

After all' date=' from the perspective on a species survival it isn;t all that valuable a characteristic and there is no reason it should be selected for more readily than any other.[/quote']

This idea is popular in certain circles. However, it is not science, but cynicism. Being smarter than ones potential prey/hunters is very valuable for the survival of a species.

 

If one doesn;t want to go that far' date=' it is more reasonable to think that the sort of tehcnolgocial stepping-stones required to reach the stars were only reached or survived on earth, and that by the skin of our teeth -- we very nearly didn;t survive learning how to split the atom, after all, and still mgiht not.[/quote']

The problem with this, is that just because humanity has come close to harming itself with some technologies dose not mean (A) other species would do so, nor ( that other species would go through the same or similar sequence of technological change. A species that, say, discovered how to work with electricity long before developing steam power would possibly not cause widespread ecological devistation (deforestation, acid rain, global warming, etc.). Or, say, a race on a planet with little available metals (copper, tin, iron) might start off concentrating on ceramics.

 

Of course, a race evolved from pure herbavores, or pure carnivores, might have better innate ways of dealing with intraspecies conflict. And intraspecies conflict, not technology in and of itself, is what has made humans endanger their continued existance as a species.

 

The result would be a cosmos in which humans would explore as much of their spiral arm as they can reach for thousands of years and still nto meet an alien species. natural genetic variation would result in humans changign as they settle in different environments, so that in, say, 3,000 years we might encoutner human sub-species that are alien in msot of the areas that matter but that are still descended from Earth's gene pool.

 

This, of course, assumes interstellar travel is possible at all, which all the evidence indicates is not true in the real world. any trip to another solar system will likely be essentially one-way, with no future contact with home at all.

 

However, even with no FTL, different "branches" of the human race may meet as different "zones of expantion" run into each other.

[Basil]

Re: Average Seperation

 

BTW, regarding the Drake Equation and the presense of planets around a star, some advice

 

Go down to your neighborhood library and check out the December 2004 copy of National Geographic. It has an article on current, real-world efforts to locate and identify planets around nearby stars. So far 130 (!) stars have been proven to have planets.

[Dust Raven]

Re: Average Seperation

 

BTW, regarding the Drake Equation and the presense of planets around a star, some advice

 

Go down to your neighborhood library and check out the December 2004 copy of National Geographic. It has an article on current, real-world efforts to locate and identify planets around nearby stars. So far 130 (!) stars have been proven to have planets.

Does it mention any trend as to the types of stars that have planets?

[DrTemp]

Re: Average Seperation

 

Does it mention any trend as to the types of stars that have planets?

 

You'll probably find tons of info about that on the 'net. One thing, though: the as-yet-detected planets are almost all of the gas giant variety. AFAIK, only one "terrestrial planet" (which means "a ball of rock") could be located, and they're not sure whether it is that or just a very small gas giant.

 

The problem with detecting extraterrestrial planets with curent technology is that one cannot spot them directly with a tetelscope or something- they simply look at the star and try to see when it is dragged a tiny bit towards a direction were it douldn't be dragged, thus assuming that there must be some planetary body whose gravity well draws thestars towards them. The exact size of that (_very_...) tiny bit tells the astronomers how large and heavy the planet is. Humanity will need a lot better telescopes for directly spotting extraterrestrial planets.

[Bucky]

Re: Average Seperation

 

So a new question... is there any basis (one way or the other) for having populated worlds be grouped together like this? If I have to alter the type of galaxy I suppose I could, but I'd like to stick with something familiar to the players. If push comes to shove, I'm running a Space Opera campaign and can just say "this is how it is" and leave it at that. I would prefer some spiffy realism though. My goal is to run an epic space opera with fantastic events, but with each nifty thing actually having a speculative basis in hard science.

Yes. The first species that developes starflight will spread and populate the nearby regions. The nearby stars in their local area, and end up (whether it is planned or not) conquering more and more star systems. This will tend to reduce the number of technically advanced, and even intelligent species. The strong will survive and end up removing any potential threats to the dominant species.

 

Slavery is not a viable option for long, as most slaves don't like it, and tend to rebel eventually. Any weakness or lack of vigalence by the Master Race will be its downfall.

 

You also have to look at Fermi plagues. This will also reduce the number of species as well. The direction of technology has been and probably always will be, to do more and more with less and less. While at one time it may have taken a very high proportion of a planet's GDP to produce, say, an atom bomb, after a few decades, GDP goes up, and cost of replicating the technology, and research becomes less. You need fewer resources, and fewer PEOPLE to do the same time.

 

Until you get to the point where too many people have so much capabilities, that one jerk can wipe out the entire planet. All it takes is one jerk to screw up anything.

