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May 7[edit]

Ismail Ibn Sharif[edit]

According to his Wikipedia biography, Moulay Ismaïl is alleged to have fathered 889 children. This is widely considered the record number of offspring for any man throughout history that can be verified. It is thought that Ismaïl would have had to copulate with an average of 1.2 women per day over 60 years to achieve that number of children.

Semen tend to be thinner after continuous sex. How did he fathered so many children, I mean how is it biologically possible? --HoulGhostjj (talk) 01:04, 7 May 2011 (UTC)[reply]

How did you get 1.2 women per day ? I get 15 women per year. And, of course, they don't always get pregnant the first time, so, if you figure maybe 10 times each, that only requires sex 150 times a year. If you increased that in his prime and decreased it later, it seems possible. StuRat (talk) 05:18, 7 May 2011 (UTC)[reply]

Wilt Chamberlain claimed to have slept with 20,000+ women, so if this were true (he kept score?) and Ismaïl were his match, it would have taken less than 1 pregnancy per 20 hops in the hay. Stu, you get 15 per year? I bow to your awesome studliness. Clarityfiend (talk) 06:18, 7 May 2011 (UTC)[reply]

@ StuRat "And, of course, they don't get pregnant the first time..." Sorry, am I being a bit thick here, what does that mean? Are you suggesting that women don't get pregnant from their first sexual act? Richard Avery (talk) 07:25, 7 May 2011 (UTC)[reply]

I'm pretty sure he just means that copulation does not have a 100% chance of producing live birth, and it would be sloppy to estimate the math by assuming that.SemanticMantis (talk) 14:15, 7 May 2011 (UTC)[reply]

Yes, that's what I meant. I've added "always" to my previous post to clarify it. StuRat (talk) 18:53, 7 May 2011 (UTC)[reply]

Uh, hang on here... 889 children... with 889 women available, at 1 per day, you could accomplish that in less than 3 years. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:20, 7 May 2011 (UTC)[reply]

Not every act of copulation results in impregnation. --Jayron32 20:23, 7 May 2011 (UTC)[reply]

If he was exceptionally virile, and the 889 women were sufficiently fertile, it wouldn't take very long. I'm trying to figure out where the 60 years came from. ←Baseball Bugs ^{What's up, Doc?} carrots→ 20:31, 7 May 2011 (UTC)[reply]

Well, assuming he has no idea over the fecundity of the individual women, for large sample sizes as this, the numbers should fall back to the statistical averages. That is, if we know, on average, how many days per month a woman may become pregnant from an act of copulation, AND what percentage of copulation acts which occur during the proper window of time actually result in pregnancy, we could extrapolate an ideal number of sexual acts needed to produce 889 children. While, again hypothetically, the minimum under ideal conditions could be less than 889 acts (considering that 1/40 births are twins, we can safely knock 20 or so sex acts off of our minumum number), there are factors which will stretch it to be somewhat longer. --Jayron32 21:17, 7 May 2011 (UTC)[reply]

Somewhat longer, maybe, but it shouldn't necessarily require anywhere near 40 years (as the article indicates) or 60 (as someone said above). It depends in part, of course, on how many "wives" he had. And as far as I know, the female monthly cycle was well-known to the ancients, i.e. they knew when a woman was most likely to be fertile. They didn't understand the mechanism, of course, but they had the cycle pretty well figured out from observation. Supposing the time period is 40 years rather than 60, that's still only 22-23 pregnancies a year, or about 2 a month, which certainly seems do-able. ←Baseball Bugs ^{What's up, Doc?} carrots→ 21:25, 7 May 2011 (UTC)[reply]

It's the child support that isn't do-able. Googlemeister (talk) 13:28, 9 May 2011 (UTC) [reply]

Inch of water[edit]

At least one of the conversions in the inch of water article (the one to cmH2O) seems to be way off. This puts all the rest of these figures, and by extension the others added by the same editors to other articles, into question. Can someone check these, please? -- Chronulator (talk) 03:00, 7 May 2011 (UTC)[reply]

Fixed. It was a simple mistake. they used the inverse of the correct conversion factor. Dauto (talk) 03:22, 7 May 2011 (UTC)[reply]

I need to clean a disgusting sink: question about bleach and ammonia...[edit]

So... I have to clean a sink that appears to be ridden with mold, it is my friend's sink. It is to my understanding that if you mix ammonia and bleach, you create ... chlorine gas I believe. My fear rests in the fact that I know at one point my friend may have tried to clean said sink with ammonia, and my current plan is to clean it with bleach. So.. for you science guys, some questions:

1. If ammonia based soap was ever used on this sink, is there any chance some ammonia molecules may still be resting amongst the very dense mold in the sink, thus making the use of bleach on the mess a deadly choice?

