About our Sun


Since the last quarter moon is on June 21, and the new moon is on June 29, if you want to stay up late, this will be a good time to look at the night sky. Since the dark night is going to be short for the next month, I thought I'd tell you about our universe. Today I will give you some interesting information about our Sun.

Our Sun is a local star that's relatively close to us. It's a 4.6-billion-year-old medium size yellow star and is obviously the largest object in our solar system. There is some interesting information about it. To start, it takes 25 to 29 days to make a rotation with an average of 27 days.

It's an incandescent ball of hot plasma (ionized gas) with 750 times the mass of all our planets. The core temperature is 28.3 million degrees Fahrenheit and has nuclear fusion reactions that produce helium from hydrogen. It generates huge amounts of energy that escape from the Sun as heat, light, and other types of radiation including x-rays, UV radiation and radio waves.

There is a specific light-emitting layer called the photosphere, which is tens to hundreds of miles thick. It also emits solar wind which is a stream of charged particles. After 5 billion years, it will swell into a red giant and destroy the inner planets including Earth.

The photosphere is its visible surface with a temperature of 9,570 degrees F. Beneath that is the convection zone where hot gas bubbles rise to the surface, cool, and then sink back down. The next layer down is the radioactive zone where energy is radiated from the core to the convection zone. The core makes up 2% of the Sun's volume and about 60% of its mass.

The atmosphere has three layers. Just above the brilliant photosphere lies the chromosphere which is about 1,200 miles deep. Above that is a thin irregular layer called the transition region where the temperature rises from 36,000 degrees F to 1.8 million degrees F. The outer layer is the corona which is a million times less dense than the photosphere and extends for millions of miles into space.

During a solar eclipse, the corona appears as a halo around the Sun. It looks like a hazy red-orange area above the Sun. The corona is so hot that some of its particles have enough energy to escape from the Sun's gravity and stream into space. This is called solar wind.

Sometimes they come to Earth at 1 million mph and collide with atoms to create an Aurora. In our Northern Hemisphere, it's called Northern Lights or Aurora Borealis. It's most often seen 10-20 degrees from the North Pole, but occasionally it can move this far south. But in all my life, I've never seen one. Please remember that you can't observe the Sun without using a special solar filter to protect your eyes.