Wikipedia:Reference desk/Archives/Science/2016 July 18

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July 18

Roughly how many people may have been alive during the last glacial maximum?

Just like the headline, I'd like to know if there is any estimate as to how many people (in the world) may have been alive during the last ice age. My guess is about 500,000, but I could be way off. I would accept an estimate for any point of the last ice age. I'm not picky! Thanks! Lighthead ^þ 00:47, 18 July 2016 (UTC)

It has been recently estimated that the human population reached a minimum size of 130,000 individuals during the LGM, but this is highly speculative [1]. The field of paleodemography has attempted to produce estimates based on genetic and archaeological data, but this gets more speculative going further back (with people often doubting any estimates prior to 10,000 BCE), and the genetics is limited in that it can only produce estimates of the number of people at a given time who have currently living ancestors (though you can then estimate based on simulations how many people there were total). Someguy1221 (talk) 00:57, 18 July 2016 (UTC)

Note this estimate is only for the population of Europe. World_population#Past_population gives a global population estimate of 4 million at 10,000 BCE which was around the time that temperatures reached near-current values after the last glacial maximum. The same article gives an estimate of <15,000 at 70,000 BCE, when ice sheets had reached near maximum following the onset of glaciation. As Someguy1221 points out all of these estimates need to be taken with a few grains of salt, or a whole shaker-full.

There's a nice figure here comparing δ¹⁸O (an indication of glacial ice volume) to prehistoric human activity. Shock Brigade Harvester Boris (talk) 02:48, 18 July 2016 (UTC)

[EC] Paleodemography is the go-to article. Technically, of course, we are currently still in an interglacial period of the Quaternary glaciation, but I guess you probably mean the Last glacial period, which has different names in different localities and ended about 12,000 years ago. {The poster formerly known as 87.81.230.195} 2.123.26.60 (talk) 01:02, 18 July 2016 (UTC)

Thanks for all the responses! Lighthead ^þ 02:58, 18 July 2016 (UTC)

Websites extracting phone numbers

Is it possible for a website to find out the phone number of a smart phone that is used to visit the site ? - WikiCheng | Talk 08:10, 18 July 2016 (UTC)

When accessed via a web browser, the answer should ordinarily be no. A malicious or hacked website that tricks you into downloading a computer virus to your phone might be able to do that, but I've never heard of an example of that. If you are using an specialized app or game on your phone to access some web service, then they may or may not have access to your phone number depending on what permissions you have given the app. Dragons flight (talk) 09:22, 18 July 2016 (UTC)

As Plugin or AddOn to the webbrowser, some VoIP and internet telephone software highlight possible phone numbers to start a call. A prankster who thinks evil doing due AddOns of some browsers come in source code as well. --Hans Haase (有问题吗) 09:47, 18 July 2016 (UTC)

Searching For Easiest Way

Is there any easy way to study completely about the geological timeline of Earth ?(ie. from Azoic to Phanerozoic Eon with their divisions) — Preceding unsigned comment added by Achyut Prashad Paudel (talk • contribs) 13:55, 18 July 2016 (UTC)

You could start with Geologic time scale. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:19, 18 July 2016 (UTC)

Simple Wikipedia has an article about Historical geology. AllBestFaith (talk) 19:32, 18 July 2016 (UTC)

I recall that there was a mnemonic device for geologic time periods, but (of course) don't remember what it was. Google search finds several sites such as Order of geological time periods on 'Mnemonic Devices Memory Tools' site. --However, memorizing is not the same as studying, or - more importantly - learning. --2606:A000:4C0C:E200:8558:6C31:688B:8595 (talk) 23:32, 18 July 2016 (UTC)

Was it "PolyCystic Ovarian Syndrome Does Cause Problems That Judicious Contraceptives Partially Negate"? Sagittarian Milky Way (talk) 23:43, 21 July 2016 (UTC)

About Latitudes

The climatic condition of place is determined by latitudes but why it can't in case of Country of Nepal? — Preceding unsigned comment added by Achyut Prashad Paudel (talk • contribs) 13:59, 18 July 2016 (UTC)

Latitude is only one factor. Much of Nepal is in the mountains, and altitude has a significant impact on climate. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:18, 18 July 2016 (UTC)

Altitude is important - so is distance from the coast, and where you are in relation to the main weather patterns. Nepal is mostly high altitude, well inland, and in the direct track of the Indian Ocean monsoons. Wymspen (talk) 15:32, 18 July 2016 (UTC)

Agreed. This is why meteorologists and climatologists must be given a wide latitude. StuRat (talk) 20:07, 18 July 2016 (UTC)