2. If yes, does anyone have any better solutions as to how I should approach cleaning this disgusting sink.

PS: I'm not sure the filth is entirely mold, much of it appears to be fungus like... is mole a fungus?

Thanks for your help. I am new with posting here sorry for any lack of etiquette. —Preceding unsigned comment added by 71.204.172.247 (talk) 07:13, 7 May 2011 (UTC)[reply]

I'd stick to the bleach if I were you. If you're unhappy that the mould might have trapped some ammonia molecules, flush the sink well with (boiling) hot water. My plan of attack would be: Open the windows and doors wide. Put the plug in the sink. Fill sink with hot water and let stand for a few minutes. Pull the plug and let it drain. Repeat but this time add bleach. If you're worried about the presence of ammonia, only use a little bleach. Pull the plug and now get to work with a scourer, and you should find the grot comes off easily. By the way, if the sink is enamel you might have to get a specialist enamel cleaner as the bleach may remove the glaze. --TammyMoet (talk) 07:53, 7 May 2011 (UTC)[reply]

And in answer to your last question, yes the word mould (I use the UK spelling) is used to refer to a range of fungi with certain living habits. --ColinFine (talk) 09:50, 7 May 2011 (UTC)[reply]

I can't see a significant amount of ammonia being retained. The bleach fumes themselves will pose more of a hazard than any miniscule amount of chlorine gas produced. Whenever using bleach, open the windows and put fans in them, apply the bleach quickly, then leave the area. Better yet, leave the residence for a few hours (time the use of the bleach for just before you planned to leave anyway). StuRat (talk) 18:49, 7 May 2011 (UTC)[reply]

In any case, Chlorine gas is much denser then air, so unless there is a lot going on to stir the stuff up, it should go down the drain. Googlemeister (talk) 13:26, 9 May 2011 (UTC)[reply]

Chlorine bleach + ammonia doesn't just produce chlorine gas, it also produces things like chloramines and hydrazine. Yes, given enough time, these will go down the drain, but they won't do so fast enough to keep you from being poisoned. --Carnildo (talk) 01:09, 11 May 2011 (UTC)[reply]

Just be carefull, hot bleach can cause stainless steel to form rust on prolonged exposure. Plasmic Physics (talk) 10:47, 11 May 2011 (UTC)[reply]

Black body radiation question[edit]

what is the absorption power of a perfect blackbody? (four options)

1. zero
2. infinity
3. 1
4. 0.5 —Preceding unsigned comment added by 116.71.175.198 (talk) 09:09, 7 May 2011 (UTC)[reply]

Please do your own homework.

Welcome to Wikipedia. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know.

You may find the Black body article helpful. Red Act (talk) 09:38, 7 May 2011 (UTC)[reply]

And Attenuation coefficient too, although I'm not sure if "absorption power" is exactly the same thing. I kind of feel bad that both of those articles taken together don't really have enough information to answer this question as it is stated. 99.39.5.103 (talk) 23:56, 7 May 2011 (UTC)[reply]

Yeah, that is kind of pathetic that Wikipedia articles alone don't seem to be adequate to answer this simple question. The correct term appears to be absorptive power, and while there is a redirect for that, it goes to an article that doesn't define that term. Here is an external link that tells you what you need to know.[1] Unfortunately, the phrase "absorptive power" appears to also have a different definition, other than the one used when discussing black bodies.[2] Red Act (talk) 01:49, 8 May 2011 (UTC)[reply]

What species is this frog?[edit]

--Inspector (talk) 11:13, 7 May 2011 (UTC)[reply]

Where was it ? It looks like Kaloula pulchra. Sean.hoyland - talk 15:28, 7 May 2011 (UTC)[reply]

Ah, I see you are in the PRC. I see those in Thailand very often, or something very similar. The Kukri vipers in my garden seem to like them. Sean.hoyland - talk 15:37, 7 May 2011 (UTC)[reply]

No wonder. They're nice and plump. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:59, 7 May 2011 (UTC)[reply]

Laser as a weapon[edit]

