For the last few weeks, if you’ve been admiring the colorful new flowers in your yard and the fresh green leaves on the trees, have you stopped to appreciate that they wouldn’t be growing without the amazing processes going on inside our star, the Sun? Let’s examine what’s going on.
According to our current knowledge, about four and a half billion years ago a huge cloud of mostly hydrogen gas and a little dust in our galaxy was weakly held together by gravity. A shock wave from a nearby massive star compressed the cloud causing it to heat up as gravity made it to fall together and shrink. After a few million years the core of the cloud got so hot and dense that the growing internal pressure caused the collapse to slow and then stop. Gravity tried to keep the collapse going, but the core of the cloud was so hot and dense that the hydrogen began to fuse into helium and release energy from nuclear reactions. The heat released was great enough to push back against gravity and a fairly stable balance was reached. Our star was born! The history of how we discovered this story is amazing and worth a whole shelf of books.
We theorize that the planets formed as some of the cloud’s gas and dust spiraled around the newborn Sun and coalesced into a variety of bodies (like planets, asteroids, & comets) whose characteristics depended on their distance from the new star. We’ve discovered over 5.000 planets around other stars. Their properties seem to confirm this theory. Our Earth formed in the “Goldilocks Zone” from our star, where it was not too hot, not too cold, but just the right temperature for liquid water to exist. Energy for life on Earth has depended on the Sun’s stable energy output for flowers and trees and you and me to live ever since.
There is a problem though. The Sun produces just enough energy to hold itself up against collapse by fusing hydrogen in its hot core. The Sun began its life with a limited amount of hydrogen fuel. About half of that fuel has been depleted. When the fuel is used up, the Sun will collapse and die. Don’t worry though. We expect this won’t happen for billions of years.
The Sun is going to be of special interest in the next year as our Moon will pass in front of the Sun twice and block its light on the Earth. These solar eclipses are rare and will happen this year on October 14, and then on April 8, 2024. In Mississippi, we will see the Sun only partially covered by the Moon.
If you would like to learn more about the Sun and the coming eclipses, there will be a program on Friday April 28 at 5:30 PM in Kosciusko at the Mid-Mississippi Library. The event will include observing the Sun with special solar telescopes, hands on activities, and an indoor slide show.
This is a family event to put on your calendar. I hope to see you there.
For questions or comments: James Hill, Mississippi NASA/JPL Solar System Ambassador. jhill6333@gmail.com
