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Planets In The Habitable Zone
mistah_monkey writes: "The BBC reports that an international team of scientists have identified some planets in what they call the habitable zone. Apparently, the planets may be as big as Jupiter, but exist in a region surrounding the stars they orbit in which water can exist as a liquid, which is good news for those of us who believe that little green men might actually be out there somewhere."
> 4.3633 * 10^14 m/s.
um, isn't light 2.99792458 * 10^8
does anyone else see a problem with this??
I would assert that the chances of life everywhere in the universe being relatively paralell to our own on this planet (humanoid, mamallian, reptilian, etc) or life being radically different in form and survival throughout are about equal. With only our own planet as a base for the time being, it is difficult to establish accurate foresight.
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The Internet is designed as a communications medium, so putting one's contact information on-line seems to me to be a logical thing to do, much like listing one's phone number in Real Life. Do you think that listing one's phone number is "just asking for abuse"? I, personally, am on the net because I *want* people to be able to get a hold of me, by phone or fax or email or instant message. If I don't want to be bothered, I can do what I do in real life, and yank my network connection for a while.
You have not thought this through.
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Ceres is, per unit volume, quite a bit more dense than Jupiter - but it has many fewer units of volume until all it's mass is accounted for. So it is much less massive than Jupiter, and therefore has a much lesser gravity - hence no ability to retain an atmosphere.
It is the gravity of a body than keeps it's gravity from floating off into space, not it's density. Density can only be viewed as playing a role when the two bodies are of similar volume, at which point a greater density is a sign of greater mass - not vice versa.
To put it another way, density and gravity both depend on mass. Density also depends on volume within which the mass is contained.
I'm not sure of the accuracy of the following (maybe an astronomy geek can back me up) but if you were to take the mass of the Earth, and distribute it over ten thousand times the volume - making a nebula - it would be just as able to retain it's atmosphere as it is now.
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Using space and ground-based telescopes, I should think it would be possible to look for "artifacts", evidence of technology. As an example, how about searching for the flares produced by Bussard ram-jet drives? These should be visible for hundreds of lightyears, at least. Also, look for cosmic anomalies that might point to massive engineering projects by highly advanced civilizations, such as Dyson Spheres, "ringworlds" (a la Niven), etc.
You mean, like Europa and Titan, moons of gas giants in our own solar system that are capable of supporting life?
And you mean "tides" as opposed to "tidal wasves(sp?)", correct? Tidal forces on a moon of a gas giant would be very impressive, to say the least.
"Don't mind me cutting myself on Occam's Razor"
Okay, not war. How 'bout overconsumption? It has certainly ended numerous civilizations here on Earth, and no one is even sure if the six billion we hope to support right now is a sustainable population long-term.
And the thing that makes it a much better curtain-closer than war is that we will sit around and watch it happen and be unwilling or unable to change our way of life enough to stop it. Witness global warming.
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The paper only talks about two planets, not the three referred to in the BBC article. The first one mentioned has a "year" of only a few Earth days, which the paper calls "51 Peg"-like, alluding to one of the first planets detected, and the class of extra-solar planets named after it. The second star is a brown dwarf candidate with a mass between 46 and 190 times that of Jupiter. I see no mention whatsoever of the really exciting third planet which supposedly has a period of a little over one Earth year, orbiting a Sun-like star. The most exciting possibility is not that liquid water would exist on the gas giant (it can't), but that it might have terrestial moons at a habitable temperature. Empirically, moons have been observed to have volcanic activity (Io) as well as atmospheres (Titan), which could pave the way for life to come into being.
The article does bring up the interesting point that the "51 Peg"-like stars are ideal candidates to be observed during a transition (like an eclipse, the planet is temporarily between us and the star in a transition). However, it seems that the astronomers conducting the so-called "Anglo-Australian Planet Search" were unable to observe one. It would be ideal to see one, though, because it would provide strong evidence something is actually there (they haven't actually seen anything besides the stars!), and tell the astronomers the inclination and radius (which would instantly give us mass and density of the planet to within experimental error).
There is no water on Jupiter.
Ummm, that's just plain wrong. Sure, our probe found less water than expected, but it dropped into a hot spot. Besides, do you think Shoemaker-Levy contained no water at all?
If there is any oxygen at all there, it's in very trace amounts
Well sure, everything that's not hydrogen or helium on Jupiter you might call "trace," since that's not really a quantitative term. Still, Jupiter is big enough that there is plenty of H2O and CO. I would advise against treating the Galileo probe's measurements as authoritative for Jupiter's entire atmosphere. There very well may be concetrations of oxygen in certain portions of that vast ocean of gas.
There is no "solid" mass on Jupiter, unless you consider pressurized hydrogen a solid mass.
Also incorrect. Jupiter is believed to have a rocky core. Do you really think that in the enitre history of Jupiter, nothing rocky ever hit it and sank through all that gas?
Proof and likelihood are two different animals. Evidence doesnt not always point to probability.
And even if evidence did exist on earth, we may not even recognize it for what it is, or alternatively assume humans hands were those that created it.
Alien life may choose not visit us apes, may decide the majority of us are far too superstious to accept an alien life form into our cultures. They may not even wish to colonize in the very human traits of greed, expansionism and imperialism, may not even need to due to their biology, society, or culture.
Life is far too diverse to catagorize it so simply, and under our own definitions of what we "think" life may be, and in what forms it will take, how it will act, react, feel and think.
Besides, and heres the good part, if this life does exist, and i most certainly believe it does, how do you know they believe in life outside their planet? They may think you a mythical being, they may think that I am a statistical anomoly because I should not exist. And even if they do know we are here, what makes us so important to visit. Frankly, id just drive on by.
Historically, we are a dangerous race for first contact even in our own terrestrial matters.
Insert something insightful here, or I'll insert something painful there.
Thanks for the link. Though I should point out that the authors note that tidal forces may sustain a smaller moon's geological activity for a sufficient period of time.
Which makes me think. If there were a habitable moon due to some lucky combination of size, parent's orbit, magnetosphere, tides, etc. would its inhabitants sit around saying: it's so unlikely that these factors combined to make our world habitable, what are the chances that a planet in the habitable zone could support life? All the while not knowing that a *different* set of lucky circumstances had done so?
My point being that even if it takes an intricate balance of physical factors to make life possible, the sheer number and variety of such combinations makes many such intricate balances possible. Just as there are many different intricate ecologies on Earth, and many of the creatures in any one habitat would go extinct from the slightest change, and yet all of these intricate ecologies support life in some form.
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I think Monty Python refers to the speed of the Earth's surface at the Equator - but in knots (nautical miles an hour) not statute miles per hour. The Equator is roughly 22,400 nautical miles all around. Divide that by 24, and you get a speed of 933 knots at the equator. The earth's orbital speed would be:
2 * 150,000,000 * pi = 942,477,810km
942,477,810 / 8760 = 107,588 km/h
In miles per hour this is:
107,588 / 1.6 = 67,242 mph - just a touch faster than 900 mph!
270,000 / 67,242 = a sedate 4 times faster than the Earth.
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That would depend on the orbit of the moon. A couple of Jupiter's and Saturn's moons are over 1 AU out from the planet, if I'm remembering the reference chart from "The Handbook of Chemistry and Physics" correctly. (Someone slap me if I'm remembering this wrong ;)
The tidal force at such a distance would be less than what the sun does for Earth (varied also by the radius of the moon in question,) because the mass of the planet is likely to be a lot less than a star (or else it most likely would have collapsed into a star.)
Still, if there were many moons around a planet this size, like Jupiter or Saturn, as well as the effects of the star in the system, this would all combine to create some interesting tidal charts.
I'm not sure I'd like to sail a ship with a deep draft on a world like this.
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What the Hell is this "Zone"???? A region around 1 AU? NONSENSE! Earth is probably more an lucky aberration than a rule of the thumb. It is probable that it is extraordinary that Earth formed at such distance of the Sun with all the parameters to keep a large amount of liquid water on it. Look at the Moon for an example of what I'm saying... In fact the "habitable zone" should be generally be a bit more far away than Earth. I mean the highest probability zone. Because all this is a probability function based on the theories of planetary formation. It is considered that planets are formed from a planetary nebula. And that the "habitable zone" will be a region where water will have the chance to condensate AND later to keep its liquid form.
In general, in the case of a sun-like star this would look like a probability function that starts at zero from the center of the system, keeps zero up to regions between Venus and Earth, sharply rises between Earth and the asteroid belt, and slowly lowers up to a region beyond Jupiter. We know that there were oceans in Mars. We know that the Moon shows Earth as being on the EDGE of this zone. We know that there is the high chances for Europe to have an inner ocean. And we have a hot Io showing that tidal phenomena may trick the whole game of temperature distributions. So if one searches for "habitable zones", then he should search for a region much larger then the Solar System and surely not at 1 AU. Mars lost its water for some damn cosmical impact that send into bubbling to Cosmos. And there are indications that, even now, water makes a good part of the landscape.
