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

Science desk
< March 6	<< Feb | March | Apr >>	March 8 >

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.

March 7

Where will earth get swallowed up in sun's R Giant Branch?

This article said Earth will get swallowed up because of the tidal interaction. Dr. Schroedor and Dr. Smith estimated Earth will be swallowed up at some point of sun's RGB. But I am confused where will earth be swallowed up? is it at 1 AU or 1.2 AU. My astronomy teacher said once sun reach Earth orbit, then Earth is destroyed. At beginning of sun's RGB, or at the end-in 7.59? When will sun reach Earth's orbit? 5 billion years, 6 billions? When sun first become a R Giant Star it will reach Venus' orbit first or Earth's orbit first?--69.226.42.88 (talk) 01:25, 7 March 2012 (UTC)

Here is a document which outlines the findings (Wiki's spam filter is not letting me link it, google "The Sun and Earth in the distant future") There is a graph which seems to suggest earth's orbit is slowly and steadily expanding up until it gets "sucked in" by the expanding sun, but only to about 1.1AU by the looks of it. Don't worry about that though, because as the future of the earth article explains, the Earth's oceans are going to evaporate in only about 1.1 Billion years and all procaryotic life will be extinct by about 1.6 billion years, long long before any engulfing takes place. Vespine (talk) 03:05, 7 March 2012 (UTC)

(Edit Conflict)It would have to reach Venus's orbit first because Venus orbits considerably closer to the Sun than the Earth does – a brief look at a diagram of the Solar system should make that obvious.

As to exactly when in the Sun's Red Giant phase this will happen, and exactly how large the Earth's orbit will be at that time, nobody can tell you for sure: astronomers have been discussing this and making different calculations and coming up with different answers for decades, and doubtless will continue to do so.

The newspaper article you link to above is talking about the most recent scientific work on the subject, and according to that article, Schroeder and Smith have calculated it will happen "about 7.59 billion years from now" (which means about 2.6 billion years after the Sun's Red Giant phase starts): that's the best guess answer anyone can give you for the moment.

The article doesn't mention what Schroeder and Smith say the Earth's orbital radius will be – we'll have to read the work itself after it's formally published in the Monthly Notices of the Royal Astronomical Society; it won't appear there until next month at the earliest (I've just checked the March contents list, and it's not there), and anyway one will have to be a member of the RAS (I'm not), or talk a library into buying it, or pay for it oneself (it will likely cost tens of $/£), in order to read it (unless one can find a library that already gets it), but doubtless the details will be widely republished in due course.

In any case, the newspaper article reports that Smith has already said he thinks his and Schroeder's calculations might be a little wrong (implying that Earth will be destroyed a little earlier than he and Schroeder calculated), and doubtless other scientists will also suggest possible errors, and in someone will make further and (maybe) better calculations based on newer knowledge we haven't discovered yet. This is how Science proceeds, and one has to learn patience and not expect everything to be answerable straight away – I've been following and studying astronomy for nearly 50 years, and new or better answers come along all the time. {The poster formerly known as 87.81.230.195} 90.197.66.160 (talk) 03:14, 7 March 2012 (UTC)

Do we know exactly how big the sun will get in 7.6 billion years? Is this possible (and there is a chance) it can reach out to Mars, and there is a chance (although less likely than Earth will) to even destroy Mars. I thought Mars will survive for sure. Can we promise Mars will survive for sure? I don't think it can get as big as Mars orbit, although some reference said 700 times current radius. Yahoo answers estimated 160 times bigger, their language can mean 160 times it's current sun size, that's beyond Mars orbit.--69.226.42.88 (talk) 03:38, 7 March 2012 (UTC)

The document I linked in the 1st reply seems to suggest the sun will not consume Mars, however I can't see that it actually states by how much it will "miss". It does say that a possible solution to keep the earth from being consumed is to "nudge" it away from the sun using gravity from kupier belt objects, not possible with today's technology but not unimaginable with technology a few centuries from now. Vespine (talk) 04:37, 7 March 2012 (UTC)

