Wikipedia:Reference desk/Archives/Science/2012 June 13

Science desk
< June 12	<< May | June | Jul >>	June 14 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

June 13

What's in a Galileo thermometer?

I've checked the relevant article, but what I see is: A Galileo thermometer … is a thermometer made of a sealed glass cylinder containing a clear liquid…. I'd like to know what the "clear liquid" might be.

Why do I ask? I had one of these thermometers on top of a cabinet. Something (a CO monitor, not that that's relevant) inexplicably fell off the wall and knocked the Galileo thermometer onto the floor, where it smashed, disgorging the contents onto the carpet. I mopped it up as best I could, expecting it was water, but a) though odourless it felt more like a very light oil and b) the carpet is now "lifting" as if the liquid has soaked into the backing and has caused some damage. At the worst I'll just put up with it (or enjoy the "claim on my home contents insurance" game) but I'd be interested to know in more detail what's inside one of these things. Tonywalton ^Talk 00:05, 13 June 2012 (UTC)

The article to which you linked says "The clear liquid in which the bulbs are submerged is not water, but some inert hydrocarbon[clarification needed] whose density varies with temperature more than water's density does. DriveByWire (talk) 00:14, 13 June 2012 (UTC)

Oops, I missed that. Thanks for pointing it out. I'd appreciate some clarification as tagged in the article, though. The stuff was completely odourless. No "oily" smell at all, and nothing like carbon tet, ethanol or anything ketone-y. Tonywalton ^Talk 00:22, 13 June 2012 (UTC)

In short, the most likely reason for it feeling like a very light oil is that it is a very light oil, and consequently, it dissolved some oil-soluble component in the carpet backing. --Carnildo (talk) 00:23, 13 June 2012 (UTC)

I assumed this novel thing would be patented (and from that would have at least an example of what sort of thing could be used) but am unable to find it on the uspto web-search system. A statement about its origin and link to patent would be a nice bit of history for our article if anyone can find it. DMacks (talk) 00:26, 13 June 2012 (UTC)

Google Patents turns up a few — e.g. this one for a liquid in them. It seems like there are a lot of candidates for what the liquid could be, though, and any patent worth its money wouldn't be exclusive about which one they'd use. You'd be better off tracking down the manufacturer and asking them than looking into patents. --Mr.98 (talk) 16:20, 13 June 2012 (UTC)

If the glass cylinder is sealed, and there's little or no headspace, how does the volume (and density) of the liquid change at all (Beyond the small change in the volume of the glass cylinder itself)? 203.27.72.5 (talk) 01:11, 13 June 2012 (UTC)

I have three of them and they all have "headspace" in the cylinders. I used to have four, but one fell onto hardwood flooring and smashed. Unlike Tony Walton's experience, the liquid in mine smelled awful -more like a rotting meat than anything else. I am really glad no carpets were involved. Bielle (talk) 01:45, 13 June 2012 (UTC)

non colinearity in solar cells or solar panels

With early solar panels, if a cell was shaded, it turned into a resistor and could burn out as all the power of the panel was pushed through it. Diodes were added which protected the cells of the panels but still, the loss of power from a shaded cell was more than expected from the percent of the panel that was shaded. At present solar panels have dropped to around a dollar a nominal watt. We are getting to the sort of cost that would make it economically worthwhile to put solar panels on East and West rooves as well as Northern roves (I am in New Zealand). Does the technology exist to get the full power from panels that are not colinear without them interfering with each other. Then we come to electric cars. Already the Prius has a roof retrofit that gives about 10km of power for a day in the sun. A nice little bonus. Soon it will be possible to clad the entire car, if desired, with solar cells. No two cells will be pointed in the same direction. Does the technology exist to get the full power that each cell is absorbing to the in-car battery. William

William Hughes-Games Waipara, N. Cant, NZ — Preceding unsigned comment added by 125.239.168.182 (talk) 02:45, 13 June 2012 (UTC)

To understand this, you need to know 2 things: a) a given panel under certain illumination supplies a certain voltage up to a certain load, and above this load, voltage falls with increasing load. b) for any given panel under a certain illumination, there is an optimum working voltage that gives maximum power. The optimum voltage increases with increasing illumination. Optimum Power Point Tracking regulators allow the panel voltage to be independent of the load voltage and thus can optimise the panel voltage to extract maximum power.