Besides I don't see the good point to remark huge planets in highly elliptic orbits. Because they are inside the 1 AU? And what about the escape velocities produced by these orbits? We surely will not find Extra-Jupitereans. We can only rely on the possible sattelites around these planets. And these planets will have very thiny chances of possessing big sattelites with enough conditions for life. Because they need to be big and fat. Or else they will be cooked like the Moon.
Besides what about the chance of Jupiters at Jupiter's distance but with Mars-sized satellited. It is quite possible. And we know that the tidal game may trick the production of enough heat to give habitable conditions to these planets. While these would be exceptions, they are not far from the conditions we even see on Jupiter. At least everyone says there is a good chance to find Life in Europe. There is no arguments to dismiss this fact, on the contrary. And sincerly Life doesn't exactly need the surface of a planet to live and survive. So "underground" habitable zones may extend even further...
Here here, I couldn't agree more sir
I think most humans tend to catagorize life quickly and easily as "something like us" or "something chemically/geneticall/biologically" like us" in terms of needs/structure.
Extraterrestrial life may well defy definition for a long time, simply because either we havent experienced it yet, or we have and didnt recognize it for what it is.
To truely quantify something like life in such broad terms, and compare it to a universe, is as hard a task as has ever been set, because the only baseline we have of life, that we can compare to what we may find, is what we already have on this small rock. Compared to a galaxy, we have a rather small control group.
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I can see it now.... It's the 23rd century and all the surfers have left earth to ride the waves on the fifth moon of HD179949. ;-)
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The article states that we are able to detect these planets only because they are so large and close to their stars, that their gravity causes the stars to appear to "wobble".
It will probably be quite some time until we can determine things such as rotation, revolution, presense of moons, virtual communities, etc...
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You are absolutely correct. Although there is water on the moon, it is innaccesable. It would be much easier to get it from Jupiter, obviously. 120 million miles of space is a much smaller barrier than 1 mile of rock. I don't want there to be the same barrier between us though, so please reply and tell me what you think of this.
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There is no
While very large masses can be excluded by other arguments (the planet would be more luminous than the parent star), there is still a fairly large range for the planet mass.
Has any one read a meeting with Medussa? or it is kind of mentioned in adoyysey II by Arthur C. Clarke.
Basically he makes many references to these giant animals (or plants) in jupiters atmosphere, and gives the facts to why they could actually be there. They are extremly light because they are made of giant bubbles or something.
There is a whole system going on with Grazers and herders and Carnivores.
Very interesting, anyone who has read the book lately care to enlighten?
One problem I have yet to see a satisfactory explanation for is this; since most of the stars in our galaxy are older than our own by millions of years, if there were any other intelligent races with anything in common with our mindset at least some would have evolved long long before us.
Even with todays technology, and completely disregarding the possibility of FTL travel, the capability of building generation ships travelling at a fraction of the speed of light would be within grasp of a civilization similar to our own. If a species evolved even some hundred million years ago they would have managed to populate most of the galaxy within a short period of time (on the astronomical scale of time). This should lead to at least some sign of intelligence, but why isnt some found?
Just us? You're kidding, right? :)
(In desperate search for a cool
grumble.. I should remember that the circumference of a circle is not pi*r^2, but 2*pi*r. duh. I was only off a factor 12 billion.. *sigh*
//rdj
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If I remember correctly, Jupiter-size gas giants usually don't have a solid surface, because they mostly consist of light gases like hydrogen and helium - those are the most abundant elements ind the universe. Earth and the other small planets in the solarsystem have lost most of these light elements, because their gravity is not high enough to prevent them escaping into space. Only the hydrogen that is chemically bonded to heavier elements, like in water, has not been lost. Life forms in those gas giants - if they exist - would probably be very different from terran life. A gas giant has at most a very small solid core, where the pressure is so high that even hydrogen would be solid. I don't think anything could survive there. Possibly something could live in the upper atmosphere where the pressure is not so high that it crushes everything. I don't know if such life forms could ever develop any technology. If they ever attempted space travel, their problems would be daunting - not only escaping the gravity of their planet, but even constructing a ship that can contain their high-pressure atmosphere in a vacuum. But gas giants in the solar system have a lot of moons, some bigger than Earth's moon. If those extrasolar planets have moons too - we don't have the technology to find them yet - they would probably be able to support life under Earth-like conditions. Stefan
I totally agree. I notice scientists are always looking for planets with evidence of water on them. Well, yes, as far as we know, things need water to live. But who is to say that there isn't a planet out there with some other form of life that doesn't need water to survive. Just because today's science says that organic matter needs water to live, doesn't exclude the possibility that there might be life out there that doesn't need water to survive. Considering the size of the universe, how could scientists possibly rule this out?
This hypothetical civilization colonizes the galaxy in a few million years?
And in all that time, this race has no wars, no economic hard times, no diseases? That could slow them down. It could be that it is culturally a very difficult thing to do, to colonize other planets, light-years away. Given the cultural drift that can occur in two societies that are isolated and unable to communicate, the likelyhood that wars would erupt seems almost a guarantee.
And, even if it IS NOT possible to travel faster than the speed of light, what if it is not technically feasible to colonize another world at all? I mean, we like to draw parallels with sailing the Santa Maria across the Pacific, but it's not quite that simple. It takes a huge amount of resources just to get a paperweight into orbit. Now, how about putting a ship large enough to be home to 1000 or more people for generations, into space, and across the gulf of light years - barring again, disease, cultural instabilities, technical difficulties, etc. Yes, we all want to believe that these problems can be surmounted by a sufficiently advanced civilization - and I'm not saying that they can't. We don't know that. But what if, just what if, that IS the case, that as far as technology goes, we've gone just about as far as we can? What if fusion power is not feasible? What if 1000 people on a generation ship kill eachother? What if life on a generation ship is not sustainable, or requires a much larger biosphere than can be constructed without threatening the economy of the civilization that is building it? What if, 50 years into the journey, an airlock seal blows because a greedy contractor cut corners? There are a lot more reasons why this wont work than simply a civilization blows itself up with atom bombs. And even if it can be made to work, what if it's just a lot harder than we think it is. In that case, the rate of colonization may be much, much, slower than this theory states.
These estimates, that the whole galaxy ought to be colonized by now, in my opinion, are far too optimistic. It has been theorized, how it could be done, but was the full economic impact on the civilization measured? Were ships designed beyond the basic features and principals? This ought to be done with current human technology, to see if it can be done at all. We're not even sure if we can technically put a human on Mars and bring them back - there are many unanswered questions, such as, radiation, human endurance, margin for error, the martian environment (dust, it seems, will be a very seriously major problem, as yet, unaddressed).
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Yeah, nobody's asked about something that's pretty unique to Earth, namely: "has to get whacked by a Mars-sized impactor real early in its development".
Any ideas if that impactor was ice-rich and if any water vapor from impact could have hung around as the resulting mess cooled (and produced the Moon)?
Seems to me the "big whack" comes in handy for:
The moon - nice tidal energy pumps to stir the oceans
The water (maybe, as I'm wild-assed-guessing in my first paragraph)
The seasons - the 23-degree axial tilt that lets the sun drive energy back and forth across the surface of the planet I'll accept that big whacks are pretty common (Uranus' axial tilt, etc.)
This doesn't cut down on the number of habitable planets from the point of view of a colonist from a technologically-advanced civilization.
But if it's a major factor (or an essential), it may cut down significantly (like, say, eliminate 2/3 of the planets - asusming Earth, Whatever-Got-Mushed-And-Made-The-Asteroids, and Uranus - 3 of 9 whacked planets) on the number of habitable worlds on which life actually evolves.
(Yeah, the only way to find out is to do lots more planet-hunting, huge-ass interferometry, attempt to get spectra and what-not... the nice thing is that younger /. readers may actually see the results of the research in their lifetimes...)
I remember seeing an interview with some members of a panel that was looking into likely forms of extraterrestrial life. They basically concluded that any life form not evolving with a similar composition and under similar circumstances to our own would be sufficiently different from us that we would have a difficult time even distinguishing it AS life. If you don't know what to look for, you'll have a terribly difficult time finding it. First looking for conditions and life similar to our own seems entirely logical. Remember, sci-fi is just that - fiction. LEXX PS - I know, I know, some reality has come of our fictions, but we have no warp drives, replicators or transporter beams, and likely won't for quite some time, if ever.
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not only is tidal locking a serious problem, but as others pointed out, variations in temperature due to varying distance to the sun, or shading by the main planet would also have some harsh effects.
Also, IIRC, Jupiter has some pretty intense radiation belts. Intense enough, that they pose a challenge to probes navigating the moons. IIRC, Gallileo had some hard resets when it passed through them. Now that doesn't mean that life cant exist, but all of these factors together make it unlikely to be stable - in other words, able to undergo speciation, let alone, develop into something that can post on slashdot.
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And it probably came from the little green men peeing in their corner of the universe.