Is this possible we can actually use Kuiper Belt Objects, to use technology to alter Mercury and Venus orbit to even keep them from being consumed? 1 billion year from now, if technology is that rich can we actually do the same thing to move both Mercury and Venus away from the sun with changes of technology to avoid them from being consumed?--69.226.42.88 (talk) 05:39, 7 March 2012 (UTC)

It's hard to make any predictions about the state of humanity and human technology that far in the future. 1 billion years is thousands of times longer than the entire history of human civilization. So I guess the answer is yes, it's not impossible. Rckrone (talk) 06:31, 7 March 2012 (UTC)

Homo sapiens has not existed as a species for much more than as much as 500,000 years (depending on your definitions); 5 million years ago our ancestor species were tree-dwelling apes, still dividing into the distant forerunners of Chimpanzees and Humans; 5 billion years is a thousand times longer in the future than that was in the past. It is very, very, very unlikely that Humanity or any organic descendants remotely resembling us will still exist that far in the future, and totally impossible to meaningfully guess what the descendent of our, or any then existing alien, technology might be capable of then.

As for your questions about exactly how big the Sun will get, or exactly how big Earth's orbit will then be: we keep trying to tell you, nobody yet knows: someone has just come up with another stab at these factors, but people will still be doing that, and getting doubtless different answers, a hundred years from now. {The poster formerly known as 87.81.230.195} 90.197.66.250 (talk) 08:07, 7 March 2012 (UTC)

EC with Vespine's response is few centuries in the future is not even a thousand years. If human still exist then (that is like the year 2400, 2500, 3000, 4000), they might try to bother move earth further away from the sun by machine technology. If technology is that rich, it is possible we can live colonize anywhere in the solar system, even on Mercury and Venus with super-technology. I thought replacing planetary atmosphere is impossible even with hypertechnology. Did Dr. Smith just suggest/guess this idea to use Kuiper Belt Object to move earth further away is just a speculation or it is likely the idea will actually work successfully.--69.226.42.88 (talk) 00:45, 8 March 2012 (UTC)

Free tools for visualization of time-varying vector fields

Are there free tools available for visualizing time-varying 3D vector fields? If so, what would be a good one in terms of the ease of creating an animation? — Preceding unsigned comment added by 173.49.12.132 (talk) 12:53, 7 March 2012 (UTC)

Octave_(programming language) can do that. It's relatively easy to learn the syntax (matlab style), but it will require some time investment. I've not personally used the Yapso package here [1], but it seems to be aimed at simplifying the creation of this sort of plotting and animating in Octave. SemanticMantis (talk) 14:29, 7 March 2012 (UTC)

One Fundamental Interaction

A lot of stuff I read about the Big Bang talks about how the four fundamental interactions were unified at first, then split up as the universe cooled. What evidence do we have that this is the case, other than the fact that we've had success unifying the forces in the past (Electromagnetism, Electroweak, for example). How do we know that it wasn't just gravitation, the strong force, and the electroweak? - Goodbye Galaxy (talk) 14:53, 7 March 2012 (UTC)

That's the first I've heard of that. I would like to know too. Npmay (talk) 22:12, 7 March 2012 (UTC)

There is no experimental evidence; it's just theoretically plausible, since the forces all have a similar character and it's known to happen in the electroweak case. See grand unified theory and Kaluza–Klein theory. -- BenRG (talk) 01:46, 8 March 2012 (UTC)

It's not quite true that there's no experimental evidence. If the forces unify, they all have to have the same strength at some high energy scale. And in fact if you take experimental data and extrapolate it to high energy, the three forces of the standard model (strong, weak, and electromagnetic) do seem to unify at an energy pretty close to the Planck scale, where gravity also has roughly the same strength. Waleswatcher (talk) 05:11, 8 March 2012 (UTC)

Mickey Mouse Logic

While reading the book, The Art of Electronics, by Paul Horowitz and Winfield Hill, I have come across the term "Mickey Mouse Logic". What does it mean? Google has not turned up anything authoritative. Gulielmus estavius (talk) 17:32, 7 March 2012 (UTC)

We have a Mickey Mouse logic, though the target of that redirect doesn't seem to use that term. DMacks (talk) 17:48, 7 March 2012 (UTC)

