Yeah, and NASA knew about this evidence last week BEFORE the deadline too. How much you wanna bet O'Keefe got bribed with a lifetime supply of free shrimp to keep mum a few extra days, eh?
Unlikely, the uncertainties of the atmospheric entry result in a landing footprint that's (IIRC) a few thousand square miles. The chances that we could get a new rover down within driving range of an existing rover is pretty small. By the time we've got rovers capable of driving those sorts of distances or landings that are accurate enough to make that plan practical, I think that we'd have enough experience that there wouldn't be much to be gained from going back and looking at the old rovers.
Although most of the evidence for martian life in the meteorite was later disproven, the magnetite crystals still stand as a fairly persuasive argument for martian life. There was a rebuttal to the magnetite particles but I'm not at all convinced by it - researchers have been trying to make magnetic particles like the ones in the meteorite/Earthly magnetotactic bacteria for decades without success. I'm very dubious, therefore about the report that a simple geology simulation can form those particles. Given that a significant fraction of the Martian particles are identical to Earthly ones to the atomic level, we can't throw out the meteorite evidence just yet.
To follow up what I mentioned above, I was reading some of the other posts and down near the bottom, some folks mentioned that there are some objections to the peroxide interpretation of the Viking data, including the maker of the original instrument.
I'd never read the primary sources refuting the peroxide argument before and now that I've read them a bit, I think that the stance I take in the message above should be softened a bit. I'm still dubious that surface conditions on Mars are hospitable to organic life but there's more wiggle room on that than I had thought previously.
IIRC, the interpretation of the anamalous chemical reactions found by the Viking probes was due to extremely high levels of peroxides. Although there is a certain endogenous level of peroxides in all oxygen-using life, the levels are extremely low and there are a large number of enzymatic systems that are used to keep it in very tight control to prevent it from converting to the much more deadly superoxide and hydroxyl radicals. The levels of HOOH found by the Viking probes was predicted to be fatal to any reasonable organic life. It doesn't take too much HOOH to sterilize even resistant organisms - the peroxide you can buy at the drugstore for an antiseptic is only 3% by volume and will go through bacteria that have plenty of peroxidases like a cannonball through wet tissue paper.
There was a Wired article (this month's I think) where they detailed a series of scientific missions to the Atacama desert down in S. America. The conditions closely mimic Mars in the extremely low water levels and high UV exposure. The result was that they were unable to find ANY bacterial life in the soil, even when digging several feet down. (although I have some issues with the subsurface results they got) Even an attempt to seed the soil with extremophiles from another desert failed.
It's possible that there might be something buried under the dirt in the Martian soil but even that's pretty chancy. Without a source for energy generation, those bacteria won't be able to repair damage from natural radioactivity in the soil. In our soil there's plenty of organics that bacteria can use for a power source but that carbon ultimately came from solar-driven photosynthesis which the surface conditions rule out.
These are the only possibilities I can think of for Martian life:
1: underground life that is able to sustain at least some basal metabolic rate from a chemical energy source. That energy source would be either organic deposists from an aearlier period of Martian life where photosynthesis was possible or some sort of geological organic chemical formation pathway or hydrogen gas generated from natural radioactivity.
2: Life in geothermally driven water sources or locked into ice. There is a significant amount of life even in the dry plains of Antarctica which indicates that even solid ice is capable of supporting life.
3: some sort of non-standard biological chemistry which is far beyond my ability to speculate about.
Don't forget that many other materials can form into dendritic shapes like snowflakes under the right conditions - metals crystallizing out of melt are well know for this.
Most people don't realize the coolness of biominerals. Although engineers can make materials with better specific properties, we are still hard pressed to be able to match their combined properties. (eg: building materials with the strength/weight ratio of wood)
Nature tends to work with really lousy starting materials which ultimately limits the total performance of those materials. Nontheless, the performance that evolved biomaterials manage to eek out of those materials is quite impressive. For example - the calcium carbonate (chalk) mother of pearl of abalone shell has a total material toughness that is in the same range as nanostructured boron carbide. If we could nano/microstructure our materials after biominerals, a 10-20 fold increase in the materials properties of those materials would not be impossible to believe.
Another good example is tooth enamel. Most people think that tooth enamel is some sort of featureless white material. If you actually look at enamel under magnification, after a quick acid etch to bring out the features, it looks like burlap. It's actually a 3-D woven calcium hydroxyapatite fiber matrix composed of millions of interwoven ceramic fibers that are woven in all three dimensions in a specific fashion that prevents crack propagation. Each fiber is also composed of hundreds of tiny ceramic nanofibers - each being about 40x60 nm single crystals. There are some researchers that believe these nanocrystallites can be over 1mm in length despite their thinness.
The arrangement of the weaving of the larger fibers is uniquely tailored per tooth to maximize the overall strength of the tooth. For example, your incisors and molars and even different portions of those teeth have different weaving paterns that serve to maximize the strength of the tooth with respect to the type of chewing action that it normally sees.
Um, not only was this a Slashdot story a couple months ago (not that this is anything new) this is really old news. I saw Dan Morse give a talk about 5 years ago about the details of what's described above. Seriously - the silicateins were ID'd and characterized about 6-7 years ago and by the time I saw him talk, they were already generating new peptides designed from scratch.
Coming from a research group that's done similar work to the Morse group in the past, this is cool but rather old work.
The silica fibers generated by sponges are high quality but probably useless for standard telcom use since they contain relatively high levels of water which strongly absorbs in the bands that telecoms transmit at. However, the layered structure that these fibers have tend to have much better fracture resistance than pure silica fibers which might make them useful in things like box-to-box connectors for in-home use where the cables going to get stepped on or hit with some regularity.
