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Billions of Habitable Planets?
cbv writes: "MSNBC has an interesting article about new calculations by Charly Lineweaver and Daniel Grether, both of the University of New South Wales in Australia, which provides an interesting answer to the question on how many potentially habitable planets exist in our galaxy."
Because by the time we can find another one that is, this one won't be.
--Blair
"Keeping up with the Gbrtlrxzes."
What will it take to get a program going to actually send people out to them?
Scientists restrict study to entire physical universe; creationist
N = R* × fp × ne × fl × fi × fc × L
Where,
N = The number of communicative civilizations
The number of civilizations in the Milky Way Galaxy whose radio emissions are detectable.
R* = The rate of formation of suitable stars
The rate of formation of stars with a large enough "habitable zone" and long enough lifetime to be suitable for the development of intelligent life.
fp = The fraction of those stars with planets
The fraction of Sun-like stars with planets is currently unknown, but evidence indicates that planetary systems may be common for stars like the Sun. more info
ne = The number of "earths" per planetary system
All stars have a habitable zone where a planet would be able to maintain a temperature that would allow liquid water. A planet in the habitable zone could have the basic conditions for life as we know it. more info
fl = The fraction of those planets where life develops
Although a planet orbits in the habitable zone of a suitable star, other factors are necessary for life to arise. Thus, only a fraction of suitable planets will actually develop life.
fi = The fraction life sites where intelligence develops
Life on Earth began over 3.5 billion years ago. Intelligence took a long time to develop. On other life-bearing planets it may happen faster, it may take longer, or it may not develop at all. For more information, please visit Dr. William Calvin's "The Drake Equation's fi"
fc = The fraction of planets where technology develops
The fraction of planets with intelligent life that develop technological civilizations, i.e., technology that releases detectable signs of their existence into space.
L = The "Lifetime" of communicating civilizations
The length of time such civilizations release detectable signals into space.
"For now, no one knows whether our solar system represents a common method of formation and evolution. In fact, discoveries over the past six years seem to indicate otherwise. Most of the roughly 80 planets discovered outside our solar system are much more massive than Jupiter. They also orbit perilously close to their host stars, locations that would likely prevent rocky planets from forming in so-called habitable orbits.
But experts attribute these findings to the limitations of technology. "
Hmm, WAG anyone? Wild assed guess for those that are AC (Acronmyn-Challenged).
I would bet a terabyte of New Zealand Sheep porn that tomorrow there will be 500 stories debunking this. More "proof by way of media" sounds like to me.
I loved this comment:
'?Our solar system is Jupiter and a bunch of junk,? as Lineweaver puts it.'
Yeah baby, I live on a hurling mass of yesterdays dinner and some junk mail....wohooo.....
Sent from your iPad.
I think you'll find that history bears out that it was those on the American continent who were wildly ill-prepared for those who found them.
The only original take is that those 'one percents' are getting replaced with percentages actually based in reality.
Speculations like this used to be popular because astronomy was nowhere near the technology needed to actually see planets out there. If I remember correctly, the first true proof of planets around other stars occurred around 1995 when these first gas giants started to be detected.
With the detection methods getting better every year though, it's only a matter of time before we can directly detect terrestrial sized planets around other stars. That's the point where these statistical guesses get kind of silly.
"I bet there's a thousand planets out there!"
"Actually, there are 1422. We can just count them now."
stipe42
www.pcwatch.com
From Douglas Adams...
Number of Planets in the Universe = infinity
Number of Populated Planets in the Universe = N
n
--------- = 0
infinity
...Billions and Billions...
</sagan voice>
Boy, I'll miss that guy! One of the many people who triggered lots of tech interest in me and made me who I am!
Thinking that Earth is the only inhabitable planet in the galaxy or even the universe is so last millenium.
;)
It doesn't take a genius (just a bit of open-mindedness) to figure out that in the vast reaches of just our own galaxy (not to mention the universe) the chances are good that additional systems similar to Sol were formed.
