One further followup: so far as humankind "RIGHT FUCKING NOW" is the kind of species that is *willing and able* to bring about *global extinction,* then I don't want humankind to survive and spread into the universe "RIGHT FUCKING NOW". If humans are necessarily as terrible as you posit, then the only ethical thing to do would be to sabotage --- by whatever means necessary --- humankind's ability to spread (at least until they become something else). Like the German resistance fighters against the Nazis, only trying to prevent future *interplanetary holocaust* by a species that, at all costs, must be stopped. I don't think humankind is all that bad --- but if you do, why do you consider it such a noble prerogative to preserve the species?
Yes, that's the kind of more pressing problem that I think it's more important for humanity to buckle down and deal with than Mars colonization. And it won't help to be burning an extra gazillionty-zillion gallons of fuel for rich folks to gallivant about in space.
Disastrous global ecosystem changes from climate change --- while a terrible thing from which billions will suffer in starvation and war --- isn't a "wipes out humanity" type of event (even in rather pessimistic predictions). It's certainly not worth *accelerating the pace* of climate change to get a few people on Mars (still *far, far* less inhabitable than a climate-change ravished Earth). So, if you're looking for a "save humanity" type project over the next couple centuries: yes, you should be far more worried about climate change than Mars colonization. But it seems that you're only "worried" about climate change so far as you can use it for an argument for Mars colonization --- and imagine leaving everyone on Earth to rot in misery so long as you and/or your children can make it to Mars.
If enough humans can't survive on Earth with poor outdoor crop yields, unpleasant temperatures, and bad weather, then we won't be surviving on Mars (where the weather forecast is "You die, puny human!" 24/7/697).
Because humaity will have to fucking EVOLVE before those problems go away, and mars one is RIGHT FUCKING NOW
Global extinction events only occur on "evolutionary" timescales. You're "hedging bets" against events that might occur between once in a million and once in a billion years. Thinking on "humans can evolve" timescales is perfectly appropriate for thinking about addressing events that occur on "we'll be a completely different species by then" timescales. Yes, I think people/society will need to "evolve" (hopefully on a much faster "memetic evolution" timescale of changing ideas than "genetic evolution" timescales) to solve problems --- but "we've got time" (with high statistical probability) before a "planet-killer" shows up. So, in the meantime, I prefer solutions that involve working towards a better, more "evolved" humanity, able to deal with the problems we have *on Earth*. Turning Mars into a new Wild West frontier for a select few to escape is not particularly a useful step along the way to "evolution" of a more robust society. Focusing resources on making Earth habitable enough (and humans good enough neighbors) that humankind won't slaughter each other back to the iron ages over the next few millennia is, in my opinion, a more pressing matter than sending some yahoos to spread capitalist violence to the next planet "RIGHT FUCKING NOW." And, I think, if humankind can progress towards more "evolved" forms of organization, it will be far easier (and far more *worthy a project*) to do "adventurous" things like living in space in the "evolved" future.
Yes, you can find a quarter of a million people eager to be groundbreaking new explorers on the adventurous forefront. But I bet if there were already 249,999 people scraping by on a Mars colony, that you'd have a harder time finding eager applicants to go on a one-way suicide mission to be the 250,000th person doomed to die on Mars. A Mars colony is conceptually exciting to a lot of people now because it is new, and expensive, and a rare distinction. But the *desirability* of heading to a Mars colony is roughly inversely proportional to the *usefulness* of a Mars colony: as a colony heads towards being a routine, self-sufficient, boring place, the only people eager to get there are people in much more dire conditions on Earth (and, with the resources required to get such a person to Mars, you could give them a fantastically luxurious life on Earth --- which they'd likely prefer once the initial "got there first!" charm of Mars wore off).
How many people on that list of brave Mars volunteers would be equally happy to trade their life savings, and their life, for a chance to live a couple years before dying on the shores of Antarctica? A trip like that was once the forefront of human exploration --- and the brave, bold, and proud would risk their very lives in perilous journeys to reach the South Pole. But now it's boring and routine; some people are willing to winter over to run scientific experiments in Antarctica, but no one is lining up to sacrifice their life for the opportunity.
After you strip away the hype and hubris of those selfishly wanting to be immortalized in the pages of history, Mars isn't so hot as a practical solution to potential real problems. So, yes, you can find a lot of eager support for Mars --- but that doesn't mean you've found a lot of people being smart and rational about the subject. All you've proved is that a spectacularly flashy suicide is an attractive prospect to many.
1) these structures must already exist, when no apparent threat is known of.
Just like a Mars colony. Only several orders of magnitude less expensive to build per inhabitant.
2) people must be actively livng inside them when the calamity hits.
Just like a Mars colony. Only you've also got a lot more time/resources to move many more people into said structures, in addition to the skeleton crew needed to keep them prepared.
3) the structures must survive the initial upheval and chaos of the calamity.
Yep, just like a Mars colony would have to be able to adapt and carry on after being cut off from all Earth support.
By your own logic, 1) will never happen until humans stop being humans, because it is a big todo about "nothing".
