Is it a coincidence that the sun and the moon are the same size?

At this particular moment in the history of the Earth - although the diameter of the Sun is 400 times larger than the Moon - the Sun is about 400 times farther away. So the sun and the moon appear almost identical in size when viewed from the earth. That is why we on earth can sometimes see the most spectacular scenes of total solar eclipses.

Since no one knows how many planets and moons there are in space, no one knows the contradictions. Astronomers have so far discovered 893 planets in distant solar systems (as of June 21, 2013), and we do not know much about their moons.

Earthsky asked Miles Stondis about similarities in the scale of the Earth's moon and sun, as seen from Earth. He is a mathematical astronomer and former professor at Yale University. He worked at Caltech's Jet Propulsion Laboratory. He has published more than 300 articles, mostly in the field of solar dynamics and astronomy.

This resemblance is unique to the planets and moons that make up our solar system, our local family in space. In other words, it does not occur with any other planets or moon in space near us.

But there may be millions or billions of undiscovered solar systems.

What are the contradictions between the moon and the sun appearing almost identically from the earth? Anyone know.

In other words, although they are very similar and attractive, the sun and moon are not always the same size as seen from Earth. In fact, the moon and sun are rarely the same size. The distance of the Moon from the Earth varies slightly in a month. So the apparent size of the moon in our sky is always changing.

For a part of each month, the Moon is farthest from the Earth in its orbit. At such times it may not be large enough to completely cover the sun. When an eclipse occurs, the outer part of the sun appears as a ring around the moon.

This type of event is called a hoop or loop eclipse. This is basically a partial eclipse. The sky is not dark. You cannot see the eclipse without special filters. However, seeing any eclipse in person is so beautiful and glamorous - and standing in line with the sun and moon!

What’s more, the Moon comes 4 inches away from the Earth every year. That is, in the past, there were no ring eclipses. All eclipses are total eclipses because the moon always seemed larger than the sun in the earth's sky.

Now the moon has some total eclipses of the sun, and some are circular when viewed from Earth.

But as the ions pass and the moon moves farther away from us, its apparent size in our sky will continue to grow smaller. Eventually, those on Earth will not see the total eclipse. All solar eclipses are annular, and the moon is not large enough to completely cover the sun.

Bottom line: the Sun is 400 times larger in diameter than the Moon - and the Sun is 400 times farther away from the Earth. So the sun and moon are almost the same size when viewed from the earth. What are the contradictions?