Agreed, getting an HV TEM to get carbon lattice images at 500 C and with gasses being fed into the column is pretty damned impressive. One has to wonder, however, about the effect of the electron beam flux on the nanotube formation.
I used to work with a guy doing extremely low-loss EELS (plasmon edge stuff) and he found that he had to drop the accelerating voltage to 100kV to prevent nanotube deterioration. Though, he was working on small single-wall tubes, not the big, multi-walled behemoths you see in these images. At 200kV, he believed that he was actually seeing enough knock-on energy to produce electron-postitron pairs.
(It still never ceases to amaze me that I can use the work 'big' to describe something that's probably 100nm in diameter)
That study really highlights the fact that there isn't really an 'Alzheimer's disease' as most people think of it. It's really a constellation of closely related degenerative diseases that happen to have similar gross pathologies. Just like cancer is a wide array of different causes and disease pathways, Alzheimer is most likely going to require various targeted treatment to attack the particular root cause of the dementia.
The fact is that we really don't have any firm data on how easily life arises and how often it evolves intelligence. A 300,000,000 year difference in the age of the star is probably largely irrelevant to the probability that it has intelligent life versus our own.
Life on our own planet spent the 1st 2.5-3.5^9 years on this planet being unicellular. Only in the last ~650^6 years have complex organisms been around to our knowledge. All of the genetic and fossil evidence seem to point toward the evolution of multicellular life as being something of a fluke - a stochastic event. Therefore it is quite possible that complex life on this planet could have easily shown up a full billion years ahead of schedule. Or it could have been just as likely that the Earth would be still covered in nothing more advanced than stromatolites.
Of course, one big difference is that you can't download regular backups of your biological dog. If robotic dogs were actually learning in the field, it would probably be SOP to regularly backup the memory core to avoid the loss of all the training and field 'experience' the robot dog had acquired.
Of course, it still would suck to have your Rambo-Aibo get blasted to bits but at least you could just get what is functionally a few day-old version the next time you go back to base.
Plus, how often can you upgrade a biological dog? I mean if I want fricken' lasers on my dog right now, I'm out of luck.
True, wheels are a fairly terrible form of movement unless you have a road system of some kind. One of the Central American civilizations (Mayan or Incan) had children's toys with wheels but never implemented them in actual carts because of the rugged terrain.
Likewise, there is good evidence that the inhabitants of the Northern Sahara abandoned the wheel for the same reason.
I dunno about that. I went to a fairly decent high school near Seattle and remember when our Biology teacher gave us an impromptu geography test to satisfy his own curiosity about the state of our geography knowledge. It was a world map with no country borders drawn in and we had to roughly draw in and label something like 20 countries and the oceans.
I was fairly happy that I got everything correct except to put Mongolia on the South side of China. My friend managed to put Britain where France is. Most of the class got fewer than 1/3 of the countries right. Several people didn't know where the PACIFIC OCEAN was. (Hint: if you're living in Seattle, it's the big bunch of water next to you on the map)
Even worse, about 1/2 of the class didn't know where Canada was. (Somebody put Vietnam where Canada is at, seriously) 5 people DIDN'T KNOW WHERE THE US WAS on a map. I'm sorry but if you can't even find your own country on a map, you need to be beaten.
I''m not sure if that was more depressing than when I was doing writing tutoring as an undergrad at the University of Washington (a fairly selective 4 year public university, or so I thought) and I regularly had to show people how to write a sentence.
Yes, you read that right. Several times, I had to show people enrolled at a university the basics of subject-verb-predicate. Oh yeah, most of them didn't know what a paragraph was either - as in they'd never heard of one.
During a brief stint at a community college, I had a geography teacher that didn't know how orbits worked. He was somehow under the impression that as soon as you left the atmosphere, you just kinda hovered in space as if it were made of Velcro or something. Nice old guy, crap teacher though.
So yes, it's probably not a bad idea to reiterate that Jupiter is one of the planets.
Re:Statistically
on
Lonely Planets
·
· Score: 4, Interesting
One possibility that most people ignore is that spacefaring intelligent life has no compelling reason to communcate with us. In fact, if it does exist, it probably has compelling reasons to *not* communicate with us.
There are two possible scenarios for intelligent observers to have physically reached our region of space. The first is that they have some variety of FTL drive which implies a level of technological and scientific advancement vastly superior to our own. The other is that there is no FTL travel and intelligence spreads through space in a leapfrog manner between stars.
In neither case do I see the surface or interior of Earth or Earthly life as essential resources. FTL capable intelligence can simply travel wherever it wants to gain resources and non-FTL intelligence would be much more likely to mine asteroids and comets to avoid having to deal with the massive energy expenditures of entering and leaving Earth's gravity well. Furthermore, any non-FTL intelligence is almost certainly in the form of some sort of circuitry or AI of some variety because of the immense energy penalties of transporting organic life and its associated life support mass. Therefore it's unlikely they're here to steal our water or eat us.
The human race in either case has little to offer in the way of technological or material incentive to contact us. I would argue that our only valuable resource is cultural. This is not to say that aliens have any interest in our culture from an asthetic perspective but rather in an anthropological manner.
Imagine if we discovered some small Pacific island today that had no particularly valuable natural resources. On this island, we discover a species of primate that is showing signs of early technological development along the lines of, say Australopithecus africanus. Or, another scenario would involve the discovery of intelligent lizards or birds, whatever. We would probably consider this one of the greatest scientific discoveries of the century as it gives a look at how intelligent life develops in its initial stages.
