# Mountains and gravity **URL:** \ **Category:** Factual Questions\ **Created:** [November 8, 2013, 8:01am UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387 "2013-11-08T08:01:39Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [November 8, 2013, 8:01am UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/1 "2013-11-08T08:01:39Z")
Do large mountains (or mountain ranges) have an effect on gravity? And if so, can it be measured? Do we have to work less when moving toward a large mountain, and work more when moving away from it? ---
**Author:** ![the\_diego](https://avatars.discourse-cdn.com/v4/letter/t/7bcc69/32.png) [@the\_diego](https://boards.straightdope.com/u/the_diego)\ **Post date:** [November 8, 2013, 8:09am UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/2 "2013-11-08T08:09:02Z")
The Earth’s gravity has a strong effect on the mountain. The mountain’s own gravity is not so significant (won’t draw you towards it.) Even if it has a does have a strong pull, the Earth’s own pull on us will make it un-noticeable. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [November 8, 2013, 10:18am UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/3 "2013-11-08T10:18:34Z")
> [@panache45](#): > > Do large mountains (or mountain ranges) have an effect on gravity? And if so, can it be measured? Yes and yes. [Schiehallion experiment - Wikipedia](http://en.wikipedia.org/wiki/Schiehallion_experiment) > [@](#): > > Do we have to work less when moving toward a large mountain, and work more when moving away from it? I’m not sure that question is even answerable as posed. What’s your direction of travel? ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [November 8, 2013, 10:21am UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/4 "2013-11-08T10:21:26Z")
Anything with mass has a gravitational effect on anything else with mass. It may be insignificant, even infinitesimally small, but it still exists. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [November 8, 2013, 1:27pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/5 "2013-11-08T13:27:33Z")
In several of my courses, it was mentioned that the attraction of the Himalayas was observed during the Great Arc surveying of India by Everest and others. But they rarely went further and never gave references. Here’s one on it: [http://www.himalayanclub.org/journal/the-attraction-of-the-himalaya/](http://www.himalayanclub.org/journal/the-attraction-of-the-himalaya/) You should also read John Keay’s **The Great Arc** > **[The Great Arc: The Dramatic Tale of How India was Mapped and Everest was Named:...](https://www.amazon.com/Great-Arc-Dramatic-Mapped-Everest/dp/0060195185)** > > The Great Arc: The Dramatic Tale of How India was Mapped and Everest was Named \[Keay, John\] on Amazon.com. \*FREE\* shipping on qualifying offers. The Great Arc: The Dramatic Tale of How India was Mapped and Everest was Named ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [November 8, 2013, 3:17pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/6 "2013-11-08T15:17:54Z")
I know sensitive gravity measurements were affected by a stadium nearby filling with spectators. ---
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [November 8, 2013, 3:23pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/7 "2013-11-08T15:23:18Z")
In the oil/gas business, the use of gravimetric analysis for exploration is well established. Here’s a [US Geologic Survey](http://pubs.usgs.gov/circ/1966/0530/report.pdf) paper on it from 1966, so you can see there’s a decades long track record of it. It’s more useful for near surface exploration, though. As you might imagine, measuring gravity variations to high levels of confidence is much harder the deeper you go. And that’s just bits of hydrocarbon already inside rock. Gravity effects from large mountain ranges are much more easily measured. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [November 8, 2013, 5:05pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/8 "2013-11-08T17:05:25Z")
AIUI, you will weigh less on the top of a mountain than you would on the surface of the Earth because you are farther away from the Earth’s center of mass. The mountain adds additional mass below you, but it is not enough to counteract the distance. ---
**Author:** ![SeldomSeen](https://avatars.discourse-cdn.com/v4/letter/s/7ba0ec/32.png) [@SeldomSeen](https://boards.straightdope.com/u/SeldomSeen)\ **Post date:** [November 8, 2013, 5:48pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/9 "2013-11-08T17:48:33Z")
> [@Johnny\_L.A](#): > > AIUI, you will weigh less on the top of a mountain than you would on the surface of the Earth because you are farther away from the Earth’s center of mass. I recall reading somewhere - sorry, no cite, the story sounds apocryphal but was presented as historically correct - that long ago when alchemy was practiced this fact was used to give an impression of “manufacture” of gold. A himalayan holy man weighed a small amount of gold on a very precise scale at the top of a mountain. The gold was then carried - with appropriate ceremony - down the mountain by a congregation of monks chanting prayers and whatever else monks do. When the gold reached the lowlands it was weighed again, _et voila!_… found to have increased somewhat in weight, thereby producing gold out of thin air (and the fervent prayers of the saints). A similar concept is much in vogue at the pesent time, to wit: that constant reduction of wages and taxes accompanied by fervent prayer will somehow bring prosperity for all… SS ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [November 8, 2013, 6:38pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/10 "2013-11-08T18:38:33Z")
> [@SeldomSeen](#): > > I recall reading somewhere - sorry, no cite, the story sounds apocryphal but was presented as historically correct - that long ago when alchemy was practiced this fact was used to give an impression of “manufacture” of gold. A himalayan holy man weighed a small amount of gold on a very precise scale at the top of a mountain. The gold was then carried - with appropriate ceremony - down the mountain by a congregation of monks chanting prayers and whatever else monks do. When the gold reached the lowlands it was weighed again, _et voila!_… found to have increased somewhat in weight, thereby producing gold out of thin air (and the fervent prayers of the saints). That would have to be some amazingly precise and accurate scale. The difference between weight at the top of Everest and sea level is, if I haven’t screwed up the math, two parts in a million. I doubt there are any spring scales that precise. If there are any, they wouldn’t be that accurate after being carried down a mountain. And note that if you were using a balance scale (which I think even alchemists knew were more accurate), there wouldn’t be even a theoretical difference, because a balance scale would give the same answer (as the object in the pan and the weights on the other side would both be affected equally). ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [November 8, 2013, 8:28pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/11 "2013-11-08T20:28:25Z")
