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How Predictable Is Evolution?
sciencehabit (1205606) writes "If the clock rewound, would organisms evolve the same way they did before? Humble stick insects may hold the answer to that long-running question in biology. Through studies of these bugs, whose bodies match the leaves the insects live on, researchers have found that although groups of the bug have evolved similar appearances, they achieved that mostly via different changes in their DNA. 'I think it says that repeatability of evolution is very low,' says Andrew Hendry, an evolutionary biologist at McGill University in Montreal, Canada, who was not involved with the work."
Just look at how many times Eyes have independently evolved, yet they all have the same basic components.
We put water, methane, CO2, etc. in a closed system, ran some simulated "lightning" through, and got amino acids and what not forming. Various experiments show similar (even more prominently supporting) results: Nature and physics shapes the beings that exist within it.
There are plenty of other examples of evolution coming to similar results from different ends -- Just look at the shapes of sharks and whales. Not going to further dignify this anti-intellectual ignorant rubbish. Use a damn search engine, that's what we built the web for.
Convergent evolution suggests it is somewhat predictable, unrelated species having evolved similar solutions to similar problems. If a solution is clearly better nature will tend to go there given sufficient time and experimentation (mutation).
The fact that a trait may be expressed by different DNA sequences doesn't really seem to undermine this. The DNA sequences are implementation details. Evolution is about solutions and environments not DNA sequences.
The degree of molecular similarity in the DNA changes to achieve a particular result will depend strongly on the type of change one is looking at.
For the case of toxin-resistance, which is much closer to the molecular level, the odds of similar changes to the DNA are much higher than for complex morphological changes.
Molecular changes like toxin-resistance are more likely to involve a single gene that codes for a single enzyme, changing the enzyme so that the toxin is no longer metabolized in a harmful way. There are going to be a very limited number of ways to do this because it's pretty close to a one-gene/one-enzyme mapping in many cases.
Morphological changes, on the other hand, involve a whole network of genes that are turned on over the course of development, and the network can be altered in many different ways to get to the same result. Think about it like a road network where you're used to taking a particular route to get from A to B. If a bridge goes out on your your usual route, you may choose different alternatives depending on time of day, the kind of vehicle you drive, etc. Networks create choices.
Even then it will depend on the kind of morphological change we are talking about.
For example, there is a lizard in Mexico, which was studied in the '80's or '90s. There were several related species living inland, and a couple of isolated species on the coast near the Yucatan peninsula. Both the coastal species had an extra cervical (neck) vertebra, and it had been assumed on the basis of this similar morphology that their evolutionary history had been a general migration to the coast, an adaptation to coastal environments that involved having a longer neck, followed by a general die-back that resulted in the two existing but separate populations.
It turns out based on their genes the two coastal species hadn't had a common ancestor for millions or tens of millions of years, and the adaptation to coastal living had happened independently but fairly recently. In this case, because certain aspects of body plan are controlled by a highly conserved and relatively simple set of genes, the additional vertebra were the result of similar sets of genetic changes.
Things like body width, which is what TFA is talking about, are a lot more complicated in their regulation, so more likely to be achieved via different genetic changes that have the same morphological outcome.
I'm going to throw in a shameless plug here because it seems relevant to the topic at hand. I've just published a hard SF novel that's premised on a what-if about the role of mathematics and law-like descriptions in evolution. If you're interested in that sort of thing you should check it out: http://www.amazon.com/Darwins-...
Blasphemy is a human right. Blasphemophobia kills.
If I'm reading this wrong, and I hope I am, please let me know.
...researchers have found that although groups of the bug have evolved similar appearances, they achieved that mostly via different changes in their DNA. 'I think it says that repeatability of evolution is very low...
I read this as "Stick bugs have reached similar appearances through different means thus the same change probably won't make the same result".
Is this equivalent to "People can change their appearance to include a hole in the abdomen through different means (bullets and knives). Thus shooting or stabbing people are unlikely to produce holes in people"?
It may make it more difficult to guess which DNA change caused them to look like that (without an actual DNA test), but it in no way implies that those DNA changes won't necessarily cause them to look like that.
There are humans similar to us on other Earth type planets. Dinosaurs too. Maybe even some sentient avians and aquatics?
Looking at cows, dolphins and horses genetic proximity shows unexpected results, as cows and horses are not the closer in the trio, despite their similar features.
That suggests environment drives evolution in a predictable way, while the genetic evolution is not. This is the really amazing point: evolution find similar solutions to similar problems, but it does so through different ways.
Refer to Stephen Jay Gould and his "Wonderful Life" http://en.wikipedia.org/wiki/B... also. Gould mentions that there were a range of various paleobiological doohickeys bopping around at the same time, and we come from one group that happened to swim better, or whatever. Next time round, we'll have five eyes.
Well, I'm not explaining it right, but that's why there's books...
"The greatest lesson in life is to know that even fools are right sometimes" - Winston Churchill
We need to see how things evolved on other worlds, evolving entirely independently of the life forms on this planet, which may have in some way influenced eachother, in order to even begin to gauge how predictable evolution is.