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the laws of probability say there SHOULD be other forms of self-replicating material (aka simple life) out there. have we heard anything to suggest there isn't or can't?
http://kered.org
These jovian type planets in the habitable zone of their stars may have tidally-locked moons that are dense enough to harbour life. In our own solar-system, Jupiter's moon Europa is suspected of having a liquid water layer under an ice crust, maintained in that state by a constantly deforming rocky core.
Larger mars-size satelites (or even larger earth- or venus-sized ones) could be orbiting these planets at distances that lock them tidally, or further out, giving them an even more tectonically active crust than we have as a result of our moon.
In any case, such a world (they wouldn't technically be planets) would have all the same ingredients for life that we do, just in varying proportions, possibly leading to life, not as we know it, but at least recognizable as such by us.
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The seasons don't do anything to promote life. By far the greatest concentrations of life in the tropics; both on land and in the sea, and they don't have discernable seasons. In fact, seasons are a hurdle to life: places with the largest seasonal differences (like the arctic) have the least biodiversity.
Agreed. And it's possible that some other forms of life could be so unlike us that we wouldn't even recognize them as life. And the same with them for us. It might even be impossible for us to even see each other.
"When it rains, it pours." --Morton's Salt
Exactly. Drake had no illusions that the equation could answer the question. It was just meant to clarify the question, which it does quite well.
Any "solutions" I've seen of the equation were plainly tentative -- "If I'm right about these values, then this is the result." Sloppy thinkers/writers might not be clear about that, and -- at least as likely -- sloppy readers might miss the qualifiers. But that's not a problem with the equation itself.
Well taking a good look at some of these orbits I would doubt we could find such repositories. zi mean the high elliptical ones. First we know that at 1 AU and less, Moon-sized moons would be virtually cooked by the star. And every planet with a wrong wobble would get into the same fate... Then we should take into account the huge tidal forces produced by these orbits. So probably most moons would look more as hot melted cheese. And then we should think if there are such moons at all, as the escape velocities would be tremendously high for large moons.
Considering the number of such elliptical planets, chances are much lower than one should expect...
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For most of earth's history, life was in the form of single-celled organisms. It wasn't until recently (in geological time) that multi-celled life came into existence. Further, humans only developed after a comet slammed into the earth and wiped out the dinosaurs. Technology is another element that must also be developed in order to communicate beyond one's planet of origin. The probability of all these developments occuring with significant frequency is low. Therefore, the likelihood of finding intelligent life on other planets is very low.
Is there intelligent life somewhere in the Universe? Most likely given the estimated size of the Universe of 100 billion galaxies with 100 billion stars each (10^22 stars).
Is there intelligent life somewhere in the Galaxy? That's a tough one. It is possible but it is not probable that we will find it. Even if intelligent life developed somewhere else in the galaxy, it may not have developed at the same time we did. We've only had the technology to communicate to other planets for 50 years. Further, there is also the issue of huge power requirements to communicate across long distances in space which is yet another obstacle to finding intelligent life.
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I'm not sure if this was a troll or not, but I'll feed the little blighter anyway...
>I mean, when the model considers a star to be made from hydrogen, helium and "other stuff" how can you take it seriously?
You can take it extremely seriously. Stellar modelling codes do just fine for many types of stars by representing their constituents as hydrogen, helium, and 'all the other stuff', misnomered as 'metals'. An astronomer's Periodic Table looks very simple - H, He and Z, where Z represents all the heavier elements lumped together. Since most stars are virtually all H and He, the models do spit out good comparable stellar models.
>Whilst these discoveries are great for further illuminating what's out there, they yet again cast doubt on much of astrophysical "theories".
No, they don't. Before, planet forming theory was difficult because the ONLY data points were from the Solar System. Now we have more data, its back to the computers and models they go. An ounce of observation beats a ton of theory, but then isn't that the case for all science?
> We need to remember that as a subject, it's one of the shakiest scientific disciplines around.
Not unless you count biology, but then is that a science? *grin* Anyway, the practical classes in astronomy are absolute bastards to do... "Take 10^30 kg of Hygrogen, and allow to settle for 10^10 years. Write down your observations."
Matt (about to get lynched by a horde of angry biologists).
Gravity scales lineary to the ratio between different radiuses for planets with the same density, so even if they have like, 3, 4, or 5 g-force, life can be developed on them if the right materials are combined in the right temperatures.
I love it when the Drake equation is invoked as a way to calculate a meaningful result with some relavance to human or alien civilization.
The Drake equation is calcualted by multiplying seven terms together. 3 of those may be obtained from reasonable sources in astrophysics and planetary formation research (albeit they are continually changing as we learn more!). The other 5 terms are picked essentially at random, and therefore have no meaningful value.
The only thing the Drake equation is good for is exploring the relative impact that manipulating various terms may have on hypothetical contact. Due to 5/7 of the numbers being completely arbitrary, it has no value beyond that limited application.
Use of the Drake equation is a great example of "subjective" science. Adding an additional term defining the probabability of the society creating Twinkie's and eating themselves to death in a cream filled orgy before transmitting would have no detrimental impact on the reliability of the answer.
Yes, for if we find such a place, with water, air, light, and plants... but, with major earthquakes... we'll never find life there. Except for the plants... or did you mean silk plants?
He obviously meant power plants, who in their right mind would live in some place without electricity?
There could be easily accessible water on the moon, ice from comet impacts at the bottom of craters that are never exposed to sunlight. But this isn't proven yet and it would not be much in any case. If I remember correctly, the Saturn rings are mostly ice - that would be the easiest way to get lots of water, if there are big, soldid chunks of it. You could fix a large, nuclear-powered drive to it - that could use part of the ice chunk as reaction mass to move it to any place in the solar system you like.
Stefan
If they are as big as Jupiter it's gonna be difficult to support life (like we know it).
First of all: Planets of these sizes are mostlikely to be gas-giants. And it's damn difficult to built houses on gas-giants. But if it is a solid planet grafity is gonna be to strong for normal lifeforms to walk around.
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I think we should all keep in mind that if there are any other life forms out there, they don't necessarily have the same needs for survival as we do. So far in our research of the universe, we havn't came across any other planet that is exactly like Earth yet. Not saying there isn't any out there, but I think we should be more open to the other needs that may exists out there, that perhaps don't need water. Our sciences are based on our small spec of paint, on the canvas of the world, and is very limited.
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I've heard that the moons of such planets are the more likely repositories of life. The moons would have liquid water, and a gas giant might be a source of additional heat if they emit more heat than they take in like Jupiter does in this solar system. I do wonder about sunlight, though, with a gas giant providing eclipses.
Logic ... merely enables one to be wrong with authority. -- Doctor Who
Don't forget the moons.
Most of people there are claiming that
jupiter-sized planets are too different to either have any life in it or then it will be so very different there is no way for us to understand those beings, and they are probably right but almost all seem to forget the moons.
Jupiter sized planets can have several Earth sized satellites. Think about Europa, or Titan, even those are speculated to maybe host life, yet they are very cold and very far away from then sun. What if Jupiter-sized planet would be at Earth distance from its star and have Europa-like moon?
Hah! Got me there. That's what I get for posting after 4 hours sleep. Hit submit instead of preview, too. :)
Yeah, we know everything about big objects like, black holes, galaxies, and the Universe itself . . .
Whether or not Jupiter has a solid core is still being debated. Most notable astrophysicists agree that there is no way of knowing if Jupiter has a core mass or not. The last time I heard anyone argue FOR the solid core was 1989.
Of course it's impossible to know for certain if Jupiter has a rocky core without direct measurement, and some people may not believe until they reach out and touch it with their hands, but that's not happening anytime soon, and is irrelevant. As for the '1989' date, you seem to be implying that no one believes in the rocky core anymore. Perhaps, then, you should try the following experiment. Go to Google. Enter "jupiter rocky core". Press "I'm feeling lucky." See JPL mention rocky core. Or, just press "Google Search" and read links that deal with the concept more directly. This, of course, does not prove that the core exists, but rather goes to refute the idea that you present above, which is that scientists no longer believe that it exists.
Maybe that's just me. You're right, though, it is believed to have a rocky core. But it is also believed to not have one. You tell me to disregard Galileo's data but you don't have a problem quoting implied data from Pioneer 10 and 11. If you meant that YOU believe it has a rocky core, I would like some more justification.
You're right. While you (I assume you wrote the post to which I replied, AC) can come out and state that 'there is no "solid" mass on Jupiter' and give no justification whatsoever, mere mortals such as I must give it. And I didn't say that one should disregard Galileo's data, merely that not finding the expected abundance of water along the probe's entry path (which infrared images revealed to be a relatively unclouded area) does not imply a total absence of water on Jupiter. I never argued that there was as much water as we originally thought, merely that there is some water.
What "rocky core" do you propose can sustain it's solid phase at the awesome pressure and temperature at the core of Jupiter, after being immersed in liquid metallic hydrogen?
Sure, the temperature is an issue, but the "awesome pressure" would encourage most materials to go into solid phase (except for weird ones like water, of course). And what the heck does the liquid metallic hydrogen sitting above it have to do with anything? Are you proposing that it would dissolve the core or do you just think the words "liquid metallic hydrogen" are going to convince me that you know what you're talking about?