Just like a Mars colony; only Earthbound shelters offer a much better "return on investment" --- much lesser resources required to make a lot more people likely to survive major disaster. So, if you're actually worried about saving some humans in the event of "extinction type" events, then you'd be enthusiastic about much more efficient and effective Earth-based solutions. Of course, "manifest destiny" space nutters have deep-seated irrational concepts that "live on Mars!" must be the one true solution to problems, instead of considering much more practical steps to achieve the same supposed ends.
Yes, I think protecting against once-in-millions-of-years to once-in-trillions-of-years events is a poor use of humankind's present resources, when "everyday" problems are much more pressing. However, for anyone who does want to get a head start on protecting against hypothetical disasters, you might want to employ far more practical (better chance of success for less resources invested) approaches like building self-sustainable "sealed" habitats on Earth --- unless the entirety of your scientific knowledge and engineering judgment comes from reading Sci-Fi fantasies.
Also, your rebuttle of the extinction reason for building the colony is not well established, and is easily picked apart, since it is based on suppositions, and not substantiated past events, ad relies heavily on magical thinking that humans are magically capable of adapting to anything (that isn't on mars of course!).
Not sure where you're getting the "magical thinking" or "assuming that humans are capable of adapting to anything" from my post above, but here are some basic science/engineering reasons why a worst-case Earth (atmosphere not directly breathable; solar input reduced to Martian levels by dust; death of most biomass) is still easier to deal with (without need for "magic"): - Atmospheric pressure still exists. Habitation structures only need to block/filter undesirable atmospheric contaminants; not also hold 15psi of pressure. Far easier to create basically livable spaces (correct pressure and temperature to not immediately kill you) than in vacuum, without so much risk of structural failure turning areas deadly within seconds. - Basic resources for life --- human and agricultural --- still readily available in large quantities, even if requiring some additional processing. Water, oxygen, and highly importantly: soil, containing the immensely complex mix of trace nutrients needed for life, are all available in massive quantities from day one. - Transport: a lot easier to get people to on-Earth disaster shelters, both in order to save those people and to bring helpful expertise on site, than year-long journeys requiring expending a few typical lifetime's worth of energy/resources for each individual. - Prior to a hypothetical disaster, all construction/testing/development takes place with the ease of doing things on Earth. - Terraforming: over many decades, the Earth will pretty much automatically recover ecosystems, and terraform itself back into a hospitable planet. Although re-emerging ecosystems will be quite different (with initially greatly reduced biodiversity), in just about any conceivable "planetary extinction" scenario there is still plenty of raw material for surviving life forms to repopulate. Scatter tons of seeds on Mars, and they shrivel and die; but even if you razed every square inch of the Earth's surface with fire, everything is still teeming with viable life. This is based on "substantiated past events" that you seem to insist on. - Political support: Earth-based disaster shelters, that can save large numbers of Earth-dweller's lives from catastrophic events, are much more likely to gain political support for the necessary massive expenditures by Earth-dwellers.
Making colonies on Mars may not be "impossible," but it's damn hard --- and isn't a better solution to the types of problems it's supposed to fix ("eggs in one basket") than applying considerably less resources to the far easier (yet still very hard) tasks of making "disaster-proof shelters" that could assure survival of large numbers of humans on Earth in the case of global extinction type events.
The "avoid mass extinction event" reasoning is basically rubbish. If we have the technology to survive on the surface of Mars --- no water, air, or food except what you bring and raise in your sealed habitats; open a window and you die --- then we can survive the very worst planetary extinction events right here on Earth. Giant meteor smashes into the planet; toxic dust cloud blocks out 50% of sunlight; ecosystems thrown into havoc; flaming ashy death raining down from the skies for decades? *Still* easier to survive than Mars. The engineering know-how to create sustainable human habitats on Mars could do much more on Earth, even in such a worst-case scenario.
All the recent Russian meteor did was remind me of how gigantic a panic is made over extremely rare events, causing very little harm, while millions of people are dying from much easier to fix problems. We can start worrying about once-in-a-million-years vague possibilities after we've solved the issue of murdering each other for profit on a daily basis.
From a practicality perspective, moving enough dirt and making a stable dome structure that can hold up the weight of ~10m overburden is a lot harder than just digging tunnels (or using existing cave / lava tube structures) --- if you can move and reinforce enough dirt for 10m over the living space volume, then you could more easily tunnel out and reinforce a 4m-high underground habitat.
Of course, "practicality" isn't really a concern for Mars Colony considerations, because a Mars Colony is a stupid and impractical idea (at least at anywhere near our current level of technology). There are a lot of easier places to colonize/survive on Earth: deep underground; the ocean floor; etc. --- all of these are technologically far easier than Mars, yet still daunting challenges. Send rovers to Mars for science.
Note that the earth's atmosphere, at ~15psi sea level pressure, is equivalent to being under ~10m of water. While there's less solar irradiation at the surface of Mars, there's also not much of a magnetosphere to divert lots of charged radiation. So, to rough order of magnitude, one would need about the same amount of shielding as offered by Earth's atmosphere: about fifteen pounds of material per square inch, requiring a shell on order of 10 meters thick. That's a lot of material to melt/form! We're not talking about a couple-inch-thick shell, but an extremely thick and heavy structure. Tunneling underground would be a much more practical way to accomplish this than trying to sinter new structures on the surface. Of course, that doesn't fix the problem of dangerous doses on the trip over.