File under 'M' for 'Manic ranting'
Yes you are reading that wrong. What they are saying is that since you can end up with similar looking creatures that took different DNA routes to get there, it's only the results that matter and not the DNA framework.
If you can end up with the same body style with different DNA then if you rewind the clock and started over there would be no reason to believe that you would end up with the same creatures we have today.
What can be asserted without evidence, can be dismissed without evidence.
Sorry sir, I'm not in charge of the Ig Nobel Prices. Tell you what, I'll give you a "contextomy of the month" price.
Can we get a Star Trek like movie but instead of meeting human looking weirdos in outer space, let's meet species that look really weird, yet make friends with us and we commnunicate. Like Octopuses, and Snake-people, bug-looking-people, birds with intellect, Koala bear looking chess players, etc.
How do people like you even have the brain power for breathing?
We know precious little about how evolution proceeded here, and we know nothing at all about how it might have proceeded elsewhere.
We can guess that it would be carbon based, because carbon has four covalent bonds and would have been formed sooner than silicon (with 4 bonds, but lower energies) would have. Beyond that, we'd need a few dozen D20 dice to calculate the odds.
But any real scientist knows that at some point, we have to admit WE DON'T KNOW how it might turn out. Wild-assed guesses aren't science, even if some people who claim to be scientists are sometimes wild-assed guessers.
Forgive me for trying to boil this down into more simplistic terms to understand the concept:-
So what you're saying is that just because 2 different drivers drove from Town 1 to Town 2 (similar results), it does not necessarily mean that they took the same route. Driver A had to buy groceries, pick up his daughter, visit the video store so he drove a certain route. Driver B had to top up his gas, return a library book and buy dinner so he took a different route (evolutionary pressures). But both of them ended up in Town 2.
Would this be a reasonably accurate metaphor?
not imaginative enough. Life in outer space would be less similar to us than bacteria on Earth is (so bird-like and octupus like is too "tellocentric"). Having said that, certain body plans are likely to reoccur like light sensors (eyes have developed several times independently on Earth) likely close to the proccesing unit ("brain", could also be distributed like in an octopus) and feeding organs.
Anyone human-like advanced enough to locate us and travel to us would be cyborg anyway. A brain cased in a robot 1000 times more advanced than us.
Or, Iron Giant style. All that'd be left of the foreign civilization is AI war machines.
The sci-fi going for "unlike human" almost always goes to insect (Starship Troopers, Aliens), but nearly all Sci-Fi stays human-like for the purposes of depicting it on TV/screen.
Learn to love Alaska
Solaris (book more than movies) is IMHO just about the only popular SF that's pointed out plainly that aliens are likely to be truly alien. Most of the book is about how a vast amount of work in a century since contact did little other than reflect the views the researchers had before they even came in contact with the alien/s. Even with godlike powers the alien/s couldn't get a message through from the other direction either.
Greg Egan had another approach where a chain of cloned and increasingly altered intelligences could form a bridge to communicate with aliens.
Wrong, Duh!
It's mutant ninja turtles all the way down
Table-ized A.I.
There's a great book by the artist Wayne D. Barlowe, called "Expedition". it shows the life forms of a fictional planet called Darwin 4 . With dense atmosphere and low gravity, Everything evolves big, and almost nothing has anything like eyes (sonar is both popular and often very advanced). Without giving too much away for those who still haven't run across this, there are several common body plans that tend to run through whole phyla, and which don't occur on Earth, but make really good sense on Darwin 4. The underlying science is generally sound - I base this on the way various people who have read it point to this or that creature as less probable than the others, but seem to pick out different ones. This book has become my standard for SF aliens.
Who is John Cabal?
Plenty of scientific evidence exists.
It's not our fault if you don't like it.
A god botherer interested in proof? That makes a change but then again you only throw out those statements since you will not read any proof
According to http://en.wikipedia.org/wiki/E... "Complex, image-forming eyes evolved independently some 50 to 100 times"
>There were created numerous times by a single individual.
I thought your imaginary friend was a trinity? so shouldn't it be three individuals (i could never work out who the holy spook was though)
oh dear, another deluded fool. Kent Hovinds is part of a group of complete idiots.....
"The hands that help are better far than lips that pray." - Robert Ingersoll (1833-1899)
Right, but planets with different atmospheres intercepting different output from their local star(s) will favour the evolution of different light sensors and the features around them. We see this on Earth, with the optical pigments, crystallins, eyeball depth, gross periocular morphology, retina, and visual areas of the brain being substantially different between flightless and low-flying birds and high-flying birds, and between aves generally and terrestrial mammals, between land and marine mammals, between land and air animals and fish, between fish who occupy salt and fresh water and water with very different turbidity, and between vertebrates and invertebrates.
Something grossly recognizable as "eyes" might evolve in a planet whose atmospheric and upper oceanic environments have about the same optical window as Earth's, but even Goldilocks Zone planets around stars with, say, a reddish sun, would strongly select for large changes in any population possessing terrestrial eyes if it were left to evolve there, simply because *all* terrestrial eyes would function poorly unassisted in such an environment. Visual systems evolving natively might take a wholly different route, and might not even explore something immediately recognizable as a photopsin.
