Wikipedia:Reference desk/Archives/Science/2012 April 7

= April 7 =

How much extreme weather damage can the world economy take?
The international reinsurance company Munich Re says that the amount of damage from extreme weather tripled from 1980 to 2010, and they expect that trend to continue. Assuming that remains true, (1) how long until the damage from extreme weather causes the world economy to collapse? And, (2) assuming global wind power growth continues along its current trend, will it prevent such a collapse in time? 71.215.74.243 (talk) 02:52, 7 April 2012 (UTC)


 * At some point neither private companies not governments will be able to insure people living in high risk areas, like below sea level in a place regularly hit by hurricanes. This will result in people no longer being able to get mortgages to build there, and will thus limit damages from future storms, restoring the balance. StuRat (talk) 03:09, 7 April 2012 (UTC)


 * So do you think the world economy can absorb an infinite amount of storm damage? 71.215.74.243 (talk) 11:07, 7 April 2012 (UTC)


 * No, but an infinite amount of storm damage isn't possible, so that's pointless to worry about. You seem to be making a common extrapolation error.  Whenever anything is increasing, all you have to do is assume it will forever increase at the same rate to conclude that it will eventually become infinite.  The assumption that anything which is currently increasing must therefore increase forever is fundamentally flawed. StuRat (talk) 17:10, 7 April 2012 (UTC)


 * I agree. Let me rephrase my question: If the amount of economic damage from extreme weather continued to tripple every 30 years, do you think the world economy would still remain functioning indefinitely? Or are you saying that the damage must eventually level off before it causes economic collapse? 71.215.74.243 (talk) 22:20, 7 April 2012 (UTC)


 * Yes, it will level off or even reduce. For example, now that global warming is fairly well established, people will eventually stop building on eroding coastlines. StuRat (talk) 22:33, 7 April 2012 (UTC)


 * The premise is false. Data from impartial sources show that there's no such increasing trend.
 * Also the global wind power cumulative capacity can't grow forever either, since the total amount of available wind power on Earth is limited. Anonymous.translator (talk) 03:18, 7 April 2012 (UTC)


 * You don't think that graph you linked to shows a trend? Wind power can't grow forever but there is enough for dozens of times expected human needs even assuming everyone started using US per-capita power. 71.215.74.243 (talk) 03:31, 7 April 2012 (UTC)


 * Looking at the dotted line, no, I don't see a clear increase. For most years the damage is roughly $10 billion while in the occasional "disastrous" years the damages spike up.Anonymous.translator (talk) 03:47, 7 April 2012 (UTC)


 * Do you think the average of the dotted line in, for instance, the first, middle, and most recent third of the graph comprises a trend? 71.215.74.243 (talk) 11:07, 7 April 2012 (UTC)


 * I'm pretty sure that as a publicly traded company whose core business is insurance, Munich Re has a legally mandated duty to be honest about the past claims they have honored and the future claims they expect. As a global company, I would expect they actually have a better picture of climate related losses than data that solely comes from the US.  That said, I seem to recall that Munich Re also blames most of the trend on increased human development in vulnerable areas, and relatively little of it on actual changes in weather conditions.  Dragons flight (talk) 05:11, 7 April 2012 (UTC)


 * One thing I left unstated is that most of the damage is due to people building in unsafe areas. Once we stop that, the problem is largely solved. StuRat (talk) 04:27, 7 April 2012 (UTC)


 * Yes. People need to remember such things as the fact that flood plains are for floods. HiLo48 (talk) 05:31, 7 April 2012 (UTC)


 * Indeed, Munich Re used to say that sort of thing, but not in the past several years. Their 2010 report linked above, for example, says, “In Germany, extreme precipitation resulting in floods is becoming increasingly common. This affects not only people living on rivers: there are more and more cases of heavy rain and flash floods. Anyone may be affected.” 71.215.74.243 (talk) 11:07, 7 April 2012 (UTC)


 * That's a rather meaningless statement, rather like saying that anybody can be struck by lightning, so you might as well play golf on top of a hill in a thunderstorm. While anyone can be affected by some type of bad weather, by no means is the risk equal in all locations, far from it.  StuRat (talk) 16:16, 7 April 2012 (UTC)


 * One line on that graph is normalized for inflation but not for population growth or overall real estate value. Wnt (talk) 15:44, 7 April 2012 (UTC)

Not much, and the weather doesn't have to get a lot more extreme overall. According to a recent BBC Horizon documentary, we're now seeing significantly more fluctuations in the weather, while the average has only shifted slightly due to global warming. The latter is driving the former. A prediction of climate models is that cyclones can hit places where they have sitorically never occurred, e.g. Dubai seems to be at risk of being washed into the ocean by a category 5 hurricane.

