Earth has a star {Sun}.
location
Sun is in galaxy horizontal plane, 27,000 light-years, 2/3 galaxy radius, from galaxy center, in Sagittarius arm.
orbit
Orbit around galaxy takes 2.5 x 10^6 years.
speed
Speed through space is 12 miles/second. Speed around galaxy is 150 miles/second.
formation
Sun and solar system formed 4,600,000,000 years ago, from gas cloud.
energy
Sun electromagnetic radiation is 10^33 ergs per second. Photons from Sun hit Earth with energy 1 eV, which is average needed for chemical reactions.
properties
Sun gas has atomic nuclei and electrons, with density 1.5 g/cm^3 at surface. Sun has average size. Mass is 2 x 10^30 kilograms, 10^6 times Earth mass. Diameter is 432,000 miles.
temperature
Temperature is 10^7 K at center and 5800 K at surface.
rotation
Equator rotates once every 27 days, around axis perpendicular to ecliptic. Polar regions rotate once every 23 to 24 days.
vibration
Sun vibrates with period 10 to 48 minutes after surface activity.
cycle
Sunspots, solar flares, and magnetic storms follow cycle of 11.1 years, with maximum at 1994 and 2005.
Physical Sciences>Astronomy>Star>Sun
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Date Modified: 2022.0224