There's 2 ways of handling the situation:-

(1) use diodes in series with each set of panels and parallel the panels + diodes. In this case the panel set that has the strongest illumination will tend to supply all the power, and the worst angled panel set will tend to contribute less than it can, as it will produce insufficient voltage to bias it's diode on. Where the load is suficient to pull the strong panel's voltage down so that the weaker panel can contribute, so it isn't as bad as it may seem.

(2) use separate electronic optimum power point tracking regulators for each panel set and parallel (with diodes if not already provided) the regulator outputs, not the panels. You get more total power this way, becasue the separate regulators allow each panel to operate at its own optimum voltage. A further major advantage is that each panel set can be for a different area and thus design nominal voltage. NOTE: this is the way to go with vehicles, which must have at least some panels not optimumaly angled wrt the sun and with various dissimilar areas in each position, but for a building, you will always get the maxiumum possible energy if you install ALL panels at the optimum angle and direction. A lot of houses where I live have installed panels, becasue of the government subsidy. But they always have them installed to conform to their existing roof pitch and direction. If they used a frame to install all the panels at the optimum angle and direction, it might not look so neat, but they would get a lot more energy. Keit60.228.241.58 (talk) 03:26, 13 June 2012 (UTC)

In case this helps. Roof-mounted PV arrays are usually connected in blocks of say 5 or 6 panels. So when the sun comes round to one block they all come on line together (series-connected), and then when the sun moves away that panel goes off and another may come on. This helps a lot on E or W mounted installations or if there is some shading. Itsmejudith (talk) 22:39, 13 June 2012 (UTC)

Linearity of Lorentz Transformations

I asked this question in the math ref desk but I didn't get an answer, so I figured I'd have better luck here.

The article on the Lorentz transformation says that "[i]f space [and time are] homogeneous, then the Lorentz transformation must be a linear transformation." It's intuitively clear that this is true (if there are terms like x^2, it would be difficult to see how homogeneity would be preserved), but despite going through a dozen pages of Google I could not find a (reasonably) rigorous proof of this statement (that didn't introduce any new assumptions), except for one that was far too involved for something this simple. Can anyone here help? Thanks. 65.92.7.168 (talk) 04:14, 13 June 2012 (UTC)

The Math desk thread got several replies. I think Quondum's was pretty good. "If space and time are homogeneous, then the Lorentz transformation must be a linear transformation" makes no sense in a vacuumwithout context. If you adopt the usual definition of "Lorentz transformation" then it's true simply because the Lorentz transformations are, in fact, linear. The interesting part of these arguments is usually the assumptions they make, not the reasoning from there to the conclusion. -- BenRG (talk) 05:37, 13 June 2012 (UTC)

I was short on time when I wrote that and I still am, but a quick follow up: the assumption that space(time) is homogeneous doesn't really help, because it doesn't say anything about the Lorentz transformations. Presumably the idea is that the Lorentz transformations should preserve that property, but I'm not sure I know what it means to preserve homogeneity. One could say that it means to preserve the spacetime metric, but it hardly seems fair to assume the metric up front. The trick in these arguments is to come up with a set of assumptions that uniquely characterize the Lorentz transformations without appearing to do so—and ideally that sound as obvious as possible. There are certainly arguments of this kind, one of them in Einstein's original paper, but I don't think I've ever understood what their assumptions are, counting all the hidden ones. Somebody somewhere has done it (probably in print, not on the web). -- BenRG (talk) 15:00, 13 June 2012 (UTC)

It's funny that you mention Einstein's 1905 paper, because when he derived the Lorentz transformation he made a statement similar to the one above: "In the first place it is clear that the equations must be linear on account of the properties of homogeneity which we attribute to space and time."

That said, I also don't know what it means, mathematically at least, to preserve homogeneity. I guess it would mean that the Lorentz transformation (defined to be the correct transformation law between space-time coordinates of uniformly moving observers whose origins coincide (if (x,t)=(0,0), then (x',t')=(0,0)) would take the same form between if the origin is displaced. I don't know if this is correct, or how to use this to prove the linearity of the Lorentz transformation, but it's a thought. 65.92.7.168 (talk) 03:33, 14 June 2012 (UTC)

Does it have anything to do with space and time being mutually inclusive?165.212.189.187 (talk) 16:27, 14 June 2012 (UTC)

It's not clear to me you need to assume that it is linear, though. If you start with the space-time interval and demand that it stays invariant, you'll arrive at the Lorentz transform without any assumptions about linearity. Count Iblis (talk) 17:20, 14 June 2012 (UTC)

But the postulate that the spacetime interval dt^2 - dr^2 is invariant is a stronger postulate than the postulate of the constancy of the speed of light, so in the end you remove an assumption by adding an assumption. 65.92.7.168 (talk) 18:41, 14 June 2012 (UTC)

Extreme peaks in electricity demand

As I understand it, a lot of money is sometimes spent on electricity generation capacity which will only ever be called upon under extreme peaks (less than 40 hours per year year was the figure quoted for Melbourne, Australia where I live).

