Actually there are limits to what gravitational assists can do (unless one s waiting to spend a loooong time, using the "interplanetary highway" of chaotic gravitational influences). About a third of Galileo and half of Cassini's mass was propellent needed for the initial capture burn (and subsequent "retargeting burns" needed by the probes to, yes, take advantage of the gravitational assists).
In addition, neither probe tried to go into ORBIT around any of the moons in which case gravitational slingshots from the other moons would have been useless. Gravity assists only change velocity relative to (a larger) central body like Jupiter when using the moons or the Sun when using the planets. Europa is a large moon so going ino orbit around it (and landing on it!) would require a great deal of additional fuel.
Still, gravitational slingshots are a VERY useful technique for reducing the amount of fuel needed for these missions. Until NASA gets into the habit of using high efficiency ion drives (and maybe learning how to aero brake in a gas giant's atmosphere a la the movie '2010") they are the only way we'll be getting to and then exploring these systems. Sorry I neglected to mention them in my original post, I'm a really big fan of them (I've been fortunate enough to talk with the guys at JPL about how they use the computer generated "pork chop" book of gravity assisted trajectories to choose the paths these spacecraft take).
From the previous slashdot story about "Rare Earths". The argument was made that the a large moon (which may be very rare) might be necessary to keep a planet's axis from wobbling. But what about an exo-moon around a (much larger) planet?
If having a large moon helps stabilize the earth's rotation, what about if an exo-"planet" is, in fact a moon around a much larger (probably gas giant) planet, just like Pandora in the movie "Avatar"? One would imagine that any variation in its climate due to wobbling would be completely eliminated.
While the "exo-moon" would almost certainly be tidally locked to the giant planet, as long as the orbital period wasn't too long (a week?) the difference in temperature between night and day would hopefully not be too pronounced. For example Io, has a period of 1.7 days. If the moon had a really thick atmosphere (like Titan) then this would probably not matter in the slightest as the "air" would likely distribute the heat quite effectively (but could be windy!).
Another thing we've learned by looking at these moons orbiting the gas giants is that they could have almost any amount of tectonic activity which is important for things like plate tectonics which is sometimes regarded as being essential for its effects on our climate. From super-volcanic Io to frozen Callisto, we see that tidal effects from a gas giant can pump hugely varying amounts of energy into a moon.
Of course, radiation may be a concern for most DNA based life (some DNA based life, like tardigrads are remarkably resilient though). I don't know why some gas giants like Jupiter have lethal (to us) amounts of radiation while others don't. So maybe this is a non-issue.
So maybe we should be looking for exo-moons orbiting gas giants in the habitable zone! How many are there? Obviously I don't know but there don't seem to be any dearth of gas giants orbiting other stars. As for the number of moons orbiting these gas giants, who knows but judging from our own solar system (Jupiter has 33 satellites of which 4 are "large") it seems that one or more would be at the right distance from the planet to benefit (but not too much) from tidal energy. Just for an example imagine if Jupiter was in the habitable zone. All the Galilean satellites except Io would be excellent candidates for COMPLEX life (presumably underwater).
What wavelength radio waves penetrate underwater? Maybe SETI should be listening on those frequencies!:)
So if having a large moon helps stabilize the earth's rotation, what about if an exo-"planet" is, in fact a moon around a much larger (probably gas giant) planet, just like Pandora in the movie "Avatar"? One would imagine that any variation in its climate due to wobbling would be completely eliminated.
While the "exo-moon" would almost certainly be tidally locked to the giant planet, as long as the orbital period wasn't too long (a week?) the difference in temperature between night and day would hopefully not be too pronounced. For example Io, has a period of 1.7 days. If the moon had a really thick atmosphere (like Titan) then this would probably not matter in the slightest as the "air" would likely distribute the heat quite effectively (but could be windy!).
Another thing we've learned by looking at these moons orbiting the gas giants is that they could have almost any amount of tectonic activity which is important for things like plate tectonics which is sometimes regarded as being essential for its effects on our climate. From super-volcanic Io to frozen Callisto, we see that tidal effects from a gas giant can pump hugely varying amounts of energy into a moon.
Of course, radiation may be a concern for most DNA based life (some DNA based life, like tardigrads are remarkably resilient though). I don't know why some gas giants like Jupiter have lethal (to us) amounts of radiation while others don't. So maybe this is a non-issue.
So maybe we should be looking for exo-moons orbiting gas giants in the habitable zone! How many are there? Obviously I don't know but there don't seem to be any dearth of gas giants orbiting other stars. As for the number of moons orbiting these gas giants, who knows but judging from our own solar system (Jupiter has 33 satellites of which 4 are "large") it seems that one or more would be at the right distance from the planet to benefit (but not too much) from tidal energy. Just for an example imagine if Jupiter was in the habitable zone. All the Galilean satellites except Io would be excellent candidates for COMPLEX life (presumably underwater).
What wavelength radio waves penetrate underwater? Maybe SETI should be listening on those frequencies!:)
They claim inconsistencies in the design and with pictures of the crash site (like how it probably was demolished when it crashed at several hundred miles per hour).
I thought it looked like a fiberglass mockup. Anyway, good to know this, I read that to get any real use out of the drone, it would have to be almost completely undamaged because tolerances are very important when it comes to aerodynamics and stealth (I guess that's why those air force guys don't like it when I go about measuring their F-117s with my calipers at various air shows!)
