Discussion in 'Science & Technology' started by Disgustipated, Sep 29, 2010.
Wake me up when they find a planet orbiting Delta Trianguli.
Fabulous sci fi from Roger Zelazny
Jack of Shadows
And Pioneer isn't even headed in the direction of the Alpha/Proxima system!
Let's see... acid rain, semi-molten surface, crushing pressure on Venus... no ozone layer on Mars to keep the UV from frying people...
I don't think either place will let us wander around in shirt-sleeves any time soon.
As for this new planet, just because it might have liquid water, that doesn't mean it's suitable for life. It's not like we can just pack up and move there (assuming we had the means to travel there).
What would the hypothetical plant life be like there? A red star would not produce the same kind of light we have here on Earth. And a tidally-locked planet? Thanks, but I'll pass. There might be some interesting bits of life there, but it's not the sort of place where intelligent, technologically advanced beings can evolve. The geological and meteorological factors are not in their favor.
Sounds like the biggest threat on life for this planet.
All the water, you mean it would travel to the cold side? How so? I mean on earth there are polar zones and they don't gather lots amounts of water. There would probably be some exchange of heat, eg if there's a pool of water shared between cold and hot side.
But this planet is "smack in the middle" of the goldilock zone, not on the fringes. The system actually have one planet on either edge just like our.
Actually, from what I've heard so far (the 1h video I linked above) the weather could actually be a lot better there than on our planet - on the twilight zone that is. According to one of the scientist, weather on tidally locked planet have been modelled and there would be light winds but no storms like on earth. Being tidally locked, any creature could pick its own favourite temperature and live there.
In fact it makes me wonder how fast the evolutionary process could be on this planet, when there's almost no environmental change to bully life. Also if red dwarfs lacks UV light there will be fewer mutations. Furthermore, life essentially have an 2-dimensional band to spread, easily cut off by oceans. Combine that extremely slow evolutionary process with an instable sun that will cut off any attempts to develop intelligent life (only lush plant life with the tastiest fruit will survive) and we may well have a planet ready to be colonized.
Too bad all these speculations is based on measurements on how much this and the other planets tug on the star. Slightest error can remove planets or change their size by magnitudes.
If the planet supports life, it may not exactly be ready for Human colonization. And even if it is, there are many challenges for example alien diseases etc.
Even if we can get to the planet, I doubt majorly we'd colonize it anytime soon.
There are zones between the absolute light and absolute darkness that have habitable ranges.
Ah but if there is no change then there is no reason to evolve, so I would conjecture that a static enviroment would infact have the opposite effect and life would never get out of the green goo stage.
Not quite, at a constant 1G acceleration a spacecraft would hit light speed in about a year (impossible, but thats another discussion) So you can only accelerate for a year, not half the trip, and then decelerate for another year at your destination.
Heres a nice little bit of trivia, Voyager 1, currently travelling @60,000 km\hr would take approx 76,000 years to reach our nearest neighbour Proxima Centauri @4.3 light years (to reach the planet in this discussion 350,000 years, give or take). The fastest speed ever attained by one of our ships is Helios 2 @240,000 km/hr (Sol sling shot) at that speed we could reach Proxima Centauri in 19,000 years, thats 66km/sec, or as a comparison a powerful gun can get a bullet up to approx 1.5km/sec.
At the fastest speed we could theoretically go, Nuclear pulse propulsion, we could get to Proxima Centauri in 85 years, 85 years to our next door nieghbour! 455 years to Gliese, which at best might have some green goo, but wont support human life. And thats assuming that we dont hit anything larger then a grain of sand in that time, which at those speeds would tear any ship apart. Now take into account the odds of discovering a world capable of supporting a complex life form like us, within say 100 light years. Thats probably in the range of 15,000 stars, extremely unlikely, better chance at winning the lottery... four times in a row . So now we have to go outside of 100 light years, or over 2000 years travel time, and more then likely outside of 1000 light years, if were lucky, thats 20,000 years travel time. Now thats just finding a planet 'capable' of supporting complex life, the odds of such life developing are again astronomical.