My two questions are:

1. Besides for intense heat (where most people are using their air-conditioning), which other circumstances can place an electricity network under this sort of upper-peak capacity strain?

2. Besides for clothes dryers (which use a LOT of electricity per minute), which industrial or household processes can be shut down or put in standby under these circumstances, without causing massive disruptions? Can an aluminium smelter, for example, be put in standby when a heatwave hits (or is due to hit)? Which other industries can / should be made to wind down for these 40 hours or so per year?

(Don't bother suggesting people be made to switch off their air-conditioning under extreme heat. It's not realistic). 203.45.95.236 (talk) 07:04, 13 June 2012 (UTC)

Turning off aluminium smelters (and other smelters) is not going to solve your problem. They chose the location so it has a cheap, reliable energy source and the power plant is built to cater for it. If you make the power plant smaller and tell the smelter operator that they will have to shut down when people turn their air conditioners on, they will build it somewhere else. Quite often they're the main driver of developement in the region (see Gladstone), and the inhabitants running their air conditioners are incidental to the smelter existing. They can (and do) shut down for maintenance, etc. but it's a major drama starting them back-up especially if the shutdown was not planned.

Electrical appliances like TVs and stereo equipment use a lot of power just sitting on standby. Turn those off and you'd save a fair chunk. Individually, they don't use as much as a dryer but together they do add up. Refridgerators use a fair bit, but they can shouldn't be shut down lightly.

All of that extra capacity isn't wasted money anyhow. It allows for future expansion without needing to install new generators.203.27.72.5 (talk) 07:46, 13 June 2012 (UTC)

Regarding question 1 although it's not a peak load in the way you mean, as it's more of a daily rather than yearly thing, I remember when I visted Dinorwig Power Station, a pumped-storage hydroelectricity plant in Wales, that one of the main daily surges in demand in the UK is just after a popular television show ends when millions of people simultaneously switch on their electric kettles to make a cup of tea (this recollection is confirmed in the article). In anticipation Dinorwig, which operates as a so-called "short term operating reserve" spins up some of it's turbines just as the credits start to roll. This sort of energy storage approach is an another approach to reduce the need for traditional generating reserve, by providing a storage reserve instead. Equisetum (talk | contributions) 09:35, 13 June 2012 (UTC)

It is intertesting that the OP hails from Melbourne Australia, which has had for many decades an off-peak electicity scheme. This is where the consumer has two sets of meters and distribution within the building. Off-peak electricity is charged at a lower tarrif - in return the power company/authority turns the off-peak supply on and off each day at times to suit themselves. When I worked in a Melbourne high-rise office, each tenant on each floor had electric storage heaters - these had a large thermal storage media inside. In winter they stored heat energy when the power company turned the off-peak electricity on, and continued to deliver heat to the offices from storage while the off-peak electricity was off.

Most (if not all) power companies charge their major comercial customers not a flat rate of so many cents/kw.hr, but a complex scheme whereby there is a base rate, plus a surcharge for electricity consumed during defined peak periods, and an additional surcharge for electricity consumed at a rate above a certain level or levels. This does encourage major consumers to even out their electricity usage. This is not to be confused with the off-peak system mentioned above, because it lets the consumer draw whatever power he wants whenever he wants - but it may cost him.

Trying to reduce peak load by messing about with small dwelling / domestic airconditioning is pretty futile, but commercial and high-rise building aircon is a different story. Such installations can have signicant thermal storage, and nearly all will have so-called economy cycles fitted. By adjusting the temperature setting up a degree or two, and sometimes increasing airflow to compensate, the time each day the building stays in economy mode can be lengthened without affecting tenants too much.

How much a power company can reduce its worst case (as in a few really bad days in a year) depends somewhat on their attitude and their relationship with their major customers. Many telephone company sites, computer server farms, hospitals, and the like may draw megawatts in each site, and together may be a significnat fraction of a power company's total load. Such sites have diesel generator backup in case of power company supply failure, plus battery backup to cover the diesel startup time. To assit a power company on days of extreme load, these customers can run the diesels. Often they don't mind doing so, becasue their fuel cost is often less than or comparable to the power compnay electricity charge, and they need to run the diesels at least once a month anyway to keep the diesels in prime condition. The downside for the power company is that they MUST accept the immediate full load if someone's diesel fails for some reason.

