In mathematics, eccentricity is a parameter associated with every conic section. It can be thought of as a measure of how much the conic section deviates from being circular. In particular:
To calculate the eccentricity of any ellipse, measure the semi-major axis and call it a. Measure the semi-minor axis and call that measurement b. Now:
- eccentricity = e = √( 1 - b^{2}/a^{2})
where √ is the
square root sign.
In
astronomy, the eccentricity of an
orbit can be calculated using this formula. For example, the eccentricity of the
Earth's orbit is 0.0167.
In popular usage,
eccentricity refers to unusual or odd
behavior on the part of a person, as opposed to being
normal. Eccentric behavior is often considered whimsical or quirky, although it can also be strange and disturbing. American millionaire
Howard Hughes, for example was considered to be very eccentric, and stored his
urine in glass jars and never cut his hair or nails. Other people may have eccentric taste in
clothes, or have eccentric
hobbies or collections.
Many of history's most brilliant minds have displayed many unusual behaviors and habits, and eccentricity is sometimes thought to be a sign of genius. However, many eccentrics are cranks, rather than geniuses.
Extravagance is a kind of eccentricity, related to abundance and wastefulness.
List of notable eccentrics
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