Look guys, sorry if you misconstrued my comments. I honestly don't know why they made an experiment with this design. I was thinking, if they wanted to remove the effects of gravity, shouldn't they do a 2D simulation using a (relatively) thin flat plate of liquid sodium held horizontally? But then I have no clue if this would give any better results. I've heard that 2D supercomputer simulations of exploding supernovas turn out to be completely different (wrong?) from 3D simulations (which are much more expensive to carry out).
Anyway, the point is that I'm completely unqualified to judge these experimental designs, I was just wondering why something as obvious as gravity could be ignored. Is it that convection does not play a part in the phenomenon they are examining? Almost always I add something like "I am not an experimental physicist" to my postings, you'll see this on my (many!) prior postings. I guess I was just in a hurry this time. I have the absolute highest respect for scientists, my best friend is a tenured professor of theoretical chemistry and I know I couldn't do one-hundredth the math related stuff he does (I know, I've tried). I really wish I was smart enough to be a scientists; I consider myself to be very creative (I used to design theme parks!) but I just don't have what it takes. Sometimes I think Einstein was wrong when he said "imagination is more important than knowledge" but maybe he wasn't referring to knowledge of math.
That said, here's some puzzles that I've been thinking about while pondering this sodium sphere; if you wanted to model the convection caused by gravity (and heat) using a 2D analog, could you use a spinning disk filled with small particles and a refrigeration (cooling unit) at the center? When spun, the colder denser particles would be flung to the periphery of the disk whereupon they would be heated by contact with the "surface" and then sink back towards the center. By reversing the "forces"; centrifugal force (I know it's a "fake" force) instead of gravity but also reversing the hot and cold sources, wouldn't you have a good 2D simulation of the hot earth core and inwardly attracting gravity?
Now, as I said earlier, I've heard that 2D simulations sometimes are grossly incorrect at modeling 3D phenomenon. Too bad there is no way to spin something so that all points on a sphere have a centrifugal force. Or is there? Remembering that spinning a disk is just rotating a 2D plane in the third dimension, I was wondering can a 3D sphere be rotated in a (hypothetical) fourth or higher dimension?
Certainly I don't have any ability to do, if I had access to the fourth dimension I'd be using it for a lot of other things than rotating spheres! (Like robbing banks). But what if THE ENTIRE 3D UNIVERSE was rotating as some physicists have wondered, except not in the third dimension but in the fourth dimension. Would all the pieces feel an outward acceleration like a spinning plate? Wouldn't every object feel a force the was proportionately as strong as it was from the "center"? Would this explain cosmic inflation or even dark energy?
See sometimes not knowing (enough) math and science allows you to think really crazy things!
Soooo.... does the fact that the military is funding SETI entitle them to a kill switch if the Paul Allen array (I assume this is the recipient of the funding) finds anything? In addition to the obvious socio-political implications of the discovery of ET, I have heard that the armed services are rife with religious fundamentalists who might be very upset to know that God didn't create this universe solely for them?
Anyway, perhaps we should be concerned if prominent SETI researchers suddenly start to go missing...
How can this produce accurate results that will possibly match that of reality? This device (unless they are planning to put it on the space station) will be overwhelmingly influenced by the (real) earth's gravity. Convection will obviously be way off.
So, unless they are trying to model how the earth's core would act if it were enclosed in a giant metal sphere and placed on a gigantic table subject to one-gee, won't this simulation be way off?
Even if they put it in space, I'm not sure the simulation would be correct, the forces provided from the self-gravitation would probably be off.
Interesting correlation! Maybe it also plays a role as to whether or planet is suitable for life, a lot weaker and we'd lose too much of our atmosphere to space. A lot stronger and we'd end up a gas giant. But these might be pretty broad limits.
However, once life gets started, I'm not sure that the strength of gravity is tied closely to the development of life (life evolved into quite complex forms in the oceans). As far as INTELLIGENT life, I also am not sure if there's any correlation. Perhaps our ancestors evolved exceedingly good hand eye manipulative skills while swinging from branch to branch; I'm not sure how making gravity weaker (or stronger!) would make this better or worse.
So, too bad we didn't evolve on an exo-moon like Titan (or "Pandora") where getting to space would be much easier (low gravity, dense atmosphere). Or too bad we didn't evolve on a world that was subject to lots of radiation from the local star (no magnetic field?), then nuclear rockets would be very appealing because we'd be immune to high levels of radiation!
Again, I'm just paraphrasing from his book (but I think I'm remembering it correctly). It was a scene where they were pitching the idea of the space elevator and talking about the fact that the (unspecified) rockets of he future would be producing unacceptable environmental damage.
In his defense I think he was talking about "astronomical" (ha ha) levels of space traffic, something we can only hope for in our wildest dreams of a true space faring civilization with millions going to space DAILY. But who knows? He's dead.:(
Sorry, but that's the first thing I think of when a new super material is described.
I can't think of any other technology that, barring a really huge breakthrough (like anti-gravity) would truly make space travel a practical reality for millions. Even Arthur C. Clarke in his "Fountains of Paradise" book alluded to this saying that the supposedly hyper-efficient rockets of the future would create so much environmental damage (pollution, sonic booms) that really heavy traffic couldn't be sustained.