The point raised in TFA is that evolution is not highly repeatable with our biology and that therefore convergent evolution is because of strong selection pressures in the environment. If another biology (or our early biology transported to another compatible but different planetary environment) were to be similarly non-repeating, then that planet's environment might select strongly for features that are enormously different from those we see in large multicellular organisms. Likewise, if we rewound our own biology and environment to the distant past and did it over again, we might end up without grasses, flowers, insects, or vertebrates rather than seeing subtle changes to only some of those.
Can we get a Star Trek like movie but instead of meeting human looking weirdos in outer space, let's meet species that look really weird, yet make friends with us and we commnunicate.
I can imagine a world without war, a world without hate, a world where everyone lives together in peace. I can imagine us attacking that world.
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- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
And don't make them all speak English...
I can see this point several times over. For instance, if complex animals developed on land before sea, perhaps we would have a eye better suited for terrestrial conditions instead of one that has to work in suspended aqueous solution. A terrestrial eye would benefit a great many species. Instead we managed to get this one trait passed on from generation to generation only modified to work in the existing environment. The downside of complex evolution is once you have committed to a certain path, getting rid of a trait can be next to impossible unless that trait no longer serves a purpose. Even then, we have moles with eyes that haven't seen light for generations.
Place something witty here
Fine. If Star Trek were today, instead of headridge-of-the-week they'd have belly fat-fold-pattern-of-the-week.
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
the one who is better adapted will always win. That's as predictable as it gets. Everything else is just variations on the theme.
Mutation is random.
I used "alien/s" above because in the book it wasn't even clear after a century+ of research whether the scientists were dealing with one alien creature or many.
We don't actually know how mosquitos evolved in the first place so my guess would be probably not.
Sector General: The TV Series! I'd watch the shit out of that show. There are few concepts that allow for multiple truly alien species all living and working together that don't involve exploration and warfare; a massive hospital space station built for the express purpose of intercultural contact is a brilliant way to do it.
Can we get a Star Trek like movie but instead of meeting human looking weirdos in outer space, let's meet species that look really weird, yet make friends with us and we commnunicate. Like Octopuses, and Snake-people, [and...]
No. Because biology (even xenobiology) is biology and budgets are budgets. And never shall the twain shall meet (other than via an NSF grant).
That is all.
Great book, but might be hard to find. There hasn't even been a copy available on Amazon for at least a year, and on eBay it goes for $120. There was a film version on the Discovery Channel about a year ago, so you might be able to see it on Youtube or somewhere, though I don't think it does much with the narrative and "notes" which were another great feature.
Also, Lovecraft's "The Colour Out Of Space" dealt with an incomprehensible life-form landing in rural Massachusetts.
I forgot to mention, the prize comes with a job offer from a major US political campaign group or media outlet (right, like there is any difference).
There is a tv special made based on that book called Alien Planet. I had not heard of the book before you mentioned it, but I recognized the name of the planet and the strange types of creatures on it. It was interesting even though it is all made-up speculation and there is no real science in it. It is on Netflix if any one wants to check it out. I particularly liked the ideas on how the remote AI flying rovers would be designed and programmed each with a slightly different personality so they won't all befall the same mishap.
-- ssoorrrryy,, dduupplleexx sswwiittcchh oonn.. -Quote found on actual fortune cookie.
Hmm, sonar actually seems like a poor choice for one important reason: it's *active* - meaning that in order to be able to "see" something you basically have to scream at it, which would make both hunting and fleeing predators far more difficult since stealth is not an option. Meanwhile the very first creature to develop even crude imaging eyes would have a massive advantage. Also, it's considerably more complicated, so unlikely to prove a viable means of detection until the organism has independently developed both some sort of "ears" and a way to make loud sounds, whereas so long as there is light in the environment "eyes" start becoming useful as soon as an organism develops light-detecting compounds, and the benefit improves smoothly as directionality and imaging evolve.
Basically on Earth very few creatures use sonar, and typically they are apex predators (very few things hunt whales or flying bats). I suspect that's for a very good reason.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
What do you mean by 'terrestrial eye'? An eye filled with air instead of liquid? It won't make any difference in efficiency. You really can't make eyes to look much different than they are.
Determinism of state is fundamentally at odds with quantum mechanics. But that doesn't preclude the fact that the mind is a machine, as also machines are not deterministic for the same reason.
Yeah. I mean Star Trek get's a pass because all the aliens share our DNA....but the fact the most aliens in Sci-Fi are basically human is pretty sad.
What a lack of imagination.
For example, female aliens shouldn't have breasts. Human breasts are an anomaly in the animal kingdom...why would that be a common feature among aliens?
If you ignore ACs because they are anonymous - you're an idiot.
The whole "same DNA" thing in Star Trek was just a retro-active excuse to finally justify all the cost-cutting that ST:TOS had done by using human actors for everything. The original klingons were so bad they even had to poke fun at it in the TOS/DS9 crossover episode.
Most female mammals only have noticeably larger breasts when breastfeeding. Compare a regular female dog to a female dog that has just delivered a litter of puppies, only the recently pregnant one has what we would call breasts. Most of the time, there is no noticeable difference between male and female dogs
This doesn't necessarily rule out breast-feeding alien females having large breasts, however. Moderen domesticated cows (especially Holstiens) show that breast size differences between genders can be achieved though selective breeding. In the case of humans, natural mating selections somehow favored women who always looked like they were breast-feeding, even when they weren't.