Presuming that alien intelligence has discovered us, it probably has some sort of scientific bent given its spacefaring nature. Presuming that its rise to intelligence is even remotely similar to ours, it has probably lost most information about the rise of its own intelligence and culture - not unlike how we can only speculate as to how society, agriculture, speech, etc developed. A developing intelligence such as our own would present a golden opportunity to this intelligence to watch such a process in action.
In such a scenario, the alien intelligence would have great disincentive to make contact with us as it would 'contaminate' our development.
The new astigmatism correctors on STEM's these days can push down well below an Angstrom in resolution although doing so is by no means a routine proceedure. I've seen figures claiming resolution down to 0.2 A but the real-world performance with sample damage, etc is probably much less impressive.
Eh, seeing as how the Beagle 2 never had the ability to move, I think that your Pay-per-view money could be better spent on a more exciting match, say a snail steel cage match...
In addition to the replies that have already gone up to your post, I might point out that these new giant telescope *are* distributed smaller scopes. All of the designs I have seen as well as older scopes such as Keck are a bunch of smaller mirrors bundled together. The 100m OWL isn't going to have a giant mirror but a field of smaller reflective elements. Mirrors like the one in Palomar are about as big as single mirrors are going to get with present technology. The difficulties in trying to make a stable optical element that big are nearly as ridiculous as back in the 50's.
Also, I think there was a/. story about LOFAR a few days ago which is basically the sq km array V 0.5
IANARA but what I understand is that computer tech is now getting to the point where you can basically make a reverse phased array. In a phased array you can generate a fully steerable radar beam with no moving parts by having a grid of radio emitters. Each emitter puts a specific delay on the waveform it generates so that the constructive interference of all the elements makes a big beam that you can scan all over the sky. Also, you can generate multiple beams this way. This is great if, for example, you detect an incoming airplane with the main beam, you simply divert a small portion of the beam to track that airplane while the rest of the big beam continues sweeping the sky.
Well, if you have a large array of simple detectors - they don't have to actually be dishes, simple aerials will do, you can take and run a computer network to look at all the incoming raw radio data and back extract the intensity and direction of each incoming signal. With this system, you can watch an artibrary number of signals at once, only limited by computing power. Furthermore, your 'telescope' watches the entire sky at once. Here's a rundown of this array vs traditional radio astronomy:
Array tech: Can view multiple object at once Can track rapidly moving sources Easily discriminates space from Earthbound or LEO sources Detects short, transient sources Requires massive amounts of computing power
Traditional (big dish) tech: Can only view multiple objects if they are very close to one another Can only track moving sources as quickly as the dish can be accurately turned Has trouble discriminating between space and earthbound sources unless you take the time to move the dish (to see if the signal goes away - an earthbound source that's bleeding into a dish will still be present even if the dish is turned slightly) Only sees transient events if it happens to be looking at them when they happen. Requires little computational power
The primary limitation is computer power. The square km array is basically a radio telescope that will cover the better part of Australia with a total reciever area of a square km, easily outpowering all of the radio telescopes ever built. However, this telescope, at full resolving power can only look at a few objects at a time at a single frequency, not the entire sky since doing so for so many elements would require something like a metric fuckload of teraflops. Instead, some elements will be dedicated to a low resolution/sensitivity whole sky scan to detect transient events and the rest of the array will train its virtual beams on various objects of interest or on said transients within a fraction of a second of their detection with the wide scan.
Here's where I think amateurs could come in: the square km array, if it's ever built, will only look at the Southern hemisphere. Furthermore, it will be taken up by radio astronomers, not SETI or amateurs. I know Paul Allen is setting up some sort of massive SETI system not unlike this but, IT would be nice to have more than one group doing this.
So here's what should be done: Set up a system of radio recievers that people can easily build/buy to put on their computers. Have these computers slaved to some sort of very accurate time clock, eg: GPS Have each computer pull out all of the waveforms from a pre-agreed frequency, eg: standard SETI search frequencies) Set up a central or distributed system to pull out any non-Earthbound sources. (this array tech is great for IDing non-human sources since widely spaced recievers can easily triangulate distances to nearby sources out to a few hundred km, eliminating the vast majority of non-ET tr
They forgot France units. Everything has to be compared to the size of France.
-127,273 times the number of square millimeters in the country of France.
It somewhat suprises me that the fac that the plumes come from the upper mantle as well is a surprise. I just finished reading the Self Made Tapestry by Philip Ball. (I'd highly recommend this book if you're interested in self-organized behavior or chaos theory. It's getting a bit old but still a very good introduciton to the topic)
In one chapter, he discusses fluid convection dynamics and the tendancy for self-organized structures to form in diferentially heated fluids. He then goes on to mention a simulation done by Paul Tackley in *1993* which predicted the formation of two layers of convection cells. (the layers are seperated at the 660 km discontinuity in the mantle) Furthermore, these two layers are incompletely seperated and plumes originating from both the 660 km discontinuity and the core-mantle boundary reach the surface. There's a picture of the simulation results and they look strikingly similar to the the ones in the article.
What suprised me the most was that the Yellowstone plume was absent. I thought that what was supposed to be why the great plains are about a mile higher than they whould be. Did the yellowstone plume poop out recently or something?
OK people, repeat after me: 1: Lasers are NOT monochromatic. A monochromatic light source would violate Heisenberg's uncertainty principle. The atoms in a lasing medium all have different energies and therefore a laser has a very small but very measurable energy dispersion.My quantum physics is too rusty to recall if a laser cooled to 0K would be monochromatic but I seem to recall that even them there is an energy range.