Maybe if we had cold fusion (or something like it like muon catalyzed fusion or zero-point energy) space travel on a large scale would be practical but these "breakthroughs" might be just as far (or impossibly far!) away.
By the way, did anyone see the developments (at MIT?) where they showed a nano structured "tape" able to support the weight of a full grown man with only a few inches of surface area? And it was able to be re-used thousands of times before using its grip? Perhaps the space elevator could be made of material structured this way, I mean if that thing is ever going to be built it will essentially be a gigantic 23,000 mile long SINGLE MOLECULE anyway so nano structuring should be almost trivial!
I never knew that (or really thought about it), are you sure it's true though? I don't know a lot about astronomy but isn't the plane of our solar system pretty different from that of the galaxy? Still I realize that even some correlation would, as you say, skew my numbers off. Have astronomers been able to verify that extra-solar systems are not randomly oriented? Would they be able to figure that out by looking at dust disks which are the only structures I can think of resolvable with out current technology? (I'm sure they can't resolve the disks for any but the largest, nearest stars and see which way they're spinning).
Remember that Kepler looks at stars using the "transit" method. Basically it stares at the little point of light for a looooong time, never blinking and waits to see if the light drops just a teeny bit due to something passing in front of it. How long? Well since it has to calculate the orbital period, it must watch at bare minimum for at least 1 year to see 2 passes (assuming its looking for a planet in an earthlike orbit around a sun-like star). Then, in order to make sure that it isn't some OTHER planet passing in front of the star, or an object in our solar system, or "sun spots" on the star, or maybe space butterflies getting in the way, the scientists must wait for a THIRD confirming pass (at the predicted time of course with the same drop in intensity) to be sure the observation is "real".
I think these guys have found the first "earth-sized" object that has made three confirmed passes. Note that the period is a bit less than a year so they've had enough time to get three observations in the three years. Soon, they'll be announcing confirming "third passes" on more and more planets that have periods in roughly the one-year window that indicates it's in the habitable zone around a sun-like star.
There are two things to note here: First, Kepler can only see planets that pass between it and the target star, that is the planet's orbit must be almost exactly edge on for us to see it. How close to edge on must it be? Well for example; the earth's orbit is a circle (very) roughly 100 million miles from the sun and the sun is roughly 1 million miles across. So, if the orbit was tilted more than 1/100 or 1%, from some distant observer, they wouldn't see it cross in front. (The size of the earth is inconsequential in this calculation because it is so small in relation to the sun). Similarly, for the kind of planets Kepler is looking at circling around sun-like stars, we are only seeing BY PURE CHANCE 1% of them. So if we see 100 planets circling these stars in their habitable zone; that means there are really 10,000 of them! So for a sample size of 150,000 stars, that means that one out of every 15 sunlike stars has planet in it's habitable zone! Amazing, especially when you consider our galaxy to have perhaps 10 BILLION sunlike stars!
Secondly, Kepler was launched before astronomers "discovered" that the best place to find "habitable" planets wasn't around sunlike stars but around smaller cooler stars. For various reasons, the habitable zone (where water can be a liquid) is proportionately larger in these "mini" solar systems (everything is smaller, like the orbits). They realized that even if a planet was tidally "locked" so that one face was always facing the sun, the atmosphere would redistribute the heat enough so the planet would be "habitable" (must sure be windy though). Another advantage is that these smaller stars live much longer than our sun giving life longer to come to well... life! Finally these smaller stars are much more numerous than sunlike stars. Anyway, I think Kepler was focusing mainly on sunlike stars and not these smaller, more numerous and perhaps easier to detect (because the orbits are smaller you don't have to wait as long for three passes) targets. Maybe Kepler II will go after them!
Just so that you know, Kepler is likely (has already?) been giving tons of other interesting data. I understand that its sensors are sensitive (and stable enough!) so as to detect possible sunspots in these stars. Also by paying close attention to the timing of the transits, they can determine whether other planets are gravitationally "tugging" at the transiting planet and perturbing its orbit (that's how Neptune was discovered). Finally, the resolution of the 'light curve" of the transit may be sharp enough to reveal any large moons in orbit around the transiting planet. So even if the planet in the habitable zone is too large to support life as we know it, it may have a right sized moon! (think "Pandora").
So, when will we be able to get a spectrographic reading on its atmosphere to see if there is free oxygen there? If an amateur using a 10" scope can see the dust around another star, is there any way the very best techniques using twin 10 meter scopes with' anti-aberration lasers can block out enough of the stars light to see just the planet's atmosphere?"
You know, one of the great things about the Internet (and the slashdot posting system) is the relative anonymity it provides.
I'm glad because it has limited my embarrassment for making such an ill-considered statement without doing the most cursory investigation. (If you Google "Lucy Koh", the very first listing is the Wikipedia entry with her bio.). At least I don't have to face up to my mistakes in my "real" public life.
However, the other nice thing about the anonymity the Internet provides is that it helps keep one's ego from getting in the way of an admission of being wrong.
So, boy I was wrong to imagine that Ms. Koh might have been unduly influenced; with her upbringing, education and qualifications, it is very unlikely that this would've happened. My apologies to all the other posters who wasted their time on this thread.
As a fellow Korean American, I'm wondering what kind of position she would've been under; with her husband (assuming he's also of Korean extraction), her relatives, classmates (if she was educated in Korea), and perhaps church (if she had been going to, as is often the case, a Korean church); if she had blocked Samsung.