I'm sure someone had this idea before, but, why wasn't it implemented? It might not kill, but blinding is a huge blow on enemy forces. Quest09 (talk) 12:39, 7 May 2011 (UTC)[reply]

In what way would a laser be better than a gun? --Tango (talk) 12:59, 7 May 2011 (UTC)[reply]

See Laser weapon and Protocol on Blinding Laser Weapons. PrimeHunter (talk) 13:06, 7 May 2011 (UTC)[reply]

A gun shoots one bullet at one place at one time. A laser could cover a broad area without pause. Quest09 (talk) 15:07, 7 May 2011 (UTC)[reply]

I agree, but then you are presumably thinking about air to ground or space to ground operations. So, from a geostationary satellite, you could easily take out targets in North Korea and then immediately switch to Libya or Iran if the need were to arise. Count Iblis (talk) 15:22, 7 May 2011 (UTC)[reply]

Or put a laser in a unmanned aircraft, breaking havoc among enemy troops, putting moral and legal issues by side, of course. Quest09 (talk) 15:36, 7 May 2011 (UTC)[reply]

A rapid fire gun would also work... --Tango (talk) 19:53, 7 May 2011 (UTC)[reply]

Some reasons not to use them:

1) They really couldn't be used as a wide angle, as the brightness would then decrease too much to be useful. Lasers are only effective as a narrow beam. (I don't think it would even meet the definition of a laser if it wasn't in a narrow beam.)

2) Unlike with a gun (barring tracer rounds), firing a laser gives away the position of the shooter.

3) Any new technology tends to cause objections as being "cruel and unusual". The unusual is true, of course, as it's not the usual weapon used. But, any new way to kill or injure people tends also to be seen as more cruel than the older methods.

4) Lasers are weather-dependent, in that their energy is absorbed on foggy days. Smoke on the battlefield would also interfere with their operation.

5) If they worked, soon both sides would use them, and after the war, we would all have large numbers of blind soldiers going home. (Although I suppose an argument could be made for this making the cost of war more apparent, and thus preventing future wars.)

6) Countermeasures could be developed, such as simple sunglasses, or, for brighter lasers, using a camera and video display rather than looking directly at the enemy. StuRat (talk) 18:44, 7 May 2011 (UTC)[reply]

As PrimeHunter linked above, it's illegal. Additionally, to date, a major problem has been the lack of portable energy sources that are powerful enough. Also the bad guys would issue mirrored sunglasses to their troops, and they would laugh scornfully at our tech. Comet Tuttle (talk) 18:55, 7 May 2011 (UTC)[reply]

It has been implemented. US navy destroyers are starting to mount powerful lasers for less than lethal use. Although they can kill a human being and are actually lethal, they're incredibly accurate and are used for destroying the engines of small boats when causing casualties is undesireable.[3] They're also working on a laser replacement for the Phalanx CIWS to shoot down anti-ship missiles and aircraft[4].

StuRat you claim lasers are visibible, unlike bullets. They aren't. A "laser gun" would be less visibiel than a rifle or whatever because there is no loud report or muzzle flash.--92.251.146.168 (talk) 19:23, 7 May 2011 (UTC)[reply]

You seem to have confused "visible" with "audible". And our ears aren't nearly as precise at locating objects as our eyes, so a loud sound isn't likely to give away your position, especially on a noisy battlefield. StuRat (talk) 06:51, 8 May 2011 (UTC)[reply]

A photosensor on a missile could easily detect and home in on a laser, if it were nearby. Goggles could shield the eyes, either by blocking the wavelengths used for such blinding attacks, or by being instant darkening like welding facemasks. Soldiers without access to such high tech could go pirate and wear a patch over one eye, so they could fight after the attack was over. A blinding attack would likely be considered a war crime, and the other side would also use it. Edison (talk) 19:44, 7 May 2011 (UTC)[reply]

A laser is invisible unless it is pointed directly at you (unless there is some mist or smoke scattering it). --Tango (talk) 19:53, 7 May 2011 (UTC)[reply]

And smoke/dust are quite common on a battlefield. Also, at night, I suspect that the particulate matter in even "clean" air would be enough to make such lasers visible. StuRat (talk) 06:48, 8 May 2011 (UTC)[reply]

I think any laser powerful enough to be used as a weapon would have enough scattered normally to see, providing it uses a visible wavelength, which it probably wouldn't. Atomic Rockets has some interesting things about laser pistols and laser cannons. — DanielLC 20:53, 7 May 2011 (UTC)[reply]