Remember: The absence of proof is not the proof of absence.
On a lighter note, I really hope they'd hurry up and colonize another planet. Then, next time some ecologist gets on my nerves by saying: "THINK OF THE PLANET!" I can retort: Sheesh, it's not like it's the only one we've got!".
And yes, I know I stole that from Futurama
As the article says, Jupiter-like planets can act like a debris-magnet to protect Earth-like planets from comets, asteroids, and the various other junk floating around solar systems. Their immense gravity can either force and object out of the solar system entirely or force it to collide with the large gas giant. (An impact which would leave Earth near-barran for centuries is barely felt on Jupiter gas giant.)
The moons of the Jupiter-like planet offer another possibility for life. Like Europa, gravitational stresses from orbiting such a large planet can cause heat to warm up a normally frozen world. This heat might help melt ice into water (as is thought to be on Europa under the ice shell). And where there's water, life might not be far behind.
Now this isn't to say that life=intelligence. We might be talking about the ET equivalent of bacteria, here. Still, the discovery of ET-bacteria would be a huge matter.
My sci-fi novel, Ghost Thief, is now available from Amazon.com.
If there are aliens, where are they?
Sounds silly? I agree. Sounds like "The Fermi Paradox" is too fancy a name for a natural objection? I agree on this too. However, when you think about it, it becomes fairly obvious that it really is the only argument in this debate that is somewhere between strong and very strong.
"If you think education is expensive, try ignorance" - Derek Bok
I expect by the time we have useful interstellar travel, we will have reached the point that raw materials and construction are essentially free. Building space habitats is cheap with the right tech. All you do is set a few self-replicating robots loose in an asteroid belt. Of course, teraforming planets is cheap too, with that kind of tech (plus the sort of biotech we'd probably have by then), but it still takes a really long time.
Maybe if the planet is earth-like enough that you can just land, go outside in your T-shirt, pitch a tent and stay the night, it'll get colonized. But there isn't much point if you have to do any serious work, like, say, replacing a reducing atmosphere or getting more water from somewhere.
This space unintentionally left unblank.
That's all part of "L". The lifetime of the civilization. It doesn't matter how we die, if all of humanity dies, or falls below the level of technology able to communicate, then we drop out the Drake equation.
Our universe is probably a mere atom inside a larger universe, and these radiation bursts are simply the efforts of their Einstein trying to split us.
Can anyone tell me the difference between a 'metric buttload' and an 'Imperial buttload'? Thanks.
But not the worlds that have developed life or advanced civilizations. There's a big difference.
Its also fair to wonder, how many spacefaring civilizations are there? By that I don't mean, how many have launched someone into space, but how many have actually colonized worlds outside of their home solar system?
It has been shown, that given extremely slow, but reasonable travel times between stars, and assuming it would take 500 years (for an already technologically advanced society) to develop a world and the rest of the solar system, then advance on to the next one. With this in mind, such a civilization would only require about 3 million years to completely colonize the galaxy. Considering the billions of years the galaxy has existed, 3 million years is but a brief moment in time. If it was going to happen, it would have already happened.
Now consider our own situation. We're 4.3 light years from the nearest star. We're in the perfect location to drop off a few test subjects (humans with no technological knowledge) and see what happens. It would take a long time before they'd discover what really happened. And others could observe and reflect in that time.
-Restil
Play with my webcams and lights here
I don't care how many worlds there are in the Galaxy. I'm NOT going to wear a red shirt when I beam down to one of them.
"Giving money and power to governments is like giving whiskey and car keys to teenage boys." - P.J. O'Rourke
Don't forget that the degree of axial tilt AND periodicity of axial tilt oscillation are thought to play a huge role in climate change cycles, and therefore the formation and evolution of life.
How many planets of the right size, right consitution, right size and distance and periodicity of large satellites, right distance from sun, right periodicity of solar orbit, right periodicity of rotation, right frequency of asteroid collisions, right strength of magnetic field, right type of sun, right stage of solar lifecycle, right stellar neighborhood (no local supernovae). . .