I always have to chuckle at the people who think aliens are here like its some kind of weekend getaway @earth, they just have no concept of the distances involved and the rarity of not only an earth like planet but of intelligent life developing on such a planet. Now somebodys bound to bring up some fictional Star Trek science we have yet to discover, so lets play the FTL card (pure fiction) and do some calculations... if you could visit one star, PER DAY, it would take over 1 billion years to map our milky way galaxy.
As amazing as all that is, one of the most amazing things about it, is our little planet, full of our little sentient humans, probably the single most rarest thing in the entire universe... and the saddest part, that we are risking destroying it for the profit of a tiny minority, meaningless figures they amass, that in the end amount to absolutly nothing.
Actually... The habitable zone is a really poorly defined concept. It's defined as where they estimate, assuming an earth-like planet in terms of mass and composition, where enough energy lands on the planet to keep water liquid.
How do they decide how much energy? They estimate distances away from Sol where they would have enough energy to keep a planet liquid, and then take the brightness and extrapolate it to other stars.
Of the ~10 papers I read, only one (a rather old one IIRC) mentioned that Venus was in the habitable zone, and it was only very early in the solar system's existence before it was pushed out.
Mars is considered "in" the habitable zone for other models, but it is not similar enough to Earth for the habitable zone model to apply.
Eh, tidally locked can be negated with having either a thick atmosphere, or a large ocean. Then you get nice currents to circulate the energy around, so things tend to not suck in the dark as much.
It's the same reason why Britain is far warmer than Canada in the winter at the same latitude.
There aren't very many currents to the north/south poles.
North Pole gets some currents, but the continent placement isn't optimal for currents to go there. There are continents in the way for the South Pole. That is a huge factor, as there were no polar ice caps at the time of the dinosaurs with all the land in Pangaea, while when the (rather large) continent of Rhodesia sat on the South Pole, we had snowball earth.
Careful... "slow evolution" is primarily a result of a lack of selection pressures. The Cambrian Explosion is due to the development of bony features, which allowed predators to easily slaughter prey. Then the biological arms race built up, with prey developing bony features as armor, increasing swimming speed by reducing armor while retaining a nice endoskeleton for rapid muscle movements, developing lungs to move onto land and avoid water-borne predators, etc.
Radiation helps, yes, but selection pressures produce larger effects. (the sun isn't the only source of radiation also; radon from uranium decay is another, and that actually outweighs the UV light ionizing radiation effects)
Yeah, but discoveries such as these tend to be carefully examined first before release. If you rush your discovery, and then end up having to retract it later, your reputation is flushed down the toilet.
Still, give it a year or so as they bring more powerful instruments to bear now that we've gotten a good target to probe to reduce the error bars.
Contrary to what the movies say, alien diseases will be the least of your worries.
First off, the chances they will have developed the same the same molecular chirality, the same amino acid building blocks (of the 60 types of amino acids, only 20 are used by all life on earth), the same trace element requirements (phosphorous vs arsenic is a classic), as well as a whole pile of chemical processes that need to be carefully balanced for compatibility (they might be the equivalent of our extremophiles, and can only survive in high salinity/acidic/basic/heat environments else dissolve/denature) that alien diseases is considered a non-factor.
It's like picking up a random combination lock and trying a random combination. Chances are, it's not going to match. However, macroscopic creatures you have to worry about, because large animals biting/clawing/blunt-force doesn't care so much about the molecular processes, but whether or not forces can affect you.
The article just mentioned that we found one within 20 light years.
Also, where are you pulling your probabilities from?
Life appeared on earth very soon after the late heavy bombardment period. On Earth, pretty much the moment when rocks stopped making the surface of the planet a molten wreck, life appeared. If statistics have anything to say, life developing is nearly inevitable.
Aliens wandering on Earth unlikely. FTL travel also unlikely. Aliens flat out not existing is unlikely.
Even the life on earth can exist in a huge range of temperatures, salinity, pH, etc. It's not a long stretch to say that life can exist on other planets. The visiting us part is the unlikely part, because of the aforementioned scale.