[Dust Raven]

Re: Average Seperation

 

I'm kinda the unstuddied layman on astromomy, so correct me if I'm wrong: Would that tiny little bit of movement be the result of the cumulative gravity of all the planets orbiting a star? If all we can detect is the difference, how do we know how many planets there are and what size? Couldn't a shift in one direction mean one really large planet, or several smaller ones. How could we tell the difference?

[Bucky]

Re: Average Seperation

 

Does it mention any trend as to the types of stars that have planets?

 

At present there appears to be no reason any star to not have planets. Planets appear to be a natural byproduct of the star forming process.

 

Now, whether those planets are habitable, that is another question altogether. Most rocky planets are probably barren. The larger the star, the faster it burns through its fuel, and life does not have time to form. And alot of planets in the green zone may not have adequet water.

[Dust Raven]

Re: Average Seperation

 

Yes. The first species that developes starflight will spread and populate the nearby regions. The nearby stars in their local area, and end up (whether it is planned or not) conquering more and more star systems. This will tend to reduce the number of technically advanced, and even intelligent species. The strong will survive and end up removing any potential threats to the dominant species.

 

Slavery is not a viable option for long, as most slaves don't like it, and tend to rebel eventually. Any weakness or lack of vigalence by the Master Race will be its downfall.

 

You also have to look at Fermi plagues. This will also reduce the number of species as well. The direction of technology has been and probably always will be, to do more and more with less and less. While at one time it may have taken a very high proportion of a planet's GDP to produce, say, an atom bomb, after a few decades, GDP goes up, and cost of replicating the technology, and research becomes less. You need fewer resources, and fewer PEOPLE to do the same time.

 

Until you get to the point where too many people have so much capabilities, that one jerk can wipe out the entire planet. All it takes is one jerk to screw up anything.

How would this group together different alien races? It sounds more like the spreading of a single race over all the nearby planets.

[Bucky]

Re: Average Seperation

 

I'm kinda the unstuddied layman on astromomy' date=' so correct me if I'm wrong: Would that tiny little bit of movement be the result of the cumulative gravity of all the planets orbiting a star? If all we can detect is the difference, how do we know how many planets there are and what size? Couldn't a shift in one direction mean one really large planet, or several smaller ones. How could we tell the difference?[/quote']

 

By looking at the waveform of the doppler shift.

If its one planet, it will come out as a smooth sine wave. If multiple planets, you end up with slightly more complex waveform that will be a sum of the sine waves produced by each planet individually.

 

Different planets will inhabit different orbits, and will not stay in the same relative position to each other.

[Bucky]

Re: Average Seperation

 

How would this group together different alien races? It sounds more like the spreading of a single race over all the nearby planets.

 

Grin, that is a toughy. BUt not much of one.

 

Now, if you are a weaker species, facing a galaxy conquering one, bent on destroying your world, what do you do? Run. Where do you run to? Hopefully a stronger species than the one that is invading your space.

 

Plus the fact that you have allied yourself with another species, does present the potential of creating a force stronger than the ones that kicked you out of your homeworld.

 

Another way is persuasion, or commerce. Its a lot less violent, and less destructive. And encourages different species to come together and pool their various talents.

[Nyrath]

Re: Average Seperation

 

I'm kinda the unstuddied layman on astromomy' date=' so correct me if I'm wrong: Would that tiny little bit of movement be the result of the cumulative gravity of all the planets orbiting a star? If all we can detect is the difference, how do we know how many planets there are and what size? Couldn't a shift in one direction mean one really large planet, or several smaller ones. How could we tell the difference?[/quote']

By the cycle. Due to the laws of orbital mechanics, it is well nigh impossible for several planets to orbit in lockstep, so a line drawn from the star to the nearest planet would always intersect the other planets.

 

This means it is impossible for a series of planets to mimic one huge planet.

 

Since they are not in lockstep, eventually one would be on one side of the star while the others were on the opposite side, and the star would not be tugged in the same way.

 

The shifts that the astronomers observe is in a simple cycle, which means a single large planet. There may be other planets around that star, but their tugs are too tiny to detect.

[Nyrath]

Re: Average Seperation

 

Go down to your neighborhood library and check out the December 2004 copy of National Geographic. It has an article on current' date=' real-world efforts to locate and identify planets around nearby stars. So far 130 (!) stars have been proven to have planets.[/quote']

No need. You can find all that info at the Extrasolar Visions site. It has the data on 132 planets, two more than National Geographic.

 

Interested parties might also want to examine my HabHYG database. It has about 31,000 stars, with the "likely-to-have-a-human-habitable-planet" stars flagged (as per the HabCat database). Note that this is only human habitable, different stars would be suitable for energy creatures, gas giant dwellers, and other life-as-we-don't-know-it.