Good example.
Dense atmosphere and low gravity is nonsense, unless you have very high molecular weight materials, which tend to boil at higher temperatures, such as sulfuric acid on Earth sized Venus at 10 bar and very high temperature. But as far as we know almost all life on Earth directly connected to the atmosphere is photosynthetic origin as it's energy core (with the exception of deep ocean volcanic eruption sulfur chemistry cycle based lifeforms), so you'd assume low molecular weight oxygen in the atmosphere, to support carbon combustion of aerobic lifeforms, and therefore not that much density of atmosphere. Earth might be on the lowest possible gravity side of possibilities for life, as Mars has a very thin atmosphere, because of both low gravity but also because of lack of magnetic field/lack of solar wind shield. So you can't really have a life connected to an atmosphere in its function on a planet the size of our Moon, because there is no atmosphere at all on such sized a thing, because of insufficient gravity to hold one. So elephants on Earth might be the largest possible land based life forms in the entire Universe, but there might be a whole lot of places with say double or triple maybe 5x the gravity on Earth, and then most likely the largest lifeforms are bug-sized, with huge leg muscles compared to total body weight. If the gravity is too high, then we run into situations like Jupiter and Saturn and Uranus, that are full of captured gaseous hydrogen, as hydrogen is the most abundant element in interstellar and interplanetary space, and the only reason why Earth is not full of gaseous hydrogen is because it does not have sufficient gravity to retain it in the atmosphere at its escape-velocity escape region temperature. So if life is possible on these gas-giants in our solar system, then there are a lot of possibilities out there, but most likely life is only possible within a limited gravity range, Earth being on the lower end as Mars and Luna can't really support life (i.e. can't hold low pressure unboiled unvented to outers space liquid water to dissolve carbon based organic chemicals in essential for life), and on the gas giant high end you have issues with atmospheric hydrogen coexisting with oxygen during a lightning flash, and the whole atmosphere exploding - even if life is possible in/on gas giants, it cannot be carbon dioxide/oxygen photosynthetic/oxygen combusting hydrocarbon based, because of hydrogen explosions, but deep ocean hydrothermal vent type lifeforms might be possible, all you need is a sufficient driving force, high enough head for a local caloric waterfall.
Easy, they don't waste any of it on thinking.
This article itself points out that they look the same, it is the genetics that is different. On other worlds there would be strange solutions to niches but there would also be some oddly similar species as well. If you look back at the history of mammals, forgetting the understandable fascination with dinos, you will see that there have been many different kinds of mammals but certain forms are roughly similar: herbivores, large (very large) grazers, carnivores, tree dwelling. Not always but quite often there are similarities. On an alien world given similar situations then some similar forms are likely to evolve. However, sometimes a new environment may arise that creates new opportunities, if they are unique to a particular world then the creatures may not resemble anything we are familiar with. For example, the evolution of grasses and flowering plants. Some things would be universal: vision using light (IR to UV approximately), two eyes, smell sense, nervous system, some kind of brain though it may be more distributed, herbivores vs carnivores, etc. Life being Life however, there is always the opportunity for surprises.
Bitter and proud of it.
People talk about how the solar wind blows away a planet's atmosphere, and to that I've said all you need is a magnetic field and van Allen belts to deflect the solar wind. I just thought about this a little more. The wind itself does not blow away the atmosphere, as in physically blow it away, because a particle impacting the upper atmosphere at high speed is like a super fast ball inside a lottery urn, or when breaking in pool, the initial ball at high velocity, its velocity gets transferred and distributed over to the other particles of the atmosphere, raising the temperature, but not really knocking anything off the planet's surface. There is probably a dynamic equilibrium of the size of the atmosphere, a balance between particles captured and lost, particles captured by gravity from the solar wind, and lost from gravity if they ever reach the escape velocity from random thermal motions (the Maxwell Boltzmann velocity distribution of gas molecules has a sizable tail in the high velocity region) in the very upper zones of the atmosphere. The temperature in the troposphere matters the most, and the higher the troposphere the colder the temperature, the more it retains the atmosphere, and the troposphere becomes even higher, so the size of the atmosphere may be very sensitive to temperature, and has to be in a very narrow range to retain all nitrogen and oxygen and CO2, but let hydrogen fully escape (else you have an explosion in the atmosphere from a lightning strike, or can never build up much oxygen because it keeps turning to water from the captured hydrogen). Too cold a troposphere may retain too much hydrogen. In fact the gas giants Jupiter, Saturn, Neptune and Uranus are probably silicate cored just like Earth, might have water too if they have lightning strikes, but they have so much gravity and sufficiently low troposphere temperature they retain all the hydrogen, increasing gravity which retains