The Sun is a star, just like all the other stars you see at night.  The Sun, however, is much closer than any other star, so it appears much bigger and brighter.  Actually, our Sun is of average size compared to other stars.  The closest star to Earth, outside of our Sun, is in the Alpha Centauri star system, 4.3 light years away.

Active Sun -  Solar flares are visible


Solar Corona seen during eclipse (NCAR)

Sunspots visible on Sun's surface

 (photo by Ted Cook)


The Sun is approximately 94% Hydrogen and almost 6% Helium.  Elements including Carbon, Oxygen, Nitrogen and others make up the remaining less than 1%.  Inside the Sun, Hydrogen is converted to Helium by thermonuclear reactions.  These reactions produce the heat we feel and the light we see here on Earth.  Radiation in all wavelengths from x-rays to infrared, including the visible and UV, is sent out into space by these reactions.  In addition, the Sun generates magnetic fields which produce the Aurora and can also disrupt communications on Earth.  The sun also produces neutrinos that are sent out across space.


Sunspots are areas of enhanced magnetic field strength and appear dark because they are cooler than the surrounding area.  The number of sunspots vary from year to year on a cycle of 11 years, called the solar cycle.  The magnetic disturbances produced are sent into space, reaching Earth, and are attracted to the magnetic poles producing the Aurora Borealis (Northern Lights) and the Aurora Australis (Southern Lights).


The Sun is at an average distance of 93 million miles (150 million km) from Earth.

The Sun is 900,000 miles (1.4 million km) in diameter.

It takes light 8 minutes to travel from the Sun to Earth.

You could fit about 1 million Earths inside the Sun.

The Sun is approx. 4.5 to 5 billion years old (It is about middle aged).

WARNING: NEVER look directly at the Sun with your eyes!  It can cause permanent damage.  Only view the Sun using specialized equipment and filters specifically made for solar viewing.

©2016  Squak Mountain Telescope Gang

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