Bottom line, Mars is an extremely hostile environment for humans --- it won't be an attractive location for large-scale human habitation until we've overpopulated the much more attractive and liveable regions like the Antarctic continent and the entire ocean floor (and, based on current trends, population growth will turn around well before then). And, for pure science research purposes, remote robotic rovers are already super awesome (and will only continue to get better in the future); far preferable to sending humans.
If you said "billions and billions of random events occurred to create anti-entropic self-organizing entities" people would say "well, Occam's Razor says no."
If you said that in a world where we have no evidence for such self-organizing principles to occur, then that would be a crazy leap to make. But, in our world, we have abundant data for self-organizing systems developing and increasing in complexity. Specifics in a few gaps are missing, but the overall framework is certainly there for explaining the generation of life from "chance interactions" between organic precursor molecules demonstrated to form "spontaneously" under early-earthlike conditions. "Occam's Razor" calls for explaining all the *known data* with a "minimalist" set of additional assumptions --- do you have a better "minimalist" explanation for our currently known data backing our understanding of chemistry, biology, evolution? Note, saying "the great invisible space lemur did it" isn't particularly "minimalist," since you've just required introducing a very complex and powerful entity with little empirical support.
The problem with this approach is that it only works in cases where the researcher already has the clout to publish open-access in the first place. You clearly want to publish open-access --- as any academic will. But why don't you already? Perhaps because there are pressures "from above" to publish-or-perish in particular prestigious (but closed) journals. Any researcher who is currently "unable" to publish open access because of forces against their will would still be unable with $1 California grants being handed out: whoever is currently keeping you from publishing open access would have your ass for making a "stupid move" like applying/accepting a $1 grant with strings attached (you'd probably be compelled to drop the grant and give back the dollar). To fix the problem, we need to get *your own* funding sources (and/or those in positions to currently prevent your open-access publication) to get on board the open-access bandwagon.
I personally agree. And, in my opinion, you could spend $1M to put together ~20 really high quality educational astronomy setups, truck them around the country, and bus students out from urban areas to proper viewing sites --- to give a lot more kids some really awesome hands-on work with a nice telescope setup. I think "getting pictures from a space telescope" would be more exciting to kids (at levels not advanced enough to appreciate much more than the "ooh, pretty" factor) than "getting pictures from a more advanced remote-operated dark-site telescope," but hands-on looking through the eyepiece of a 6" apo refractor or 12" Dobsonian would be even better (plus doing some real science with simple instrumentation attached to said scopes).
Wait, so you figured out how to reduce some impacts of diffraction (sounds like you've re-invented apodization, which is nothing new at all) --- and that's why you think camera lenses will have *more* diffraction (larger diffraction-limited spot size, ~20-30um) than what "plain physics" says (~5um)? In your world, is 30 a smaller number than 5? And where can I get some of the plants you've been "testing" with your bong?
They say "public access," not "free access" --- this'll be a pay-to-play "tourist attraction," with some time handed out free* (*paid by donations/grants, or the taxpayer as a tax write-off) for education/outreach. It'll be available "to the public" in the sense that anyone in the public can plop down a couple hundred bucks per snapshot from it (as opposed to needing to write a grant through a research institution). So you won't be getting any "Galactic Street View" time slots on this telescope unless you're willing to pay, which will limit the demand to the available supply.
Since the popularization of adaptive optics, the atmosphere has become much less of a problem. Before adaptive optics, you were strongly limited in how big a telescope would be useful for resolving power --- even on a perfectly clear night, atmospheric fluctuations would cause different parts of your big telescope aperture to see different areas of the sky, destroying any resolution advantage over smaller scopes (though you at least still got more light for a brighter blurry picture). But now, with adaptive optics, you can make your earth-based telescope as big as you want (or can afford). This project is not a good deal for raw telescope performance --- for $1M, you could get a *much* better terrestrial telescope, remotely located in an optimal dark site (or a few sites around the world). The $1M cost of this one is for the outreach/publicity impact of being in space, not the raw data-taking capability.
Space telescopes are still useful for imaging outside the visible spectrum, in ranges that are blocked or washed out by the atmosphere. You can't get the Spitzer space telescope's deep-IR capabilities from earth-bound devices. And, a whole lot of the useful scientific information for astronomy is outside the visible band. Space telescopes also have no background from scattered atmospheric light, so you can see far dimmer objects that would be washed-out by background on even the darkest earth viewing; but taking advantage of this requires a considerably bigger/better telescope and sensor package than this low-budget project.
$10k is a bit low for a top-notch 8"+ amateur refractor, but a $50k budget (and serious amateur astronomy setups do get up into this range) should get you a setup that will be more capable than this telescope *on a good seeing night at a dark sky location*.