even more hydrogen, and this process would go on indefinitely weren't it for the fact that there is so little hydrogen in outer space, it takes forever to grow a millimeter for the size of the planet. These gas giants are probably growing, and the closer they are to the solar wind source, the Sun, the faster they must be growing, Jupiter growing faster than Saturn, etc, if the hydrogen concentration decreases in outer space when going farther from the Sun. In fact the silicate core of Jupiter might have started off about the same size as Earth, but because it was so much lower temperature in its troposphere, it retained the hydrogen and it grew into a massive gravity object which now heavily attracts all kinds of meteorites and comets, so its silicate core is probably much bigger now than Earth's. So anyway, what I was trying to say at first was that Venus may not need a magnetic field if its temperature is low enough, the atmosphere may absorb the impact of the solar wind, as long as the fully dispersed diffuse Aurora Borealis phenomenon across even the equator happens deep enough in the atmosphere that the hot particles impact colder ones above and lose their escape velocity, and never escape. It's very hard to create a natural magnetic field if you don't even understand why such a thing arises. It might have to do with a huge nickel-iron core, and if Venus lacks that, that's very expensive to gather in outer space and dump into Venus. If it's lava is not molten enough, it's also very expensive to find radioactive containing silicates and dump it into Venus.(It may be that simply Venus does not have the perfect size for a lava, not enough insulation to get the core hot enough, even if it has the same average concentration of radioactive trace elements as Earth, or the Moon, or Jupiter.) If push comes to shove, it's possible to put up superconducting magnets by the Lagrange point to deflect off some of the solar wind. But a cold average temperature of the planet is a must before water and oxygen and nitrogen get retained in large quantities, especially water. I just read up on the atmospheric composition of Venus, it
Bumping Ganymede or Io into Mars on the other hand might be safer than bumping them into Venus, as long as they get put into orbit with low eccentricity around the Sun that never crosses Earth's height about the Sun. There is probably still a risk from moving such large objects in our planet system, but the risks might be minute enough to be acceptable. There is probably a long way to go before Mars can be built up into a planet large enough to hold water, but vent all hydrogen. What is the gravity/temperature range for Mars for this to happen in its present orbit. If Mars gets built up to a larger size by interplanetary ping pong, it might be worth to send it closer to the Sun, and in fact you could have a trio, Earth, Mars, Venus almost sharing Earth's orbit equally spaced from each other, not across the Sun from Each other, this way they are always visible to each other and communication is easy. Almost sharing as in at different heights around the Sun, never getting close enough to each other to toss each other into random unpredictable orbits. (Note: the 3-body problem in physics is a great chaos generator, it's very unpredictable sometimes.) They could have a prize for the best analysis of the safest orbits, where the temperature/distance from the Sun is considered. The economic analysis is the most important, as it may be cheaper to put up shades and keep Venus into higher but still low orbit compared to Earth, and Mars very high with possibly a focusing Fresnel lens at it's Lagrange point, on 3 out of each other's plane orbits where the 3 never meet each other. As different height orbits around the Sun go around with different speeds, putting all 3 planets into exactly the same orbit might be the safest way to guarantee they never catastrophically or unpredictably meet each other. Also, just how expensive would it be to send the useless Mercury up into Venus, in a way that also sends the blasted off momentum conservation ejected stuff from it not deep into the Sun, but into some usable, higher area orbit where people could get to it.
Sending Mercury into higher orbit and ultimately into Venus would simply require speeding it up as it goes round and round the Sun, so it stabilizes in a higher and higher orbit. While speeding it up, the material ejected off its surface would still end up in the Sun, unless it has enough negative velocity to stay in orbit going in the opposite direction. So reusable material saved for later use by humans would have this issue of going the wrong way around the Sun (all planets go the same direction, there is this concept of conservation of angular momentum of the initial dust that formed the solar system, still present today, and all planets rotate in the same direction, unless they were later hit by huge asteroids in an unlucky way that made them spin the wrong way.) So the material ejected off the surface of Mercury would have to go with sufficient negative speed, negative angular momentum to compensate for the increase in angular momentum of Mercury. Such an object could be used as an energy harvesting station spinning the wrong way, or it could be consumed by sending it all the way up to Mars, and taking away angular momentum from Mars, so it comes closer to the Sun. That way no stuff would be flying about the Sun the wrong, dangerous direction. Mercury only has a 0.055 Earth's mass, Venus 0.815 Earths, and as long as the average density is the same, there is room to bring Venus to full Earth's mass. For every average density there is a specific mass (and volume to go with it) that creates the correct 9.78 m/s2 on the surface.