Seems pretty farfetched to me.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
Personally, I have to say that I lean towards the conclusions found in Rare Earth by Peter Ward and Donald Brownlee. I think they make a very compelling argument for there being far fewer earth-like planets than all of these starry-eyed astronomers are predicting.
Science Fiction has clouded our vision of reality. Consider:
Nearest star is just over 3 light years away, so, traveling at 1/10 the speed of light, it would take you 30 years to get there.
1/10 speed of light = 66.9 Million Miles per Hour
Therefore, the problem becomes:
You must somehow build a spacecraft that can travel at 66.9 Million Miles per hour, non-stop for 30 years, and can accomodate a crew for that same 30 years.
http://xxx.lanl.gov/abs/astro-ph/0201003
If viral plagues were capable of wiping out species or civilizations, it would be factored into L. However, diseases DO NOT kill off 100% of anything -- being too deadly is an evolutionary dead end. Smallpox and ebola are not new diseases; AIDS might be, be it's far more likely that various simian HIV viruses have been picked up by Africans who ate undercooked ape meat at various times for millenia. It was recognized as a disease in the US only when nutrition, medical care, and availability of antibiotics had eliminated so many other causes of death, and after certain sub-groups of Americans had completely abandoned traditional inhibitions about sex. There is no chance whatever of it actually bringing down our civilation. With sufficient promiscuity, AIDS or other STD's can easily wipe out a village -- but until recently most Africans didn't travel enough to make it likely to spread too far before people simply learned to stay away from those from the "sick" village, while cultures that did travel widely (Arabs, upper-class Europeans) tended to be obsessed with controlling sex...
Smallpox and the bubonic plague are real killers, but not civilation-killers. The Black Plague killed somewhere between 1/4 and 3/4 of Europeans in less than a century, but European civilation not only survived but thrived. The survivors were richer and more willing to look at new ways of doing things. Especially, the shrinking workforce forced craftsmen to look at labor-saving devices -- for instance, ironworks replaced much manpower on bellows and hammers with waterpower, and in a few decades were making more and better iron than ever before.
The early course of smallpox in Europe is not too clear, but it is clear that there were centuries when it was simply accepted that at least 50% of each generation would catch it, and over 25% would die. All it meant was that fewer peasants had to starve to death or be hanged for theft, and there were more chances for peasants to become middle class or middle class to become noble...
In north america, a whole cluster of European diseases swept through a native population with no immunities. (There may have been some deliberate attempts at germ warfare like giving away smallpox-infested blankets, but the diseases were spreading so fast on their own that it hardly mattered.) Sometimes these diseases wiped out an entire tribe in one year, when the tribe was camped in one village (and probably not eating very well either), but other (maybe better fed, or more dispersed) tribes were only lightly hit. Possibly smallpox killed up to 75% and measles, etc., brought it up to 90% on the average. That didn't end most of their cultures -- it just made it a lot easier for white men to shoot and drive off the survivors.
It is highly unlikely that any one disease will ever kill more than 75%. And a real civilization can survive that quite well. There's considerable disruption in deciding how to scale back businesses to the smaller work force and customer base, but the problems are buffered by all that inherited wealth...
Do we have all the facts to say for sure that the Moon had nothing to do with formation of life and maybe even of intelligent life on this planet? Our closest neighbour is only 300,000km away from us and it is also a HUGE satellite for our planet. It has a profound effect on this planet, an effect that Deimos and Phobos of Mars can only dream about. How about tides that Moon enforces on our largest pools of water? It is possible that life was created specifically because of these tides, in the puddles of water that were left behind a tide (well that's a theory anyway).
So, how many of those planets have comparable Moons around them?
You can't handle the truth.
I will give you half of my share of the planets if you can tell me how to get there and back, safely and for a reasonable price.
Bush's education improvements were
No matter how badly we mistreat this world, it won't be worse than anything we find out there, unless one happens to have extremely Earth-like life on it already, the kind of place they find all the time on Star Trek, with lumpy-foreheaded humans and grass and spruce trees (foam boulders optional).