Impact events would make no difference one way or another, unless you are implying that Jupiter collided with another planet. That could give it a core mass.
Oh, sure, that's scientific. So, an asteroid couldn't do it, but a planet could? What about a really big asteroid, or a really small planet? My point is: what magic line determines that a body is big enough for you to dub it a "planet" and simltaneously allow your imagination to grant it the power to give Jupiter a rocky core, where all other impacts "would make no difference"? Give me a break.
Where did this theoretical planet come from? Extrasolar?
Oh, sure... the only bodies around while the solar system was forming are the ones we see today, is that what you are saying? Your argument keeps getting better and better.
Most of the extrasolar planets we have ever discovered are gas giants themselves, and larger than Jupiter to boot.
Right, this is irrelevant, but I suppose you believe that those numbers are in no way skewed by the detection methods currently in use? Obviously if we look for planets by looking at the gravitational wobble of stars, we're going to detect massive ones that orbit close to their stars. Heck, that much is even in the article to which this story referred, if you were unable to figure it out for yourself using basic physics. If there were any previous indication that you were scientifically qualified, this last paragraph is squashing that.
Which would mean Jupiter used to BE an extrasolar planet, and collided with a smaller planet with the orbit Jupiter now holds. If that is your theory, I advise you to examine the feasibility of it.
Wow. Where are you getting these ideas and whatever it is that you are smoking? That's quite a ridiculous theory that you put in my mouth, and I will shortly spit it back at you.
Well that was fun. Let me take some time out at the end here, leaving all the problems with what you just said behind, to explain the problems with your initial argument. The bottom line is that you have made statements that cannot be reasonably defended.
You say that "there is no water on Jupiter" [emphasis mine]. Now, I could talk about solar oxygen levels and the presumed abundance of oxygen in the early solar system and so on, but I don't have to. I'm even willing to believe that Jupiter has a relatively low oxygen abundance in its atmosphere. Nevertheless, we all saw a bunch of chunks of frozen water slam into Jupiter a few years back. Discarding for the sake of argument the idea that there was any water present on Jupiter before the impacts, if one single molecule of water from the impacts survived, then there is water and it's on Jupiter, so you lose; end of argument.
Similarly, you say "there is no 'solid' mass on Jupiter". Again, if there is a single speck of dust on Jupiter, you lose; end of argument.
The smart thing to do would have been to admit that you were exaggerating (that's why I gave you that "out" at the top of my post), and then we could have settled into a more reasonable discussion of planetary formation and elemental abundances. Instead you went off on these weird tangents, became insulting, and capped it off with ridiculous statements like the one about extrasolar planets mostly being giants, which thoroughly discredits you, made it a joy to write this reply, and makes it certain that neither I nor anyone else will pay any mind to anything more you have to say.
Even the "example" you quote, that of "how the Universe came into existence," about which you say, "the fact of the matter is that we know nothing..." is a poor one. Like all scientists, astrophysicists have formulated a theory (namely, inflationary Big Bang) which explains certain observational facts, makes certain predictions, etc.; furthermore (and quite significantly), it is generic in the sense that the results it predicts are not sensitive to a large number of parameters. I could yak on about this ad nauseum, but briefly, observational corroboration includes the existence of a Hubble flow (velocity is proportional to distance), the existence AND detailed properties of the cosmic microwave background (to wit, its isotropy to one part in 10 ^ 5 or so, the fact that it has the spectrum of a perfect 2.7 K blackbody, and the manner of the very small-scale anisotropies), and the ratio of light element abundances. Show me another theory that predicts all these things, in a natural way (ie, without invoking 27 free parameters to tune as you wish), and I'll listen to you; but hell, do that and you've probably won a Nobel anyway, so why bother with me? Furthermore, the physics of the Universe before nonlinearity should actually be very well described by "normal" physics -- and if it's not, that's a fundamental problem, independent of the application; the kicker, though, is that we have no solid evidence that the physics here doesn't work.
To sum up, my NSHO is that you are a) unclear about what exactly astrophysics entails, is, and relates to, and b) are unable to back up your broad claims of illegitimacy with fact. Your one anecdotal evidence of the evils of astrophysics, regarding the greenhouse effect on Venus, is so incidental as to be laughable: I know jack about the atmosphere of Venus, or about greenhouse gases in general, or really about planetary science in general, but then again I don't really have to; the vast majority of topics in astrophysics have absolutely zero to do with it. My totally biased opinion is that Carl Sagan probably has given more thought to this than I have, or than you have, or even (perish the thought) than Gunnar Heinsohn, whoever the hell he is. Your argument is like suggesting that if a chemist can't predict the bonding properties of C60, all of chemistry is flawed.
Have a nice day. :-)
It's an antiquated expression, whereas 'sublimes' is more accurate and more acceptable in modern circles. 'Camphoring' is more likely from Middle English than technical. It uses a substance to describe a process, similar to the way 'ice' implies the substance 'water,' but could describe other substances solidifying.
The important thing is that a planet must have a good degree of pressure. On tall mountains, you can boil water away in a paper cup, but on a depressurized surface like Mars, you couldn't get water into liquid form to begin with, unless it is pressurized. On the moon, they're not about to look for liquid water, but it is believed that it can exist in solid form (ice) located in shadowed wells.
We're here !!!!! Seriously though, given the fact that modern man appeared suddenly all over this planet 60K or so years ago, with language, pottery, alphabet etc indicates a possibility that we just might have colonised this planet. Some Polynesian tribes (isolated from Inquisitors) believe that we all lived in an egg and hatched to colonise the world.
I'm not a archelogist, but apparently there are almost no remains of human residence from a period of -60K to -800K (then you have remains of various Neanthertals). 60K years ago mankind appears all over the world, with formed culture, pottery, basic woodworking skills etc etc.
Food for though.
Revolution = Evolution
Sure, we can discern some of the many differences between atmospheric density (pressure) and mean density of a planet's various layers... There can be/is great variety in each planet's frame. If you vaporize the metalic core, or even substitute it with an equivalent mass of atmospheric gases, what have you got? You'd have less than 1G coming from the earth-equivalent mass (Newton's Law of Gravity says the increased distance, *squared*, would proportionally reduce the gravitational force.)
Heating and cooling poses interesting questions... A solid mass stabilizes a lot of the mean temperature. Would the gases quickly take off, cooling the nebula in disappation? Would they heat like a greenhouse, and begin radiating like a gas-giant? Probably both, but in what portions? Actually, a scientist friend of mine points out that space's so-called vacuum is actually rather hot to the gases travelling through it... the free-flying particles have neither the shade nor the dense gravity to slow their velocity. Of course, a solid mass in shade might not notice, unless it were small enough for the exchange with light gas to transfer comparable tempurature/mass.
It takes a lot of gravity to make a gas giant. If you could stand on the surface of the Sun and sense the pull of distant planets, Jupiter has more than 11 times the pull of Earth, despite having four times its distance.
1. Starting an uncontrolled nuclear chain reaction requires lower tolerances than controlling a chain reaction that is just subcritical. This means that fusion bombs are technologically simpler than nuclear rockets or fusion power plants.
2. Elliptical orbits with periapsis belows a planet's surface are lower energy than circular orbits at the ellipse apogee. This means that ICBMs are technologically simpler than orbital rockets.
Science fantasy authors love to write stories about "silicon-based life", but anyone with sufficient training in biochemistry can tell you silicon won't work as a basis for organic life.
And if you're going to consider even more exotic ideas ("photonic life" a la Star Trek, or neutronium life), you might as well be discussing ghosts and gremlins. They're just as plausible.
The main candidates out there are carbon/water life vaguely similar to stuff on Earth, and possibly machine intelligence (previously built by carbon/water life).
The inhabitants would have significant advantages in the world of e-commerce. They are already running on "internet time".
-no broken link
So, where are they?
They are us. We are not actually the descendants of apes; we're the descendants of the people who killed the descendants of apes when they crash-landed here a couple million years ago. We haven't been able to contact the planet we came from because the people who remained all died out from a disease spread from a dirty telephone booth.
(With apologies to Douglas Adams...)
--
BACKNEXTFINISHCANCEL
The Earth probably didn't capture the moon. Latest theory is that another planet about the size of Mars crashed into the Earth at very low angle and sheared off a lot of rock that went into orbit. After a while, some of the material collected to form the moon.
Don't just absorb the environmentalist line, think about it. They're only about half right.
Any life on a planet such as this would be subjected tremendous amounts of gravity. Basic movement would be difficult. Even if they (the aliens that is) were extremely intelligent, it would be difficult for them to construct advanced societal structures (buildings, transportation, etc). It is exciting that scientist are believe that their could be "conditions that are more favorable" for life in the habitable region, but if you are expecting little green men, they would have to be extremely flat (think little green beaver tail, without beaver).
| Ceci n'est pas une pipe.