Furthermore, alchemy in the sense of attempting to create gold was a European and Arabic Muslim tradition. It was not practiced by “Himalayan holy men” (who would generally be Buddhists or perhaps some variety of Hindu). Three were so-called “Chinese alchemists”, in the Taoist tradition, but they were mainly concerned with finding a elixir of life rather than making gold, and they are are still quite distinct from “Himalayan holy men”. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [November 8, 2013, 10:11pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/12 "2013-11-08T22:11:15Z")
> [@SeldomSeen](#): > > A similar concept is much in vogue at the pesent time, to wit: that constant reduction of wages and taxes accompanied by fervent prayer will somehow bring prosperity for all… > SS [Moderator Note] Let’s avoid extraneous political commentary in General Questions. No warning issued. Colibri General Questions Moderator ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [November 13, 2013, 2:52pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/13 "2013-11-13T14:52:30Z")
> [@Johnny\_L.A](#): > > AIUI, you will weigh less on the top of a mountain than you would on the surface of the Earth because you are farther away from the Earth’s center of mass. The mountain adds additional mass below you, but it is not enough to counteract the distance. You’ll also age slower than the people in the valley. But then again, high-altitude, mountain life is rough, and probably not worth the extra second or three you’ll gain over your lifetime. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [November 13, 2013, 3:01pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/14 "2013-11-13T15:01:03Z")
I think relativistic effects are less than those due to increased exposure to radiation. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [November 13, 2013, 4:28pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/15 "2013-11-13T16:28:10Z")
Of course I am sure you are aware that the first realistic attempt to ‘weigh’ the earth was done by The Reverend Dr Nevil Maskelyne in 1774 on Schiehallion in Perthshire, Scotland. He used the observed deflection of a pendulum by the mass of the mountain as the basis of his calculations. > **[Nevil Maskelyne](https://en.wikipedia.org/wiki/Nevil_Maskelyne)** > > Nevil Maskelyne FRS FRSE (/ˈmæskəlɪn/; 6 October 1732 – 9 February 1811) was the fifth British Astronomer Royal.\[a\] He held the office from 1765 to 1811. He was the first person to scientifically measure the mass of the planet Earth. He created the British Nautical Almanac and Astronomical Ephemeris for the Meridian of the Royal Observatory at Greenwich using Johann Tobias Mayer's corrections for Euler's Lunar Theory tables. > Maskelyne was born in London, the third son of Edmund Maskelyne of P... ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [November 13, 2013, 4:45pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/16 "2013-11-13T16:45:56Z")
I read somewhere just this week that if your digital scale is accurate to more than 2 decimal points, it may need to be recalibrated when you get it home, depending on where it was manufactured, because the effects of gravity at the place of manufacture may be different than where you’re using it. Wish I could remember where I read it, because for the moment, I’m citeless. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [November 13, 2013, 7:26pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/17 "2013-11-13T19:26:02Z")
As in a digital bathroom scale? 1/100th of a pound/kilo, I would think, would be well above the margin of error threshold than any gravitational discrepancies that would be present, from sea level to the Himalayas. Maybe 7 or 8 decimal places? But I don’t know of any scale that needs to be that accurate outside of a lab. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [November 13, 2013, 8:23pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/18 "2013-11-13T20:23:55Z")
Ah, here we go. It was one of Randall’s random factoids, speaking in the context of what would happen if the earth expanded: > [@](#): > > t = 1 month: > > After a month, the Earth would have expanded by 26 kilometers—an increase of 0.4%—and its mass would have increased by 1.2%. Surface gravity would only have gone up by 0.4%, rather than 1.2%, since surface gravity is proportional to radius.[6] > > You might notice the difference in weight on a scale, but it’s not a big deal. Gravity varies by this much between different cities already. This is a good thing to keep in mind if you buy a digital scale. If your scale has a precision of more than two decimal places, you need to calibrate it with a test weight—the force of gravity at the scale factory isn’t necessarily the same as the force of gravity at your house. [http://what-if.xkcd.com/67/](http://what-if.xkcd.com/67/) ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [November 15, 2013, 3:06pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/19 "2013-11-15T15:06:39Z")
> [@WhyNot](#): > > Ah, here we go. It was one of Randall’s random factoids, speaking in the context of what would happen if the earth expanded: > > [Expanding Earth](http://what-if.xkcd.com/67/) As usual, great article. But he’s hypothesizing an earth expanding in mass, uniformly in circumference, by 1 cm/s. So, that calculation is assuming an earth with an extra 26 kilometers worth of crust, worldwide (after 1 month’s time). That’s a LOT of extra mass. However you may be right. I haven’t had my coffee yet… ::scratches head:: ---
**Author:** ![James\_Toothpaste](https://avatars.discourse-cdn.com/v4/letter/j/e56c9b/32.png) [@James\_Toothpaste](https://boards.straightdope.com/u/James_Toothpaste)\ **Post date:** [November 15, 2013, 3:40pm UTC](https://boards.straightdope.com/t/mountains-and-gravity/673387/20 "2013-11-15T15:40:29Z")
Everything has gravity. [Next page](https://boards.straightdope.com/t/mountains-and-gravity/673387.md?page=2)