2: Laser light is NOT parallel. The light is generated by the photons bouncing back and forth in a lasing cavity. Even if you assume that the mirrors are *perfectly* parallel to each other, a photon can easily enter off axis and still be able to bounce several times before running off the mirrors. In a high efficiency lasing medium, this can lead to large amounts of off axis light. Semiconductor lasers regularly have outputs that have 20 degrees of divergence.
Everyone assumes that lasers have no divergence because of the old gas lasers like HeNe and Ar. These have very low lasing efficiency and so a photon has to make many passes through the lasing medium to generate an appreciable amount of lasing light. Furthermore, the lasing medium was commonly a long glass tube. Therefore the divergence angle of the light was very small. For some reason this became - "laser light does not diverge'. On the contrary, the lasers they bounce off the moon get to be something like a km in diameter when they reach the moon.
In fact, when working with lasers, there is a 'waist diameter' where the beam has a miminal diameter (varies on laser optics geometry but usually at the laser output) and then the beam diverges just like any other. Laser pointers and the like use lenses to collimate the beam into a relatively non-diverging beam.
Mind you, lasers are much better than standard light sources like light bulbs since the emitting area can be quite small and therefore you can generate a parallel beam much closer to the theoretical ideal than with something like a big humk of glowing tungsten.
Last time I checked a few years ago, Seattle weather forcasts were right less than 50% of the time. 'Course being by an extended arm of ocean and between two mountain ranges tends to do that.
IMO, the forcasts there need a 'for entertainment purposes only' discalimer in front of them.
Be careful in just taking what a hospital technician might tell you. Most of the med techs I've known or met were pretty good but some have just mind-boggling levels of ignorance. I was in for a barium contrast CT this spring and the tech told me that the barium solution would feel hot when injected theough the IV. He then went on to tell me that this was because of 'friction between the Barium and the inside of my blood vessels'.
It took all my will power to not kick him.
Anyway, you can't really focus X-rays in a normal setting, the mirrors involved for X-ray manipulation are very expensive. Rather what happens is that a single straight beam is sent theough the tumor at different angles. Think of several flashlight beams crossing at the same point. Where the beams cross, it's much brighter. This lets you get the correct amount of X-rays to the tumor and minimize the amount in the surrounding tissue.
Also, re the previous post - X-rays are from X-ray energy photons, not gamma energy photons. It's a bit nit-picky but there is a huge energy difference between X-rays and gamma rays.
Nanofibers in fabric IS nanotech. Drawing a distinction between assemblers and small fibers which were designed with knowledge of how materials interact on the nano level and then manufactured and integrated into a material is hair spliting. Who cares how the atoms get into their final position? It's quite likely that a truly general, practical assembler is impossible. At best, we'll have many different assemblers custom tailored to specific applications - basically like ribosomes but for different types of chemistry.
Assembler nano will never completely replace normal maufacturing techniques. If you want to make a big hunk of metal are you going to forge it for a few bucks or try and assemble it? Don't forget that nanoassembly can't circumvent thermodynamics and so the thermal and energy cost of moving all those atoms around and maintaining low entropy the whole time is horrendous. (the way nature gets around this problem is to use an engineering model that is inherently very sloppy and tolerant to that slop which greatly reduces the energy requirements - however, don't expect to be able to ape nature's model and be able to photocopy objects or build a digital computer.) Also, the speed of the assembly is very slow - look at how long it takes a tree to grow a pound of wood. This works in certain business models but if you want a hunk of metal now, an expensive, energy hungry, finicky process that takes 3 months is NOT going to completely supplant the 'ol heat 'n beat technology we have now.
Furthermore - my real point here - we have quite a bit of control over the nano-architecture of matter already:
Many chemists argue that organic chemistry IS top-down nanotech and I think that there's not too much dispute about the benefits of that... Biotech is also mature nanotech - modern bioengineering involves the angstrom resolution modification of specific structures and is now starting to design de novo structures for novel applications. These molecular structures are designed from a nanoscale information template and assembled on bonafide molecular assemblers. Hell, photographic media is nanotech - silver halide nanoparticles.
Insights from nanoscale are essential to materials science where I work. Back as far as the 50's, we've been studying steel (the most significant material of the last 100 years, not silicon) and how it's atomic structure is modified by processing. If you're not familiar with the level of knowledge we have of steels, you'd be amazed. US Steel back in the 60's owned most of the world's electron microscopes in research labs that rivaled ATT and IBM. By altering carbon and other impuruties and going through carefully controlled heating and cooling cycles, we have an amazing control over the final nanostructure of steel.
Modern metallurgy is even using nanoscale powders to achieve unheard of combinations of hardness and flexibility.
Plastics are another example of nanotech - modern polymer work involves fine control of the branching, structure, phase seperation and fluid interactions of polymer chains. Car bumpers are made of plastics because of the invention of block copolymer thermoplastics which use structure polymer chains to combine hardness with ductility. Hell, even in the last few years, plastics have changed. Any molecular biologist will tell you, the polypropylene they use in newer pipet tips and tubes is dramatically different in that the adhesion of fluids to them is now nearly zero (important when you're working with microliter volumes) because of control of the polymer structure at the plastic surface.
By adding a tiny fraction of a percent of size-tuned gold nanoparticles to optically active plastics for photovoltaics, you can extend the lifetime by a factor of 100 by tuning the gold surface plasmon through nanoscale mechanisms and 'short out' the energy states that lead to photoinduced chemical breakdown.
