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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."
What will it take to get a program going to actually send people out to them?
Scientists restrict study to entire physical universe; creationist
What, if any, businesses are preparing to exploit that life, if possible. This shouldn't seem such a far out idea, after all, 500 years ago someone set sail with three ships across the Atlantic and look how ill-prepared they were for what they found.
Suppose M$/MSN has a plan to spread influence extraterrestrially?
Shudder.
A feeling of having made the same mistake before: Deja Foobar
By the time we have the sufficent amount of technology for exploring the billions of Eaths out there, I am sure we will have plenty of technology regarding space stations. The only purpose I see in colonizing planets is for just mineral mining and for exploration. There should be no need to try and terraform or have to shape the Earth-like planets to our needs, we should just build space stations. At least then we do not have to worry about having insuitable worlds, or worlds that are unproductive. Also, a space station would be customizable for purpose and for people. There is no need to colonize many planets!
Kyle "DotCom" Lynch
...I need some cheeze-its...
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
Well, I'm no expert (I'm not even an amateur), but I have heard that an array of optical telescopes (particularly if they could be placed on a solid airless body like the moon) could have the ability to optically resolve planets around other stars.
This would be an expensive undertaking, but it would resolve the issue pretty quickly. I think that positive confirmation of extrasolar Earth-like planets would be an amazing, culture changing phenomena, right up there with actually discovering extraterrestrial life.
PI think my info on optical telescope arrays came from Entering Space by Zubrin.
-- stream of did I lock the front door consciousness
so the argument goes that since jupiter in some manner made life possible for earth, and total destruction for many other planets . . . this doesn't sound like a very intelligent way of going about it at all! "Hey, let's find all the giant planet destroyers because they sometimes, in very rare and complicated circumstances, factor into making possible in their own limited way!" somehow, i don't think so.
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
True. And as for habitability, has anyone considered the importance of plate tectonics and tides for life? Or the possibility of a causal relationship between massive collisions early in a planet's existence, and extended periods where plate tectonics continues?
Compare Earth, Venus, and Mars:
Venus: Probably no massive collision early in its life. Boring world, no way for CO2 to be recycled into a big liquid water carbon sink. Looks geologically-dead.
Mars: A mostly-geologically-dead world, too small to retain much of its original heat, and, of course, no massive collision early in its life. Had liquid water once upon a time.
Earth: Smacked by a Mars-sized impactor early in its life. Debris coalesced to form huge satellite called "the Moon". Frighteningly geologically-active. Big-ass oceans sink lots of CO2. Plate tectonics keeps it underground rather than letting it vent into the air.
A sample size of "three" is pretty slim, but to my (untrained - any exogeologist-types out there care to comment?) mind, the facts that Earth got whacked and the fact that the Earth still has a thin crust (while Mars, and more interestingly, Venus, have cooled off) appear to be more than coincidence.
Bring in an exobiologist -- perhaps "tides" (think "tidal pools" are handy for forming life. Also think about the impact that tectonic activity (and life) has in recycling CO2 on Earth.
Does anyone know if Earth's core is "too hot" to be accounted for simply by heat from 4.5 billion years of radioactive decay of its initial components?
I'm speculating that the impact that created the Moon also added a metric buttload of heat to the still-forming planet's core, while simultaneously stripping the proto-Earth of some of its lighter silicates. If the impactor came from "far enough away" in the solar system, it may have brought a metric buttload of water ice with it. The result was a glob of metal-enriched rock, water, water, everywhere, a double-planet system with tides (useful for future development of life) and recycling of crustal material via plate tectonics due to the planet's thin crust.
(jumping off the deep end into wild-ass speculation now...)
Perhaps this is another reason to go to Pluto. Perhaps the Pluto/Charon system formed in a manner similar to Earth/Moon. If we found evidence that Pluto had a metallic core, and that it was warmer than could be accounted for by radioactive decay...
If we assume (or can demonstrate) that things like plate tectonics and tides are "good" for the formation of life (at least, they seem "better" than the situations on Mars and Venus that arose from the lack thereof), it'd be nice to know that early massive impacts were common. It'd be even nicer to know that there was a correlation between such impacts and "warm" planets with lots of water.
(Sigh... still holding out for the day we see the spectrum of light reflected from a rocky planet in orbit around another star... a spectrum showing lots of oxygen that should have reacted itself away by now unless something on the planet's surface was replenishing the supply...)
Fact is that if there was life on another planet we would not be able to get there with current technology and understanding of physics. It would take to long traveling at what scientists today call the maximum speed limit 'the speed of light'. Maybe someday when we understand space and time better but not now.
Watch Discovery channel now and then as they already went over alot of this stuff. They made a discovery a while ago and discovered how to detect the 'gas giants' as they call them (jupiter / sturn sized planets) orbiting a star by watching the stars wabble.
And for you real space fanatics http://www.spaceref.com/ and www.space.com are great sites.
Lastly I cant type and spell so don't point out my typoes and spelling errors it is really laim.
Only 'flamers' flame!
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.