At least with aluminium smelters I know about, they have their own power station. If a deal can be worked out between them and the local power company, it can be the case that they can help with peak demand, with or without shutting down or reducing smelting. This is the case with Alcoa in Western Australia. Large chemical and fertiliser plants can aslo assist by reducing or shutting down. Sometimes deals are reached with power companies, as it may not cost that much to shut down a large automated plant for short period, and the power company may be prepared to pay some compensation.

Many governments have Emergency Supply Laws, where, in a declared emergency, such as unprecedented peak demand, or a power station unplanned outage, they can direct industrial consumers to shut down, in order to keep consumers deemed to be more important (hospitals, shopping centres, electric trains systems, etc), with power.

Ratbone120.145.53.76 (talk) 13:18, 13 June 2012 (UTC)

Our article on the UK's National Grid Reserve Service says that automatic relays cut off the power to steel works if too much load is placed on the Grid, with a standing reserve of industrial diesel generators kicking in at the same time to alleviate the strain. These generators are supposedly contracted to provide power for up to two hours. Note that in the UK, this is probably enough to negotiate some extra juice being pumped in through the HVDC Cross-Channel lines. Brammers (talk/c) 14:49, 13 June 2012 (UTC)

You might find the articles Control of the National Grid#Short term and instantaneous load and generation response mechanisms and Load management interesting reads, oh and Demand response Also this website http://www.dynamicdemand.co.uk/grid.htm which shows the balance of the grid at any time (UK grid this is). I find all this stuff fascinating but have struggled to find an 'accessible' (i.e. not insanely technical) book that provides an interesting read on how the grid works. ny156uk (talk) 17:50, 13 June 2012 (UTC)

I'm not convinced it's good, in the long term, for consumers to reduce their peak power usage. This allows the power companies to get by with the bare minimum power generation capacity, which means, when they lose part of that capacity (due to accidents, weather, age, terrorism, etc.), the system is then immediately overloaded and breaks down. Only by having them hit the capacity limit every hot day can you get them to build up the needed spare capacity. StuRat (talk) 21:20, 13 June 2012 (UTC)

You can't turn off the smelters. I was reading about a time when Grand Coulee Dam went offline unexpectedly, and one of the main concerns of the grid controllers was finding load they could shed or additional power sources they could draw on to keep the smelters from cooling down. They failed, resulting in millions of dollars of damage. --Carnildo (talk) 00:56, 14 June 2012 (UTC)

Different types of smelter operate very differently, but aluminium is always smelted using the Hall–Héroult process and it requires an uninterupted power source to avoid damage. If power to the cells is lost, the cryolite mixture sets and destroys the cell. 203.27.72.5 (talk) 01:25, 14 June 2012 (UTC)

Some US utilities have special rates which allow them to remotely shut down loads for up to some specified period (say three hours) on short notice (say 10 minutes) when found advisable due to a shortage of power to supply peak load, or even just economics (avoidance of paying exhorbitant rates for emergency power from a neighboring utility). Today it would likely be done through an internet connection, but years ago it was via a sequence of tones sent on a dedicated radio frequency, and not by the customer doing the shutdown when they were good and ready, or not at all. . Customers who agreed to such interruptions included an electric arc furnace which made steel alloys, a smelter, and a plastic injection molding company. In exchange, they paid a lower rate all year. Some years, there were no such interruptions, other years there might be ten interruptions. It was up to the customer to devise and carry out a plan for what to do when the bell rang signalling the interruption was coming in 10 minutes. They might just dump the molten or half-molten metal in a pit. If they were wise, they had automatic shutdown (stop feeding material into a process) rather than let their equipment be damaged. If the utility had a blackout due to insufficient generation to supply the peak load, they would lose power probably with no warning at all and be worse off. Edison (talk) 19:35, 14 June 2012 (UTC)

My brother had what they call interruptable electrical service, meaning they could shut off electricity to his A/C during an "emergency". But, as it turned out, they called every hot day an emergency, meaning he could only use his A/C on cool days. He dumped that service quickly. StuRat (talk) 04:13, 15 June 2012 (UTC)

Soluble component of starch

Which component of strach is more soluble in water --- Amylose or Amylopectin?

It says amylose is insoluble in the link

But it says amylose is soluble in the links Bulto95 (talk) 16:17, 13 June 2012 (UTC)

References, --Gilderien Chat|List of good deeds 16:23, 13 June 2012 (UTC)

Essjay - grandiose delusions?