The telescope itself isn't, in this case, a groundbreaking state-of-the-art super-expensive instrument. It's a reasonably nice 'scope by amateur astronomy standards, and the viewing from space is great --- but the main point of this project is education/outreach. For a million bucks, you can build a lot more capable telescope on earth (including a dark site location); but that might not have the awesomeness factor to eighth-graders as controlling a space telescope for their class project. If you want a space telescope with groundbreaking scientific capabilities that you can't get (at any price) from Earth, you might need $1e9 dollars; but $1e6 (plus a whole lot of free mission/design support that would get counted in the budget of a $1e9 project) seems reasonable for putting an "advanced amateur" telescope in space.
??? I'm not even sure what you're trying to say here?
In your post above, you seemed to be indicating that a 20-30um spot size was close to the diffraction limit. This is simply false; I gave an example (lens with f8 aperture, at mid-visible-spectrum green light) showing that diffraction limits are significantly smaller than 20-30um. Good lenses both "then" (in the film days) and now have significantly higher resolution than 30um spot sized --- diffraction-limited at f8 (~6um spot size) is relatively commonplace, and some best-of-class film-era lenses can reach f4 diffraction limits (~3um spot sizes). Such resolutions are out of the range of typical color film emulsions (which had to be somewhat thick to permit multiple color layers, fundamentally limiting resolution), but possible to measure with special-purpose black and white films. Hence, even back in the film days, good lenses were designed to high specifications --- better than the color film could use, and also plenty high resolution for today's high-resolution digital sensors.
The older Canon lens actually has L series glass in it
There's no such thing. The "L" designation is just a marketing/branding designation by which Canon identifies their higher-end products; it's not a particular type of material or manufacturing process. The only thing that makes one lens "L series glass" and another not is whether Canon decides to call it so, and puts a red ring on the lens.
GP post is correct when referring to Canon FD-series lenses, the manual-focus predecessor to the autofocus EF mount. The FD lens mount was closer to the film plane than the EF mount, so you can't fit old Canon FD lenses onto EF (or EF-S, same physical dimensions) mounts without either additional compensating optics, or physically modifying the lens mount to shorten the optical path. Some FD telephotos have enough extra adjustment range for the focus that they can be used with thin, optics-free adapters.
Diffraction limit spot size at f=8 for 560nm light is d ~ 1.22*lambda*f = 5.3 microns (first null of Airy disk). A 30um circle of confusion is basically a spec for 4x5 inch prints (at ~300dpi), not the limits of film or lenses. So, you can do a lot better than 30um (by ~10x, for the very best commercially available lenses diffraction limited at ~f4). Color film is not higher resolution than 24+ Megapixel digital cameras; but that is besides the main point --- good quality older lenses significantly exceeded the resolving power of color film even back in the film days, as tested on higher-resolution black and white films or direct optical bench measurements.
No, this is a specific example of military-industrial complex "efficiency" --- a particular order that combines the very worst of private monopolistic greed with unaccountable, secretive, wasteful spending. Governments tend to be rather efficient (much more than private markets) at supplying *public goods* like roads, healthcare, education, transportation, infrastructure, utilities, etc. --- things with clear public benefits easily evaluated by the public. Joe Citizen can tell when his roads have potholes, his tapwater tastes like ass, his kids have a lousy school, and he can't get decent medical care; and this will show at the next election. Few people who support increased government spending for public good are also big fans of handing blank checks to the military-industrial complex to build the next generation murder-machine boondoggle; generally, the most enthusiastic supporters of unchecked military spending are the same folks who rail against any publicly beneficial forms of government spending (since they are ideologically committed to proving government is a failure, by making it so whenever they get in power).
When done as part of a long, slow cycle of rotating between different locations --- where patches of land have decades to recover between burnings --- "slash and burn" agriculture is actually a highly sustainable system (that has worked continuously for hundreds to thousands of years in some parts of the world). The problem is when slash-and-burn traditions are combined with corralling traditionally wide-ranging groups of people onto tiny demarcated sections of land ("why should those stupid peasants need all that empty forest they aren't using at all?") --- so the same parcel of land gets burned over and over, without recovery, and rapidly is turned into desolate wasteland.
This *is* about the market (and Western investors jumping onto the land/resources grab to expropriate everything of agricultural value). Imperialists coming in to map your resources is like burglars snooping around to case a joint --- "we're just peeping through the windows to help survey the quantity and location of valuables in this house."
Improving agriculture through scientific management of soil resources can be a good thing --- but the good is gained when this knowledge is *disseminated to help the people,* not *concentrated to help the wealthy.* Instead of mapping soils to fill a comprehensive UN almanac, spread resources (simple equipment and knowledge) so that *local communities* can *map their own soil,* and manage/improve their own resources (no need to centralize the information on a continental scale). Investors in London, Berlin, and New York should not be the ones to know soil conditions --- the farmers and communities *living on top of the soil* are the ones who should be empowered to collect and interpret this information.
They need to repeat that phrase over and over again, because the *real* use will be to help Western mega-agribusiness "investors" rape the fucking shit out of the land, destroying anything of value to the local inhabitants in pursuit of quick profit. Giving a warm-fuzzy justification for the mapping helps sell the project better than "ADM will know *exactly* where to target campaigns to expel locals from the most valuable resources for producing products to ship overseas for more profitable sales (padding investors' pockets, while the indigenous population starves even more)".