Flat works. Many of the reasons for being tall are either to be taller than competitors, or to gain gravitational potential energy. Both of these scale down pretty well - you can get the same effect, just by reducing everyone's height in the same proportions.
There's a superb book on similar subjects; "Newton Rules Biology" by C J Pennycuick. It's over-priced and keeps going out of print, but it's an essential read. What happens if you take an elephant and make it bigger ? How big can you make it before its legs simply collapse under its own weight ? How small can a hummingbird get before it can no longer keep warm ? Why can't bees fly ?
amazon.com have it in at present, but not amazon.co.uk.
There's also a classic of '50s cheeezy sci-fi (whose title I can't remember) of an extremely flat alien who was a "mariner" of sorts on the surface of a spinning neutron star (the spin was important).
-Al Gore
Wouldn't that be nice...
Will code a sig generator for food
Mare Infinitus. Endymion, damnit.
Wait, that's four. Damnit, now it's eleven.
--
Habital Zone? Ahh they must mean within a 10 minute walk of good take-away and has optical fibre cabling pre-installed!
mv
I did not mean to suggestion we refrain from thinking about the topics altogether. Instead I suggested, and attempted to illustrate with my comparison to man's attempts at flight, that we fix fundamental flaws in our math before we start applying our formulae. Just like flight was not a frivolous or fruitless pursuit, astrophysics and (maybe) abiogenesis are not, either. I hesitate to call abiogenesis anything but bunk because of the math involved. We need to stop thinking about applying our useless formulae, start thinking about the problems therein, fix them, and then apply them. To address your other concern, namely that I did not provide any new models, I did so intentionally because I realized the mere act of arguing against the methods used in the study was a long task. I will give you a general idea about the other models I to which I alluded. Current science is based upon uniformitarianism, the belief that processes observed today are processes very similar to those in either different parts of the Universe, different times in the Universe, or maybe even both. In other words, Sol is burning much like it was a billion years ago. Unfortunately, there are manifold problems with the uniformitarian model(s), so many that periods of time that fit the model are more anomalous than the anomalies. The other school, which stands in stark contrast to uniformitarianism, is catastrophism. Immanuel Velikovsky was a pioneering astronomer in this field. Most catastophists are spending their time trying to figure out facts and derive models that incorporate those facts. While this was once what astrophysicists and biologists at large attempted, it appears now we have quite a well established doctrine and look for facts to further that doctrine. I have yet to see a school of catastophists attempt to tackle the Universe with a model (it's just too hard to observe), there are several great theories about our Solar System in particular. Try here and here if you are interested. I would give a rundown myself, but I know moderators don't take kindly to rogue astronomy and biology. Kidding. If you need further information, just post again and I'll answer concerns you might raise. As for your last question, btw, I have no innate dislike of abiogenesis of which I know. If life came from nonlife, then it came from nonlife and there isn't room for like or dislike. The math seems irrevocably against the concept, though. I felt its discussion pertinent to /. posters who felt that a little water and some heat was all that is necessary for self-replicating objects. Life is anything but common.
Errare humanum est sed diabolicum perseverare
Ahh... they know what they should be looking for, that's not the problem...
The nature of the technique and the technology available means it is not presently possible to detect Earth-sized planets.
"As a result, searches are picking up all the weird giant planets first," said Dr Chris Tinney of the AAT.
and doesn't he sound like a good old geek saying that!!!
you gotta love it...
___________________________
http://www.hyperpoem.net
hyperpoem.net
Um, having a hard time visualizing that; gotta link?
Why are they squished?
"Don't mind me cutting myself on Occam's Razor"
The sun *does* affect the tides, though; neap and whatever is anti-neap tides happen when the Moon and the Sun are in alignment and at right angles. respectively.
I will agree with your last point; better just use a nice shallow raft...
"Don't mind me cutting myself on Occam's Razor"
high density==pressure: the density of a planet is completely unrelated to the atmospheric pressure Venus is slightly less dense than Earth, but its atmospheric pressure is 90 times higher. Even the Suturn moon Titan has a higher atmospheric pressure (1.6 Bar) than Earth. And it is the atmospheric pressure that determines the range of temperatures where water is liquid.
small size==low gravitational mass: Earth has the third largest surface gravity of all planets in the solar system (in case you wonder, the 'surface' of a gas giant is defined by its radius, which is the level where the atmospheric pressure is one Bar). And it is the surface gravity that determines the (mechanical) stresses on an animal or plant.
Proximity to Sun==dynamic energy ('chaos'): From which cult/religion is that taken ?
Wow. Amazing. Well, since you took the time to be sarcastic, snide, and insulting, why don't I return the favor?
I did nothing of the sort. It amazes me how defensive people get here at slashdot, and, though I am not a qualified psychologist (you seem to care a great deal about credentials), I think what you need is a heaping dose of "get over it". It would be a shame if you turned into a troll before my eyes. I infer that you think I was trying to be argumentative, which is not the case. I'm rather sure of it since you constantly refer to "the argument" and your victory. You may not believe this, but not every conversation is an argument. The world isn't out to get you! I attacked neither your belief nor you personally, I just asked for elaboration. If that is enough to get you to write a 2 page flame post, I hope you don't typify the vast majority of people. Originally this post was much longer, but I realize now I can't reach you no matter how elaborate I get. It's plain that some people get it and some don't. I recognize my error, and if you were offended I apologize. I never claimed to be an authority, and it was your mistake to assume that. If the fact that my last post was not in my name bothers you, though I can't imagine why it would, remind yourself that I am not the author of the code slashdot uses, and therefore have no control over when it authenticates me and when it doesn't.
Your (slightly) interesting point has pinched me hard enough to engender this (even more slightly) interesting reply:
To learn why astrophysics is still "baby science", just follow the money. Astrophysics is currently chronically underfunded compared to other branches of investigation. Great leaps have been made, but there is a long way to go as you correctly suggest (although I don't agree with your choice of examples).
The question asked by politicians - "Of what earthly use is it?" has scotched many a big telescope or worthwhile stellar observatory or deepspace array.
Of course, the answer is simple:
"To know our origins, our present astronomical topography and our possible future."
We rely on our piddly little star for LIFE ITSELF. Wouldn't it be cool to know how it works????
, the sun that is the source of all our power.
Hey, cool! I never expected to see a Julius Sumner Miller reference on slashdot. The old prof. spent much time here in Australia, and was much loved by the public - due to his appearance in a long-running series of Cadbury's chocolate commericials, nearly everyone in my generation can ask "Why is it so?" in a Millerian accent :)
But he wasn't British (or even Australian): he was American. There seems to be some confusion on this point (even the web page for the Julius Sumner Miller Fellowship at the University of Sydney refers to his "unmistakeable Canadian accent" but in the prologue to his second book of Millergrams, Miller himself refers to his "native New England". Unless he meant the AUSTRALIAN New England ...
The real Captain Avatar is a fictional character, so I suppose he doesn't mind if I impersonate him.
You forgot the next line, which goes something like:
"It's orbiting at 90 miles a second, so it's reckoned, 'round a sun that is the source of all our power."
Which would put it at about 324000 MPH. Maybe it was "19 miles a second"...I can't remember exactly.
Chris Kuivenhoven is a thief, beware
Funny--everything I read about this seems to state that water is obviously needed to sustain life. Sure--it is for us, but how do we know that it would be required for life to exist elsewhere?
Direct quote:
The astronomers stress that this not an Earth-like object and is unlikely to host any sort of life - but if the planet has any rocky moons then they could have conditions that are more favourable.
--
Dyolf Knip
Hmm.... so the maximum distance that a planet could orbit our Sun and be spontaneously habitable (i.e. without terraforming) is about
1.25 AU.
At this distance a Terrestrial planet with the standard inventory of CO2 and H2O would have started off some 4.5 billion years ago with
a surface temperature and pressure very similar to modern Mars. As the sun warmed, the planet would slowly warm too. After about 1.5 billion
years, the planet would thaw enough for liquid water to be stable at the equator, and the process of conversion of CO2 to carbonate rock would
begin and the extensive CO2 pole caps would begin to disappear. Once consumed, their depressing effect on temperature (caused by the
reflection of sunlight back into space) would be removed and the planet could warm up appreciably. At the present day, such a planet would have
Earth-like temperatures but would need a large proportion (15%) of CO2 in the atmosphere to acheive this. 15% CO2 is poisonous to higher life
forms, but extremophiles can survive and if this was the planet's atmosphere, then life could well evoilve to tolerate it.
There's no reason why life couldn't evolve on a colder planet, further from the Sun. But it would be forever restricted to underground habitats
where volcanic activity warmed the ground. In nature, this life would resemble extremophile bacteria and algae on Earth, which appears to have
been the first form of Terrestrial life from which everything else evolved.
My (very approximate) calculations show that the planet's travelling at about 270,000 miles per hour, 300 times faster than the earth, if my Monty Python is correct.
MY calculations are:
2*6,000,000*PI = 38,000,000 kilometers
38,000,000/72 = 530,000 kph
530,000/2 = 270,000 mph
270,000/900 = 300 times faster than Earth
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
If life does not exist anywhere else in the universe now, it will later, because we will take it there.