A small perturbation is enough to let the World economy crash, because the economy has been mismanaged anyway. We were about to hit a global depression, simply due to mismanagement in 2008. So, it's a bit like flying a plane that could theoretically fly to the thunderstorm, but with incompetent pilots flying it, it's already at risk of crashing due to pilot error when the weather is fine. Obviously, you then don't want to fly a plane with these pilots through thunderstorm.

What I forsee happening within a few decades, is droughts and floodings causing India and China to have to import huge amounts of rice and grain for a few years in a row. They have enough financial reserves to do so, but that would drive food prices up by so much that other countries will close their markets to prevent all their rice and grain from from being exported to India and China. That will then lead to collapse of free trade agreements and ultimately to the collapse of the World economy. Count Iblis (talk) 17:42, 7 April 2012 (UTC)


 * In that case, what they need is system to collect flood water and store it until the next drought. StuRat (talk) 18:25, 7 April 2012 (UTC)


 * So simple, yet so difficult! How should this be accomplished on the massive space and time scales necessary to help? Shall we start a lobby to subsidize rain barrels? SemanticMantis (talk) 19:21, 7 April 2012 (UTC)


 * In the case of underground aquifers, it may be as simple as redirecting rivers to refill them rather than draining to the sea. StuRat (talk) 19:47, 7 April 2012 (UTC)

Going back to the original question, I don't see what wind power has to do with any of this. Additionally, the correlation between severe weather events and global warming is unknown; indeed, we should see a reduction in Atlantic hurricanes in the next decade or two due to a downturn in the West African rainfall cycle. - Running On Brains (talk) 20:33, 7 April 2012 (UTC)


 * I've read many times that it's not simply the number of Atlantic hurricanes that matters; supposedly global warming is predicted to increase their average intensity -- fewer less intense ones combined with more very intense ones = more damage. Is that not right?


 * Also, the problem is not solved once we stop building in unsafe areas (although obviously that is important too). An amazing percentage of the world's population has already built in unsafe areas -- there are lots of hugely populated coastal cities (and for good reason since coastal cities can have ports).


 * I think the questioner's point about wind power was simply that, to the extent that wind power supplants CO2-releasing power generation, we can slow down or stop the growth of CO2 levels in the atmosphere. S/he is asking whether present trends in the growth of wind power usage are fast enough to do that before we reach a tipping point. I'm pessimistic about it, but it's not all-or-nothing -- increased use of wind power might delay or minimize the extreme-weather effects of CO2 even if not stopping them entirely. Duoduoduo (talk) 21:06, 7 April 2012 (UTC)
 * It could be true: certainly increasing the sea-surface temperatures in the absence of all external factors will increase the amount of latent heat available for the hurricanes to tap into, but I've seen studies that suggest that wind shear will increase dramatically over the tropical Atlantic with a warming planet, which would lead to less intense hurricanes. We simply don't have enough information to know for sure. One thing that is known, however, is that increasing sea levels will make residents increasingly vulnerable to the hurricanes that do occur. (I'm not talking Al Gore's nonsense about a 30m increase in sea levels: even a conservative estimate of 20 cm in the next 100 years could have devastating long-term impact.- Running On Brains (talk) 21:22, 7 April 2012 (UTC)
 * As far as wind power costs, even if the world managed to stop emitting fossil fuels in the next 20 years (an impossible goal, as China is clearly not going to try to stop burning coal any time soon), CO2 in the atmosphere is far from its steady state. The residence time of CO2 in the atmosphere is hundreds of years, so it would likely take thousands of years (without active intervention) to return atmospheric CO2 to it's current levels, never mind pre-industrial levels.- Running On Brains (talk) 21:30, 7 April 2012 (UTC)
 * We not only need to stop building in unsafe areas, but move away from them. Ports can remain (and be hardened against foul weather), but the rest of the city should be moved.  This will happen slowly, as storms destroy buildings in unsafe areas and the foolish people who built there are unable to get insurance and mortgages to rebuild there again.