"Mickey-Mouse Logic" is a term invented by Don Lancaster in the CMOS Handbook, the first edition of which was published in 1977. It refers to logic gates that are cobbled together from parts rather than purchased as a single entity -- they tend to be somewhat flaky and inefficient. Looie496 (talk) 18:08, 7 March 2012 (UTC)

I've nominated Mickey Mouse logic for deletion. Clarityfiend (talk) 21:49, 7 March 2012 (UTC)

I would guess that the term comes from a Micky Mouse Watch [2] originally an inexpensive, low quality watch for little kids, with the body and hands of Mickey Mouse. The adjective "Mickey Mouse" has thus come to mean any substandard device or method, such as a Mickey Mouse approach. StuRat (talk) 18:55, 7 March 2012 (UTC)

Mickey Mouse operation is what springs to my mind. Vespine (talk) 21:34, 7 March 2012 (UTC)

If you make logic gates out of transistors without matching all the impedances and current drains for the entire analog states encountered in operation, something with 5 gates might work fine, but extending it to 6 gates might suddenly fail with no obvious reason. It's best to always balance and simulate your gate circuits if you can't make them from off-the-shelf gate ICs. Npmay (talk) 22:15, 7 March 2012 (UTC)

I have basically no knowledge of this topic, but there's something about it here - also, just browsing I get stuff like "Mixing diodes, transistors, etc. into logic circuits is known as M2L (Mickey Mouse Logic) and is best avoided. We've probably all done it (a classic example is making a one-shot out of a Schmitt inverter, capacitor and diode) but they eat into your noise margins and change behaviour with temperature." There's a textbook with a chapter about it here. Suggestion - this one might be better for the Computing Refdesk if you don't get someone who knows his stuff to answer you here. Wnt (talk) 22:44, 7 March 2012 (UTC)

Oddly enough, we have no article on the Mickey Mouse wristwatch, despite its one-time popularity. I wonder if it used this sort of circuit? Wnt (talk) 22:50, 7 March 2012 (UTC)

The Mickey Mouse wristwatches I've seen were mechanical; they had no circuitry. Jc3s5h (talk) 00:18, 8 March 2012 (UTC)

According to systems theory, a "circuit" need not be electronic. But, in any case, the link is that a Mickey Mouse watch was cheap junk, where they took inadvisable short-cuts. StuRat (talk) 00:28, 8 March 2012 (UTC)

One additional aspect here is that "M2L"/"MML" appears to be a play on "T2L"/"TTL" (Transistor-transistor logic), where TTL is the "orthodox" way of doing things and MML is the "oddball" way.--Itinerant1 (talk) 00:00, 8 March 2012 (UTC)

We had mickey mouse money here in the philippines. 203.112.82.1 (talk) 17:32, 9 March 2012 (UTC)

Pain referral in appendicitis

Hello. I am curious about something and am having great difficulty finding an answer. As the appendicitis article says, appendicitis typically presents with pain in the umbilical region, which within a few hours migrates more locally towards the appendix (i.e., lower right quadrant). This is mentioned all over the place, but nowhere can I find an explanation of why the pain refers away in this manner, then decides to move to the appropriate location. Anyone have any ideas?

Peace and Passion ☮  ("I'm listening....") 18:16, 7 March 2012 (UTC)

PS If anyone responds here, can you please drop a note on my talk page to let me know, as putting this particular page on my watchlist is a bit crazy.

Our article Rovsing's sign#Referral of pain explains why this happens: "An appendix with some early inflammation may give a non-specific irritation somewhere near the umbilicus (belly button). Should the inflammation become severe, it may actually irritate the inner lining of the abdominal cavity called the peritoneum. This thin layer lies under or behind the abdominal wall muscles. Now the pain is localized."Looie496 (talk) 18:45, 7 March 2012 (UTC)

Different sorts of intoxication

When I drink gassy beer, I get a sort of aereated drunk feeling. But when I drink vodka and tonic I get more quitely drunk. Ultimately of course, both end in me falling over; but, what could be the reason for the different feelings?--92.28.67.225 (talk) 21:03, 7 March 2012 (UTC)