Samsung is widely regarded (whether deserved or not) as a national treasure in Korea with a HUGE percentage of the ENTIRE ECONOMY (I think it's something crazy like 25%!). So I can guarantee that a decision against them would not be looked upon kindly by the average Korean.
If I may wax philosophical about my own posting, the advantage of using this "level" of encoding is that nature has, through ruthlessly efficient evolution, pruned out the almost-infinite number of non-useful proteins. Almost every DNA sequence that encodes a protein that is deleterious to the survival to the organism has been eliminated by the grim reaper. The few "bad" but non-lethal proteins that are still around in a living organism (like mis-folded hemoglobin to fight sickle cell disease) will stick out like a sore thumb with this sort of compression algorithm due to the exceptions it will throw.
But maybe I'm missing something completely obvious! (I believe I covered the intron, exon and by extension other "regulatory" aspects of DNA, they would possibly have a different library to be compared to or use a lower level compression scheme).
So, why can't they compress the data at the level of proteins? I mean it takes thousands of DNA base pairs to code for 1 protein, like hemoglobin, so instead of storing all that just say "here is the DNA sequence for protein X". Any exceptions, like mutations could then be indicated as "at position 758, the A is replaced by a G".
Of course if there is something REALLY novel, like a bioengineered virus that used different (non-standard) 3 base pair codons to encode the same amino acid, this kind of data compression wouldn't work but for 99.9999% of "natural" cases it would. (I saw this idea in the tv series "regenesis"). So for these (hopefully rare, it was for a bio-weapon!) cases a different type of compression would be used. "My" compression algorithm would, of course, break which would be a good indication this wasn't a natural DNA sequence.
I am neither a bio-expert nor a compression expert but this seems to me to be similar to the problem of compressing a vast library of books. Is it best to compress at the level of letters, words or even sentences? I'm only guessing what this entails because I'm not a linguist either!:(
(Then there's the whole business of introns or exons which "seem" to be content/protein free but I understand contain lots of regulatory information despite their repetitive nature. I would imagine these could be handled by some sort of pattern RLE.)
I'm as big a fan of the smaller, faster, cheaper paradigm as anyone but there is one thing about ALL these space probes that CAN'T be miniaturized.
It's the communications subsystem, most notably the antenna. I'm pretty sure that it can't be miniaturized due to the laws of physics dictating aperture and gain etc. (Unfortunately, I am not an physicist:( Also, ever since the Galileo probe antenna DISASTER (I call getting much less than one-hundredth the bandwidth a disaster) caused by the fact that the antenna didn't unfurl properly, means NASA is very conservative about using lightweight technologies. So unless the probe is designed to return to earth-space, bandwidth requirements will dictate a large (and heavy) antenna. (Still I'm not sure if the weight-bandwidth rule applies to coherent laser/maser communications, I understand that an upcoming mars orbiter will test using a laser link for much higher bandwidth).
That said, the advances in miniaturization (which extends to sensors and complete lab-on-a-chip) are extremely encouraging. Perhaps probes of the future will have a main "mothership" which will provide the communications link to lots of semi-autonomous micro-probes.
Great comment, did you read the NYTimes article about stereotypes of various car drivers? I think it went something like this:
BMW - Arrogant, spoiled (this perception went way up after the official's son who killed someone while driving a BMW) Mercedes - for older people Audi - powerful (don't mess with the driver. This is because many officials drive this)
American cars I seem to remember have a pretty good reputation. Who knew?;). But I guess they've been getting better.
If it did the analysis using just the "after" image (maybe by looking statistically at ithe ndividual pixel level, I dunno I'm not an image expert) that software would be SO useful for Internet dating sites!;)
Actually I'm wondering if images CAN be analyzed using statistical data from the individual pixel data to determine things like what camera was used to take the picture, maybe what software was used to edit/convert it (using gamma curves?). Then you could see (maybe) who was posting pictures of themselves from long ago (not like I've ever done that!).
Using this technique plus normal(?) traffic cameras, police could pretty quickly build up a list of habitual red light runners. (Even if they didnt actually "run" the light, they would be put under suspicion). They could be put on a list for "random" pull overs. (This presumes that video cameras with auto license plate reading are present and functioning on police car dashboards. I'm not sure this is the case nationally, but when I was in Denver recently a police car pulled over my friend because the computer had her license plate on a list. Call it the "Do Not Drive List").
This is nothing compared to when face recognition systems become widely prevalent. That'll blow away the "big-brother" predictions made by science fiction films like minority report (which used retina scans). Of course, WE'VE been supplying the government with tons and tons of this pre-edited, organized data tagged data. Thanks Facebook! (which is another reason why I don't use it). Call it the "Do Not Walk List".
That coupled with national biometrics programs (India, Afghanistan) and GPS tracking in every smartphone (Carrier IQ) and warrantless tapping/tracking of American citizens (war on terror) means we are rapidly heading towards a world where your government CAN know where you are at every moment. Whether or not they WILL know where you are is up to the battles over privacy information.
Slashdot Mirror
Actually there are limits to what gravitational assists can do (unless one s waiting to spend a loooong time, using the "interplanetary highway" of chaotic gravitational influences). About a third of Galileo and half of Cassini's mass was propellent needed for the initial capture burn (and subsequent "retargeting burns" needed by the probes to, yes, take advantage of the gravitational assists).