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One further followup: so far as humankind "RIGHT FUCKING NOW" is the kind of species that is *willing and able* to bring about *global extinction,* then I don't want humankind to survive and spread into the universe "RIGHT FUCKING NOW". If humans are necessarily as terrible as you posit, then the only ethical thing to do would be to sabotage --- by whatever means necessary --- humankind's ability to spread (at least until they become something else). Like the German resistance fighters against the Nazis, only trying to prevent future *interplanetary holocaust* by a species that, at all costs, must be stopped. I don't think humankind is all that bad --- but if you do, why do you consider it such a noble prerogative to preserve the species?
Yes, that's the kind of more pressing problem that I think it's more important for humanity to buckle down and deal with than Mars colonization. And it won't help to be burning an extra gazillionty-zillion gallons of fuel for rich folks to gallivant about in space.
Disastrous global ecosystem changes from climate change --- while a terrible thing from which billions will suffer in starvation and war --- isn't a "wipes out humanity" type of event (even in rather pessimistic predictions). It's certainly not worth *accelerating the pace* of climate change to get a few people on Mars (still *far, far* less inhabitable than a climate-change ravished Earth). So, if you're looking for a "save humanity" type project over the next couple centuries: yes, you should be far more worried about climate change than Mars colonization. But it seems that you're only "worried" about climate change so far as you can use it for an argument for Mars colonization --- and imagine leaving everyone on Earth to rot in misery so long as you and/or your children can make it to Mars.
If enough humans can't survive on Earth with poor outdoor crop yields, unpleasant temperatures, and bad weather, then we won't be surviving on Mars (where the weather forecast is "You die, puny human!" 24/7/697).
Because humaity will have to fucking EVOLVE before those problems go away, and mars one is RIGHT FUCKING NOW
Global extinction events only occur on "evolutionary" timescales. You're "hedging bets" against events that might occur between once in a million and once in a billion years. Thinking on "humans can evolve" timescales is perfectly appropriate for thinking about addressing events that occur on "we'll be a completely different species by then" timescales. Yes, I think people/society will need to "evolve" (hopefully on a much faster "memetic evolution" timescale of changing ideas than "genetic evolution" timescales) to solve problems --- but "we've got time" (with high statistical probability) before a "planet-killer" shows up. So, in the meantime, I prefer solutions that involve working towards a better, more "evolved" humanity, able to deal with the problems we have *on Earth*. Turning Mars into a new Wild West frontier for a select few to escape is not particularly a useful step along the way to "evolution" of a more robust society. Focusing resources on making Earth habitable enough (and humans good enough neighbors) that humankind won't slaughter each other back to the iron ages over the next few millennia is, in my opinion, a more pressing matter than sending some yahoos to spread capitalist violence to the next planet "RIGHT FUCKING NOW." And, I think, if humankind can progress towards more "evolved" forms of organization, it will be far easier (and far more *worthy a project*) to do "adventurous" things like living in space in the "evolved" future.
Yes, you can find a quarter of a million people eager to be groundbreaking new explorers on the adventurous forefront. But I bet if there were already 249,999 people scraping by on a Mars colony, that you'd have a harder time finding eager applicants to go on a one-way suicide mission to be the 250,000th person doomed to die on Mars. A Mars colony is conceptually exciting to a lot of people now because it is new, and expensive, and a rare distinction. But the *desirability* of heading to a Mars colony is roughly inversely proportional to the *usefulness* of a Mars colony: as a colony heads towards being a routine, self-sufficient, boring place, the only people eager to get there are people in much more dire conditions on Earth (and, with the resources required to get such a person to Mars, you could give them a fantastically luxurious life on Earth --- which they'd likely prefer once the initial "got there first!" charm of Mars wore off).
How many people on that list of brave Mars volunteers would be equally happy to trade their life savings, and their life, for a chance to live a couple years before dying on the shores of Antarctica? A trip like that was once the forefront of human exploration --- and the brave, bold, and proud would risk their very lives in perilous journeys to reach the South Pole. But now it's boring and routine; some people are willing to winter over to run scientific experiments in Antarctica, but no one is lining up to sacrifice their life for the opportunity.
After you strip away the hype and hubris of those selfishly wanting to be immortalized in the pages of history, Mars isn't so hot as a practical solution to potential real problems. So, yes, you can find a lot of eager support for Mars --- but that doesn't mean you've found a lot of people being smart and rational about the subject. All you've proved is that a spectacularly flashy suicide is an attractive prospect to many.
1) these structures must already exist, when no apparent threat is known of.
Just like a Mars colony. Only several orders of magnitude less expensive to build per inhabitant.
2) people must be actively livng inside them when the calamity hits.
Just like a Mars colony. Only you've also got a lot more time/resources to move many more people into said structures, in addition to the skeleton crew needed to keep them prepared.
3) the structures must survive the initial upheval and chaos of the calamity.
Yep, just like a Mars colony would have to be able to adapt and carry on after being cut off from all Earth support.
By your own logic, 1) will never happen until humans stop being humans, because it is a big todo about "nothing".