However, if they have little qualms of sending members of their species on century long journeys, especially if they have long lifespans, it becomes more feasible. Why they would want to visit us is another thing. What can we possibly offer them for them to come talk to us?
Also, you don't need to physically send the same person to every star, nor send a person to every star. We've done a good job mapping out stars in our galaxy (especially the nearby ones) the past hundred years (and done a good job with them discovering planets in the past 10), and you don't need to visit a place physically in order to gather detailed information from it. We've detected these planets without physically photographing them.
Thats a huge leap, a planet that maybe able to support some kind of life, to a planet that can support human life (mars is considered a planet that can support life) Regardless of what Vogt thinks, there are far more factors involved then just having a planet in the zone.
Out of my a.. but I still say the odds are astronomical.
I think you misunderstand me, I mean sentient beings, not just life... I'm of the thinking that we will find life everywhere, we will even find it in mutiple areas in our own solar system. Like has been said, life takes hold everywhere, but theres life and then theres life, and even if conditions are right to create the kind of complexity and diversity we have here on earth, that still doesnt mean there will be sentient life... if the Dinos hadnt died in that mass extinction, we would not be here now.
I concur, and didnt claim otherwise, I would even go futher and say Aliens (as in sentient beings) is pretty much guaranteed... somewhere in the universe. Now Aliens existing inside of a thousand light years of us, or ten thousand, well, I be pulling some odds out of my a.. again
Regarding the habitable zone issue,
That is true that there are many factors involved for it to be ultimately human habitable, but it is the primary concern for life as we know it. All other factors is considerably more trivial for life in general. So long that life (as we know it) has an energy and carbon source, and a source of water, it will find a way to live. Bacteria have even been found within rocks living off of the energy generated by radioactive decay of radioisotopes splitting water for example. Given enough time and energy flow, they may evolve into something that thrives in environments we normally consider inhospitable.
If you want "human life" as opposed to "life as we know it", it's rather trivial from an engineering standpoint to build ways to create an environment suitable for human habitation on a planet compared to a spacecraft used to get there. Having the exact conditions for you to plop a bunch of people down there and abandon them, and expect them to be able to survive is virtually zero.
That is also true on earth to an extent; people are horribly adapted to living not in the tropics without technology. If no technology is made available to them, people living far from the tropics will all freeze to death come winter. People evolved in warm climates, and simply adapt to their surroundings via technology, so you must consider that if you want something for human habitation. Intelligent life by no means requires conditions comfortable, or even survivable to humans.
True. But a question.
What do you consider sentient life? Dolphins and Monkeys are very capable of intelligent thought to the point where they have individual names and even gossip about each other behind their backs, many animals (some bird species, elephants, otters) regularly use tools, most predatory animals have some way of learning rather quickly by experience and observation, and Octopus are even intelligent enough to be required by law in some countries to require anesthesia when performing surgery on. Intelligence is not an unusual concept for nature to develop, if we are currently alive with a large multitude of species across different phyla, and certainly many classes with a working form of some sort of intelligence.
However, life with great enough intelligences to develop advanced technologies may possibly be the equivalent of the overspecialization that does not happen very often in biological history, much like massive biological arms races develop increasingly faster and faster cheetahs and antelope, or a particular species of snake and poisonous newt. It may have simply been that there was a rapid change in environment that selected for further intelligence in an already intelligent species that left us with humans.
Anyhow, since the galaxy is 100,000 LY in diameter, I'd be rather surprised if there isn't intelligent life within 10,000 LY, or even 1,000 LY considering how we are inhabiting in the galactic habitable zone. (stellar and metallicity content is high enough to generate enough carbon and silicates for life and rocky planets, while stellar density is low enough for supernova events to take place statistically far enough away to not devastate the planet with too many GRBs)
Uh...no. You can accelerate with a force of 1G forever (well, as long as your fuel lasts), without ever hitting light speed. If you're talking about traveling at those speed you have to take relativity into account. And that would include things like that the travel is shorter for those inside the ship. Only those staying on earth would have to wait at least twice the time it takes the light to get there.