Also I found out why Venus has no magnetic field - it's not rotating! It has enough internal temperature
The Universe will manifest itself, will tell you if you're rotating or not. The principles of Galilean relativity apply against Newton's absolute space, where, if locked inside a black box such as an elevator, you cannot tell whether you're moving in a uniform rectilinear motion of constant velocity, or standing still, as standing still is nonsense, only standing still vs. another object moving with a uniform rectilinear motion is definable. Also, when inside a black box you cannot tell whether you're in a gravitational field or a uniform rectilinear accelerating field, which was the source of Einstein's general relativity principles applied to gravity. (We still don't really know what gravity in as much detail as we'd like to.) Rotation is not rectilinear uniform motion. That's all Venus really needs to jumpstart its natural dynamo and get a solar wind shielding van Allen belt magnetic field, and some Aurora Borealis at its poles. To get Venus spinning, you need to smack something into it at the correct position - to spin it toward the east, you smack something into it toward the east side, to spin it to the west, you smack the same thing on a slightly different path, on the west side. So whatever gets smacked into Venus, probably has to get its trajectory corrected right after it comes back from the Sun, as relativistic calculations apply near the Sun, plus you got solar wind, and solar flares might hit it, there is uncertainty of the path enough to miss off target. The earlier the correction, the greater the effect later, so you probably can't wait til last minute if all you have is a few tiny bombs buried inside the artificial comet, and you can set any of them off as needed to create a trajectory correction. Also its always easy to add more weight to Venus, but very difficult to take any away, because the atmosphere slows down explosions blasting stuff into outer space, and instead you need cannons + rocket like continuously firing things to get stuff off of Venus. So whatever gets smacked into Venus, should be of relatively high speed and small mass to get it spinning, and keep the mass on the low side. We probably don't wanna get a planet where we're heavier than we're on Earth, but lighter is OK - such as long distance jumps get more fun, and you'd have a world record on Venus different than one on Earth, if you're lighter there. The Asian martial art movies where the girls revenge their murder of their fathers by biting their braided pigtail hair while fighting 200 enemy soldiers and jumping up on the roof from standing still, well, those jumps would be more believable on Venus.
That reminds me, why don't space agencies use a maglev-like device to accelerate their rockets, at least through the initial part of the ascent? A whole lot of rocket fuel is wasted on getting the rocket from 0 mph to 1 mph, when you could easily get it to 1000 mph first on a rollercoaster-like maglev track, then ignite the rockets once you left the track at the end. There is a big altitude gradient from the ocean and the Andes, in South America, near the equator, shooting eastward up, there is some less nice but still good near the Himalayas, but a mountainside somewhere in Utah might do just fine, how much track length do you need?
The space shuttle was a marvelous invention were it not for the huge amounts of liquid O2 it had to lug around. Hydrogen is light, but the O2 was 8 times heavier, as H2O has a molecular weight of 18, out of which 2 is H2 and 16 is O, so 8/9th the shuttle weight was liquid O2 and 1/9th was H2. If you could get the O2 out of the Moon's silicate rock, you could save rocket weight by an order of magnitude. NASA had a competition challenge back in like 2002 about this, it expired a while ago, but I been thinkin about it.
Geoffrey A Landis at Nasa came to a natural conclusion that Calcium reduction is a catchall method to treat any rock, as shown at http://lib.znate.ru/pars_docs/... You could do a thermite-like reaction with excess metallic calcium and get calcium oxide plus silicon, aluminum, magnesium(evaporated), iron, etc. You don't need a huge device for that, as astronauts might play around with it out in the open Moon surface as shown by this thermite reaction http://www.youtube.com/watch?v... (thermite railroad welding) or https://www.youtube.com/watch?... (thermite out on grass and bricks). Calcium will do a thermite reaction stronger than aluminum with everything (magnesium might be difficult, barium and calcium stay as oxides (which is OK), but aluminum and silicon, the bulk or rocks, and especially iron, should be OK.) So GA Landis' problem is still how to get O2 out of the CaO, and his best process is CaCl2/CaO melt. That has huge issues, the biggest being that it is Cl2 not O2 that comes out of that melt if electrolyzed. A CaF2/CaO mix might work, but now you're talking huge temperatures to melt that. An Iridium crucible and Iridium anode (for cathode there are many options) with a CaF2/CaO electrolyte might be workable, which might be the reason for the iridium signature from the dinosaur extinction layer is geological rocks - it might have been a spaceship full of tiny alien creatures destroying their ship Jabal al Tariq (ibn Ziyad) style (from whom Gibr Al Tar iq is named.), after some 70,000 year trip, millions of years ago, before humans or even monkeys ever stepped foot on this planet. Iridium is almost the heaviest thing in the world around us, with some uncertainty about osmium. To maintain high enough heat some of the electric energy has to be used to melt the CaF2/O mix, similar to the calcium carbide making electric furnace, and the expensive fluoride needs very careful recycling, including distillation of the metal Ca, or amalgam extraction (in which case now you got a Hg recycling problem), or who knows what.
Another option is dissolving CaO in water, as quicklime, and electrolyzing that, as Sir Humphry Davy did 200+ years ago when first making metallic calcium on this planet. The problem of this aqueous electrolysis is conductivity compared to a molten salt, therefore production rate/scale of device, but on the other hand it can be conducted at low temperature, and mercury recycling issues might be smaller than fluoride recycling issues out of calcium metal, especially once you extract the amalgam the following way: Davy distilled off the mercury, and as only like 0.5% or less can be a liquid amalgam, that's a huge amount of distillation energy wa
Oh, btw, if you're going to do the iridium anode/CaF2/CaO electrolysis, the calcium has to be distilled off at the cathode, otherwise it loves to dissolve back into the salt as some monovalent ion and go to the anode and react with the gaseous oxygen there. Present industrial Ca production uses aluminum vacuum distillation of the oxide, similar in concept to the ferrosilicon silicothermic Mg production named Pidgeon process, because of the redissolution issues of Ca salt electrolysis (such issues are not prevalent with alkali metals, as they can't go to half valent from monovalent, or even Mg electrolysis probably doesn't have this issue.) There is a section in the 1911 Encyclopedia Britannica talking about calcium electrolysis with continuously raised rods, and the Ca metal forms as a stick, as a bar, and being held above the liquid salt, it does not dissolve back too much, as long as the rate of deposition is faster than the local redissolution at the tip of such stick. So the best idea at the high melting point of CaF2 is to distill off the Ca metal instead of having it as a stick, and then if the cathode is under vacuum, the anode has to be too, and you'd get the oxygen out as a very high temperature vacuum gas. But the device may nevertheless be small scale, because of the superhigh electric conductivity of a molten salt and high reaction rates at such huge temperatures, only this vacuum consideration adds some volume, but not that much weight.