Is this nanotech with little robot arms? No. But it's still nanotech. My point is that, ye
Slashdot Mirror
Yeah, and NASA knew about this evidence last week BEFORE the deadline too. How much you wanna bet O'Keefe got bribed with a lifetime supply of free shrimp to keep mum a few extra days, eh?
Unlikely, the uncertainties of the atmospheric entry result in a landing footprint that's (IIRC) a few thousand square miles. The chances that we could get a new rover down within driving range of an existing rover is pretty small. By the time we've got rovers capable of driving those sorts of distances or landings that are accurate enough to make that plan practical, I think that we'd have enough experience that there wouldn't be much to be gained from going back and looking at the old rovers.
Although most of the evidence for martian life in the meteorite was later disproven, the magnetite crystals still stand as a fairly persuasive argument for martian life. There was a rebuttal to the magnetite particles but I'm not at all convinced by it - researchers have been trying to make magnetic particles like the ones in the meteorite/Earthly magnetotactic bacteria for decades without success. I'm very dubious, therefore about the report that a simple geology simulation can form those particles. Given that a significant fraction of the Martian particles are identical to Earthly ones to the atomic level, we can't throw out the meteorite evidence just yet.
To follow up what I mentioned above, I was reading some of the other posts and down near the bottom, some folks mentioned that there are some objections to the peroxide interpretation of the Viking data, including the maker of the original instrument.
A link is here.
I'd never read the primary sources refuting the peroxide argument before and now that I've read them a bit, I think that the stance I take in the message above should be softened a bit. I'm still dubious that surface conditions on Mars are hospitable to organic life but there's more wiggle room on that than I had thought previously.
IIRC, the interpretation of the anamalous chemical reactions found by the Viking probes was due to extremely high levels of peroxides. Although there is a certain endogenous level of peroxides in all oxygen-using life, the levels are extremely low and there are a large number of enzymatic systems that are used to keep it in very tight control to prevent it from converting to the much more deadly superoxide and hydroxyl radicals. The levels of HOOH found by the Viking probes was predicted to be fatal to any reasonable organic life. It doesn't take too much HOOH to sterilize even resistant organisms - the peroxide you can buy at the drugstore for an antiseptic is only 3% by volume and will go through bacteria that have plenty of peroxidases like a cannonball through wet tissue paper.
There was a Wired article (this month's I think) where they detailed a series of scientific missions to the Atacama desert down in S. America. The conditions closely mimic Mars in the extremely low water levels and high UV exposure. The result was that they were unable to find ANY bacterial life in the soil, even when digging several feet down. (although I have some issues with the subsurface results they got) Even an attempt to seed the soil with extremophiles from another desert failed.
It's possible that there might be something buried under the dirt in the Martian soil but even that's pretty chancy. Without a source for energy generation, those bacteria won't be able to repair damage from natural radioactivity in the soil. In our soil there's plenty of organics that bacteria can use for a power source but that carbon ultimately came from solar-driven photosynthesis which the surface conditions rule out.
These are the only possibilities I can think of for Martian life:
1: underground life that is able to sustain at least some basal metabolic rate from a chemical energy source. That energy source would be either organic deposists from an aearlier period of Martian life where photosynthesis was possible or some sort of geological organic chemical formation pathway or hydrogen gas generated from natural radioactivity.
2: Life in geothermally driven water sources or locked into ice. There is a significant amount of life even in the dry plains of Antarctica which indicates that even solid ice is capable of supporting life.
3: some sort of non-standard biological chemistry which is far beyond my ability to speculate about.
Don't forget that many other materials can form into dendritic shapes like snowflakes under the right conditions - metals crystallizing out of melt are well know for this.
Most people don't realize the coolness of biominerals. Although engineers can make materials with better specific properties, we are still hard pressed to be able to match their combined properties. (eg: building materials with the strength/weight ratio of wood)
Nature tends to work with really lousy starting materials which ultimately limits the total performance of those materials. Nontheless, the performance that evolved biomaterials manage to eek out of those materials is quite impressive. For example - the calcium carbonate (chalk) mother of pearl of abalone shell has a total material toughness that is in the same range as nanostructured boron carbide. If we could nano/microstructure our materials after biominerals, a 10-20 fold increase in the materials properties of those materials would not be impossible to believe.
Another good example is tooth enamel. Most people think that tooth enamel is some sort of featureless white material. If you actually look at enamel under magnification, after a quick acid etch to bring out the features, it looks like burlap. It's actually a 3-D woven calcium hydroxyapatite fiber matrix composed of millions of interwoven ceramic fibers that are woven in all three dimensions in a specific fashion that prevents crack propagation. Each fiber is also composed of hundreds of tiny ceramic nanofibers - each being about 40x60 nm single crystals. There are some researchers that believe these nanocrystallites can be over 1mm in length despite their thinness.
The arrangement of the weaving of the larger fibers is uniquely tailored per tooth to maximize the overall strength of the tooth. For example, your incisors and molars and even different portions of those teeth have different weaving paterns that serve to maximize the strength of the tooth with respect to the type of chewing action that it normally sees.
Um, not only was this a Slashdot story a couple months ago (not that this is anything new) this is really old news. I saw Dan Morse give a talk about 5 years ago about the details of what's described above. Seriously - the silicateins were ID'd and characterized about 6-7 years ago and by the time I saw him talk, they were already generating new peptides designed from scratch.
Coming from a research group that's done similar work to the Morse group in the past, this is cool but rather old work.
The silica fibers generated by sponges are high quality but probably useless for standard telcom use since they contain relatively high levels of water which strongly absorbs in the bands that telecoms transmit at. However, the layered structure that these fibers have tend to have much better fracture resistance than pure silica fibers which might make them useful in things like box-to-box connectors for in-home use where the cables going to get stepped on or hit with some regularity.