Just like a Mars colony; only Earthbound shelters offer a much better "return on investment" --- much lesser resources required to make a lot more people likely to survive major disaster. So, if you're actually worried about saving some humans in the event of "extinction type" events, then you'd be enthusiastic about much more efficient and effective Earth-based solutions. Of course, "manifest destiny" space nutters have deep-seated irrational concepts that "live on Mars!" must be the one true solution to problems, instead of considering much more practical steps to achieve the same supposed ends.
Yes, I think protecting against once-in-millions-of-years to once-in-trillions-of-years events is a poor use of humankind's present resources, when "everyday" problems are much more pressing. However, for anyone who does want to get a head start on protecting against hypothetical disasters, you might want to employ far more practical (better chance of success for less resources invested) approaches like building self-sustainable "sealed" habitats on Earth --- unless the entirety of your scientific knowledge and engineering judgment comes from reading Sci-Fi fantasies.
Also, your rebuttle of the extinction reason for building the colony is not well established, and is easily picked apart, since it is based on suppositions, and not substantiated past events, ad relies heavily on magical thinking that humans are magically capable of adapting to anything (that isn't on mars of course!).
Not sure where you're getting the "magical thinking" or "assuming that humans are capable of adapting to anything" from my post above, but here are some basic science/engineering reasons why a worst-case Earth (atmosphere not directly breathable; solar input reduced to Martian levels by dust; death of most biomass) is still easier to deal with (without need for "magic"):
- Atmospheric pressure still exists. Habitation structures only need to block/filter undesirable atmospheric contaminants; not also hold 15psi of pressure. Far easier to create basically livable spaces (correct pressure and temperature to not immediately kill you) than in vacuum, without so much risk of structural failure turning areas deadly within seconds.
- Basic resources for life --- human and agricultural --- still readily available in large quantities, even if requiring some additional processing. Water, oxygen, and highly importantly: soil, containing the immensely complex mix of trace nutrients needed for life, are all available in massive quantities from day one.
- Transport: a lot easier to get people to on-Earth disaster shelters, both in order to save those people and to bring helpful expertise on site, than year-long journeys requiring expending a few typical lifetime's worth of energy/resources for each individual.
- Prior to a hypothetical disaster, all construction/testing/development takes place with the ease of doing things on Earth.
- Terraforming: over many decades, the Earth will pretty much automatically recover ecosystems, and terraform itself back into a hospitable planet. Although re-emerging ecosystems will be quite different (with initially greatly reduced biodiversity), in just about any conceivable "planetary extinction" scenario there is still plenty of raw material for surviving life forms to repopulate. Scatter tons of seeds on Mars, and they shrivel and die; but even if you razed every square inch of the Earth's surface with fire, everything is still teeming with viable life. This is based on "substantiated past events" that you seem to insist on.
- Political support: Earth-based disaster shelters, that can save large numbers of Earth-dweller's lives from catastrophic events, are much more likely to gain political support for the necessary massive expenditures by Earth-dwellers.
Making colonies on Mars may not be "impossible," but it's damn hard --- and isn't a better solution to the types of problems it's supposed to fix ("eggs in one basket") than applying considerably less resources to the far easier (yet still very hard) tasks of making "disaster-proof shelters" that could assure survival of large numbers of humans on Earth in the case of global extinction type events.
The "avoid mass extinction event" reasoning is basically rubbish. If we have the technology to survive on the surface of Mars --- no water, air, or food except what you bring and raise in your sealed habitats; open a window and you die --- then we can survive the very worst planetary extinction events right here on Earth. Giant meteor smashes into the planet; toxic dust cloud blocks out 50% of sunlight; ecosystems thrown into havoc; flaming ashy death raining down from the skies for decades? *Still* easier to survive than Mars. The engineering know-how to create sustainable human habitats on Mars could do much more on Earth, even in such a worst-case scenario.
All the recent Russian meteor did was remind me of how gigantic a panic is made over extremely rare events, causing very little harm, while millions of people are dying from much easier to fix problems. We can start worrying about once-in-a-million-years vague possibilities after we've solved the issue of murdering each other for profit on a daily basis.
From a practicality perspective, moving enough dirt and making a stable dome structure that can hold up the weight of ~10m overburden is a lot harder than just digging tunnels (or using existing cave / lava tube structures) --- if you can move and reinforce enough dirt for 10m over the living space volume, then you could more easily tunnel out and reinforce a 4m-high underground habitat.
Of course, "practicality" isn't really a concern for Mars Colony considerations, because a Mars Colony is a stupid and impractical idea (at least at anywhere near our current level of technology). There are a lot of easier places to colonize/survive on Earth: deep underground; the ocean floor; etc. --- all of these are technologically far easier than Mars, yet still daunting challenges. Send rovers to Mars for science.
Note that the earth's atmosphere, at ~15psi sea level pressure, is equivalent to being under ~10m of water. While there's less solar irradiation at the surface of Mars, there's also not much of a magnetosphere to divert lots of charged radiation. So, to rough order of magnitude, one would need about the same amount of shielding as offered by Earth's atmosphere: about fifteen pounds of material per square inch, requiring a shell on order of 10 meters thick. That's a lot of material to melt/form! We're not talking about a couple-inch-thick shell, but an extremely thick and heavy structure. Tunneling underground would be a much more practical way to accomplish this than trying to sinter new structures on the surface. Of course, that doesn't fix the problem of dangerous doses on the trip over.
