Spheroid
A spheroid, or ellipsoid of revolution, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters.
If the ellipse is rotated about its major axis, the result is a prolate (elongated) spheroid, like an American football or rugby ball. If the ellipse is rotated about its minor axis, the result is an oblate (flattened) spheroid, like a lentil. If the generating ellipse is a circle, the result is a sphere. A spheroid has circular symmetry.
Because of the combined effects of gravity and rotation, the Earth's shape is not quite a sphere but instead is slightly flattened in the direction of its axis. For that reason, in cartography the Earth is often approximated by an oblate spheroid instead of a sphere. The current World Geodetic System model uses a spheroid whose radius is 6,378.137 km at the equator and 6,356.752 km at the poles.
The word spheroid originally meant an approximately spherical body, admitting irregularities even beyond the bi- or tri-axial ellipsoidal shape, and that is how it is used in some older papers on geodesy (for example, referring to truncated spherical harmonic expansions of the Earth).
Podcasts:
Spheroid
ALBUMS
- Collection 1: Opening released: 2001
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by Safri Duo
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by Safri Duo
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by Safri Duo
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by Safri Duo
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by Safri Duo
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by Safri Duo
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by Safri Duo
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by Safri Duo
SWEET FREEDOM
by: Safri DuoNo more runnin’ down the wrong road
Dancin’ to a different drum
Can’t you see what’s goin’ on
Deep inside your heart
Always searchin’ for the real thing
Livin’ like it’s far away
Leave all the madness in yesterday
You’re holdin’ the key
When you believe it
Shine sweet freedom
Shine your light on me
You are the magic
You’re right where I wanna be
Oh sweet freedom carry me along
We’ll keep the spirit alive on and on
We’ll be dancin’ in the moonlight
Sailin' with the risin' sun
Livin’ like we’ve never done
Goin’ all the way
Reachin’ out to meet the changes
Touchin’ every shining star
The light of tomorrow is right where we are
There’s no turnin’ back
From what I’m feeling
Shine sweet freedom
Shine your light on me
You are the magic
You’re right where I wanna be
Oh sweet freedom carry me along
We’ll keep the spirit alive on and on
Coz there’ll be starlight all night
When we’re close together
Share those feelings dancin' in your eyes
Tonight they’re guiding us