Are Essjay's alledged PhDs, etc, classifiable as grandiose delusions? Zaminamina (talk) 18:51, 13 June 2012 (UTC)

No one here is qualified to diagnose someone's through the computer. As far as I know, his behavior would be classified as deceit, but as to what the cause of that deceit was, it would be anyone's guess. --Jayron32 18:57, 13 June 2012 (UTC)

To be a delusion, he would have needed to believe it himself. He seemed to be completely aware that what he was saying wasn't true. --Tango (talk) 22:30, 13 June 2012 (UTC)

Please identify the black spots on my garden furniture

Hi, My garden plastic furniture, as well as the marble tiles in my garden are all spotted with thousands of black spots, depicted in the photo. What are these, and how can they be cleaned? Gil_mo (talk) 19:19, 13 June 2012 (UTC)

Plastic garden table stained with black spots

Pertinent details missing: Where in the world is this photo taken? What is the proximity to flower beds, mulch, or wooded areas? Are the spots dry, or sticky/ moist? Do they have any odor? Have you tried cleaning with basic soap and water? Supplying this info will help us give you better answers. SemanticMantis (talk) 19:48, 13 June 2012 (UTC)

Photo taken in Israel (now in late spring), proximity to plants (mainly grass) about 3-4 meters. The spots are hard dry, odorless. Hard to scrape them off using a fingernail. Haven't tried to do real cleaning, but identification would be enough to start with. Gil_mo (talk) 21:04, 13 June 2012 (UTC)

Looks like mold, but we'd need a much closer up picture. Suggest you try something that says removes mold and mildew. μηδείς (talk) 20:22, 13 June 2012 (UTC)

Here's a closer picture, click it to enlarge.

Spots on window sill

Gil_mo (talk) 21:37, 13 June 2012 (UTC)

Is there much air pollution in your area, say from a nearby airport ? As for cleaning, I suggest bleach. You need to use it in a well ventilated area, but outside should be fine. Wear rubber gloves, goggles, and old clothes you don't mind damaging, when you clean with it. Use a sponge to scrub it in, especially on the plastic, which might be scratched by anything abrasive. StuRat (talk) 21:10, 13 June 2012 (UTC)

Could they be bird droppings, say from birds which ate berries ? The lack of splash marks indicate they didn't fall far, but perhaps a flock of birds walked around your yard and pooed all over one day while you were at work. If this is it, and the problem recurs, I suggest you get an outdoor cat to chase them away. StuRat (talk) 21:54, 13 June 2012 (UTC)

It could be something like this [1]. SemanticMantis (talk) 21:59, 13 June 2012 (UTC)

It is a fungus, and no, a cat will not help. Really, StuRat?!?! μηδείς (talk) 22:11, 13 June 2012 (UTC)

You're absolutely, 100% sure it's a fungus, are you ? This seems unlikely, to me, since most of Israel has a rather dry climate. I did suggest how to handle that (bleach). As for keeping it from recurring, direct sunlight should prevent it. However, direct sunlight can damage some plastics. Storing the lawn furniture someplace dry, when not in use, would also help. The granite tiles are more problematic, as they presumably can not be moved. Just cleaning them with bleach periodically is the best you can do there. StuRat (talk) 22:19, 13 June 2012 (UTC)

I came across a number of sites recommending first, soap & water & scrubbing, and second white vinegar for harder to remove mildew. Baking soda was also indicated - example --Tagishsimon (talk) 22:31, 13 June 2012 (UTC)

Baking soda might scratch plastic. StuRat (talk) 22:32, 13 June 2012 (UTC)

So might the cat. --Tagishsimon (talk) 22:36, 13 June 2012 (UTC)

LOL. StuRat (talk) 22:43, 13 June 2012 (UTC)

Yes, actually, I am certain it's mildew. You don't need a constantly wet climate to have a mildew, just transient moisture will do. μηδείς (talk) 23:45, 13 June 2012 (UTC)

I'm wondering if it could be frass of some sort? Wnt (talk) 00:12, 14 June 2012 (UTC)

It is mildew. The second picture shows a typical moisture condensation pattern by a window sill. Or maybe its the space aliens running Mossad. That or mildew. μηδείς (talk) 02:14, 14 June 2012 (UTC)

I often get condensation inside the window, during winter, but never get condensation outside them. It would have to be hot and humid to get that (jungle conditions), and you'd need powerful A/C with poorly insulated windows. StuRat (talk) 04:40, 14 June 2012 (UTC)