In addition, neither probe tried to go into ORBIT around any of the moons in which case gravitational slingshots from the other moons would have been useless. Gravity assists only change velocity relative to (a larger) central body like Jupiter when using the moons or the Sun when using the planets. Europa is a large moon so going ino orbit around it (and landing on it!) would require a great deal of additional fuel.
Still, gravitational slingshots are a VERY useful technique for reducing the amount of fuel needed for these missions. Until NASA gets into the habit of using high efficiency ion drives (and maybe learning how to aero brake in a gas giant's atmosphere a la the movie '2010") they are the only way we'll be getting to and then exploring these systems. Sorry I neglected to mention them in my original post, I'm a really big fan of them (I've been fortunate enough to talk with the guys at JPL about how they use the computer generated "pork chop" book of gravity assisted trajectories to choose the paths these spacecraft take).
From the previous slashdot story about "Rare Earths". The argument was made that the a large moon (which may be very rare) might be necessary to keep a planet's axis from wobbling. But what about an exo-moon around a (much larger) planet?
If having a large moon helps stabilize the earth's rotation, what about if an exo-"planet" is, in fact a moon around a much larger (probably gas giant) planet, just like Pandora in the movie "Avatar"? One would imagine that any variation in its climate due to wobbling would be completely eliminated.
While the "exo-moon" would almost certainly be tidally locked to the giant planet, as long as the orbital period wasn't too long (a week?) the difference in temperature between night and day would hopefully not be too pronounced. For example Io, has a period of 1.7 days. If the moon had a really thick atmosphere (like Titan) then this would probably not matter in the slightest as the "air" would likely distribute the heat quite effectively (but could be windy!).
Another thing we've learned by looking at these moons orbiting the gas giants is that they could have almost any amount of tectonic activity which is important for things like plate tectonics which is sometimes regarded as being essential for its effects on our climate. From super-volcanic Io to frozen Callisto, we see that tidal effects from a gas giant can pump hugely varying amounts of energy into a moon.
Of course, radiation may be a concern for most DNA based life (some DNA based life, like tardigrads are remarkably resilient though). I don't know why some gas giants like Jupiter have lethal (to us) amounts of radiation while others don't. So maybe this is a non-issue.
So maybe we should be looking for exo-moons orbiting gas giants in the habitable zone! How many are there? Obviously I don't know but there don't seem to be any dearth of gas giants orbiting other stars. As for the number of moons orbiting these gas giants, who knows but judging from our own solar system (Jupiter has 33 satellites of which 4 are "large") it seems that one or more would be at the right distance from the planet to benefit (but not too much) from tidal energy. Just for an example imagine if Jupiter was in the habitable zone. All the Galilean satellites except Io would be excellent candidates for COMPLEX life (presumably underwater).
What wavelength radio waves penetrate underwater? Maybe SETI should be listening on those frequencies! :)
So if having a large moon helps stabilize the earth's rotation, what about if an exo-"planet" is, in fact a moon around a much larger (probably gas giant) planet, just like Pandora in the movie "Avatar"? One would imagine that any variation in its climate due to wobbling would be completely eliminated.
While the "exo-moon" would almost certainly be tidally locked to the giant planet, as long as the orbital period wasn't too long (a week?) the difference in temperature between night and day would hopefully not be too pronounced. For example Io, has a period of 1.7 days. If the moon had a really thick atmosphere (like Titan) then this would probably not matter in the slightest as the "air" would likely distribute the heat quite effectively (but could be windy!).
Another thing we've learned by looking at these moons orbiting the gas giants is that they could have almost any amount of tectonic activity which is important for things like plate tectonics which is sometimes regarded as being essential for its effects on our climate. From super-volcanic Io to frozen Callisto, we see that tidal effects from a gas giant can pump hugely varying amounts of energy into a moon.
Of course, radiation may be a concern for most DNA based life (some DNA based life, like tardigrads are remarkably resilient though). I don't know why some gas giants like Jupiter have lethal (to us) amounts of radiation while others don't. So maybe this is a non-issue.
So maybe we should be looking for exo-moons orbiting gas giants in the habitable zone! How many are there? Obviously I don't know but there don't seem to be any dearth of gas giants orbiting other stars. As for the number of moons orbiting these gas giants, who knows but judging from our own solar system (Jupiter has 33 satellites of which 4 are "large") it seems that one or more would be at the right distance from the planet to benefit (but not too much) from tidal energy. Just for an example imagine if Jupiter was in the habitable zone. All the Galilean satellites except Io would be excellent candidates for COMPLEX life (presumably underwater).
What wavelength radio waves penetrate underwater? Maybe SETI should be listening on those frequencies! :)
According to this story http://abcnews.go.com/Blotter/us-rq-170-sentinel-stealth-drone-shown-iran/t/story?id=15115781 the drone shown on Iranian tv is, according to officials, a fake.
They claim inconsistencies in the design and with pictures of the crash site (like how it probably was demolished when it crashed at several hundred miles per hour).
I thought it looked like a fiberglass mockup. Anyway, good to know this, I read that to get any real use out of the drone, it would have to be almost completely undamaged because tolerances are very important when it comes to aerodynamics and stealth (I guess that's why those air force guys don't like it when I go about measuring their F-117s with my calipers at various air shows!)
