Tracing the Sun’s Path: A Figure 8 in the Sky

We're used to seeing the Sun rising and setting every day. It rises in the east and sets in the west. It happens all the time. But did you know that the Sun actually makes a figure 8 in the sky? This might seem strange, but it's true. It just takes longer and you have to be paying attention!

How does this happen?

Well, the Earth is tilted with respect to the Sun and, as it orbits the Sun, it is constantly shifting. In the summer, it is tilted towards the Sun and in the winter, it is tilted away from the Sun. It takes 365 days for it to go around the Sun one time.

When the Earth is tilted toward the Sun around June 20–21 (the summer solstice), the Sun appears high in the sky. When the Earth is tilted away from the Sun around December 21–22 (the winter solstice), it appears much lower. Over the course of the year, the combination of the Earth’s tilt and its elliptical orbit makes the Sun’s position in the sky trace a figure-eight pattern!

Test it Yourself!

If you want to see it for yourself, you can, but it will take a lot of patience. What you have to do is set up a camera and take a picture of the Sun once a week for an entire year and then stack all the images together. Another way is to make a pinhole camera with some photographic paper and expose it once a week for a year. 

When you do that, you can see in the picture that you get lots of little pictures of the Sun and they make an 8! The shape of this 8 changes if you're really far north or really far south, but it's an 8 in the sky!

Watch for Where the Sun is in the Sky

We just had the fall equinox on September 22 and that means that the Sun is right near where the two loops cross. On December 21, the Sun will be at the bottom of the loop. So the next time you see the Sun, remember that it changes how high it gets throughout the year because of the Earth's tilt as it orbits the Sun!