In WW2, both sides were prepared for poison gas attacks by the other side, but I haven't read of either side using such weapons. Each side feared the inevitable retribution. Ditto for blinding the enemy with lasers, most likely. Edison (talk) 21:02, 8 May 2011 (UTC)[reply]

There are invisible lasers on the battlefield already. I think those are infrared. If the beam was visible it would be very bad news for the soldiers trying to designate a target, especially at night. I believe that even though they are invisible, infrared lasers can still blind if they are powerful enough. Vespine (talk) 23:59, 8 May 2011 (UTC)[reply]

If you were going for blinding, wouldn't UV be better for your laser then IR? Googlemeister (talk) 13:23, 9 May 2011 (UTC)[reply]

No. Near-infrared, about 1 micron wavelength is the most dangerous for vision. UV is mostly absorbed in the cornea, so you get a corneal burn. Near infrared passes through to the retina, and is nicely focused by the eye's lens, producing severe damage. Unlike the cornea, the retina won't heal. It's also a lot easier to make a near-infrared laser.--Srleffler (talk) 16:55, 9 May 2011 (UTC)[reply]

If bin Laden had a medical need for dialysis[edit]

How could he have got treatment for 6 years at home? That must have been a huge annoyance ... —Preceding unsigned comment added by 212.169.191.38 (talk) 15:04, 7 May 2011 (UTC)[reply]

No evidence of medical equipment was found at his home. Also note that Al Zawahiri used to be a surgeon, so he could have helped him out when they were together earlier. But the evidence suggests that Bin Laden did not have any kidney problems. Count Iblis (talk) 15:09, 7 May 2011 (UTC)[reply]

Snopes has an article on that: [5]. The status is 'undetermined.' Maybe he got some treatment in the nearby military infirmary. THAT would be funny. Quest09 (talk) 15:15, 7 May 2011 (UTC)[reply]

Some forms of renal impairment indicating dialysis are temporary (I'm not sure but I think about 10% of people treated with dialysis eventually go off it--can anyone find that number?), and a kidney transplant can solve those which are not. Bin Laden had a large pool of potential donors. I think the chance that someone with that many kids and access to cash would not get a kidney transplant are very slim. 99.39.5.103 (talk) 23:02, 7 May 2011 (UTC)[reply]

The problem here is also not the transplant, but getting the logistics right without getting caught. If you believed he had a kidney problem, the trick here was to watch out for nephrologists, people buying dialysis machines and the like. However, if the CIA followed this lead, it went nowhere, since this need for dialysis was bogus. More about it from the nytimes: "Contrary to a widely-held belief that Bin Laden was on dialysis to treat a kidney ailment, Pakistani investigators said last week that his youngest wife told them he was healthy. “He was neither weak nor frail,” one of the investigator quoted the wife as saying. She told them, they said, that Bin Laden had recovered from two kidney operations a decade or more ago."

Inactive ingredients in medicines[edit]

Looking at the fine print of drug packages, there are a lot of inactive ingredients, aka nonmedicinal ingredients.

Here for an example is the list for a medication used to lower blood pressure and for other purposes. (This medication) "is available as tablets for oral administration, containing 40 mg, 80 mg, 160 mg or 320 mg of valsartan. The inactive ingredients of the tablets are colloidal silicon dioxide, crospovidone, hydroxypropyl methylcellulose, iron oxides (yellow, black and/or red), magnesium stearate, microcrystalline cellulose, polyethylene glycol, and titanium dioxide."

From the labelling I learn that the iron oxides are used to colour the tablets so different strengths are different colours.

Questions: Are all these ingredients necessary? Could they just mix the drug in with, say, cornstarch and press it into tablets?

How much of the cost (roughly) of pills would be for the inactives?

Is a list available of inactive ingredients telling what purpose they serve?