That is, if we actually had the technology to accelerate 1G over a long time.
Depends on which region of Canada. Sure, Britain has the Gulf Stream to thank for its mild weather. But Canada's west coast has the Pineapple Express to thank, and we here in Central Alberta and south to Calgary have the chinook effect to thank for the fact that we get times of shirtsleeve weather in January and/or February. Other parts of Canada as similar latitudes don't get these same effects because they are either far from any mountains, they're close to many lakes, located on the Canadian Shield, near the ocean, etc.
There's a reason Winnipeg is called "Winterpeg."
You can deal with constant acceleration in special relativity provided you mean constant acceleration in the instantaneous inertial frame of the rocket.
20.3 LY away so:
t = 21.2 years (earth frame)
T = 3.7 years (in the rocket)
Well that was my point, that finding a human habital planet within 1000ly is astronomical, and in reality even that is too far, it would have to be inside of 100ly minimum. Obviously finding something we could terraform is more likely, but thats a whole new set of problems, and terraform is probably what well need to do. Sure on earth we adjust our environment to suit us, but anywhere you go here you can stand in the open and breath. Sure technology can create places where we can, survive, but all that will ever amount to is a sparsely populated outpost. Terraforming is also turning out to be a larger problem then originally thought. Take Mars for instance, seemed on the surface a reasonable thing to overcome, but now, not so much. Because of its very weak magnetic field there really is no chance of turning it into a human friendly enviroment, any effort we make to get an atmosphere going will get blown into space by the solar wind, not to mention the problem of radiation.
Well in the context I was using it I would be referring to a sentient life like us, capable of technology, and I would agree that we are not the only sentient life on earth. But really, regardless of how intelligent a dolphin gets, in its body it will amount to nothing in a civilization context, like you pointed out. So like I said and you seem to agree, even if a planet is perfect, and has sentient life, a sentient life capable of civilization is still unlikely. So if you consider the odds of finding an earth like planet and again the odds of a technological species evolving on that planet I dont think its a stretch to think there is no such place within a 1000ly, and even though @10000ly the odds are better, thats way outside of any possibility of us or them ever meeting, they may as well be in another galaxy.
I did recently see a show where they were talking about the 'galactic habitable zone' I remember why the core was considered uninhabitable, but there was a reason why they think the outer edges are too, just dont remember why. When people say theres four hundred billion stars in our galaxy it must be full of Aliens, I always thought "but wait" everything in the core you can pretty much eliminate, its just way too violent, so that eliminates, I guesstimate well over 50% of the stars in our galaxy. Then theres the multiple star systems, binarys and such, which account for most of the stars, and I think those can be eliminated as well... thats a whole lot of stars writen off before we even start. Now consider also "how long will a civilization survive?" based on our civilization it isnt going to be very long, but I'm sure not all species will be so self destructive as we are, and some will be even more so. That there is sentient technological life in the universe other then us, I agree. I would even suspect sentient techno life, at this time, in our own galaxy... but I would suspect they are very few, and very far between. I would be surprised if there are more then half a dozen such life forms in our galaxy, at this time.
Fascinating subject, and it always leaves me with the thought of just how precious our little earth is. I wish everyone could see it the way I do, but most folks cant see past thier own nose.
Yes yes, I said lightspeed is impossible, semantics, I'll fix it for you, to get to ALMOST light speed under 1g acceleration would take about a year... happy
I'm activating my hyperspace jumpgates right now.
Careful about that line of reasoning. Take ourselves 500 years into the past, and they (Europeans) thought the same about Africa. Hell, go back 20,000 years to the time without technology and the same can be argued about present day Europe and North America.
Just because something is difficult, does not mean it is impossible. It is rather difficult keeping suburbs running. They are poorly suited for manufacturing and poorly suited for agriculture. The only benefit of them is that they are good places to live, with a nice population density to meet with people, combined with open space to relax. However, being far away from work would make them rather difficult to maintain, so they didn't really develop until sufficient technology and a rich middle class developed to be able to afford the expenses and logistics to enable them to come into existence.