Agreed, getting an HV TEM to get carbon lattice images at 500 C and with gasses being fed into the column is pretty damned impressive. One has to wonder, however, about the effect of the electron beam flux on the nanotube formation.
I used to work with a guy doing extremely low-loss EELS (plasmon edge stuff) and he found that he had to drop the accelerating voltage to 100kV to prevent nanotube deterioration. Though, he was working on small single-wall tubes, not the big, multi-walled behemoths you see in these images. At 200kV, he believed that he was actually seeing enough knock-on energy to produce electron-postitron pairs.
(It still never ceases to amaze me that I can use the work 'big' to describe something that's probably 100nm in diameter)
That study really highlights the fact that there isn't really an 'Alzheimer's disease' as most people think of it. It's really a constellation of closely related degenerative diseases that happen to have similar gross pathologies. Just like cancer is a wide array of different causes and disease pathways, Alzheimer is most likely going to require various targeted treatment to attack the particular root cause of the dementia.
The fact is that we really don't have any firm data on how easily life arises and how often it evolves intelligence. A 300,000,000 year difference in the age of the star is probably largely irrelevant to the probability that it has intelligent life versus our own.
Life on our own planet spent the 1st 2.5-3.5^9 years on this planet being unicellular. Only in the last ~650^6 years have complex organisms been around to our knowledge. All of the genetic and fossil evidence seem to point toward the evolution of multicellular life as being something of a fluke - a stochastic event. Therefore it is quite possible that complex life on this planet could have easily shown up a full billion years ahead of schedule. Or it could have been just as likely that the Earth would be still covered in nothing more advanced than stromatolites.
Of course, one big difference is that you can't download regular backups of your biological dog. If robotic dogs were actually learning in the field, it would probably be SOP to regularly backup the memory core to avoid the loss of all the training and field 'experience' the robot dog had acquired.
Of course, it still would suck to have your Rambo-Aibo get blasted to bits but at least you could just get what is functionally a few day-old version the next time you go back to base.
Plus, how often can you upgrade a biological dog? I mean if I want fricken' lasers on my dog right now, I'm out of luck.
True, wheels are a fairly terrible form of movement unless you have a road system of some kind. One of the Central American civilizations (Mayan or Incan) had children's toys with wheels but never implemented them in actual carts because of the rugged terrain.
Likewise, there is good evidence that the inhabitants of the Northern Sahara abandoned the wheel for the same reason.
I dunno about that. I went to a fairly decent high school near Seattle and remember when our Biology teacher gave us an impromptu geography test to satisfy his own curiosity about the state of our geography knowledge. It was a world map with no country borders drawn in and we had to roughly draw in and label something like 20 countries and the oceans.
I was fairly happy that I got everything correct except to put Mongolia on the South side of China. My friend managed to put Britain where France is. Most of the class got fewer than 1/3 of the countries right. Several people didn't know where the PACIFIC OCEAN was. (Hint: if you're living in Seattle, it's the big bunch of water next to you on the map)
Even worse, about 1/2 of the class didn't know where Canada was. (Somebody put Vietnam where Canada is at, seriously) 5 people DIDN'T KNOW WHERE THE US WAS on a map. I'm sorry but if you can't even find your own country on a map, you need to be beaten.
I''m not sure if that was more depressing than when I was doing writing tutoring as an undergrad at the University of Washington (a fairly selective 4 year public university, or so I thought) and I regularly had to show people how to write a sentence.
Yes, you read that right. Several times, I had to show people enrolled at a university the basics of subject-verb-predicate. Oh yeah, most of them didn't know what a paragraph was either - as in they'd never heard of one.
During a brief stint at a community college, I had a geography teacher that didn't know how orbits worked. He was somehow under the impression that as soon as you left the atmosphere, you just kinda hovered in space as if it were made of Velcro or something. Nice old guy, crap teacher though.
So yes, it's probably not a bad idea to reiterate that Jupiter is one of the planets.
One possibility that most people ignore is that spacefaring intelligent life has no compelling reason to communcate with us. In fact, if it does exist, it probably has compelling reasons to *not* communicate with us.
There are two possible scenarios for intelligent observers to have physically reached our region of space. The first is that they have some variety of FTL drive which implies a level of technological and scientific advancement vastly superior to our own. The other is that there is no FTL travel and intelligence spreads through space in a leapfrog manner between stars.
In neither case do I see the surface or interior of Earth or Earthly life as essential resources. FTL capable intelligence can simply travel wherever it wants to gain resources and non-FTL intelligence would be much more likely to mine asteroids and comets to avoid having to deal with the massive energy expenditures of entering and leaving Earth's gravity well. Furthermore, any non-FTL intelligence is almost certainly in the form of some sort of circuitry or AI of some variety because of the immense energy penalties of transporting organic life and its associated life support mass. Therefore it's unlikely they're here to steal our water or eat us.
The human race in either case has little to offer in the way of technological or material incentive to contact us. I would argue that our only valuable resource is cultural. This is not to say that aliens have any interest in our culture from an asthetic perspective but rather in an anthropological manner.
Imagine if we discovered some small Pacific island today that had no particularly valuable natural resources. On this island, we discover a species of primate that is showing signs of early technological development along the lines of, say Australopithecus africanus. Or, another scenario would involve the discovery of intelligent lizards or birds, whatever. We would probably consider this one of the greatest scientific discoveries of the century as it gives a look at how intelligent life develops in its initial stages.