By "habitable" they mean planets like Mars and Venus. Places you can live on in extremely well made air-tight shelters, and maybe eventually terraform.
We could have a sustained nuclear war (presumably sustained from off-planet), stripping the planet of sophisticated lifeforms and blowing off half of its atmosphere, and it would still be a nicer place to live than anywhere else in our solar system or anything we're likely to find orbiting another star.
In terms of human habitability, we're taking pretty good care of this one. Wiping out the wilds is sad, but a choice of farms or forests is easy for hungry people. Where it appears unnecessary, done too casually for convenience rather than survival, that is just staying ahead of what the population growth will demand in a generation or two. The pollution looks bad, but it's a feature of short-lived transitional technology, and will tail off before intolerable damage is done.
On the whole, human effort is greatly increasing human habitability of Earth, not decreasing it. The pristine, wild world of a hundred centuries ago couldn't support half a billion humans, while today it supports well over 6 billion, and the way is being made for 10. Even one century ago, it probably couldn't have sustained half our current population. Things probably won't get tight here on Earth's surface until at least 100 billion, by which time we'll be seriously working on these other places to live. As it is, we haven't seriously dented the resources of our planet, just dug around a little at the choice bits on the surface.
Combine this discovery with technologies such as global computer networks, advanced robotics designed for many purposes, the ability to genetically engineer any kind of living creature and terraforming technology, and we'll be able to create entire ecosystems that produce some intended results. Call it a computer--or more accurately, a machine--the size of a planet, with its output being anything from mined materials to manufactured consumer and business products to medicines and chemicals that are hard or impossible to produce on Earth. Nobody said the atmosphere on those distant planets need to contain oxygen--they could be saturated mostly in carbon-dioxide so that genetically engineered plant life could thrive, making unbelievable things possible. Imagine... on a distant planet, where plants grow extremely fast, robots cut down millions of trees every day and ship them to Earth. No longer would it be necessary to kill trees on Earth for houses, furniture, or even paper! Materials could be mined from distant planets. Why use up our own oil, metals, minerals and whatnot, when we can mine and retreive it from another planet? Why pollute our own atmosphere to manufacture things if we can manufacture them on other planets and let those planets get polluted? If designed correctly, those planets won't even get polluted! But who cares if they do?! Garbage crisis? No problem! Put it on another planet. The beauty of it is that no human being would actually have to set foot there! The robots could fix each other when they break down, and could be remote controlled from Earth, just like the Mars lander. It would be very beneficial to all of mankind, and would open up unbelievable multitrillion dollar international businesses that deal in interplanetary sales and distribution.
!= Inhabited planets...
Recall that a couple of decades ago, Carl Sagan hypothesized that planets that could spawn intelligent life could have equal potential to self destruction to Earth... Chances are, if we manage to visit some of these planets, we'll find some ancient broken down probes, and maybe some nuked out cities, devoid of life...
Just because you can mod me down, doesn't mean you're right. Shoes for industry!
3. Such civilizations do not last a long time, and blow themselves up or otherwise fall apart pretty quickly
Or alternatively, civilizations progress at a geometric rate, transcending themselves in a few short generations, so that by the time intersteller travel becomes feasable they have lost interest and moved on to more compelling possibilities (perhaps departing this frame of reference entirely).
Once one hypothesizes a civilization significantly more advanced than our own it becomes difficult to even imagine the technologies they may have, much less what interests they would find compelling, or what goals they might set for themselves. For all we know they are all around us, unrecognized because they operate at levels as far beyond us as we are beyond the simple microbe.
The Future of Human Evolution: Autonomy
We'll eventually be able to create our own "virtual" universes, which are infinitly more interesting, since WE'RE effectively Gods there.
If I had a choice between a) slowly trekking through one boring physical universe, or b) freeing my mind from its limited primordial wetware brain, and moving into my own universe(s), I'd choose the latter.
--
Power to the Peaceful