In a few days, a total solar eclipse will cross the full width of the United States, and you can give credit for that to the just right moon.
We have looked at the “how” and “why” of total solar eclipses. We have considered what value total solar eclipses have. We have seen that a total eclipse helped to confirm a very important scientific principle. Also, we pointed out that solar eclipses happen only at the time of the new moon when the Moon is between the Earth and the Sun.
A new moon occurs about every 29 days, so why doesn’t an eclipse happen at each new moon? That’s because the plane of the orbit of the Moon around the Earth is about five degrees off from the orbital path of the Earth around the Sun. Because of that difference, a solar eclipse happens only when the Moon crosses the path of Earth’s orbit around the Sun (called the ecliptic). A TOTAL solar eclipse happens only when the Sun and Moon are exactly aligned.
What would happen if the orbit of the Moon were on the same plane as the ecliptic? At every new moon we would have a total solar eclipse, and at every full moon, we would have a total lunar eclipse. So the Sun would go dark in the daytime somewhere on Earth every month, and the full Moon would also go dark monthly. The influence of the Sun’s gravity on the lunar orbit might cause more serious problems.
No other planet has a moon that plays such an important part in creating an environment suitable for life. The Moon is right where it should be to serve life on Earth. Our just right Moon lights the night, creates the tides that clean our estuaries, stabilizes Earth’s rotation, and occasionally provides a total solar eclipse that gives us a glimpse of God’s marvelous design of our solar system.
–Roland Earnst © 2017
Here is an interesting story of how a solar eclipse helped to confirm a scientific theory and demonstrated the value of a total solar eclipse.
Yesterday, we pointed out that it’s more than a “marvelous coincidence” that the Moon can exactly block our view of the much larger Sun. It’s an evidence of design. When the Moon hides the Sun’s photosphere, scientists can study the chromosphere and the corona to learn more about the Sun and how it affects life on Earth.
In 1687 Isaac Newton presented his universal law of gravitation answering many questions about gravity. One question that remained unanswered was how gravity can act through empty space.
In 1916 Albert Einstein presented his theory of general relativity in which he proposed that mass produces gravity by warping space. Planets orbit the Sun because the mass of the Sun and the planets causes space to be curved. The theory suggested that light would also follow a curved path because of this warping. Einstein calculated how much light would bend near a massive object and proposed that light from distant stars would be bent when it passes by the Sun.
Einstein’s idea seemed hard to believe, but there was no way to disprove it since the bright Sun hides any starlight passing near it. You can’t see the stars during the day.
Then in 1919, British astrophysicist Arthur Eddington made some measurements during a total solar eclipse. While the Moon blocked the Sun’s photosphere, Eddington made precise measurements of the apparent position of stars that were visible near the Sun. Comparing those measurements with the positions of the same stars at night, he confirmed that Einstein was correct. The light was bent as it passed by the Sun.
The eclipse of 1919 demonstrated the value of a total solar eclipse. Many eclipses since then have added to our scientific knowledge. Understanding how gravity warps space has allowed us to make accurate Global Positioning Satellites. We use GPS in our cars for driving, in our tractors for farming, and in our smartphones for hiking, and for many other things. God designed and engineered an amazing world and gave us the ability to understand it through scientific study. Science and faith are friends–not enemies.
–Roland Earnst © 2017
Yesterday we talked about the upcoming total solar eclipse and the fact that the Moon can completely hide the Sun from view. That seems very strange since the Sun is about 390 times larger than the Moon. By a “marvelous coincidence” the Sun is 390 times farther away than the Moon. Since the Sun is 390 times farther away, it appears to be 390 times smaller. For that reason, when we see the Moon and the Sun in the sky, they appear to be the same size.
The Moon can exactly cover the Sun’s disc which we call the photosphere. At the same time, in a total eclipse, we can see the chromosphere, which is the very bright atmosphere surrounding the Sun. We can also see what is called the corona–jets of hot gas which follow the lines of the Sun’s magnetic field. Under normal circumstances, the chromosphere and corona are invisible because of the glare from the photosphere.
Scientists have learned much about the Sun by studying what we can see only during total solar eclipses. Only during a total solar eclipse can scientists study the “solar wind” which sends out streams of particles called coronal mass ejections (CME). CMEs can travel all the way to Earth and knock out communication satellites or terrestrial power grids. Just as scientists work to predict weather on Earth to avoid catastrophes, they want to learn how to predict CMEs to prepare for something that could potentially knock out power or communication to large areas of our planet.
Scientists have also learned some interesting things about the Sun’s temperature during total eclipses. They had measured the temperature of the Sun’s surface to be 6,700 to 11,000 degrees F (3,700 to 6,200 degrees C). However, by observations made during total eclipses, they found that the temperature of the chromosphere is up to 14,000 degrees F (7,700 degrees C) and the corona is 3.5 million degrees F (2 million degrees C)! They are still trying to discover how that is possible.
Was it mere coincidence that the Moon can exactly cover the Sun? We think that God designed it that way so that we can learn how “the heavens declare the glory of God” (Psalms 19:1). We think it is not just a “marvelous coincidence,” but another example of wisdom and purpose in design. Tomorrow we will tell you about what is probably the most significant scientific discovery made during a total solar eclipse.
–Roland Earnst © 2017