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The Changing Sun
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The Sun changes on many different timescales.
On geological timescales of billions of years, the Sun
slowly brightens. Eventually, the Sun will expand and become
a red giant, ungulfing Mercury, Venus, the Earth, and perhaps
Mars. Five billion years from now, Pluto will be a balmy world
with oceans 300 miles deep!
On human timescales of months to years, the Sun also changes.
As in terrestrial storms, sunspots come and go over weeks to months.
The average number of spots varies over a 22 year period known as
the sunspot cycle. Several SSP scientists study these changes.
On shorter timescales of days, the Sun forms giant prominences
and ejects pulses of material into the Solar System. These solar
storms affect satellites orbiting the Earth and can disrupt telephone
service, interfere with radio/TV broadcasts, and produce surges in
the electric power grid. SSP scientists study these phenomena using
satellites, including UVCS
Finally, the Sun pulsates.
Leighton & Noyes
discovered a 5 minute oscillation in the 1960's. Since then, astronomers
have identified other oscillations with periods of minutes to hours.
Several SSP scientists study the origin of these pulsations.
All of these variations teach us how the Sun works and how the
changing Sun affects the Earth and other objects in the Solar
System.
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