 * Also, there's a natural life of a building, after which it would be rebuilt (except for a few historic sites). When the buildings in unsafe areas reach that age, nobody will be willing to risk their money to rebuild there. StuRat (talk) 21:19, 7 April 2012 (UTC)


 * The idea of moving away from the unsafe areas is interesting -- the Maldives, I've read, are shopping around in Australia for land they can eventually move their entire country to; and I read very recently that one of the South Pacific island nations is also shopping around for land. But these are tiny populations. It would take an extremely long time, with an extreme amount of social disruption and a massive amount of highly expensive infrastructure investment, to move everyone in say Mumbai farther inland. And then transportation costs to the port would be higher than now. So it's not going to happen to any significant extent, unless gradually rising sea levels concentrate people's minds to organize it. Duoduoduo (talk) 21:37, 7 April 2012 (UTC)


 * There's no need to move the entire city at once. Start with the coastal area, then gradually move inland.  This could all happen over a century.  For a case where it is happening rapidly, look at Christchurch, New Zealand, which has the misfortune of being on an active fault which destroyed the downtown area recently. StuRat (talk) 21:41, 7 April 2012 (UTC)


 * Moving away from unsafe areas would tend to limit property damages, but would have little effect on the global economy. As for the original question about weather and economics that comes down to fuel for both people and machines. When the weather sufficiently disrupts either supply, the economy will suffer. Wind power may slow the consumption of fossil fuel but will not replace it without some major technology advancements. Without that fuel (or a cheap replacement) the  global economy is doomed. MadCowpoke (talk) 04:37, 11 April 2012 (UTC)


 * Why would limiting property damage have little effect on the world economy ? StuRat (talk) 22:16, 11 April 2012 (UTC)


 * The economy will either shrink or grow. It is unlikely to remain flat unless population remains flat (also unlikely). If the desire is to increase the economy, say in the form of GDP, then demand has to increase to a new sustained level.  I'll use the Christchurch, New Zealand quake and some extremely simplified parameters as an example. Estimated damages; $25B, estimated GDP; $157B, estimated life-span of replaced property; 10yrs. The 1 year increase in GDP is 15%, however over the product lifespan it is only 1.5%. If I wear out my car every 10 years, or a flood destroys it every 10, it makes no difference. MadCowpoke (talk) 06:04, 12 April 2012 (UTC)

Male sexual activity and cognitive performance
How close have any studies come to establishing or disestablishing an effect of sexual activity on cognitive performance in men? Have there at least been correlational studies that controlled for the confounding fetal-androgen effect, or lab studies using the same combination of hormones that are released in orgasm? Neon Merlin  10:18, 7 April 2012 (UTC)
 * What kind of cognitive performance? is a recent review, and  is an example study controlling for fetal androgen exposure.  includes the study of prolactin, which is the only hormone conclusively shown to be released during male orgasm. 71.215.74.243 (talk) 11:38, 7 April 2012 (UTC)

Physics LC circuit
The natural frequency of LC circuit is 1 kHZ. How do we reduce it to 0,5 kHZ, using the equation: natural frequency = 1/(2 π sqrt{LC}) I think duplicating the T (2 π sqrt{LC}) is not the correct answer? Thank you in advance!--Atacamadesert12 (talk) 17:40, 7 April 2012 (UTC) — Preceding unsigned comment added by Atacamadesert12 (talk • contribs) 17:39, 7 April 2012 (UTC)
 * if you want the frequency to be halved then 1/(2 π sqrt{LC})  needs to be halved, i.e. LC needs to be four times as large. Dmcq (talk) 19:41, 7 April 2012 (UTC)
 * Or you could increase the value of 2π - Running On Brains (talk) 20:21, 7 April 2012 (UTC)
 * Double it, to be precise, so π ≈ 6.28318530717958647652528677. Whoop whoop pull up Bitching Betty 20:26, 7 April 2012 (UTC)

Electronics on board Apollo 11 spacecraft
What were the specifications of the Apollo 11 spacecrafts' electronics? By this, I mean the motherboard, memory, processor, etc. Also, how differently would the spacecraft have been designed if it were designed today with modern electronics?--99.179.20.157 (talk) 18:40, 7 April 2012 (UTC)


