## How big is the Moon compared to the Sun and Earth?

by Wayne Boyd

This is an interesting question. I’m going to answer it with illustrations.

In answer to “How big is the Moon compared to the Sun and Earth?” I’m going to give you some illustrations that will put all of this into perspective. First, let’s look at a comparison of our Moon with Pluto and other dwarf planets in our solar system. Here’s a picture to illustrate.

So here you can see our Moon is quite large! In fact, it’s so large, it’s bigger than all of the known dwarf planets in our solar system, including Pluto!

Even though the Moon is bigger than Pluto, it’s not big compared to Earth. Here’s the comparison of that.

So the moon is relatively small compared to our big Earth. But when you bring the Sun into the mix, then you have to understand that Earth itself is not very big. In fact, the Sun is so big it dwarfs even Jupiter. Here’s the image of that comparison:

So to sum up, our Moon is big compared to Pluto and other dwarf planets in our solar system, but small compared to Earth. Earth itself is like a pebble of sand compared to the size of our Sun. Fortunately for us, the sun is also a long way away, and therefore looms the same relative size as the Moon in our sky.

I hope that sheds some light on the subject! Thanks for asking a cool question.

## Will the moon or Mars have the first permanent human population?

In my opinion, hopefully neither place because there is no valuable reason for humans other than our robots to establish a presence in either place. Robots are expendable and you don’t have to bring them back. They can transmit what they find. Both are dead planets. Both have no reason to settle there.

## The Moon is not as Close as you Think!

Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune could all fit in the gap between the Earth and our Moon with about 4,990 miles to spare

Think of Earth as a basketball and the moon like a tennis ball. How far would you have to place them apart to approximate the distance between the Earth and Moon? Five feet? Ten feet? Twenty feet? Nope! Further even then that! A tennis ball would then have to be about 24 feet from the basketball to be of the proper scale. Farther than most people visualize.
This is how it looks (See image). Kind of surprising. The moon looks bigger to us than that, doesn’t it? Well, no it doesn’t. Our minds eye just makes it look bigger. Hold your thumb out at arms length. The tip of your thumb at that distance more than covers the moon. Still, the moon is the biggest thing in the night sky, and it really stands out much brighter and bigger than all the stars, relatively.
Surprisingly, people really do think the Moon is closer to the Earth than it is. You can see from the photo taking a “mere trip to the Moon” is no easy task!
Here’s a statistic for you! Think how big Jupiter, Saturn, Uranus and Neptune, the gas giants, are in relationship to our tiny Earth.
Yet our Moon is so far from Earth that Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune could all fit in the gap with about 4,990 miles to spare (using the average Earth-moon distance of 238,555 miles).

## How Big does a Moon Have to Be?

Not very big! It would just have to be natural. Not made by man! And it wouldn’t have to be there for very long either. Just long enough for it to be in orbit.

The astronomical community doesn’t have a definition for moon other than it has to be a natural object. Thus captured asteroids can be moons. It’s even possible for a moon to have a moon!

Mars has two moons, neither of which are large enough to be round. Objects in space get round due to their own gravity. The first image above is Deimos and the second is Phobos, the Martian Moons. Deimos (top) is the smallest. It has a mean radius of 3.9 miles.

## Would there be a big advantage putting a SETI listening post on the far side of the moon?

I assume the moon would act as a large shield to diminish the radio “noise” from Earth. Obviously there would be an issue getting any information back home for the same reason.

Definitely. I once spoke to an astronomer about this. It would be a huge advantage for us to have that. The problem is building it. Just imagine. The moon is a long way away and it’s a vacuum. All that heavy equipment would have to be transported in hundreds of trips and dropped off, then assembled by … whom? Robots? People? It would be great to have it but unlikely to be built.