In the current Discover magazine (March '02 dead tree version), there is an article talking about something similar, and actually developing a technology that could filter out the starlight (1000 billion times brighter than the earthlike planet) and enable a ground-based telescope armed with this tech to "see" a planet.
Fairly interesting, and I hope these guys get their plan adopted.
Thunder
No
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
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.
I've already posted a similar comment in this thread, but since I formulated it rather bad and not too many people seemed to notice I'll make another try. And this time I'll cut and paste from this site.
One of the problems that the Drake Equation produces is that if you take reasonable (some would say optimistic) numbers for everything up to the average duration of technological civilizations, then you are left with three possibilities:
1. If such civilizations last a long time, "They" should be _here_ (leading either the the Flying Saucer hypothesis---they are here and we are seeing them, or the Zoo Hypothesis---they are here and are hiding in obedience to the Prime Directive, which they observe with far greater fiqdelity than Captain Kirk could ever muster). -or-
2. If such civilizations last a long time, and "They" are not "here" then it becomes necessary to explain why each and every technological civilization has consistently chosen not to build starships. The first civilization to build starships would spread across the entire Galaxy on a timescale that is short relative to the age of the Galaxy. Perhaps they lose interest in space flight and building starships because they are spending all their time surfing the net. (Think about it---the whole point of space flight is the proposition that there are privileged spatial locations, and the whole point of the net is that physical location is more or less irrelevant.) -or-
3. Such civilizations do not last a long time, and blow themselves up or otherwise fall apart pretty quickly (... film at 11). Thus the Drake Equation produces what is called the Fermi Paradox (i.e., "Where are They?"), in that the implications of #3 and #2 are not terribly encouraging to some folks, but the two flavors of #1 are kinda hard to come to grips with.
An alternate version of 2 is that interstellar travel is far more difficult than we think it is. Right now, it doesn't seem much beyond the boundaries of current technology to launch "generation ships," which power systems. An
alternative is robot probes with artificial intelligence; these don't seem so difficult either. The Milky Way galaxy is well under 10^5 light years in diameter and over 10^9 years old, so even travel beginning fairly recently in Galactic history and proceeding well under the speed of light ought to have filled the Galaxy by now. (Travel very near the speed of light still seems very hard, but such high speed isn't necessary to fill the Galaxy with life.) The paradox, then, is that we don't observe evidence of anybody besides us.
"If you think education is expensive, try ignorance" - Derek Bok
Ever heard of a little something called binary black holes?
This little thingies has two tightly focused, _really_ hot jetstreams of radiation going out in opposite directions, but doesn't emitt much in other directions (They're black holes after all, so they suck up pretty much everything that could make them detectable).
Well, now imagine a spinning binary black hole.
It'll be almost undetectable... until it happens to spin so that one of the jetstreams hit a planet and fry it to a crisp.
We _could_ have things like this just around the corner (astronomically speaking) and not be aware of it.
I don't know how common this type of celestial bodies are, but for life, they are definitly a Bad Thing, since they could effectivly "reset" a planet and life would have to start all over again...
"First lesson," Jon said. "Stick them with the pointy end."
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.
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.
There was an excelent ariticle at Scientific American on exactly that, with nice diagrams etc.. :) But of course there is an infinate number of possibilities in the Universe! Have a look at Possible Solutions to get you thinking more..
:)
It is a slightly depressing for those star trek style optimists like me.
There are so many considerations though, for instance Not all habitable zones equal. but one that really peaked my interest is an article about how our moon in many made our world. (sorry cant find the link) Basically the theorised formation of our moon, ie big planetoid crashing into proto-earth, ejecting large portion of earths crust into orbit with remains of other planetoid. Basically creating the plate-tectonic's we have on earth, which i might add do not exist on any other planet/moon observered.
Meaning that the plate tectonics are extremly rare, if you'll note a big factor in the creating on mountains, continents, etc is the continual movement of the plates. Getting to the point, if we didnt have a moon (and the results of its formation) and we still had water, then Earth would be a completly water world! Because without the continual movement, creation of continents / mountains etc, water would erode any land mass's in time.
I find that so interesting (even if it's all theoretical) as it's just another very rare factor that contributed to us being here. Rather than us being whales or some such.
So just maybe for the optimists (like me) most worlds out there which are habitable dont have inteligence because a huge portion of them are just water with no land. Then comes the argument of why would inteligence such as ours evolve on such a world?
!= 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!
"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."
I totally agree with you, but with a broader vision. Who says that the other lifeforms out there require the same environment as we do?
You never know...
- Mike
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
"Alan Boss, an expert in planetary system formation at the Carnegie Institution of Washington"
Now I'm sure Mr. Boss knows more about the subject than most people, but can anyone really call themselves an expert in a process we know to be happening all over the Galaxy (and most likely Universe), but for which we have only one observable study object? (And even that is 5 billion years after the fact, so much of what we "know" is conjecture.)
I mean, expert on our own solar system, yes, but planetary system formation in general?
And remember kids: Never trust a computer you can actually lift.