Science desk
< January 7	<< Dec \| January \| Feb >>	January 9 >

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

January 8

Chronology of algebras

Which of "geometric algebra" or "algebraic geometry" proceeds the other.

Wow! sushi (talk) 05:08, 8 January 2020 (UTC)[reply]

(we don't have so much time...) _ I need to confess , I am multi-personalities.

Wow! sushi (talk) 05:12, 8 January 2020 (UTC)[reply]

Geometric algebra#History 1844

Algebraic geometry#History 16th Century? Graeme Bartlett (talk) 05:50, 8 January 2020 (UTC)[reply]

Thank you. and for answering to such a rough-cut (or to say, "large-cut") question. Wow! sushi (talk) 01:39, 16 January 2020 (UTC)[reply]

Insect identification

Hello, What is this insect called? I found it in Mizoram, India. There are shells on the body and the trail illuminates in the dark.

Sandeshkumar M. 11:19, 8 January 2020 (UTC)

Are you sure this is an insect? Check the underside for number of legs. It has the same number of segments as a woodlouse. Graeme Bartlett (talk) 09:50, 8 January 2020 (UTC)[reply]

I don't really know what it is. An insect or something else. I've uploaded another image of the creature.

Sandeshkumar M. 11:28, 8 January 2020 (UTC) (talk)

To help accurate identification include -

Something to show scale: ideally that would be a ruler with millimetre graduations. A picture of the bottom of the organism. A white background for the picture - it helps to give a better idea of the colour of the organism. A picture of the bioluminescence - this would be in an ideal world. A picture of the place you found it - to give an idea of habitat. A general name like Mizoram is useful - it narrows things down. But was it in woodland or human settlement. I appreciate this is a lot of information, but accurate identification is aided by this kind of information. There are places in India where bioluminescence is common. For Mizoram, that seems to be plant based rather than animal so more information about the animal is really needed to identify it correctly.

Having said that: it does look quite like a woodlice (and definitely an isopod). But I only counted eleven obvious segments - there could be 14 which is indicative of a woodlouse - a picture of the rear end from above would help to clarify that. There appear to only be three pairs of legs - woodlouse have seven pairs of legs (they can vary in size, so only seeing three pairs might mean the others are hidden). — Preceding unsigned comment added by Hongnang (talk • contribs) 12:55, 8 January 2020 (UTC)[reply]

Isopod link. NonmalignedNations (talk) 16:42, 8 January 2020 (UTC)[reply]

This might actually be a firefly larva. Graeme Bartlett (talk) 00:06, 9 January 2020 (UTC)[reply]

Yes I also think this is a bioluminescent beatle larva. Just as it is said that there are 11 segments on its back and and the last two segments have white patches which illuminates in dark.

And thanks for all your help. But don't know which species.

Sandeshkumar M. 02:14, 9 January 2020 (UTC)

Probably Firefly Larva from India says that identifying a beetle from its larva is "difficult if not impossible" but goes on to say that "if you watch it eat a snail or slug, it is definitely a Firefly larva". Alansplodge (talk) 17:56, 9 January 2020 (UTC)[reply]

Human Predation

When a predator is removed from the food chain it is often seen that there is an overpopulation of another species. The most well-known example I can think of at present (which is not the same) is the Cane Toad in Australia, where without a predator, they have bread to enormous population sizes causing widespread destruction. Further to this, if predation on a species takes place the food item tends to populate to make up for the loss and similarly if a food source reduces the number of predators reduces too. To expand on this concept, if my reserve has 10,000 impala and I have 100 lions, (10:10,000)… if the lions eat 2,000 impala, the impala will generally have about 2,000 offspring during the next breading cycle, and the numbers (presuming they are evenly matched, lions to impala and assuming there are no other animals [work with me here people]) In the same manner, if I hunt 9,000 of my impala, my lions will die off until I have only 10 (1,000:10). Nature ensures there is an equilibrium, if all of the additional environmental factors are left in situ and allowed to run their course. What has been removed from the ecological chain to allow for the human race to overpopulate to such a degree as to cause the now seen climatic chaos. How was this element removed? Thanks. Anton 81.131.40.58 (talk) 15:56, 8 January 2020 (UTC)[reply]

Are you looking for a book on basic ecology? Humans fill a niche in the local and the global ecosystems, but your description of simplified replacement of one species by another... well, that is just overly simplified. Start with our Wikipedia article on ecological niche, human evolution, and so on... Nimur (talk) 16:15, 8 January 2020 (UTC)[reply]

Technology has allowed humans to expand from one ecological niche to many others. Chimpanzees, by comparison, only inhabit small portions of Africa. One very simple technology humans use is clothing, allowing us to live in far different climates, such as the arctic. And predation doesn't limit human numbers, since humans are more likely to kill the predators, such as sharks or lions. NonmalignedNations (talk) 16:37, 8 January 2020 (UTC)[reply]

If you hunt 9,000 of the impala and lions eat 2,000 a season, the lions will likely eat all the rest in a few generations and then you'll have no impala and no lions, or the lions will eat enough that they starve to death the next generation and you'll have problems when the impala population rebounds back above 10,000. Even if they both manage to survive, you'll have an increased risk of extinction of either species due to the ensuing genetic bottlenecks. Equilibrium is ensured for small changes only. 89.172.38.145 (talk) 06:38, 10 January 2020 (UTC)[reply]

you assume that the limiting factor to human population growth was predation, when it might not have been (my impression is it almost certainly wasn't except perhaps in the deepest of pre-history.) The human population growth and overpopulation (if any) is usually credited to things like farming, industrialization, hygiene etc. Aecho6Ee (talk) 11:36, 12 January 2020 (UTC)[reply]

Where’s Greta when you need her?