 * Apollo Guidance Computer is a good start. Almost everything would be different if implemented today; not least you wouldn't have a room full of ladies hand-knitting the program. -- Finlay McWalterჷTalk 18:43, 7 April 2012 (UTC)
 * It was the memory core that got hand-knitted, not the program.--Aspro (talk) 19:02, 7 April 2012 (UTC)
 * Maybe your right Core rope memory--Aspro (talk) 19:10, 7 April 2012 (UTC)
 * Great link, thanks! SemanticMantis (talk) 19:22, 7 April 2012 (UTC)
 * (ec)I'm not at all sure that the motherboard concept even existed at the time. Please clarify whether you are interested only in the on-board computers or all of the electronics in general. Most "electronics" don't contain motherboards, processors or memory, those components are specific to digital computers. Roger (talk) 18:49, 7 April 2012 (UTC)


 * A good resource for finding your way around more recent spaceflight computer systems is Category:Radiation-hardened microprocessors, which lists a bunch of devices that are, or have been, used in spacecraft. -- Finlay McWalterჷTalk 18:55, 7 April 2012 (UTC)
 * You should also remember that the onboard computer systems were never intended to be general purpose computers; they were calculators and autopilot controllers designed specifically for the single purpose of automating certain timing operations for the manned flights to the moon. These computers have more in common with a cockpit instrument than with modern general purpose personal computers.  For example, there is no "screen" on the infamous Apollo Guidance Computer; only a few cryptic numerical status indicators and some warning lights.  However, if you compare this to, say, a RADAR altimeter instrument in terrestrial aircraft of that era, you see that AGC actually provides much more information and control, including automatic fly by wire control of some spacecraft and propulsion systems.  Nimur (talk) 19:48, 7 April 2012 (UTC)

Using tachyons to blast something out of a black hole
Would it be possible to "rescue" people or objects from beyond the event horizon of a black hole by hitting them with a super-high energy beam of tachyons at just the right angle? Whoop whoop pull up Bitching Betty 20:37, 7 April 2012 (UTC)


 * I take you mean hypothetically. Well, hypothetically one might have better luck using a transporter. How do you think these questions up? --Aspro (talk) 20:46, 7 April 2012 (UTC)

AAAAAAAAAAAARGH!!!!! Whoop whoop pull up Bitching Betty 20:55, 7 April 2012 (UTC)


 * So...is that the sound of you trying the transporter idea? - Running On Brains (talk) 21:13, 7 April 2012 (UTC)
 * Maybe the transporter reassembled his molecules with those of a fly The Fly (1986 film)? Are hybrid flies allowed to hold a  WP account?--Aspro (talk) 21:25, 7 April 2012 (UTC)
 * BE SERIOUS!!!!  Whoop whoop pull up Bitching Betty 21:28, 7 April 2012 (UTC)
 * Verily     - but you first. --Aspro (talk) 21:36, 7 April 2012 (UTC)



I couldn't even begin to approach the highly theoretical math involved, but my understanding is that tachyons can't interact with normal matter, as this would create paradoxes. - Running On Brains (talk) 21:33, 7 April 2012 (UTC)


 * The serious answer is "no, because tachyons do not exist as far as we know, and even if they do exist, we can't know anything about them, and even if we did know all about them, we couldn't manipulate them, and even if we could manipulate them, we couldn't use them to manipulate ordinary matter." 71.215.74.243 (talk) 22:42, 7 April 2012 (UTC)