ObHakorz comment:
A firewall can not protect you from yourself. Turn off what you do not need. Do not use the firewall to do your work.
There is no water on Jupiter.
If there is any oxygen at all there, it's in very trace amounts.
You need to understand that Jupiter is not a "planet" in the classical sense, and is actually more closely a star. In fact, if Jupiter achieved a mass of about 75 times it's current one, it would reach critical mass and ignite. Jupiter is by and large mostly hydrogen, and the interesting clouds that make it so famous are just trace gasses. They would burn away quickly. There is no "solid" mass on Jupiter, unless you consider pressurized hydrogen a solid mass.
Europa is out best bet in the solar system for free water, with Titan, a moon of Saturn next.
Neptune could possibly have oxygen on it, or at least I hear that's the rumor. But then I also heard Neptune had a carbon layer, and the pressure on the planet is so great that it rains diamonds.
Guns are inanimate objects. They have not, can not and never will do anything on their own. More Guns = Less Crime.
Drugs are inanimate objects. They have not, can not and never will do anything on their own. More drugs = Less Crime.
Ficuses are inanimate objects. They have not, can not and never will do anything on their own. More ficuses = Less Crime.
Pipe bombs are inanimate objects. They have not, can not and never will do anything on their own. More pipe bombs = Less Crime.
rootkits are inanimate objects. They have not, can not and never will do anything on their own. More rootkits = Less Crime.
Sorry, but if there's a problem with gun control here, you'll have to find a better rationale. Saying that inanimate objects don't jump up and run around on their own is simply tautological, and addresses nothing substantial. It is logically inconsistent to say:
A = B
B != C
A != C (this is OK)
but therefore:
More A = less X
just doesn't work.
--
Freeper Logic
How about Europa? Out in the middle of friggin nowhere, totally encased in ice, yet there is considerable thought by Those Who Know that there may be life underneath it.
I should point out the the conditions in which life first formed here were pretty disgusting themselves. [snip] Not fun. Those tidal pools were simply a little less god-awful than everything else.
"Those Who Know" would be "Those Who Make Good Guesses", right? I totally agree that it is *possible* that there is (or were) life on Europa from what we know of it right now, but until someone lands there an checks it, I'll hold my bets (didn't Arthur C. Clarke make someone go there for water in 2010, only to be attacked by some amorphous lifeform?). You see, Europa is short on one crucial thing - readily available energy coming in at a steady state. As you put it yourself - in the middle of friggin nowhere, totally encased in ice. What energy penetrates a thick layer of ice? Not much - I seem to remember hearing that if Europa is warm on the inside it is probably due to tidal forces from its planet, combined with the good insulation of the ice. Don't underestimate the tidal force of a gas giant but tidal forces are gravity, and gravity (or the low-termperature but widespread heating it most likely causes) is not a very high quality energy-source - certainly not compared to the high-quality energy provided by the sun, that Earth receives so much of, at least compared to Europa.
I'm not arguing that there can't be life on Europa, only that it is less likely to form there than on an Earth-like planet because of a dearth of high-quality energy. But these are mere guesses, and I sure hope Arthur C. Clarke was right about Europa :-)
Black holes are where God divided by zero
While I believe that intelligent life is extremely rare in the universe, the universe is so large that there is a lot of it, but very sparsely distributed.
Worse, I believe, if am recalling properly, that *our* first transmission strong enough to be detected from deep space was Hitler at either the 1936 Olympics or a Nuremburg rally. That would be our "first" impression on other intelligent and technically capable life.
Aide: Grant drinks too much to command an army. Lincoln: Find out what he drinks and give it to my other generals!
I've been working for years on my own little solar system generator - a piece of code that generates star systems at random. It uses physics to constrain what's realistic and what isn't, and over time iterates the systems into being. It produces fairly sane results - star systems that look like what we expect, and even some that look remarkably like our own.
The neat thing about it however, is what it predicts for life. There is life practically everywhere. Not often does it flourish like on earth, but it is common - with around 20% of star systems having a planet with life of some sort on it (most of the time just algae or hypercycles, low level stuff.)
Habitable planets, or those requiring only minimal terraforming, are much more rare however. Around 1.5% of star systems have such a planet. The requirements for habitability are temperature, gravity, atmospheric pressure, oxygen content, sufficient existing life to maintain the oxygen content, no poisonous gasses, that sort of thing. Amazingly enough, about 1% of all star systems contain a planet you could be dropped on with minimal survival gear and live indefinitely.
I've always wondered why people didn't take simulations such as these farther. We all know about ACCRETE and its derivatives - but the science has advanced over time, and so has our knowledge about life and its initial formation. I've found that I can vary nearly all of the questionable parmeters in my simulations greatly without significantly affecting the number of habitable planets.
It seems that changing your constraints in one place just forces the life to move somewhere else, and the number of habitables stays roughly constant. It is quite interesting, and somewhat comforting knowing that there are so many habitable worlds out there when you look into the night sky.
-dentin
Alter Aeon Multiclass MUD - http://www.alteraeon.com
I stand corrected. But they are sometimes very good guesses indeed.
[Europa is rather chilly]
Yeah, but look at Io. Obviously Europa doesn't have that particular level of insane tidal forces, but there's probably enough to do something. I don't have enough info on Jupiter's moons' orbits to hazard a guess, though. Just remember that tidal forces do indeed pack a lot of punch. Luna is quite far away and not very massive (compared to Jupiter), but it's still enough to relocate billions of tons of water around the world several times a day. On the Jovian moons, the change in external gravity is probably palpable, with your weight changing fractionally depending on where you stand in relation to Jupiter.
But I very much agree with you that the easiest (ha!) way to settle it would be to get someone over there. Meanwhile NASA prepares for another $10k per lb launch. Sighhh...
--
Dyolf Knip
"But sir, it's just one wafer thin mint..."
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
That's true. Io is one weird place. But I seem to remember hearing that the four (or something) innermost moons of Jupiter are within its equivalent of our van Allen belts (the Jovian ones are HUGE because of its enormous magnetic field), peppering them with radiation enough to make them sterile if they had Earth-life on them. Perhaps some very hardy bacteria (like those that survive inside some nuclear reactors - talk about tough) could live there, but in my book this further lowers the chance of life ever forming on its own. But maybe the packice of Europa protects it from that - I don't know.
Look here for more info on Jupiter and its moons. But Europa is VERY close to Jupiter - just 670000 km away according to the aforementioned website, just roughly four times the diameter of Jupiter. That'd put Luna at about 50000 km distance instead - talk about tidal waves! Besides, that would put the moon just inside the outer magnetosphere of Earth, giving Luna a good dose of radiation on its own.
Black holes are where God divided by zero
It would be arrogance to say we know all the laws of physics, as it is arrogance to say we are the only ones out there, in the entire universe.
Exactly... have you ever listened to the SETI people? It's arrogance to think that aliens will have the exact same technology as us, and will want to contact us...
Science is the art of Arrogance.
"Any sufficiently advanced technology is indistinguishable from magic" - Arthur C. Clarke.
How come Klingons (and some Romulans) could talk in their native tounge, and the Universal translator wouldn't translate it? (Best example I can think of was "The Undiscovered Country") Does it have an option that allows a speaker to turn it off remotely?
See! What did I tell ya about translation?
Steve's Computer Service, Hobbs, NM
>Earth is the most dense planet of our system.
This is not correct. Mercury is the most dense planet in our solar system. The Earth is made up largely of rock which is not that dense when compaired to the inner planets which have more nickel and iron. Go find a good solar astronomy class before try to lecture on the subject next time.
www.starstuff.org
"I'm just here to regulate funkyness." - James Gandolfini, as Winston in The Mexican
I finally got around to renting M2M last night - god what a horrible movie. "The Face" should have been "the Scarface" and it should have been made out of 100% pure Columbian white. Inside they should have found a bunch of Cuban gangsters, and maybe a high-school psychokineticist, instead of Bambi-the-space-alien.
A quick refresher of the chemistry of water, CO2, and life:
Water is an excelent solvent for polar (ionic) compounds like salt. CO2 is an excellent solvent for light organic compounds. Life consists of parcels (cells, globules) of complex chemistry, packaged in a lipid (fatty acid) membrane.
If water and liquid CO2 co-exist, they form small globules of one liquid in the other. At the interface, both polar and non-polar chemistry are possible. Lipids naturally line up at the boundary and form sheets that seal in the globules. Perhaps this is the first, crucial step towards the origin
of cellular life.
Maybe self-replicating chemicals already existed, but the packaging into cells was the vital step towards life as we know it. Perhaps conditions on the early Earth were cold enough for liquid CO2 to exist in some regions, and permit life to begin in this way? What a balance! Too cold and the water freezes. Too warm and the CO2 boils, and the greenhouse effect amplifies any change in insolation making the balance razor sharp.
If life required such a careful balance of temperatures to begin, then perhaps the habitable zone is much, much narrower than most people
imagine?