Linked to the previous question and brought to my attention recently by a much younger person, was that the current environmental crisis should resolve itself. The rationale provided for this argument was that all of the fossil fuels and Co2 gasses being put into the atmosphere are all from earth and have been part of the ecology and part of the overall cycle of minerals etc. within the planetary system. I was not able to counter this point, as my questions clearly show I am not a scientist or scientifically minded. Please would you help me to understand why this theory does not hold water, as I am sure that it doesn’t but can’t explain why. Thanks. Anton 81.131.40.58 (talk) 15:57, 8 January 2020 (UTC)[reply]

Review the Wikipedia article entitled tipping points in the climate system, which is written for a general audience but cites detailed technical sources for the interested reader.

Some complicated systems are self-stabilizing; some are subject to instability. Scientists have reason to believe that some aspects of the Earth's climate may be undergoing an irreversible alteration that deviates from the stable "self-regulating" zone, which is one of the reasons for international concern. If you're interested in why some scientists believe such things, our article is a great introduction to the science, data, and models, that drive their concern. Nimur (talk) 16:08, 8 January 2020 (UTC)[reply]

As for burning fossil fuels, those are burnt far faster than they accumulated, meaning we have thousands of years worth of fossil fuel produced gases all in the air at once. This leads to much higher concentrations of greenhouse gases than would naturally occur, and hence more greenhouse effect, and unnaturally higher tempertures. NonmalignedNations (talk) 16:54, 8 January 2020 (UTC)[reply]

Maybe we should all go back to using wood-burning stoves. ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:59, 8 January 2020 (UTC)[reply]

Actually, pellet stoves, which burn compressed wood pellets, are looked at as a renewable heat source that is much closer to "carbon neutral." But in response to the OP, NN has the obvious and correct answer that's easier to explain than tipping points and the complications of these systems. Yes, all of this CO2 was once in the atmosphere, but not all at the same time. Even if we were to assume that all of the coal we have burned (or will burn) is from just the Pennsylvanian subperiod (a lot of the coal is from that time, but not all of it), and we take the period of industrial output to be from 1760 (the start of the Industrial Revolution, and this is generous since our output has accelerated over this time period a lot), that means we have been outputing CO2 that took nature about 24 million years to sequester in the space of 260 years. In otherwords, we are releasing CO2 into the atmosphere about 90,000 times faster than nature took it out of the atmosphere. Again, these are really rough numbers and I could be off by an order of magnitude or so, but you get the general idea. That's also just for coal, it doesn't account for oil at all. --OuroborosCobra (talk) 19:07, 8 January 2020 (UTC)[reply]

There is an obvious response to this if you understand the history of the Earth. Earth was once a ball of molten rock, so if it becomes that again, there's no problem; it'll all sort itself out. Earth was once hit by an asteroid 10 miles in diameter, so if that happens again, there's no problem; it'll all sort itself out. Earth is a big ball of rock. It's not going anywhere. The problem is we're disrupting our biosphere, which we rely on for things like food. Also, heat plus humidity means in some places it can get too hot during the day for humans to survive outdoors. Earth will "sort itself out" just fine; it's just that this might involve lots of humans dying. Or in the words of the late great George Carlin: "The planet is fine. The people are fucked!" --47.146.63.87 (talk) 22:05, 8 January 2020 (UTC)[reply]

Nature always wins. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:08, 9 January 2020 (UTC)[reply]

"Civilization exists by geological consent, subject to change without notice." --Will Durant, quoted by --Khajidha (talk) 16:35, 9 January 2020 (UTC)[reply]

Help me identify raptor

The raptor above was photographed by me today, from the window of my office on the 26th floor of an office building in downtown, Brooklyn, NY. By no means is this his or her first visit; this raptor swings by approximately weekly recently, and he has been coming to my ledge at various times for a few years. I was wondering if someone with some expertise can definitively identify the species (hopefully my picture is clear enough for that). I think it's a peregrine falcon but I am far from certain in my lay identification. Thanks--Andy-Em-Ess (talk) 18:47, 8 January 2020 (UTC)[reply]

It appears to be a Peregrine falcon. When in doubt, I consult the Peterson Field Guides appropriate to my region. Those books have comparison pictures and point to the exact most distinctive markings that help disambiguate and distinguish one bird from another. Nimur (talk) 20:49, 8 January 2020 (UTC)[reply]

This report looks at Peregrines in New York. Given where you saw the bird, and the Peregrine's love of high vantage points for hunting, that identification seems almost certain. Mikenorton (talk) 09:27, 9 January 2020 (UTC)[reply]

They nest in tall buildings too; see Diary of an urban peregrine falcon nest in Chicago – in pictures. Alansplodge (talk) 17:50, 9 January 2020 (UTC)[reply]

Does it have a name? May I Suggest Mr Chubby-cheeks? Thanks. Anton 81.131.40.58 (talk) 15:39, 9 January 2020 (UTC)[reply]