We all know some things about the Sun. We know it is powered by thermonuclear fusion, that it is a G-2 type spectral star, and that it is the primary energy source for the Earth. Many of us have seen a solar eclipse when the Moon blocks out the photosphere of the Sun and lets us see its corona. We know that the Sun is not just a ball of fire but a complex globe. Here are some more interesting Sun facts that are relatively new to us:
The light that we see coming from the Sun is from its photosphere. The photosphere is a thin incandescent layer that is just 200 miles (322 km) thick. That is less than one four-thousandth of the Sun’s diameter and is like the outer skin of an onion, only thinner than that.
The energy of the Sun is created in its core, which is a very small sphere, just one two-hundredth of the Sun’s volume. Every second that small ball emits the energy of 96 billion 1-megaton hydrogen bombs. The Sun’s weight decreases by 4 million tons every second as mass is turned into energy and radiated from the photosphere.
The Sun spins on its axis once a month, just as the Moon does. The center 70% of the Sun spins uniformly like a solid ball. The remaining 30% has different spins with the poles turning more slowly than the equator. These zones spinning at different speeds meet in a recently discovered zone 130,000 miles (209,000 km) below the surface. That zone is called the tachocline, and it’s where the Sun’s magnetic field originates.
Sunspots are areas where the local magnetic field is 5,000 times stronger than on the rest of the surface. The stronger magnetic field constricts the Sun’s plasma. When sunspots are rare, it seems that Earth’s climate becomes colder. Starting in 1645 there were few sunspots for 70 years. During that time, Earth became colder, people abandoned fishing colonies in Iceland and Greenland, and the Thames River and Venice canals went through periods of freezing solid.
As scientists probe more in-depth, they learn many interesting Sun facts. Just as in many other areas, the more we learn, the more questions we have. What effect do sunspots have on life on Earth? How can they affect our climate? What will happen in the next sunspot cycle? Tomorrow, we will look more into questions about sunspots. As we learn more interesting Sun facts, we realize the amazing design wisdom of the Creator to make life on this planet possible.
— John N. Clayton © 2019
Data from Astronomy magazine, July 2019, page 20.