Look guys, sorry if you misconstrued my comments. I honestly don't know why they made an experiment with this design. I was thinking, if they wanted to remove the effects of gravity, shouldn't they do a 2D simulation using a (relatively) thin flat plate of liquid sodium held horizontally? But then I have no clue if this would give any better results. I've heard that 2D supercomputer simulations of exploding supernovas turn out to be completely different (wrong?) from 3D simulations (which are much more expensive to carry out).
Anyway, the point is that I'm completely unqualified to judge these experimental designs, I was just wondering why something as obvious as gravity could be ignored. Is it that convection does not play a part in the phenomenon they are examining? Almost always I add something like "I am not an experimental physicist" to my postings, you'll see this on my (many!) prior postings. I guess I was just in a hurry this time. I have the absolute highest respect for scientists, my best friend is a tenured professor of theoretical chemistry and I know I couldn't do one-hundredth the math related stuff he does (I know, I've tried). I really wish I was smart enough to be a scientists; I consider myself to be very creative (I used to design theme parks!) but I just don't have what it takes. Sometimes I think Einstein was wrong when he said "imagination is more important than knowledge" but maybe he wasn't referring to knowledge of math.
That said, here's some puzzles that I've been thinking about while pondering this sodium sphere; if you wanted to model the convection caused by gravity (and heat) using a 2D analog, could you use a spinning disk filled with small particles and a refrigeration (cooling unit) at the center? When spun, the colder denser particles would be flung to the periphery of the disk whereupon they would be heated by contact with the "surface" and then sink back towards the center. By reversing the "forces"; centrifugal force (I know it's a "fake" force) instead of gravity but also reversing the hot and cold sources, wouldn't you have a good 2D simulation of the hot earth core and inwardly attracting gravity?
Now, as I said earlier, I've heard that 2D simulations sometimes are grossly incorrect at modeling 3D phenomenon. Too bad there is no way to spin something so that all points on a sphere have a centrifugal force. Or is there? Remembering that spinning a disk is just rotating a 2D plane in the third dimension, I was wondering can a 3D sphere be rotated in a (hypothetical) fourth or higher dimension?
Certainly I don't have any ability to do, if I had access to the fourth dimension I'd be using it for a lot of other things than rotating spheres! (Like robbing banks). But what if THE ENTIRE 3D UNIVERSE was rotating as some physicists have wondered, except not in the third dimension but in the fourth dimension. Would all the pieces feel an outward acceleration like a spinning plate? Wouldn't every object feel a force the was proportionately as strong as it was from the "center"? Would this explain cosmic inflation or even dark energy?
See sometimes not knowing (enough) math and science allows you to think really crazy things!
Soooo.... does the fact that the military is funding SETI entitle them to a kill switch if the Paul Allen array (I assume this is the recipient of the funding) finds anything? In addition to the obvious socio-political implications of the discovery of ET, I have heard that the armed services are rife with religious fundamentalists who might be very upset to know that God didn't create this universe solely for them?
Anyway, perhaps we should be concerned if prominent SETI researchers suddenly start to go missing...
How can this produce accurate results that will possibly match that of reality? This device (unless they are planning to put it on the space station) will be overwhelmingly influenced by the (real) earth's gravity. Convection will obviously be way off.
So, unless they are trying to model how the earth's core would act if it were enclosed in a giant metal sphere and placed on a gigantic table subject to one-gee, won't this simulation be way off?
Even if they put it in space, I'm not sure the simulation would be correct, the forces provided from the self-gravitation would probably be off.
Interesting correlation! Maybe it also plays a role as to whether or planet is suitable for life, a lot weaker and we'd lose too much of our atmosphere to space. A lot stronger and we'd end up a gas giant. But these might be pretty broad limits.
However, once life gets started, I'm not sure that the strength of gravity is tied closely to the development of life (life evolved into quite complex forms in the oceans). As far as INTELLIGENT life, I also am not sure if there's any correlation. Perhaps our ancestors evolved exceedingly good hand eye manipulative skills while swinging from branch to branch; I'm not sure how making gravity weaker (or stronger!) would make this better or worse.
So, too bad we didn't evolve on an exo-moon like Titan (or "Pandora") where getting to space would be much easier (low gravity, dense atmosphere). Or too bad we didn't evolve on a world that was subject to lots of radiation from the local star (no magnetic field?), then nuclear rockets would be very appealing because we'd be immune to high levels of radiation!
Again, I'm just paraphrasing from his book (but I think I'm remembering it correctly). It was a scene where they were pitching the idea of the space elevator and talking about the fact that the (unspecified) rockets of he future would be producing unacceptable environmental damage.
In his defense I think he was talking about "astronomical" (ha ha) levels of space traffic, something we can only hope for in our wildest dreams of a true space faring civilization with millions going to space DAILY. But who knows? He's dead. :(
Sorry, I'm not an engineer or a materials scientist! And I did say "almost"! ;)
Oh c'mon now, I'm not the only one old enough to remember this right?
Sorry, but that's the first thing I think of when a new super material is described.
I can't think of any other technology that, barring a really huge breakthrough (like anti-gravity) would truly make space travel a practical reality for millions. Even Arthur C. Clarke in his "Fountains of Paradise" book alluded to this saying that the supposedly hyper-efficient rockets of the future would create so much environmental damage (pollution, sonic booms) that really heavy traffic couldn't be sustained.