Thanks, Wanderer57 (talk) 16:09, 7 May 2011 (UTC)[reply]

Many of the ingredients are there as part of the pills time release technology. One of the conundrums of medicine is Pharmacokinetics, that is basically how a drug is metabolised in the body, and most importantly for our discussion how fast it is metabolized. For many drugs, the body basically digests them faster than they can be used; meaning that you either have to take a massive overdose to ensure that enough gets to where it needs to (a dangerous solution) or you need to take a lot of little doses all day long (inconvenient, especially for those times when you are asleep). The inactive ingredients you listed are compounded with the pill in such a way as to release the drug slowly into your blood stream, providing a slow, continuous stream of medication without having to take pills like every hour or half hour. This is vital to how the medication works; and though regulation requires any non-physiologically active substance to be labeled "inactive", that doesn't mean they aren't vital to the pills formulation. --Jayron32 16:16, 7 May 2011 (UTC)[reply]

Another use of inactives in some tablets is to prevent you tasting the active ingredient - e.g Zopiclone - the active ingredient is mixed up, and made into small "centres", these are then surrounded by a layer of inactives, and maybe even a sugar coat over the top. Believe me, you would not be able to swallow one without the coating - bitter - does not ever start to describe it (I know, I've made it)! Ronhjones ^(Talk) 16:45, 7 May 2011 (UTC)[reply]

Most of the cost of expensive medications cover the research, not the production of the drug. – b_jonas 17:15, 7 May 2011 (UTC)[reply]

Agreed, productions costs are typically tiny in comparison. One funny ingredient is silicon dioxide, which is essentially sand. I suspect that this is used as filler, to make the pill large enough to handle easily. The titanium dioxide, on the other hand, is white coloring. I suspect that this is either used alone, as white, or combined with the other colors to make pastels. StuRat (talk) 18:30, 7 May 2011 (UTC)[reply]

Pharmaceutical executive salaries, bonuses, and other compensation probably exceed the actual cost of drug production by now, and if they continue to increase at the rate they have over the past 30 years, they will overtake research costs, too. 99.39.5.103 (talk) 23:07, 7 May 2011 (UTC)[reply]

Thank you all. I am once again hugely impressed by the people at the Reference Desk.

Wanderer57 (talk) 20:18, 7 May 2011 (UTC)[reply]

about tunnelng effect[edit]

why classical particles do not shows tunneling effect?

Because they are not allowed to have negative kinetic energy since that would mean an imaginary speed (or negative mass) which make no sense classically. Dauto (talk) 18:10, 7 May 2011 (UTC)[reply]

Genetic bottleneck due to Great Famine of 1315-1317?[edit]

Can one detect the crash of the population due to the Great Famine of 1315–1317 and/or the following Black Death epidemics using the genetic diversity of the population of Europe today? Also, are the descendants of the survivors more susceptible to becoming obese? Count Iblis (talk) 18:34, 7 May 2011 (UTC)[reply]

How do you propose to do a comparative study involving the non-survivors and their descendants? TenOfAllTrades(talk) 18:41, 7 May 2011 (UTC)[reply]

I would be very surprised to see a population bottleneck from any of these events. While such bottlenecks do occur, as in the genetic history of indigenous peoples of the Americas or in certain town with unusual characteristics like Cândido Godói, I don't think that any famine or plague has been bad enough to create a truly small population size. Also bear in mind that humans have an effective population size which is much smaller than the total population size. If the plague kills half your town, you're more likely to go over to the next town for a mate, and thereby inbreeding is decreased and genetic diversity is maintained anyway.

The effect of this and other natural selection events on obesity is probably fairly large, but likely has gone on over many millions of years. Selection of symbiotic intestinal bacteria may also be important; also I suspect epigenetic effects. The best way to study this effect would not be by trying to find genetic traces in live individuals dozens of generations later, but by testing corpses from known famines that have been stored in crypts, catacombs, or other mass graves. Wnt (talk) 20:10, 7 May 2011 (UTC)[reply]

I seem to remember that it only takes hundreds, not thousands, of fertile mammals to avoid a dangerous bottleneck, assuming some kind of prevention of inbreeding. The inbreeding of aristocratic classes is usually much worse than any disease or natural disaster. Relatively isolated Polynesian island populations in the low tens of thousands without specific taboos against inbreeding remained viable for ~25,000 years in some cases. 99.39.5.103 (talk) 23:13, 7 May 2011 (UTC)[reply]

I see, so there is no bottleneck. I still wonder if people of European descent are more susceptable of becoming obese than the average African. My not so scientific personal observation suggests that this may be the case. I know quite a few people (all Europeans) who seem to survive on very little food. Count Iblis (talk) 23:41, 8 May 2011 (UTC)[reply]

Are there any known substances that are harder than diamond?[edit]

--75.40.204.106 (talk) 19:37, 7 May 2011 (UTC)[reply]

A politician's skull? ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:39, 7 May 2011 (UTC)[reply]

