Solar Eclipse Why is the sun hidden? June 24, 17:19

A partial solar eclipse observed in Japan for the first time in half a year. Do you all understand how solar eclipses work? Let's think while looking at the entrance examination problem.

Challenge the entrance exam!

Problem
"The phenomenon that one celestial body covers part or all of another celestial body is called "eclipse." The phenomenon of the sun being hidden is called an eclipse. was seen. This can be seen in Hokkaido again in 2030. in addition, in 2035 you can see the total solar eclipse that will be hidden in the sun all month in the northern Kanto region from Hokuriku.
the sun from the earth Why does it become an annular eclipse or a total eclipse if the distance to is unchanged?"

The right is an annular solar eclipse and the left is a total solar eclipse. Why do different phenomena occur even though the sun and moon are the same? We interviewed Hidehiko Agata, Associate Professor at the National Astronomical Observatory of Japan.

Earth, Moon and Sun aligned

First of all, what kind of phenomenon is eclipse in a nutshell?

Mr. Agata
"The phenomenon that the sun, the moon and the earth line up in a straight line. The moon hides the sun as seen from the earth."

Seen from space, when the earth, the moon, and the sun line up in a straight line, the light of the sun is blocked by the moon, and the shadow of the moon falls on the earth. You can see the solar eclipse in this shadow.

Chance ratio

Next, it is said that there is a secret in the distance between the earth and the moon, the sun, and the size of each. The size of the moon is about a quarter of the earth. Why can we hide the big sun, though it is so small?

The distance from the earth to the sun and the distance from the earth to the moon are 400:1.

On the other hand, the ratio of the diameter of the sun to the moon is about 400 to 1. Therefore, if the sun, the moon, and the earth line up, they will overlap.

Mr. Agata
"Two round objects of different sizes, the sun and the moon, happen to appear to be the same size from the earth. That is a very lucky coincidence."

Difference between total solar eclipse and annular solar eclipse

Then, what is the difference between the total solar eclipse and the annular solar eclipse in question?

The moon travels around the earth in a slightly elliptical shape. Therefore, it may be closer or farther from the earth.

If the moon completely covers the sun, a total solar eclipse will result. If the moon is farther from the earth than that time, the apparent moon becomes smaller. It is an annular solar eclipse because the sun cannot be completely covered.

Mr. Agata
"If the distance between the sun and the earth doesn't change in this problem, I think the reason why the size changes apparently is that the moon will be closer or farther. This is probably noticeable even by elementary school students. I think that is the case."

Even if you don't know that the moon's orbit is an ellipse, it's a question that you can answer if you understand that the size of your appearance changes with the sense of perspective. Mr. Agata says that solar eclipse is a miracle-like phenomenon that was born from chance.

Mr. Agata
“Solar eclipse is a very mysterious phenomenon, and the more you know the reason, the more lucky you are to be able to see the eclipse. Youths, children in particular. I hope they will be interested.''

So the answer is "the distance from the earth to the moon changes."

In this solar eclipse, annular solar eclipse was seen in Africa, India, China, etc.

The closer to the place where an annular solar eclipse is, the more chips are lacking, so in Naha, more than 80% of the diameter is missing, and the ratio of chipping becomes smaller toward the north.

Although there was a problem, the ring eclipse in Japan can be seen in Hokkaido in 2030. In 2035, a total solar eclipse will be seen where the sun is completely hidden from Hokuriku to the northern Kanto region. It's a little ahead, but let's look forward to it.

“Weekly Marukai News” (broadcast at 9 am on Saturday), “Migake, Curiosity!”, delves into the news every week, focusing on current affairs issues that were presented in the entrance examination.
Let's think "Why?" and "the first place" that you really want to know as Kamakura Caster!