Maybe if we had cold fusion (or something like it like muon catalyzed fusion or zero-point energy) space travel on a large scale would be practical but these "breakthroughs" might be just as far (or impossibly far!) away.
By the way, did anyone see the developments (at MIT?) where they showed a nano structured "tape" able to support the weight of a full grown man with only a few inches of surface area? And it was able to be re-used thousands of times before using its grip? Perhaps the space elevator could be made of material structured this way, I mean if that thing is ever going to be built it will essentially be a gigantic 23,000 mile long SINGLE MOLECULE anyway so nano structuring should be almost trivial!
I never knew that (or really thought about it), are you sure it's true though? I don't know a lot about astronomy but isn't the plane of our solar system pretty different from that of the galaxy? Still I realize that even some correlation would, as you say, skew my numbers off. Have astronomers been able to verify that extra-solar systems are not randomly oriented? Would they be able to figure that out by looking at dust disks which are the only structures I can think of resolvable with out current technology? (I'm sure they can't resolve the disks for any but the largest, nearest stars and see which way they're spinning).
Remember that Kepler looks at stars using the "transit" method. Basically it stares at the little point of light for a looooong time, never blinking and waits to see if the light drops just a teeny bit due to something passing in front of it. How long? Well since it has to calculate the orbital period, it must watch at bare minimum for at least 1 year to see 2 passes (assuming its looking for a planet in an earthlike orbit around a sun-like star). Then, in order to make sure that it isn't some OTHER planet passing in front of the star, or an object in our solar system, or "sun spots" on the star, or maybe space butterflies getting in the way, the scientists must wait for a THIRD confirming pass (at the predicted time of course with the same drop in intensity) to be sure the observation is "real".
I think these guys have found the first "earth-sized" object that has made three confirmed passes. Note that the period is a bit less than a year so they've had enough time to get three observations in the three years. Soon, they'll be announcing confirming "third passes" on more and more planets that have periods in roughly the one-year window that indicates it's in the habitable zone around a sun-like star.
There are two things to note here: First, Kepler can only see planets that pass between it and the target star, that is the planet's orbit must be almost exactly edge on for us to see it. How close to edge on must it be? Well for example; the earth's orbit is a circle (very) roughly 100 million miles from the sun and the sun is roughly 1 million miles across. So, if the orbit was tilted more than 1/100 or 1%, from some distant observer, they wouldn't see it cross in front. (The size of the earth is inconsequential in this calculation because it is so small in relation to the sun). Similarly, for the kind of planets Kepler is looking at circling around sun-like stars, we are only seeing BY PURE CHANCE 1% of them. So if we see 100 planets circling these stars in their habitable zone; that means there are really 10,000 of them! So for a sample size of 150,000 stars, that means that one out of every 15 sunlike stars has planet in it's habitable zone! Amazing, especially when you consider our galaxy to have perhaps 10 BILLION sunlike stars!
Secondly, Kepler was launched before astronomers "discovered" that the best place to find "habitable" planets wasn't around sunlike stars but around smaller cooler stars. For various reasons, the habitable zone (where water can be a liquid) is proportionately larger in these "mini" solar systems (everything is smaller, like the orbits). They realized that even if a planet was tidally "locked" so that one face was always facing the sun, the atmosphere would redistribute the heat enough so the planet would be "habitable" (must sure be windy though). Another advantage is that these smaller stars live much longer than our sun giving life longer to come to well... life! Finally these smaller stars are much more numerous than sunlike stars. Anyway, I think Kepler was focusing mainly on sunlike stars and not these smaller, more numerous and perhaps easier to detect (because the orbits are smaller you don't have to wait as long for three passes) targets. Maybe Kepler II will go after them!
Just so that you know, Kepler is likely (has already?) been giving tons of other interesting data. I understand that its sensors are sensitive (and stable enough!) so as to detect possible sunspots in these stars. Also by paying close attention to the timing of the transits, they can determine whether other planets are gravitationally "tugging" at the transiting planet and perturbing its orbit (that's how Neptune was discovered). Finally, the resolution of the 'light curve" of the transit may be sharp enough to reveal any large moons in orbit around the transiting planet. So even if the planet in the habitable zone is too large to support life as we know it, it may have a right sized moon! (think "Pandora").
So, when will we be able to get a spectrographic reading on its atmosphere to see if there is free oxygen there? If an amateur using a 10" scope can see the dust around another star, is there any way the very best techniques using twin 10 meter scopes with' anti-aberration lasers can block out enough of the stars light to see just the planet's atmosphere?"
You know, one of the great things about the Internet (and the slashdot posting system) is the relative anonymity it provides.
I'm glad because it has limited my embarrassment for making such an ill-considered statement without doing the most cursory investigation. (If you Google "Lucy Koh", the very first listing is the Wikipedia entry with her bio.). At least I don't have to face up to my mistakes in my "real" public life.
However, the other nice thing about the anonymity the Internet provides is that it helps keep one's ego from getting in the way of an admission of being wrong.
So, boy I was wrong to imagine that Ms. Koh might have been unduly influenced; with her upbringing, education and qualifications, it is very unlikely that this would've happened. My apologies to all the other posters who wasted their time on this thread.
