Chapter 1
The flat myth and the ancient curve
Chapter 2
The spin that squashed the poles
Chapter 3
The lumpy gravity of the geoid
Chapter 4
Mapping a round world on a flat screen
YOUR GOAL
Master of The lumpy potato we call home
Ch 3 · The lumpy gravity of the geoid
007skaty Convective currents of rising and sinking mantle rock create permanent mass variations, forming the largest lumps on Earth's
BETA
007skaty Spin the planet to discover why our wobbly Earth is not a perfect sphere.
Fun Fact
Satellite nicknames: The twin satellites of the GRACE mission, which mapped Earth's gravity, were nicknamed 'Tom' and 'Jerry' after the famous cartoon.
Glossary
geoid (noun)
The hypothetical shape of the earth, coinciding with mean sea level and its imagined extension under land areas. This model drops to its lowest point of 106 meters below the ellipsoid near southern India.
The hypothetical shape of the earth, coinciding with mean sea level and its imagined extension under land areas. This model drops to its lowest point of 106 meters below the ellipsoid near southern India.
Quiz
Which European Space Agency satellite, launched in 2009, measured gravity with centimeter accuracy?
Quiz
What was the name of the joint NASA-German satellite mission launched in 2002 to map gravity?
Quiz
What is the maximum deviation of the geoid's lumpy surface compared to a smooth ellipsoid?