Who will plant the plants? You need farmers.
Aaarrgh....must....fight...it....no.... The impulse is too strong.....
Imagine a Beowulf cluster of those.
Not confused enough? http://translate.google.com/translate?u=www.slashdot.jp&hl=en&ie=UTF8&sl=ja&tl=en
messages from other worlds
I wish michigan were in a habitable zone. Water only exists as snow here.
"It is well that war is so terrible, lest we grow too fond of it."
Time is fun when you're having flies.
-Kermit the Frog
Thank you, brother. The Drake equation is the scientists version of: "{while twirling hair}I just can't believe we're the only beings out here!"
Who the hell is/was Drake, anyway? If an equation like this were my only claim to fame, I think I'd prefer anonymity....
Still, the best reason to look for planets like that is they might be good candidates for a new home when we destroy/overpopulate/get-bored-with/quarantine/etc . earth.
And it evidently uses non-standard rules for addition, too....
/.
/. If the government wants us to respect the law, it should set a better example.
Considering the kind of sick places here on Earth that life is perfectly willing to put up with, it seems very likely that even barely habitable worlds would develop some form of life.
This is not necessarily the case. The life you find in those god-awful places like 3 km below the packice or in some deep sea volcanic vent didn't start there. Some lifeforms adapted to those harsh conditions, but on a planet with 3 km of packice all over it may not get started at all.
Just because there's life all over Earth doesn't mean that life could have started in any of the almost non-inhabitable places. From what I've heard, the current theories include something like tidal pools.
Black holes are where God divided by zero
So let's go back to the notion that we're not talking about extraordinary life, thriving under pressure. Let's talk worlds we can personally colonize. We really aught to be seeking small planets like ourown, but dense ones:
Earth is the most dense planet of our system. Just divide Mass by Volume, and the greatest mean density is our own. Saturn has hte least, which may account for its lovely rings. But there are many fine balancing points working in Earth's favor:
- High Density==needed pressure for liquid water.
- Small Size==low gravitational mass, ==fewer sheering stresses fighting life's 'order.'
- Proximity to Sun==dynamic energy ('chaos') for creating (mixing) and sustaining (maintaining) life.
- Distance from the Sun==cooler order to prevent life from burning away in excessive energy.
So earth is unique to our system in being a light-weigth pressure cooker for life. We actually have a better chance outside our own solar system, where greater planetary densities exist, if getting there can be trivialized. Then again, the technology to make insterstellar travel trivial would likely make terraforming even more trivial.Furthermore, even if it could, its body would surely explode due to the low atmospheric pressure. Or, perhaps the weight of the organism could not be suspended by the atmospheric pressure and it would crash to the center of the planet.
There is also the thin atmosphere. The planet is small enough, but its atmosphere is a tiny shell and hasd a relatively massive solid core. That leaves little room for life to develop.
I tell you, Earth is no more habitable to life than Mars is now ever since the Matrians turned their gas giant into a desolate rock!
Anyone who watched FOX in the early nineties knows why they are green...
There was darkness, there was light
There was day and there was night
There was wrong and there was right
And then there was me...
You didn't even know me but you treated me like dirt
You didn't even know me but you called me a jerk
I'm from a planet near a star you wouldn't know (its very far)
They're calling me the man from mars
And I think they're insulting me
They tried to take my special suit
They said my head looks like fruit (what is fruit?)
(Put your hands up or I'll shoot)
I don't have hands, across the galazy I flew
Heard a peaceful message sent by you
Now I find your judged by color and size
I can't believe what you call my...
I's the guy who sails the sky
But I think I'd like to live here
I'd like to share your mountains
Share your trees and share your rivers
I've never seen so many beings of so many colors
I'd like one day for you to say that I can call you brother
And then there was we...
I'd like to learn about your pizza and your weather
And we could learn about how beings live together
And then there was we...
So if you're thinking about being a spaceman
It don't matter if your black or white
Or purple or green or blue or red
Or yellow with polka dots on your head
Or made of snow
Or made of wheat
Or looking like somthing thats... kind of a tree
I like your hat
-Barenaked Ladies - The Ballad of Gordon-
Are you happy now??
Blaming guns for crime is like blaming keyboards for first posters. More Guns != More Crime
Here's a link to the scientific paper
If the
Since I can't change that, I guess I'll leave it this way.
The old way was "catchier", but what the heck.
Blaming guns for crime is like blaming keyboards for first posters. More Guns != More Crime
Ever heard of spectroscopy?
Gas giant moons would quickly become tidally locked (facing one side to the planet), so the tidal bulges produced by the planet would stay put. The only ebb-and-flow would be from solar tides.
/.
/. If the government wants us to respect the law, it should set a better example.
And it probably came from the little green men peeing in their corner of the universe.
Didn't you read the article? It said the most interesting planet orbits epsilon Reticulum. According to Mulder, they will be gray because of the iron deficiency in their galaxy :)
When you do the math as I suggested:
Mercury = 5.4299e+12 kg per cubic km
Earth = 5.5206e+12 kg per cubic km
That's what empiral data is good for... finding facts for yourself instead of accepting a spoon-fed generalization.
Astrophysics and abiogenetical biology are the two most FUBAR branches in all of Science. Both branches religiously attempt to rectify random creation with probability. When the attempt fails, they brush aside the entire problem, as they believe their models are the only possible explanation short of God. The fact of the matter is that we know nothing about how our universe came into existence, or how life began in the Universe, save that all our current models could not be true. Unfortunately, instead of trying to find new models, we have defended them with a fervor rivaling the most devout zealots of any religion (with less excuse for doing so than any religious person.)
What many people forget is that one solid piece of negative evidence absolutely refutes a theory, regardless of how much favorable evidence that theory has behind it. For example, the equation:
(bn - 1)/(b - 1) = b(n-1) + ... + b2 + b + 1
works for all b and n. Well, all b and n except b = 1, and all n > 0. That's an incredible success rate for the equation. There are literally infinte conditions it satisfies. Yet, Mathematicians would rightfully scorn anyone who suggested that the formula was viable and that just because it didn't work in a few anonomalous circumstances doesn't mean that it shouldn't be adopted as a general rule. To suggest such a thing shows a fundamental misunderstanding of the Scientific Method.
Yet the great majority of astrophysicists and geneticists/evolutionists (whom I collectively called abiogenetical biologists, those who concern themselves with the origins of life from nonlife) carry this misunderstanding. I will list some general problems with which the two branches have yet to contend (and will never be able to do so as long as they adhere to their current models) and then--for the dimmer of you--explain why basic flaws in our models mean that the conjecture about a "habitable zone" is a waste of our time, bandwidth, and brainpower.
From the Realm of Astrophysics
I have seen many posts attempting to describe planetary surface temperature as a function of atmospheric gases and distance from the sun. This has been tried with Venus (viz. Sagan et al.) and has failed miserably. Sagan attempted to explain Venus' 800 degrees Fahrenheit surface temperature by attributing it to a "Super Greenhouse" effect. Gunnar Heinsohn had a nice response to that absurdity:
I am not attempting to suggest that planetary surface temperature as a function of distance from the sun and atmospheric makeup is always false. The Earth seems to perform fairly well under the function. However, one solid piece of evidence negating the calculus is enough to render the entire thing moot. It would be senseless to use such a method to try to estimate appropriate planetary distances for conditions favorable to life.On an even more roguish note, we don't even understand gravity (for those of you who don't understand nerd-authored physics, see this simplification), much less are we prepared to use our understanding to calculate life-favoring gravitational conditions as a functions of planetary size and density. If someone attempts to dispute this, I will be happy to illustrate further with tangible examples.
From the Realm of Abiogenesis
Planetary conditions can never be suitable for the spotaneous generation of life. At least, not so long as our Universe is only 20 billion years old. I cut and paste from this site, which is a discussion of abiogenesis by Alexander Mebane:
Conclusion
Now, for those of you who don't understand why all of these problems with the methods of the scientists who dedicated themselves to this frivolous study render the study a complete waste of human resources, I will explain. This kind of conjecture is much like man's early attempts to fly by pasting feathers onto one's arms and jumping off a cliff. This was a waste of time, perfectly good paste and feathers, and a waste of a (debatably) valuable human life. No scientific progress was gained by performing this feat. It was based upon erroneous presuppositions. The only good it did was to serve as an example of what not to do.
Leave conjecture to SciFi writers. They're better at it (and they don't spend nearly so much time or energy doing so.)
Errare humanum est sed diabolicum perseverare
A Star Control 2 reference, I'm impressed. Hopefully the inhabitents of the gas giant don't buy second rate automated probes to explore the galaxy.
It depends. If all you have to do is dig down a mile and start scooping up the ice, then it's not much of a problem at all. If you've got to sift through tons of moon rock to get a few pounds of ice, then it may indeed be easier to go to Jupiter, or just go a little further to Saturn and bring back an ice rock from the rings. Or nab a passing comet.
--
Dyolf Knip
This could well be a double-star system with the second star just some orders of magnitude too small....;-)
Cthulhu fhtagn!