You don't need a more-powerful than normal A/C to do that. Where I work we're provided with acommodation in demountable buildings that sweat like you wouldn't believe in the hotter months when people have their A/C's turned right down. They're just normal household units (and cheap ones at that). As a result many of the rooms have so much mould in and on the walls that it amounts to a significant health hazard. And as for jungle conditions, we're in a semi-arid climate. 203.27.72.5 (talk) 20:58, 14 June 2012 (UTC)

You seem to be talking about the inside of the building. Yes, I get that, too. When you take outside air and cool it down below it's dew point, you get condensation. But the only way this can happen outside is if so much "coolth" (my own word, patent pending) leaks out of the building that it lowers the outside air below it's dew point. Obviously you can't lower the temperature of the outside of the house by much, so the outside air has to be quite close to the dew point already (hence, near 100% humidity). And you also need poor insulation, a dramatic temperature difference between inside and out, and little or no wind. StuRat (talk) 04:01, 15 June 2012 (UTC)

No, I'm talking about outside the buildings. The temperature difference probably is quite dramatic (as people here just crank their aircon down to the minimum since the company pays the power bill), and there is no insulation as these are demountable buildings. Wind is variable, but if I checked I would probably find that there's more mould in the more sheltered corners of the buildings. As I said, we're semi-arid, so the air will rarely be close to the dew point. 203.27.72.5 (talk) 08:39, 15 June 2012 (UTC)

Bird guano is white with black specks. It consists of various nitrate and phosphate salts. It is simply not found concentrated like mold where water condenses on cool surfaces. Or are you still going with the Mossad/alien hypothesis, StuRat? μηδείς (talk) 04:23, 15 June 2012 (UTC)

That's your hypothesis, not mine. Bird guano looks different depending on what they've eaten. If they eat berries, it often looks uniformly dark. StuRat (talk) 04:38, 15 June 2012 (UTC)

Well, of course birdshit is no mimic and doesn't concentrate under windowsills just in the same area as condensed moisture. The question for me at this point is do you even believe your own words. The question for you is, do you want Jay Carney's job. If so, I'll write a sure fire recommendation letter. μηδείς (talk) 05:20, 15 June 2012 (UTC)

I don't get your reference to Jay Carney. And birds might congregate around windowsills if it offered protection from the elements (like rain, or shade when it's too hot out). StuRat (talk) 16:38, 15 June 2012 (UTC)

Carney is someone who is paid to continue absurd arguments long past the point of risibility. Kind of like trying to provide ad hoc reasons why birds might have a motive to mimic mildew with acrobatic bathroom habits to the point of hanging under windowsills to defecate or doing drive by scattings like hummingbirds with a suicidal berry addiction. At this point I think we should wait to see whether the OP reports that cat scared away the fungus. μηδείς (talk) 21:43, 15 June 2012 (UTC)

where can I buy lecithin for home cooking and baking?

I don't want it as a nutritional supplement. However I've contacted several suppliers and they all seem unwilling to do business with the average homemaker. 72.229.155.79 (talk) 20:58, 13 June 2012 (UTC)

Answers to questions nobody asked

Are you sure it's suitable for cooking ? It might burn, smoke, or lose it's nutritional value. You can always open some of the capsules and try to cook with it that way. StuRat (talk) 21:04, 13 June 2012 (UTC) What? I'm using it as an emulsifier, especially for hot soups. The capsules are too expensive. I need bulk quantities of the stuff. 72.229.155.79 (talk) 21:24, 13 June 2012 (UTC) (edit conflict) Is there a reason you can't use chicken eggs? Eggs are loaded with the stuff; in fact that's sorta why they are used in cooking and baking so much, eggs are a great binder and emulsifier. Some plant sources also provide some lecithin: IIRC mustard seeds have some, so mustard can be used to help emulsify things in applications where eggs may be undesirable (like in a vinaigerette). (post EC comment to Stu): Lecithin is commonly used in foods. Many processed foods contain "soy lecithin" (extracted from soybeans) as an emulsifier. You can buy it, but as the OP notes, isolated lecithin is usuaully used mostly by industrial food processors, since the home cook usually has access to eggs. Since cracking and using eggs on an industrial level is a hassle, most industrial processors use the lecithin from other sources. --Jayron32 21:07, 13 June 2012 (UTC) Can it hold up to frying temperatures ? StuRat (talk) 21:12, 13 June 2012 (UTC) An egg? Surely you've had fried eggs? --Jayron32 21:14, 13 June 2012 (UTC) I am asking about using lecithin as a frying oil. Since it doesn't seem to be a common practice, I assume there is a good reason not to. StuRat (talk) 21:50, 13 June 2012 (UTC) One good reason not to use chicken eggs would be if the OP is a vegan, or even if not, has concerns about the cruelty involved in obtaining commercially available eggs. (Personally, I do eat eggs, but I sometimes wonder if I really should.) --Trovatore (talk) 21:18, 13 June 2012 (UTC) Eggs curdle in soup and result in an "egg drop" texture, which is not what I want. I want a very smooth mouthfeel. Can someone please just answer my question? I want pure lecithin. 72.229.155.79 (talk) 21:24, 13 June 2012 (UTC) If you're looking for that "unctuous" or smooth mouthfeel in a soup, you need a good source of stock. That's what soup bones are for. Stew some oxtail or other similar bone-in meat with lots of connective tissue for several hours at a low simmer. Strain, and you have stock. Fantastically useful stuff. Gelatin (which is what makes stock, well, stock) is also easily found. --Jayron32 23:14, 13 June 2012 (UTC)