Also, from a calcium reduction you'd recuperate the slag that contains all the oxygen, but the metalloid residue, containing silicon, aluminum, iron, sodium, potassium, magnesium, and especially titanium(lightweight strong like steel), is valuable too. Down here on Earth we have carbochlorination to get TiCl4 and SiCl4 liquids ready for distillation purification, but up on the Moon there might be a carbon shortage, and then you can use calciochlorination instead, but you have to do the steps separately, because unlike carbon+chlorine nonreacting with each other, calcium loves to react with chlorine. Silicon, titanium, aluminum, iron, magnesium/Na/K chlorides are easy to separate by fractional distillation (magnesium+alkali metal chlorides being the bottoms), though good luck running such a process, trying to not block up the conduits with unmolten magnesium/sodium chloride crust. Water can be an aid to unblock almost blocked passages, Some of the magnesium might react with the water during the slag extraction step, so during the thermite reaction it's best to let the magnesium/sodium/potassium distill off, then collect it in a remote portion of the reaction retort (if not enough excess Ca, at the tip of the retort it may be magnesium/sodium/potassium sulfide of phosphide with free sulfur and phosphorous, but most likely S and P end up as calcium salts, then as H2S and PH3 on water extraction). Some of the aluminum will react too under high pH quicklime conditions, but it shouldn't be too bad, and if it is, there might be other solvents that are between water and alcohol that dissolve the calcium oxide, but don't react with Mg and Al, maybe not even with Na, K. It's best to distill the Na, K, Mg out as metal first before water extraction of the slag.
Some of the unreacted metallic slag could be shaped into small rods and used in a solar powered or nuclear powered nailgun propulsion system to get stuff off the surface of the Moon into outer space, then recollected for later use, so they should be built nonaerodynamic but flat impact shape so they don't bury deep into the lunar surface and can be picked up for reuse. Steering becomes a huge issue with such propulsion, because you have to shoot these things towards a predefined location, not just anywhere, so you still need gaseous steering emissions, such as high temperature/pressure oxygen gas you made out of moonrock.
Pierson's Puppeteer anyone? Do you want one to be your bar tender? After you realise that they prepare your drink with their mouth?
That, I would hope to see change as producers and artists explore the capabilities of CGI. Particularly "live action" CGI.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Also the patent system's past is dynamic, and unless anyone has a record of each and every one of the millions of individual records in the patent system, it's possible to modify the past and insert patents in 2014 as if they were invented in 2013. Which is why the computing cloud is pushed so heavily, to be able to search against who has what copy of what (your mental memory does not count for much, especially if they forcefeed some memory erasing Haldol or Risperdal into you), and then it's possible to control and own intellectual property of the whole world. Which is why, like DNS on the internet with no centralized servers, it is important to have all patents mirrored at many libraries throughout the world, with local disk copies archived, to make sure the past does not get modified and edited away from everybody else as it pleases the powers that be, who like to constantly rewrite history. Old paper books are difficult to edit too, but easily editable electronic records, like medical records and ebooks stored in the Cloud are useless when it comes to defending against absolute dictatorships modifying them as they please.
Not while the "live action" CGI is still guys in suits running around being filmed then digitized.
Learn to love Alaska
If I want to see a guy in a rubber suit, I'll watch a diving video.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I was thinking Avatar, and some of the others since (Gollum), where they get a human actor to "act" the scene, then they replace the human actor with a new character that is 100% CGI, replacing it. That isn't new. Disney would generally film animated dances with people, then draw the animation to follow the human movements. Because of such biases, we'll always default to human-like characters on screen, even for bears, snakes, lions, and other animals.
Learn to love Alaska
I see enough use of modelling software to, for example, understand the biomechanics of a T.rex's walk that it's clear that the understanding of how bones and muscles interact, and how to model them (how much muscle volume is needed to accelerate a lever of mass X and moment of inertia I at Y ms^-2), is good and getting better. Which can then take the place of the Disney movies of dancers, or go directly into a 3d model and thence into a render farm.
I suspect that the constraint on production is less in the skills of the 3d modellers inventing the animals, and more in the producers afraid of what the public will pay to see (Avatar was an American film, which is why I won't willingly watch it). I guess that leaves the window open to things like animation competitions and short films to slowly push back the limits of the producer's arguments with the focus groups.