 * Can you pull something out of a black hole? E.g., what if it was a microscopic black hole, or maybe a one-pound black hole -- could you stick part of a sturdy object partway in it and then pull it out? Duoduoduo (talk) 22:56, 7 April 2012 (UTC)
 * No. As summarized in the previous black hole thread, once within the event horizon, conventional "spacewise" directions become "timewise" -- all future paths move to the singularity; all paths back out require you to move backwards in time.  Additionally, it only confuses matters to think about "an object" that stretches into a black hole.  That whatever-it-is is in fact a large number of independent subatomic particles bound together by various forces, but those forces are overcome by the black hole once the particles pass within. &mdash; Lomn 23:07, 7 April 2012 (UTC)
 * How about creating a wormhole inside the event horizon? Plasmic Physics (talk) 23:58, 7 April 2012 (UTC)
 * My understanding is that that would just create a second entry and a second event horizon for the black hole. Whoop whoop pull up Bitching Betty 11:35, 8 April 2012 (UTC)
 * Wormholes fall into the same category as tachyons - you can formulate them mathematically, but there is no evidence that they actually exist or can exist in the real universe and if they do there are all sorts of unanswered questions about how they would actually work. --Tango (talk) 14:40, 8 April 2012 (UTC)
 * It shouldn't if you face towards the future when you create the worm hole. Plasmic Physics (talk) 13:42, 8 April 2012 (UTC)


 * You mean like Jodie Foster flying though a worm hole in Contact (film) or was that just another cinematographic illusion?--Aspro (talk) 14:53, 8 April 2012 (UTC)
 * New theories are constantly being developed as to how to stablise a wormhole, including using the negative pressure exerted by the Casimir effect. Plasmic Physics (talk) 03:06, 9 April 2012 (UTC)

Radicals and VSEPR
What geometries does VSEPR theory predict for radicals? For instance, does the methyl radical have a trigonal planar geometry or a trigonal pyramidal geometry? Whoop whoop pull up Bitching Betty 21:26, 7 April 2012 (UTC)
 * Lone electrons are treated just like non-bonding electron pairs. The methyl radical is triagonal pyramidal. Plasmic Physics (talk) 22:55, 7 April 2012 (UTC)
 * Thank you. Whoop whoop pull up Bitching Betty 02:17, 8 April 2012 (UTC)


 * You can "treat it" however you like in a handwaving method that is solely an empirical analysis, but if you do so, you'll get the wrong answer:) Methyl radical is sp2 hybridized—trigonal–planar geometry with respect to the three C–H bonds and the lone electron in a p orbital. The general trend (setting aside effects of electronegativity and resonance of the substituents) is that a non-bonded electron is p not spx; one rationalization is that doing so allows a greater filling of s-like atomic orbitals (as usual, better to have vacancy in the higher-energy p levels). DMacks (talk) 14:32, 8 April 2012 (UTC)
 * Modelling software predicts a tetrahedral, trigonal pyramidal structure for methyl. The bond angles are greater than in methane, but less than 120 degrees. One s and two p AOs of carbon are degenerate, mixing with the hydrogen s AOs. One p AO of carbon is not degenerate, and is the (non-bonding) HOMO. To achieve a stable electrostatic equilibrium position, the valence MOs are distributed in a tetragonal fashion. For methane all the p AOs are degenerate with one s AO to form four degenerate MOs with the hydrogen AOs. Plasmic Physics (talk) 02:15, 9 April 2012 (UTC)
 * Experimentally by numerous types of analysis, methyl-radical is planar, and published modelling by many methods gives a slight energetic cost to the C deforming out of the plane (i.e., the model does not pre-suppose and enforce the planarity to simplify the math, but rather actually tests and finds an energy minimum at the planar form). DMacks (talk) 15:48, 9 April 2012 (UTC)
 * "One s and two p AOs of carbon are degenerate" is a severe mistake. The s and p are not degenerate with each other, but rather the p are all degenerate among themselves. They mix and the resulting sp2 hybrid orbitals might be degenerate combinations of the (non-degenerate) s and p components. DMacks (talk) 15:51, 9 April 2012 (UTC)
 * I was describing their state after mixing. Can you give a source stating that the bond angles are exactly 120 degrees or a similiar statement? Plasmic Physics (talk) 23:32, 9 April 2012 (UTC)
 * 10.1021/ja00476a054 is a good lead ref for methyl radical being planar. DMacks (talk) 01:35, 10 April 2012 (UTC)
 * That article uses weasle words of the third category as clasified by Wikipedia, such as essentially planar in quotation marks, or quasi-planar, it does not have internal consistency on that imformation. Plasmic Physics (talk) 05:09, 10 April 2012 (UTC)
 * As I said, it's a lead ref, so you can also follow its citation trail to see the strength (or not) of the sources they use when they say quite plainly in the second paragraph, with 4 footnotes, "all indicate a planar molecule." DMacks (talk) 13:55, 10 April 2012 (UTC)