Do tell. Name one.
need air: Brilliant. In a vacuum the water would boil-freeze and you'd have no more liquid water.
light: Brilliant. Without light the water would freeze and you'd have no more liquid water.
plants: What, do plants not qualify as life? Hell man, for a few billion years photosynthesizing bacteria were the only things you'd find here!
a suitably low gravity: We have absolutely no idea whether life could develop in gravities different from our own. How are you so sure?
no major regular earthquakes: What does this have to do with anything? Are you telling me primitive flora and fauna can't handle the occasional tremor?
What is the likelyhood of all these things being right on another planet: Look, if there is liquid water in any great quantities at all, a number of requirements have already been met. There is an atmosphere. There is sufficient light. The gravity is within reasonable boundaries, else the air pressure would be too wierd to allow for liquid water. Considering the kind of sick places here on Earth that life is perfectly willing to put up with, it seems very likely that even barely habitable worlds would develop some form of life.
--
Dyolf Knip
Do tell. Name one.
The dead sea.
light: Brilliant. Without light the water would freeze and you'd have no more liquid water.
So thats how a refrigerator works. The light goes off and things freeze.
plants: What, do plants not qualify as life? Hell man, for a few billion years photosynthesizing bacteria were the only things you'd find here!
No They aren't going to be sending radio communications are they?
a suitably low gravity: We have absolutely no idea whether life could develop in gravities different from our own. How are you so sure?
Speculation. We don't know life will need water.
no major regular earthquakes: What does this have to do with anything? Are you telling me primitive flora and fauna can't handle the occasional tremor?
Depends how occasional.
You clearly did not read the link(s) I supplied. I know this because the the first paragraph of the first link states:
The Drake Equation was developed by Frank Drake in 1961 as a way to focus on the factors which determine how many intelligent, communicating civilizations there are in our galaxy.
Try 145444 m/s Still fast though....
wot no sig
Possibly. A planet 84% the size of Jupiter is too small to be considered a star, but being that close to a real star would certainly make things more lively in its interior. By itself, Luna is a boring chunk of rock, but plunk it down next to us and we've practically got a double planet system.
--
Dyolf Knip
So thats how a refrigerator works: What would happen to the weather here if the sun turned off? For the fridge analogy, the only thing keeping everything from freezing is the light. Close the door and after a few years everything drops to a hair above absolute zero. Scientists are itching to get some labs on the moon because they think there are ravines there that have never been exposed to sunlight and are thus extraordinarily cold.
They aren't going to be sending radio communications are they Well, you never said it had to be intelligent life. Certainly, conditions will have to be more appealing for higher life forms to develop, but the primitive ones can sometimes help with that. This atmosphere we hold so dear to our heart was first created by all those ancient prokaryotes and whatnot.
We don't know life will need water True, but it's just such a versatile compound that its hard to imagine anything developing without it. About the only way to answer that particular question is to go exploring.
Depends how occasional [earthquakes] Ok, how's this? For any kind of high order life forms to develop, tectonic activity would have to be rare enough so that the CO2 released doesn't turn the place into Venus, doesn't cloud the sky with particles so the sun never shines, and doesn't keep lava running across 90% of the surface. Pretty much anything short of that :) is acceptable.
--
Dyolf Knip
I want to move to another planet... our only chance to save the human race is by becoming a space-faring race, and I'm all for colonizing distant balls of rock.
Although, given our track record, we would probably just turn it into a sterile ball of rock in a few hundred years.
If the scenario is only slightly comparable to our own solar system, those gas giants should have heaps of lil' moons orbiting them.
Although the oceans shouldn't be too big - just imagine the tidal wasves :-)
-- Truth suffers from too much analysis.
The astronomers stress that
this not an Earth-like object
and is unlikely to host any
sort of life - but if the planet
has any rocky moons then
they could have conditions
that are more favourable.
Our moon hasn't any water on it. We should begin to develop methods of getting planetary water from a base on a dry moon.
Try it with Earth. Then try it from Europa or Io with Jupiter. (Is there any free water on Jupiter? I don't know.. but this can be tested with any substance)
Goat sex free since 2001
Although this seems like further justification for the hypothesiss that life exists elsewhere in the Universe, the discovery of such large "exoplanets" in the habitable zone of these solar systems raises some important questions about the validity of astrophysical models of stellar birth, and indeed stellar astrophysics in general.
Now as anyone who has ever studied astrophysics knows, much of it is based upon little more than guesswork and vastly simplified models which ignore almost all of the complexity that makes our Universe a place in which we find stars, galaxies, black holes and life. I mean, when the model considers a star to be made from hydrogen, helium and "other stuff" how can you take it seriously? And that's not even the worst example of an astrophysical shortcut.
Whilst these discoveries are great for further illuminating what's out there, they yet again cast doubt on much of astrophysical "theories". We need to remember that as a subject, it's one of the shakiest scientific disciplines around. Until they can come up with theories that either have a Universe older than the stars within it or stars that are younger than the Universe they are in, I can't really take it very seriously at all.
Lots of parts of the earth have liquid water, and a lot of them have no life. More than that is needed for life to survice. We need air and light and plants as well, and a suitably low gravity. And no major regular earthquakes.
What is the likelyhood of all these things being right on another planet? Ludicrously improbable.
Enrico Fermi (created first controlled fission reaction, among other things) responded to a question like this by asking: if intelligent life exists beyond Earth, why don't we have any evidence of it yet?
.1 percent head start from the beginning of the universe, and they would have made it in plenty of time to colonize Earth before we started walking upright.
Even if you throw in very pessimistic estimates about how likely intelligent life is to evolve, and how slow and hard it is to colonize other worlds, and how few colonizable worlds there are, it is still hard to come up with numbers that don't make it likely that an intelligent species would colonize the entire galaxy within a few million years of gaining space travel.
Imagine a race on an Earth-like planet on the other side of the galaxy develops intelligence and space flight. In our case, this took 3.5 billion years after the oceans condensed, give or take a few hundred million. So in their case imagine it took the same time, but maybe their solar system formed a percent or so closer to the beginning of the universe, about a hundred million years.
Now imagine that our shared habitat is so rare, that planets like this can only be found at an average distance of 1,000 light years from each other (note that we've found 50 Jupiter-sized planets within 150 light years of us in only a decade of slow, crude searching). Imagine this race never figures out how to travel faster than light, and takes 1,000 years to make a hop to the next inhabited world. Imagine that successful colonies are rare and take time to develop, and so it takes 1,000 years on average before a colony launches its own colonization mission. Even at this slow pace, a million years is more than enough for a race to colonize every habitable planet in the galaxy, including ours, as the galaxy is only 100,000 light years in diameter.
So, this race would need less than a
So, where are they?
"You can't get something for nothing." - my grandfather, on the stock market and Reaganomics.
The REAL jabber has the /. user id: 13196
The REAL jabber has the user id: 13196
What you do today will cost you a day of your life
We have no real idea what probabilities to give to any of these events. Some of us look at Earth's history, events and timings between events, and develop gut feelings for the numbers. But we have nothing to test them on. Not now.
Besides, someone has to be first.
The Drake Equation may be useless in this application, but it has been used to determine, very accuratly, the probability of an orange suffering from stage fright. Research by D.r. Patricia K. Michaels, GmPL.
Star Trek drek aside... We ARE on Sol 3, a little planet we call Earth (dirt). I have no doubt that every single planet out there is called the linquical(sp, no don't correct, just go with it) equivilent(sp again) of 'dirt'. No doubt this would screw up any automatic translation system. We say "Welcome to Earth", the translation system translates that into 'dirt' then into the aliens equivilent of 'dirt', and the aliens hear "Welcome to Zorphlin." The aliens look at each other and think "gee, what a coincidence, their planets name is the same as ours!", or they think "hey, these guys are screwing with us!" Either way it could get confusing.
Steve's Computer Service, Hobbs, NM
Need infantry to hold land. Space/air borne militias are good for softening up land-based defenses, but ultimately, you will need infantry if you want to secure the land and keep it.
"Don't mind me cutting myself on Occam's Razor"
>The smallest of the three is an object called a "hot Jupiter" because it sits just six million kilometres from its parent star, HD179949 in the constellation Sagittarius.
>The planet, which has a mass that is 84% of our Jupiter, orbits the star in only three days.
hmm.. a 72 hour year?? wow.. not only is this thing hot.. it's quite fast at 4.3633 * 10^14 m/s.
(6M km radius, assuming perfectly circular orbit). Anyone have an idea what average earthspeed around the sun is?
//rdj
No one can understand the truth until he drinks of coffee's frothy goodness.
--Sheikh Abd-Al-Kadir, 1587
Even if there were life -- intelligent life and for the sake of this post, let's say intelligent enough to have civilizations and technology -- would it even be possible for them to build something powerful enough to escape their own gravity and ever travel through their solar system?
I know -- pointless questions -- but they are the first things that came to my mind when I saw that. I'm no Hubble, okay? :)
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seumas.com