It could just be your blood alcohol level. Different forms of alcohol may be absorbed at different rates, and people tend to have quite different reactions to mild intoxication and heavy intoxication. StuRat (talk) 21:11, 7 March 2012 (UTC)

So How many forms of ethyl alcohol are there?--92.28.67.225 (talk) 21:14, 7 March 2012 (UTC)

The ethanol only has one form. It's the matrix that differs. 203.27.72.5 (talk) 21:24, 7 March 2012 (UTC)

Whats a matrix?92.28.67.225 (talk) 21:33, 7 March 2012 (UTC)

The matrix comprises all of the drink other than the alcohol and the water. It may contain all kinds of organic chemicals that may have all manner of effects on your body. 203.27.72.5 (talk) 06:38, 8 March 2012 (UTC)

Depending on the concentration of alcohol, the rate at which it's consumed, the total amount consumed, and the other ingredients present, the ethanol will be absorbed into the bloodstream at different rates. StuRat (talk) 21:35, 7 March 2012 (UTC)

I always thought there's a good deal of confirmation bias going on there.. For no real rational reason, except for the fact that I binged a little too much on a couple of occassions, I won't touch tequila anymore. I know lots of people that have a similar liquor "ban" for similar reasons. It's not that it actually makes you sicker, it's just a mental association thing. If you expect to get a particular "kind" of drunk, I bet that actually has a big effect on how you end up feeling. Vespine (talk) 21:32, 7 March 2012 (UTC)

Coincidentally, I was about to ask an almost identical question. One unit of spirits give me a warm glow, making me cheerful and sociable, but I can still think clearly, one unit of wine makes me feel light headed and a bit confused, one unit of beer dulls my senses and gives me a hangover. Original research maybe, but they really are completely different effects for me.--Shantavira|^{feed me} 21:48, 7 March 2012 (UTC)

As you can see, many people do perceive qualitative differences in the effects of intoxication on different alcoholic drinks. For a while (USA late 1990's), there was even a fad of inhaling alcohol vapors at weird tourist bars and airports (vapor bar is a redlink; a little help ?), in part based on the claim that it delivered a different kind of buzz. StuRat points out that different availabilities/ absorption rates may come into play, and I'd also suggest that other compounds present in wines, beers, liquors, etc, may play role. Though these compounds may or may not commonly be classified as psychoactive, it reasonable to think they may have effects in concert with each other, not to mention with alcohol. And obvious example of this is the thujone in traditional absinthe, but other odd compounds in e.g. jagermeister or chartreuse could perhaps be responsible for qualitative differences in perceived effects. Even something as simple as relative sugar content could play a role, especially in individuals that commonly experience a sugar buzz.

As others point out above, psychology and culture also play a big part, so it would in principle be very difficult to disentangle the chemical/ physiological / neurological influences from the cultural / psychological ones. On a non-scientific note, you may enjoy The sun also rises, in which Hemingway describes a brilliant variety of links between certain drinks and certain effects. Some would say he's an expert on the subject ;) SemanticMantis (talk) 22:16, 7 March 2012 (UTC)

Note that the OP, 92.28.67.225 (talk · contribs), is currently on a short vacation. ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:37, 8 March 2012 (UTC)

The gas itself is, as you doubtless know, carbon dioxide unless you're drinking nitrokeg. On contact with water it forms carbonic acid in your mouth and stomach (and, of course, in the beer). Apart from affecting the taste and mouthfeel of the beer (which should have been taken into account by the recipe, which is why beer-tap sparklers which over-accelerate the CO₂'s release and flatten the beer are the devil's device </rant>), this has its own physiological effects on the blood.

It's widely accepted that sparkling (gassy) drinks cause alcohol to be absorbed into the bloodstream faster than non-sparkling ones (hence whisky-and-soda or gin-and-tonic inebriate faster than straight whisky or gin), and I dimly recall that this has been experimentally verified, but I can't point to any references just now. {The poster formerly known as 87.81.230.195} 90.197.66.156 (talk) 15:08, 8 March 2012 (UTC)