Why Does Gravity Vary Across the Globe?

  • Context: Undergrad 
  • Thread starter Thread starter OnTheCuttingEdge2005
  • Start date Start date
  • Tags Tags
    Gravity
Click For Summary

Discussion Overview

The discussion revolves around the variation of gravity across different regions of the Earth, as illustrated by a gravity map from the GRACE satellite. Participants explore potential reasons for these variations, including geological factors and the implications of gravity measurements.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants note that gravity varies globally, as shown in the gravity map provided.
  • One participant questions why gravity is particularly strong in the oceanic region near England.
  • Another suggests that higher gravity in certain areas may be due to higher density, possibly from heavy metals.
  • There is a query about whether the heavy metals are in the ocean or released from hydrothermal vents.
  • One participant proposes that the density might be located in or beneath the Earth's crust.
  • A participant observes a symmetrical pattern in gravity highs and lows between the USA and regions around Australia and India.
  • Questions are raised regarding the definition of "average" gravity and whether the term refers to the gravity field or free fall acceleration (g).
  • A humorous remark is made about living in a high-gravity area as an excuse for being overweight.
  • A participant provides an explanation of the unit of measurement (mGal) used in gravity measurements, detailing its definition and relevance.

Areas of Agreement / Disagreement

Participants express various hypotheses regarding the causes of gravity variation, but no consensus is reached on specific explanations or definitions. Multiple competing views remain regarding the factors influencing gravity in different regions.

Contextual Notes

Participants highlight the need for clarity on definitions, such as what is meant by "average" gravity and the specific gravity field being referenced. There are also unresolved questions about the geological factors contributing to gravity variations.

Physics news on Phys.org
Why is gravity so strong in the oceanic region just to the left of England?
 
presumably because there's a higher density there - perhaps due to a large quantity of heavy metals.
 
Do you mean heavy metal in the ocean or being released in hydrothermal vents?
 
Probably in or under the crust.
 
it appears that the highs and lows in the USA and the Atlantic have some vague symmetrical antipodes around Australia and India
 
the question is what the average?
and by gravity do the they mean gravity field, also known as g (the free fall acceleration)?

besides these queries, nice pic, nice colours...
 
The new rationale:

"I'm not overweight, I just live in a high-gravity area."
 
What is a (mGal) Unit, For newbies.

The gal or galileo is the CGS unit of acceleration. It is defined as 1 centimetre per second squared. The symbol for the gal is Gal.

In SI units: 1 Gal = 0.01 m/s².

The acceleration due to gravity at the Earth's surface is 976 to 983 Gal; the variation is mainly with latitude and elevation.

Variations in gravitational acceleration due to mountains or masses of lesser density within the Earth's crust, are typically tens to hundreds of milligals (mGal).

The gal is named after Galileo Galilei, a physicist who made the first measurements of the acceleration due to gravity

Gerald L. Blakley
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
4K