The Mohs scale of mineral hardness says that Aggregated diamond nanorods are harder than regular diamonds. They're still diamonds, technically, but a form of diamond that is not at all found in nature ("nanodiamonds"). They are apparently the hardest known substance. --Mr.98 (talk) 19:44, 7 May 2011 (UTC)[reply]

Well that may need to be updated: Wurtzite boron nitride can be 20% harder than diamond at some compression pressures.[6] Pure lonsdaleite would be 58% harder than diamond if someone could figure out how to synthesize it (although it's also a carbon crystal, which is probably how some people define diamond) but natural lonsdaleite has impurities putting it at 7-8 on the Mohs scale. 99.39.5.103 (talk) 23:24, 7 May 2011 (UTC)[reply]

My old chemistry book said that BN was harder than diamond. Bubba73 ^{You talkin' to me?} 23:26, 8 May 2011 (UTC)[reply]

I used to hear that Titanium was the strongest metal, and fittingly the sub that explored the Titanic wreckage was encased in a titanium alloy. Are diamonds harder than titanium? ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:40, 8 May 2011 (UTC)[reply]

A lot harder. Metals in general have properties like ductility, as determined by their electronic makeup (see sea of electrons model) such that even the hardest known metal is likely to be softer than a whole host of other materials. --Jayron32 01:01, 9 May 2011 (UTC)[reply]

I see. So, am I supposing correctly, that while diamonds are harder, their properties vs. the proterties of metals, would make diamond crystal an impractical submarine hull? (Never mind the cost.) ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:08, 9 May 2011 (UTC)[reply]

Yes. Diamonds are harder than metals, but they are also more brittle, and less able to be "worked" into a variety of shapes. You can't bend or mold or diecast diamonds, which makes construction with them nearly impossible. Plus, though hard, diamonds are not terribly tough, in terms of being able to survive an impact. Hardness is merely a measure of how well it resists scratching, NOT how well it resists, say, a sudden impact of great force. Diamond#Hardness discusses this in the last paragraph, where it notes that for a gemstone, diamonds are particularly tough, but being tough for a gemstone is kinda like being hard for a metal; most metals are probably tougher than diamond, even if most metals are not anywhere near as hard. --Jayron32 01:13, 9 May 2011 (UTC)[reply]

The key point there would seem to be the brittleness factor. The fact that metals can "give" works in their favor for this scenario. Provided they don't "give" too much. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:49, 9 May 2011 (UTC)[reply]

It is important to avoid confusing strength with hardness. Dauto (talk) 13:45, 9 May 2011 (UTC)[reply]

bcc-carbon may be harder, but at this point in time there is not much around on the earth. Graeme Bartlett (talk) 03:04, 9 May 2011 (UTC)[reply]

Frame Dragging/Conservation of energy/General Relativity[edit]

This whole gravity probe B stuff has got me wondering a few things that i believe are either a consequence of my limited understanding of the matter.

So if i understand correctly, frame dragging occurs because of the rotation of the object, which rotates the dimple in space-time. First just a general question is: Where does the force come from for gravity on the object? is the energy taken from the thing causing the dimple in space time? How exactly does this process occur? In other words, what is happening (speaking in terms of energy) when the probe is doing it's thing?

if the energy is taken from the earth, what form is it leaving the earth in and how does it transfer to the object? or is any energy even coming from the earth, and the object is merely "sliding down the dimple"? (although this wouldn't seem to make sense to the rest of physics)

All these questions may be fundamental but i can't seem to wrap my head around this stuff.

Thanks 68.49.224.135 (talk) 22:07, 7 May 2011 (UTC)[reply]

I'm not sure, but you might be able to think of the source as the same gravitational potential energy from the distance (altitude of the object) but the ordinary Newtonian conservation law is violated by GR because frame dragging doesn't change that distance so there is no transfer. On second thought, the orbiting object drags the larger rotating object's frame as much as it gets dragged by the larger rotating object, but the extent to which the larger object gets effected is proportional to the mass ratio, so the energy might come from the rotation and is conserved by torque: a tiny amount on the smaller orbiting object, and a much more minuscule amount on the larger rotating object. I hope someone who knows for sure will help me out here. 99.39.5.103 (talk) 23:43, 7 May 2011 (UTC)[reply]

There is no need for a source of energy, since the probe is not spinning up (or down). The spin is precessing which means it is changing direction. Dauto (talk)