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The Sun, Sol

Age     about 4.5 billion years
Average distance from Earth     1 astronomical unit (AU) or 92,960,000 miles
Diameter     1,390,000 km
Mass     1.989e30 kg
Temperature     5,800 K (surface)
    15.6 million K (core)
The Sun is often called a yellow dwarf or G dwarf star, and contains more than 99.8% of the total mass of our solar system. The Sun rotates faster at its equator than at its poles. Sunspots, which appear as dark areas on the Sun’s surface, are regions of intense magnetic activity and usually exist as pairs with opposite magnetic polarity. These magnetic fields are the source of solar flares and coronal mass ejections. In addition to heat and light, the Sun also emits a low density stream of charged particles (mostly electrons and protons) known as the solar wind. The solar wind and the energy particles ejected by solar flares can have dramatic effects on the Earth—power line surges, radio interference and auroral displays. The solar wind has a large effect on the tails of comets and even has measurable effects on the trajectories of spacecraft.

Our Solar System

Our solar system is located on the edge of a spiral arm called Orion’s Arm, and is one-half to two-thirds of the way (28,000 light-years) from the center of our Milky Way galaxy.

The Sun, Sol

The Inner Planets
    The Moon

The Asteroid Belt
  Dwarf planet, Ceres
  Asteroid, Ida
  Asteroid, Vesta
  Asteroid, Eros

The Outer Planets

The Kuiper Belt
  Dwarf planet, Pluto
  Dwarf planet, Eris

The Oort Cloud
  Dwarf planet, Sedna
  Comet Halley
  Comet Hale-Bopp

  Glossary of Terms
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