Presuming that alien intelligence has discovered us, it probably has some sort of scientific bent given its spacefaring nature. Presuming that its rise to intelligence is even remotely similar to ours, it has probably lost most information about the rise of its own intelligence and culture - not unlike how we can only speculate as to how society, agriculture, speech, etc developed. A developing intelligence such as our own would present a golden opportunity to this intelligence to watch such a process in action.
In such a scenario, the alien intelligence would have great disincentive to make contact with us as it would 'contaminate' our development.
The new astigmatism correctors on STEM's these days can push down well below an Angstrom in resolution although doing so is by no means a routine proceedure. I've seen figures claiming resolution down to 0.2 A but the real-world performance with sample damage, etc is probably much less impressive.
Eh, seeing as how the Beagle 2 never had the ability to move, I think that your Pay-per-view money could be better spent on a more exciting match, say a snail steel cage match...
In addition to the replies that have already gone up to your post, I might point out that these new giant telescope *are* distributed smaller scopes. All of the designs I have seen as well as older scopes such as Keck are a bunch of smaller mirrors bundled together. The 100m OWL isn't going to have a giant mirror but a field of smaller reflective elements. Mirrors like the one in Palomar are about as big as single mirrors are going to get with present technology. The difficulties in trying to make a stable optical element that big are nearly as ridiculous as back in the 50's.
That's actually a good idea. Take a look at:
/. story about LOFAR a few days ago which is basically the sq km array V 0.5
Argus NGRT
Square kilometer array
Also, I think there was a
IANARA but what I understand is that computer tech is now getting to the point where you can basically make a reverse phased array. In a phased array you can generate a fully steerable radar beam with no moving parts by having a grid of radio emitters. Each emitter puts a specific delay on the waveform it generates so that the constructive interference of all the elements makes a big beam that you can scan all over the sky. Also, you can generate multiple beams this way. This is great if, for example, you detect an incoming airplane with the main beam, you simply divert a small portion of the beam to track that airplane while the rest of the big beam continues sweeping the sky.
Well, if you have a large array of simple detectors - they don't have to actually be dishes, simple aerials will do, you can take and run a computer network to look at all the incoming raw radio data and back extract the intensity and direction of each incoming signal. With this system, you can watch an artibrary number of signals at once, only limited by computing power. Furthermore, your 'telescope' watches the entire sky at once. Here's a rundown of this array vs traditional radio astronomy:
Array tech:
Can view multiple object at once
Can track rapidly moving sources
Easily discriminates space from Earthbound or LEO sources
Detects short, transient sources
Requires massive amounts of computing power
Traditional (big dish) tech:
Can only view multiple objects if they are very close to one another
Can only track moving sources as quickly as the dish can be accurately turned
Has trouble discriminating between space and earthbound sources unless you take the time to move the dish (to see if the signal goes away - an earthbound source that's bleeding into a dish will still be present even if the dish is turned slightly)
Only sees transient events if it happens to be looking at them when they happen.
Requires little computational power
The primary limitation is computer power. The square km array is basically a radio telescope that will cover the better part of Australia with a total reciever area of a square km, easily outpowering all of the radio telescopes ever built. However, this telescope, at full resolving power can only look at a few objects at a time at a single frequency, not the entire sky since doing so for so many elements would require something like a metric fuckload of teraflops. Instead, some elements will be dedicated to a low resolution/sensitivity whole sky scan to detect transient events and the rest of the array will train its virtual beams on various objects of interest or on said transients within a fraction of a second of their detection with the wide scan.
Here's where I think amateurs could come in:
the square km array, if it's ever built, will only look at the Southern hemisphere. Furthermore, it will be taken up by radio astronomers, not SETI or amateurs. I know Paul Allen is setting up some sort of massive SETI system not unlike this but, IT would be nice to have more than one group doing this.
So here's what should be done:
Set up a system of radio recievers that people can easily build/buy to put on their computers.
Have these computers slaved to some sort of very accurate time clock, eg: GPS
Have each computer pull out all of the waveforms from a pre-agreed frequency, eg: standard SETI search frequencies)
Set up a central or distributed system to pull out any non-Earthbound sources. (this array tech is great for IDing non-human sources since widely spaced recievers can easily triangulate distances to nearby sources out to a few hundred km, eliminating the vast majority of non-ET tr
They forgot France units. Everything has to be compared to the size of France. -127,273 times the number of square millimeters in the country of France.
It somewhat suprises me that the fac that the plumes come from the upper mantle as well is a surprise. I just finished reading the Self Made Tapestry by Philip Ball. (I'd highly recommend this book if you're interested in self-organized behavior or chaos theory. It's getting a bit old but still a very good introduciton to the topic)
In one chapter, he discusses fluid convection dynamics and the tendancy for self-organized structures to form in diferentially heated fluids. He then goes on to mention a simulation done by Paul Tackley in *1993* which predicted the formation of two layers of convection cells. (the layers are seperated at the 660 km discontinuity in the mantle) Furthermore, these two layers are incompletely seperated and plumes originating from both the 660 km discontinuity and the core-mantle boundary reach the surface. There's a picture of the simulation results and they look strikingly similar to the the ones in the article.
What suprised me the most was that the Yellowstone plume was absent. I thought that what was supposed to be why the great plains are about a mile higher than they whould be. Did the yellowstone plume poop out recently or something?
OK people, repeat after me:
1: Lasers are NOT monochromatic. A monochromatic light source would violate Heisenberg's uncertainty principle. The atoms in a lasing medium all have different energies and therefore a laser has a very small but very measurable energy dispersion.My quantum physics is too rusty to recall if a laser cooled to 0K would be monochromatic but I seem to recall that even them there is an energy range.