Bottom line, Mars is an extremely hostile environment for humans --- it won't be an attractive location for large-scale human habitation until we've overpopulated the much more attractive and liveable regions like the Antarctic continent and the entire ocean floor (and, based on current trends, population growth will turn around well before then). And, for pure science research purposes, remote robotic rovers are already super awesome (and will only continue to get better in the future); far preferable to sending humans.
If you said "billions and billions of random events occurred to create anti-entropic self-organizing entities" people would say "well, Occam's Razor says no."
If you said that in a world where we have no evidence for such self-organizing principles to occur, then that would be a crazy leap to make. But, in our world, we have abundant data for self-organizing systems developing and increasing in complexity. Specifics in a few gaps are missing, but the overall framework is certainly there for explaining the generation of life from "chance interactions" between organic precursor molecules demonstrated to form "spontaneously" under early-earthlike conditions. "Occam's Razor" calls for explaining all the *known data* with a "minimalist" set of additional assumptions --- do you have a better "minimalist" explanation for our currently known data backing our understanding of chemistry, biology, evolution? Note, saying "the great invisible space lemur did it" isn't particularly "minimalist," since you've just required introducing a very complex and powerful entity with little empirical support.
The problem with this approach is that it only works in cases where the researcher already has the clout to publish open-access in the first place. You clearly want to publish open-access --- as any academic will. But why don't you already? Perhaps because there are pressures "from above" to publish-or-perish in particular prestigious (but closed) journals. Any researcher who is currently "unable" to publish open access because of forces against their will would still be unable with $1 California grants being handed out: whoever is currently keeping you from publishing open access would have your ass for making a "stupid move" like applying/accepting a $1 grant with strings attached (you'd probably be compelled to drop the grant and give back the dollar). To fix the problem, we need to get *your own* funding sources (and/or those in positions to currently prevent your open-access publication) to get on board the open-access bandwagon.
I personally agree. And, in my opinion, you could spend $1M to put together ~20 really high quality educational astronomy setups, truck them around the country, and bus students out from urban areas to proper viewing sites --- to give a lot more kids some really awesome hands-on work with a nice telescope setup. I think "getting pictures from a space telescope" would be more exciting to kids (at levels not advanced enough to appreciate much more than the "ooh, pretty" factor) than "getting pictures from a more advanced remote-operated dark-site telescope," but hands-on looking through the eyepiece of a 6" apo refractor or 12" Dobsonian would be even better (plus doing some real science with simple instrumentation attached to said scopes).
Wait, so you figured out how to reduce some impacts of diffraction (sounds like you've re-invented apodization, which is nothing new at all) --- and that's why you think camera lenses will have *more* diffraction (larger diffraction-limited spot size, ~20-30um) than what "plain physics" says (~5um)? In your world, is 30 a smaller number than 5? And where can I get some of the plants you've been "testing" with your bong?
They say "public access," not "free access" --- this'll be a pay-to-play "tourist attraction," with some time handed out free* (*paid by donations/grants, or the taxpayer as a tax write-off) for education/outreach. It'll be available "to the public" in the sense that anyone in the public can plop down a couple hundred bucks per snapshot from it (as opposed to needing to write a grant through a research institution). So you won't be getting any "Galactic Street View" time slots on this telescope unless you're willing to pay, which will limit the demand to the available supply.
Since the popularization of adaptive optics, the atmosphere has become much less of a problem. Before adaptive optics, you were strongly limited in how big a telescope would be useful for resolving power --- even on a perfectly clear night, atmospheric fluctuations would cause different parts of your big telescope aperture to see different areas of the sky, destroying any resolution advantage over smaller scopes (though you at least still got more light for a brighter blurry picture). But now, with adaptive optics, you can make your earth-based telescope as big as you want (or can afford). This project is not a good deal for raw telescope performance --- for $1M, you could get a *much* better terrestrial telescope, remotely located in an optimal dark site (or a few sites around the world). The $1M cost of this one is for the outreach/publicity impact of being in space, not the raw data-taking capability.
Space telescopes are still useful for imaging outside the visible spectrum, in ranges that are blocked or washed out by the atmosphere. You can't get the Spitzer space telescope's deep-IR capabilities from earth-bound devices. And, a whole lot of the useful scientific information for astronomy is outside the visible band. Space telescopes also have no background from scattered atmospheric light, so you can see far dimmer objects that would be washed-out by background on even the darkest earth viewing; but taking advantage of this requires a considerably bigger/better telescope and sensor package than this low-budget project.
$10k is a bit low for a top-notch 8"+ amateur refractor, but a $50k budget (and serious amateur astronomy setups do get up into this range) should get you a setup that will be more capable than this telescope *on a good seeing night at a dark sky location*.