Where in the world are you? Try this thread [2]. This place sells it, but no idea if you're anywhere near them [3]. 203.27.72.5 (talk) 21:45, 13 June 2012 (UTC)

I'm surprised the OP can't find it, as the IP address geolocates to the United States. I buy it regularly in large containers in granular form, from natural food stores such as Whole Foods Market. Any online vitamin store (Vitacost, Vitamin Shoppe, etc.) also sells the stuff in loose granular form. I use it routinely as an emulsifier for breakfast shakes and dairy-free ice-cream, to prevent added oils (flax oil in shakes, coconut or other oil in ice cream) from separating out from the watery parts. ~Amatulić (talk) 21:55, 13 June 2012 (UTC)

Answers to questions nobody asked

This sounds so American. I still can't see how you can better egg or mustard as an emulsifier. Eat food. Itsmejudith (talk) 22:35, 13 June 2012 (UTC) It is food. It comes from soy. Think about it for a moment: Egg is a poor emulsifier for uncooked foods due to the salmonella risk. Mustard is a poor emulsifier due to the flavor it imparts. ~Amatulić (talk) 23:58, 13 June 2012 (UTC) If you want a neutral flavor, use Mayonnaise, a common emulsifier in salad dressings and cold sauces. Egg is one of the man ingredients.--Jayron32 01:56, 14 June 2012 (UTC)

Go to google and type in 'purchase lecithin' for dog's sake. μηδείς (talk) 02:11, 14 June 2012 (UTC)

Stability of the Solar System

I have never paid attention to these things, but respond users keep talking about Stability of the Solar System elements giving me some motive to learn these things, it said something like Mercury and Venus or Earth collide, Mars eccentric grows to 0.2. If Mars collide with something over billions of years where will Mars collide with? Will Mars collide with Earth someday? I have never heard in my life Mars will someday collide with Earth, where did I hear Mars is growing eccentricity. Is it possible Pluto and Neptune will collide? I thought Pluto sometimes cross Neptune's orbit by 3:2 so they never collide, over next few billions of years, can Pluto and Neptune actually collide? I never thought Pluto and Neptune will actually collide. i thought that event is not even possible. I am absolutely retarded in astrophysics, and of course physics, I am totally dumb in those subjects.--69.226.45.43 (talk) 22:01, 13 June 2012 (UTC)

See here. On a time scale of hundreds of millions of years, the potential instability is caused by Mercury. When the solar system just formed, there were many more planets, which collided and merged into the planets we have today. Then you would expect that the as time goes by, you get rid of instabilities that manifest themselves on longer and longer timescales. So, it isn't a big surprise that after a few billion years, you could still have an instability that can in theory manifest itself o a time scale of a billion years or so. Count Iblis (talk) 22:16, 13 June 2012 (UTC)

Would destroying mercury (by say, pushing it into the sun) now help to improve stability in the future? Or would the act of destroying it in itself cause instability? 203.27.72.5 (talk) 22:35, 13 June 2012 (UTC)

It can be difficult to predict these things because of the large number of interactions you have to consider (see n-body problem), but I don't think pushing Mercury into the Sun would cause a problem. The effect of Mercury's gravity on the other planets is minimal because it is so small. It's only in scenarios where Mercury's orbit ends up going very close to other planets that it can affect them. The instability isn't really a problem worth solving, though - the Earth will have become uninhabitable long before Mercury's orbit changes significantly (the Sun is gradually getting hotter, so the oceans will start to boil in only one billion years or so). If our descendants survive until then, they'll have found somewhere else to live anyway. --Tango (talk) 23:38, 13 June 2012 (UTC)