As a fellow Korean American, I'm wondering what kind of position she would've been under; with her husband (assuming he's also of Korean extraction), her relatives, classmates (if she was educated in Korea), and perhaps church (if she had been going to, as is often the case, a Korean church); if she had blocked Samsung.
Samsung is widely regarded (whether deserved or not) as a national treasure in Korea with a HUGE percentage of the ENTIRE ECONOMY (I think it's something crazy like 25%!). So I can guarantee that a decision against them would not be looked upon kindly by the average Korean.
If I may wax philosophical about my own posting, the advantage of using this "level" of encoding is that nature has, through ruthlessly efficient evolution, pruned out the almost-infinite number of non-useful proteins. Almost every DNA sequence that encodes a protein that is deleterious to the survival to the organism has been eliminated by the grim reaper. The few "bad" but non-lethal proteins that are still around in a living organism (like mis-folded hemoglobin to fight sickle cell disease) will stick out like a sore thumb with this sort of compression algorithm due to the exceptions it will throw.
But maybe I'm missing something completely obvious! (I believe I covered the intron, exon and by extension other "regulatory" aspects of DNA, they would possibly have a different library to be compared to or use a lower level compression scheme).
So, why can't they compress the data at the level of proteins? I mean it takes thousands of DNA base pairs to code for 1 protein, like hemoglobin, so instead of storing all that just say "here is the DNA sequence for protein X". Any exceptions, like mutations could then be indicated as "at position 758, the A is replaced by a G".
Of course if there is something REALLY novel, like a bioengineered virus that used different (non-standard) 3 base pair codons to encode the same amino acid, this kind of data compression wouldn't work but for 99.9999% of "natural" cases it would. (I saw this idea in the tv series "regenesis"). So for these (hopefully rare, it was for a bio-weapon!) cases a different type of compression would be used. "My" compression algorithm would, of course, break which would be a good indication this wasn't a natural DNA sequence.
I am neither a bio-expert nor a compression expert but this seems to me to be similar to the problem of compressing a vast library of books. Is it best to compress at the level of letters, words or even sentences? I'm only guessing what this entails because I'm not a linguist either! :(
(Then there's the whole business of introns or exons which "seem" to be content/protein free but I understand contain lots of regulatory information despite their repetitive nature. I would imagine these could be handled by some sort of pattern RLE.)
I'm as big a fan of the smaller, faster, cheaper paradigm as anyone but there is one thing about ALL these space probes that CAN'T be miniaturized.
It's the communications subsystem, most notably the antenna. I'm pretty sure that it can't be miniaturized due to the laws of physics dictating aperture and gain etc. (Unfortunately, I am not an physicist :( Also, ever since the Galileo probe antenna DISASTER (I call getting much less than one-hundredth the bandwidth a disaster) caused by the fact that the antenna didn't unfurl properly, means NASA is very conservative about using lightweight technologies. So unless the probe is designed to return to earth-space, bandwidth requirements will dictate a large (and heavy) antenna. (Still I'm not sure if the weight-bandwidth rule applies to coherent laser/maser communications, I understand that an upcoming mars orbiter will test using a laser link for much higher bandwidth).
That said, the advances in miniaturization (which extends to sensors and complete lab-on-a-chip) are extremely encouraging. Perhaps probes of the future will have a main "mothership" which will provide the communications link to lots of semi-autonomous micro-probes.
Great comment, did you read the NYTimes article about stereotypes of various car drivers? I think it went something like this:
BMW - Arrogant, spoiled (this perception went way up after the official's son who killed someone while driving a BMW)
Mercedes - for older people
Audi - powerful (don't mess with the driver. This is because many officials drive this)
American cars I seem to remember have a pretty good reputation. Who knew? ;). But I guess they've been getting better.
If it did the analysis using just the "after" image (maybe by looking statistically at ithe ndividual pixel level, I dunno I'm not an image expert) that software would be SO useful for Internet dating sites! ;)
Actually I'm wondering if images CAN be analyzed using statistical data from the individual pixel data to determine things like what camera was used to take the picture, maybe what software was used to edit/convert it (using gamma curves?). Then you could see (maybe) who was posting pictures of themselves from long ago (not like I've ever done that!).
Using this technique plus normal(?) traffic cameras, police could pretty quickly build up a list of habitual red light runners. (Even if they didnt actually "run" the light, they would be put under suspicion). They could be put on a list for "random" pull overs. (This presumes that video cameras with auto license plate reading are present and functioning on police car dashboards. I'm not sure this is the case nationally, but when I was in Denver recently a police car pulled over my friend because the computer had her license plate on a list. Call it the "Do Not Drive List").
This is nothing compared to when face recognition systems become widely prevalent. That'll blow away the "big-brother" predictions made by science fiction films like minority report (which used retina scans). Of course, WE'VE been supplying the government with tons and tons of this pre-edited, organized data tagged data. Thanks Facebook! (which is another reason why I don't use it). Call it the "Do Not Walk List".
That coupled with national biometrics programs (India, Afghanistan) and GPS tracking in every smartphone (Carrier IQ) and warrantless tapping/tracking of American citizens (war on terror) means we are rapidly heading towards a world where your government CAN know where you are at every moment. Whether or not they WILL know where you are is up to the battles over privacy information.
Thanks for remembering that, I read "The Deep Range" a long LONG time ago.
I seriously hope if he's flying around jets like that that he doesn't have a superhero cape! ;)