It is foolish to presume something *exactly* like earth exists elsewhere simply because there are too many factors. If it is close enough, it is good enough. Slight modifications can be made to suit us, much like how slight modifications on earth have been made to suit us. I don't see anything wrong with having self-enclosed heavily insulated homes, and requiring you to wear special clothing to go outside. Take North America or Europe in the winter. It seems exactly the same; you can't step outside naked for too long without hypothermia. Add some clothing, and you're fine.
For extraterrestrial colonies, only a fool will refuse all but the most perfect of planets. (They honestly have to be more perfect than most of Earth to properly suit humans) The vast majority of people have been living in suboptimal environments all of their lives, and simply modify it or ourselves with technology to compensate for it. I don't see why that approach is impossible for a colony.
The temperature ranges are quite acceptable. The gravity is a bit more uncertain, for all we have is the mass of the planet at 3 earth masses. We don't know the density to be able to determine its surface gravity. But hey, because it is massive enough and the temperatures are in the right range, we should have the two main factors down already. Temperature, and Pressure. Building sealed environments (akin to Biosphere 2) should be able to provide us with a good place to sleep and rest without a sealed suit. Assuming the pressure is acceptable, you don't even need a bulky space suit to maintain the pressures; all you need is a wet suit to keep out the cold or a cooled suit to keep out the heat. If the temperature is in a nice limit, you theoretically only need is a breathing mask if you are wandering outside the dome.
Oh, and for Mars, you really only need a pane of glass to keep out most forms of UV light. Glass and most plastics are opaque to UV light, and you really have to work hard to let them through. (this is the reason why blacklights are expensive) The other radiation (cosmic rays) may be a slight problem, but underground cities are not unheard on Earth, so that may be used if you are too lazy (or cost prohibitive) to build a dome encompassing the colony.
Well, you are setting the bar rather high. From what I understand is that you are suggesting intelligent life can only evolve on a planet exactly the same as the earth, which is clearly not the case. We are only adapted to the conditions we are in because we adapted to the conditions, not the conditions adapted to us. Other planets with less than ideal conditions for us may have a thriving civilization which is excellently adapted for that.
Anyways, 1000 LY is a very large region. 109 stars lie within 20 LY. (note, we already found a habitable zone planet within 20 LY and we barely have done any searching) 260,000 lie within 250 LY. 600 million stars lie within 5000 LY. The numbers you are throwing out are absurdly underestimating the number of stars in the galaxy, or you are assigning absurdly unrealistic numbers to the Drake Equation.
Here is a bunch of galaxy maps I found a long while ago.
Metallicity. Lack of supernovae explosions nearby to seed it with enough metals to form rocky planets.
Don't get too trigger happy eliminating stars from consideration. Binary stars are perfectly capable of having habitable planets. Just have to take into account that there is another massive object nearby, so stable orbits are only close to a single star, or farther out orbiting both. You'd have to look at how the stars are orbiting and what type of stars they are before you eliminate them.
Also, life forming in the galactic core is improbable, but not flat out impossible. So long as there are no supernovae events nearby, they are safe. Considering how most of the core is made up of older stars (ones that won't go supernovae), so long as their star formed semi-recently, or even migrated into the core, they stand a rather higher chance at forming suitable planets due to the metallicity content, and due to longer lived stars because of higher metal content (it gets in the way of H atoms, slowing down nuclear fusion a bit).
Well... The "how long a civilization will survive" is more accurately put as "how long a civilization broadcasts wide field radio". If they cease to broadcast radio, it's as if they are dead to us. We can still contact them via other means, but they won't be visible to us.
However, what about the civilizations that expanded to other star systems? After they have built up a second star system, they are virtually invincible to mundane events. No asteroid is going to destroy both star systems at the same time, interstellar wars highly favor the defender, etc. After a civilization buds off to multiple star systems, they become neigh impossible to eradicate.
Yeah, I was thinking inland Canada when I made that comment.
Circulation does wonders at moderating climates.
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