Formation and evolution of the Solar System#Long term stability states "within five billion years or so Mars's eccentricity may grow to around 0.2, such that it lies on an Earth-crossing orbit, leading to a potential collision." The linked article Stability of the Solar System also notes that in a 2009 simulation of "2500 possible futures", "in 20 cases, Mercury goes into a dangerous orbit and often ends up colliding with Venus or plunging into the Sun. Moving in such a warped orbit, Mercury's gravity is more likely to shake other planets out of their settled paths: in one simulated case its perturbations send Mars heading towards Earth." Clarityfiend (talk) 22:24, 13 June 2012 (UTC)

Is this possible they might have planets which was closer than Mercury long ago. I never thought about it. Who said before when solar system just formed there was many more planets than there were now. Is mercury always the first planet of the solar system, or there could once be planets infront of Mercury.--69.226.45.43 (talk) 22:32, 13 June 2012 (UTC)

That's any interesting thought. I wonder, if close enough to the Sun, if a planet would experience drag from passing through the gasses expelled by the Sun (or falling into it) and thus have it's orbit decay until it eventually would fall into the Sun. StuRat (talk) 22:41, 13 June 2012 (UTC)

I think the drag would cause the planet's orbit to decay very quickly, depending on the density of the gases at the altitude. On that note, could mercury experience enough drag to significantly change it's orbit as a result of being hit, or passing through the material ejected in a solar flare? The article on solar flares doesn't seem to say how high above the sun's surface that material is sent, so I don't know if they reach Mercury's orbit. 203.27.72.5 (talk) 23:01, 13 June 2012 (UTC)

The solar wind goes out as far as the heliopause. The drag caused by that material even as close to the Sun as Mercury would be minimal, but on the scale of billions of years I guess it could have an effect. I've only heard of drag from the Sun in the context of a red giant, though. --Tango (talk) 23:31, 13 June 2012 (UTC)

What are the odds that a passing star comes close enough to the Sun to mess everything up? I don't think that's taken into account in the numerical simulation. Wnt (talk) 00:15, 14 June 2012 (UTC)

I find a few times 10^(-6) per billion years, based on taking the average distance between stars a few lightyears, the mean speed between stars being a few km/s and a close encounter defined as a star passing within a billion km distance of the Sun. Count Iblis (talk) 01:30, 14 June 2012 (UTC)

A billion km is just inside the orbit of Saturn. If a star actually passed through the solar system, it would completely destroy it. If you just want to introduce a bit of instability, then 10 billion km is probably close enough (that would definitely be close enough to throw lots of comets and things towards the inner solar system, even if it didn't destabilise the actual planetary orbits). --Tango (talk) 17:37, 14 June 2012 (UTC)

Something like that would definitely destabilise the orbits of the outer planets and send like half the Oort cloud flying everywhere. It is also still very unlikely (a few tenths of a percent chance). Whoop whoop pull up ^{Bitching Betty | Averted crashes} 17:47, 14 June 2012 (UTC)

Stability of the Solar System Sagittarian Milky Way (talk) 18:51, 14 June 2012 (UTC)

Why have you linked to that article? It doesn't seem to even mention the effects of passing stars. --Tango (talk) 18:51, 15 June 2012 (UTC)

Wow, so many new stuff to learn here, is alot of information. On the first link somebody post me "Mars was ejected from the Solar System at ~822Myr. " When the source said Mars being eject from Solar System is the 822 Myr in the future, if Mars is eject from solar system does that mean Mars gets kicked out of the solar system. If Mercury tries to cut in line of Venus at reaches Venus orbit, can Mercury just fall out to the further orbit so it never returns to its original position, and its orbit just keeps expanding the it cut in line with Earth, can Mercury also pass earth's orbit itself get further from sun than earth is? I was told over time this is possible all the planets change its position. If Pluto's orbit becomes destabilized, it is likely to affect the gas giants or the only Plutoids?--69.226.45.43 (talk) 20:27, 14 June 2012 (UTC)

Pluto's mass is so much less than the gas giants that it wouldn't affect their orbits much even if it slammed into them. (It might mess up their moons' orbits, though.) StuRat (talk) 03:53, 15 June 2012 (UTC)

If this topic interests you you will probably enjoy Larry Niven's novel A World Out of Time as well as his Ringworld series and other works. μηδείς (talk) 03:59, 15 June 2012 (UTC)