2: Laser light is NOT parallel. The light is generated by the photons bouncing back and forth in a lasing cavity. Even if you assume that the mirrors are *perfectly* parallel to each other, a photon can easily enter off axis and still be able to bounce several times before running off the mirrors. In a high efficiency lasing medium, this can lead to large amounts of off axis light. Semiconductor lasers regularly have outputs that have 20 degrees of divergence.
Everyone assumes that lasers have no divergence because of the old gas lasers like HeNe and Ar. These have very low lasing efficiency and so a photon has to make many passes through the lasing medium to generate an appreciable amount of lasing light. Furthermore, the lasing medium was commonly a long glass tube. Therefore the divergence angle of the light was very small. For some reason this became - "laser light does not diverge'. On the contrary, the lasers they bounce off the moon get to be something like a km in diameter when they reach the moon.
In fact, when working with lasers, there is a 'waist diameter' where the beam has a miminal diameter (varies on laser optics geometry but usually at the laser output) and then the beam diverges just like any other. Laser pointers and the like use lenses to collimate the beam into a relatively non-diverging beam.
Mind you, lasers are much better than standard light sources like light bulbs since the emitting area can be quite small and therefore you can generate a parallel beam much closer to the theoretical ideal than with something like a big humk of glowing tungsten.
Last time I checked a few years ago, Seattle weather forcasts were right less than 50% of the time. 'Course being by an extended arm of ocean and between two mountain ranges tends to do that. IMO, the forcasts there need a 'for entertainment purposes only' discalimer in front of them.
Be careful in just taking what a hospital technician might tell you. Most of the med techs I've known or met were pretty good but some have just mind-boggling levels of ignorance. I was in for a barium contrast CT this spring and the tech told me that the barium solution would feel hot when injected theough the IV. He then went on to tell me that this was because of 'friction between the Barium and the inside of my blood vessels'.
It took all my will power to not kick him.
Anyway, you can't really focus X-rays in a normal setting, the mirrors involved for X-ray manipulation are very expensive. Rather what happens is that a single straight beam is sent theough the tumor at different angles. Think of several flashlight beams crossing at the same point. Where the beams cross, it's much brighter. This lets you get the correct amount of X-rays to the tumor and minimize the amount in the surrounding tissue.
Also, re the previous post - X-rays are from X-ray energy photons, not gamma energy photons. It's a bit nit-picky but there is a huge energy difference between X-rays and gamma rays.
Nanofibers in fabric IS nanotech. Drawing a distinction between assemblers and small fibers which were designed with knowledge of how materials interact on the nano level and then manufactured and integrated into a material is hair spliting. Who cares how the atoms get into their final position? It's quite likely that a truly general, practical assembler is impossible. At best, we'll have many different assemblers custom tailored to specific applications - basically like ribosomes but for different types of chemistry.
Assembler nano will never completely replace normal maufacturing techniques. If you want to make a big hunk of metal are you going to forge it for a few bucks or try and assemble it? Don't forget that nanoassembly can't circumvent thermodynamics and so the thermal and energy cost of moving all those atoms around and maintaining low entropy the whole time is horrendous. (the way nature gets around this problem is to use an engineering model that is inherently very sloppy and tolerant to that slop which greatly reduces the energy requirements - however, don't expect to be able to ape nature's model and be able to photocopy objects or build a digital computer.) Also, the speed of the assembly is very slow - look at how long it takes a tree to grow a pound of wood. This works in certain business models but if you want a hunk of metal now, an expensive, energy hungry, finicky process that takes 3 months is NOT going to completely supplant the 'ol heat 'n beat technology we have now.
Furthermore - my real point here - we have quite a bit of control over the nano-architecture of matter already:
Many chemists argue that organic chemistry IS top-down nanotech and I think that there's not too much dispute about the benefits of that... Biotech is also mature nanotech - modern bioengineering involves the angstrom resolution modification of specific structures and is now starting to design de novo structures for novel applications. These molecular structures are designed from a nanoscale information template and assembled on bonafide molecular assemblers. Hell, photographic media is nanotech - silver halide nanoparticles.
Insights from nanoscale are essential to materials science where I work. Back as far as the 50's, we've been studying steel (the most significant material of the last 100 years, not silicon) and how it's atomic structure is modified by processing. If you're not familiar with the level of knowledge we have of steels, you'd be amazed. US Steel back in the 60's owned most of the world's electron microscopes in research labs that rivaled ATT and IBM. By altering carbon and other impuruties and going through carefully controlled heating and cooling cycles, we have an amazing control over the final nanostructure of steel.
Modern metallurgy is even using nanoscale powders to achieve unheard of combinations of hardness and flexibility.
Plastics are another example of nanotech - modern polymer work involves fine control of the branching, structure, phase seperation and fluid interactions of polymer chains. Car bumpers are made of plastics because of the invention of block copolymer thermoplastics which use structure polymer chains to combine hardness with ductility. Hell, even in the last few years, plastics have changed. Any molecular biologist will tell you, the polypropylene they use in newer pipet tips and tubes is dramatically different in that the adhesion of fluids to them is now nearly zero (important when you're working with microliter volumes) because of control of the polymer structure at the plastic surface.
By adding a tiny fraction of a percent of size-tuned gold nanoparticles to optically active plastics for photovoltaics, you can extend the lifetime by a factor of 100 by tuning the gold surface plasmon through nanoscale mechanisms and 'short out' the energy states that lead to photoinduced chemical breakdown.
Is this nanotech with little robot arms? No. But it's still nanotech. My point is that, ye