The telescope itself isn't, in this case, a groundbreaking state-of-the-art super-expensive instrument. It's a reasonably nice 'scope by amateur astronomy standards, and the viewing from space is great --- but the main point of this project is education/outreach. For a million bucks, you can build a lot more capable telescope on earth (including a dark site location); but that might not have the awesomeness factor to eighth-graders as controlling a space telescope for their class project. If you want a space telescope with groundbreaking scientific capabilities that you can't get (at any price) from Earth, you might need $1e9 dollars; but $1e6 (plus a whole lot of free mission/design support that would get counted in the budget of a $1e9 project) seems reasonable for putting an "advanced amateur" telescope in space.
??? I'm not even sure what you're trying to say here?
In your post above, you seemed to be indicating that a 20-30um spot size was close to the diffraction limit. This is simply false; I gave an example (lens with f8 aperture, at mid-visible-spectrum green light) showing that diffraction limits are significantly smaller than 20-30um. Good lenses both "then" (in the film days) and now have significantly higher resolution than 30um spot sized --- diffraction-limited at f8 (~6um spot size) is relatively commonplace, and some best-of-class film-era lenses can reach f4 diffraction limits (~3um spot sizes). Such resolutions are out of the range of typical color film emulsions (which had to be somewhat thick to permit multiple color layers, fundamentally limiting resolution), but possible to measure with special-purpose black and white films. Hence, even back in the film days, good lenses were designed to high specifications --- better than the color film could use, and also plenty high resolution for today's high-resolution digital sensors.
I remember that --- yay for mirror lockup and flash exposure compensation!
The older Canon lens actually has L series glass in it
There's no such thing. The "L" designation is just a marketing/branding designation by which Canon identifies their higher-end products; it's not a particular type of material or manufacturing process. The only thing that makes one lens "L series glass" and another not is whether Canon decides to call it so, and puts a red ring on the lens.
GP post is correct when referring to Canon FD-series lenses, the manual-focus predecessor to the autofocus EF mount. The FD lens mount was closer to the film plane than the EF mount, so you can't fit old Canon FD lenses onto EF (or EF-S, same physical dimensions) mounts without either additional compensating optics, or physically modifying the lens mount to shorten the optical path. Some FD telephotos have enough extra adjustment range for the focus that they can be used with thin, optics-free adapters.
Diffraction limit spot size at f=8 for 560nm light is d ~ 1.22*lambda*f = 5.3 microns (first null of Airy disk). A 30um circle of confusion is basically a spec for 4x5 inch prints (at ~300dpi), not the limits of film or lenses. So, you can do a lot better than 30um (by ~10x, for the very best commercially available lenses diffraction limited at ~f4). Color film is not higher resolution than 24+ Megapixel digital cameras; but that is besides the main point --- good quality older lenses significantly exceeded the resolving power of color film even back in the film days, as tested on higher-resolution black and white films or direct optical bench measurements.
No, this is a specific example of military-industrial complex "efficiency" --- a particular order that combines the very worst of private monopolistic greed with unaccountable, secretive, wasteful spending. Governments tend to be rather efficient (much more than private markets) at supplying *public goods* like roads, healthcare, education, transportation, infrastructure, utilities, etc. --- things with clear public benefits easily evaluated by the public. Joe Citizen can tell when his roads have potholes, his tapwater tastes like ass, his kids have a lousy school, and he can't get decent medical care; and this will show at the next election. Few people who support increased government spending for public good are also big fans of handing blank checks to the military-industrial complex to build the next generation murder-machine boondoggle; generally, the most enthusiastic supporters of unchecked military spending are the same folks who rail against any publicly beneficial forms of government spending (since they are ideologically committed to proving government is a failure, by making it so whenever they get in power).
When done as part of a long, slow cycle of rotating between different locations --- where patches of land have decades to recover between burnings --- "slash and burn" agriculture is actually a highly sustainable system (that has worked continuously for hundreds to thousands of years in some parts of the world). The problem is when slash-and-burn traditions are combined with corralling traditionally wide-ranging groups of people onto tiny demarcated sections of land ("why should those stupid peasants need all that empty forest they aren't using at all?") --- so the same parcel of land gets burned over and over, without recovery, and rapidly is turned into desolate wasteland.
This *is* about the market (and Western investors jumping onto the land/resources grab to expropriate everything of agricultural value). Imperialists coming in to map your resources is like burglars snooping around to case a joint --- "we're just peeping through the windows to help survey the quantity and location of valuables in this house."
Improving agriculture through scientific management of soil resources can be a good thing --- but the good is gained when this knowledge is *disseminated to help the people,* not *concentrated to help the wealthy.* Instead of mapping soils to fill a comprehensive UN almanac, spread resources (simple equipment and knowledge) so that *local communities* can *map their own soil,* and manage/improve their own resources (no need to centralize the information on a continental scale). Investors in London, Berlin, and New York should not be the ones to know soil conditions --- the farmers and communities *living on top of the soil* are the ones who should be empowered to collect and interpret this information.
They need to repeat that phrase over and over again, because the *real* use will be to help Western mega-agribusiness "investors" rape the fucking shit out of the land, destroying anything of value to the local inhabitants in pursuit of quick profit. Giving a warm-fuzzy justification for the mapping helps sell the project better than "ADM will know *exactly* where to target campaigns to expel locals from the most valuable resources for producing products to ship overseas for more profitable sales (padding investors' pockets, while the indigenous population starves even more)".