While talking with my girls about the weather, we noticed the weather forecast on Sarah’s phone and saw an icon of the moon and stars, and I had to explain a few things.

  1. It bothers me that “night time” is commonly represented by an icon of the moon. The moon is out durring the day just as much as it is out durring the night.
  2. Often icons like this represent the moon as a crescent, and there’s stars inside the concave part of the crescent. This is implying that the star is in front of the moon.

Do an image search for “night time weather icon” and you’ll see plenty which look like this:
night icon

So I mentioned that we’d be in big trouble if there was a star in front of the moon, and started to try to explain that many stars are much like our sun, and our sun is very big and very hot and if it was close enough to be between us and the moon like in the icon, we’d be toast.

But then I balked in my explanation, because I wasn’t sure what the relative size of the sun was to our lunar orbit. I didn’t know if the sun would actually fit inside the orbit of the moon (regardless of the consequences). So I had to look it up, and then make this graphic to get an idea of the relative sizes:

size of our sun
Click/Tap on the image for a different look at higher resolution (can you see the moon!?). Original image credit: NASA

Yeah, no way the sun is fitting between the Earth and Moon. In fact, the sun is about 3.6 times as big as the distance between the Earth and moon!

Our sun is so big, if the Earth was in the center of a ball the diameter of the Moon’s orbit, the Sun could almost hold two of these balls side by side!

The details:
Our sun is 1,391,684 km in diameter (1712 pixels). [Sun]
The Earth is 12,742 km in diameter (~16 pixels). [Earth]
The Moon is 3 474.8 km in diameter (~4 pixels). [Moon]
The average distance from the center of the Earth to the center of the moon is 384,400 km (~473 pixels). [ref])
* Please note, all pixel size references are to the full scale image

1,391,684 km / (384,400 km x 2) = 1.81

The Sun is 1.81 times as big as the average diameter of the Moon’s orbit around Earth!

WOW, the sun is big.

Now that we know what the relative size of the Sun is to the Lunar Orbit, take a look at this for an idea of how big (or small!) our sun is in general.

Revised June 19 2015, with updated graphic, edited content, and inclusion of sun comparison link (thanks Bob).