I remember seeing some of the first computer modelled and rendered animation in the late 1970s - the classic anglepoise lamps playing football (sorry, "soccer") - and realising that I was seeing the future. And it is getting closer. At about one year every calendar year.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
By the way Landis' idea about CaCl2 is not totally unworkable. It's unworkable in the FFC Cambridge process sense, where you keep adding solid chunks of oxides/rocks that get reduced by the dissolved metallic calcium in the molten calcium chloride salt - there is a continuous buildup of oxygen in the melt, as CaO, which is not very fusible, and you emit the chlorine gas at the anode, so you have an unstable molten bath that needs constant replacing/regeneration. One way to recycle the bath is to bubble HCl through it, but it cannot be done small steps at a time during electrolysis, because the metallic calcium dissolved in the salt will react Ca+HCl-->CaCl2 + H2 gas, in preference to your preferred reaction of CaO+HCl-->CaCl2+H2O vapor. A more elegant way is to not mess with an unstable bath, but electrolyze pure CaCl2 for Ca and Cl2, burn the Cl2+H2-->HCl, react the HCl + CaO--> CaCl2 + H2O, dry the CaCl2, and electrolyze the H2O-->H2+O2, you got your O2 and recycle to H2 to burn more Cl2. The advantage of the CaCl2 method is that it's lower temp than CaF2, so easier material constraints, but that may be a disadvantage if you want to distill out the metallic calcium, as with a molten CaCl2 electrolysis you can never get 100% coulombic efficiency, because some metal will redissolve and wander back to the anode and react with the gases evolved there, even if you apply that stick-drawing trick to only let the tip of the metal hang into the molten salt, to save it from dissolving away, As far as the FFC Cambridge method goes, it works ok to take a fistful of oxide and reduce it to metal (after you electrolyzed enough to build up the dissolved metallic calcium concentration in the liquid salt), but on an industrial scale it's simpler to just get the metallic calcium out of a stable and productive process, granulate the calcium metal, pulverize the oxide, stir the two together and ignite the calcium thermite (Goldschmidt-like, Al-Cr-like) reaction. It's hard to get much new intellectual property innovation in inorganic chemistry that hasn't already been tried, but organometallic catalysis at room temperature is pretty promising. In particular room temperature N2 fixation from the atmosphere would be nice.
Also the calcium-thermite reaction may or may not suffer from the high volatility of calcium metal, unlike aluminum thermite where the liquid aluminum has a very high boiling point, So the calcium reduction may not proceed as violently as the aluminum thermite reaction, never exceeding the boiling point of calcium, quenching reaction temperatures, and then a protracted reduction in a possibly externally heated vessel may be needed, similar to the Kroll process of titanium manufacture from TiCl4 by Mg metal reduction. The Kroll process takes days to proceed, but the Mg is easily distilled out of the final metal. One wonders if it worked faster with Ca metal instead of Mg, and Ca might still be distillable enough. It would be less energy efficient, but, with a higher driving force, more time efficient, and time is money. Both the Kroll process and the lunar oxygen "calcium reduction" reaction, in absence of an efficient thermite self-reaction might benefit from the FFC Cambridge salt-dissolved calcium-reduction, with the salt periodically regenerated by venting oxides from it via HCl bubbling, venting as H2O vapor. However Mg is much more volatile than Ca, and there is documented evidence of Mg doing a thermite reaction with SiO2, ignitable with a Mg-strip, and forming some Mg2Si silicide which hydrolyzes to SiH4 silane, which is one of the easiest methods to get silane, so if the very volatile Mg works fine, Ca should have no problems.
Also, on the surface of the Moon, as there is no atmosphere, a ramp-like shooting into orbit accelerating on a track might work, not a cannon-fire, as the acceleration is too sudden, but a gradual acceleration on rollercoaster-like maglev or similar track, long enough to reach escape velocity (which is much lower on the Moon, and there is no air-drag), might be the cheapest way to launch anything into orbit. However it requires a preconstructed site, as opposed to the nailgun propulsion/gaseous steering, which can land and takeoff from any uninhabited spots on the Moon, and leave the ejected material back on the surface, later reusable, unlike a gas-emission propulsion that almost-forever wastes the material into the vacuum of outer space. By the way any forever lost to vacuum material such as gases or even vaporized metal chunks should be accelerated as high a velocity as possible before ejection, through a cyclotron or similar device, and then some ICP (inductively coupled plasma) metal vapors might be preferable propulsion agents compared to others (ie. Mg, Al, Fe, Si, K, Na - some of these might be easier to accelerate/gasify than the others). In theory it's possible to create a completely matterless propulsion, to collect light through solar panels, then form a high energy laser beam and shoot it off in a direction, and as any energy is mass, there is a momentum gained by shooting it off, but the momentum gain vs. energy expended is very low from a laser, compared to using the same energy on tangible matter harvested on the Moon's surface, and accelerating that up to very high speed and ejecting it in a direction. As long as it's in a vapor form, it should be disperse and safe enough to accidentally hit some other space station object, even if it's a condensed metal vapor flying at high speed, so you could use even the metallic gas "stuff" from the surface of the Moon for propulsion purposes, not just the gaseous oxygen, though as a first step, we are after oxygen, to combine it with cheaply lifted lightweight hydrogen, and get gaseous propulsion out of the whole thing that way.