I’m trying something new here: I’m going to give you a little bit of information and a teaser, and we’ll see — in the comments section — whether any of you can figure it out.
Imagine that you went outside, each and every day at the same time, and mapped the position of the Sun. What would you see?
Doing this — taking a snapshot of the Sun at the same exact time from the same exact place on different days — gives you what’s called an analemma. Now, on Earth, the top of the analemma happens during the Summer Solstice, the lowest point of the analemma happens during the Winter Solstice, and the “crossing” takes place twice a year: once on around April 15th and once (coming soon) about August 31st. Here’s an image I found on this site that illustrates what happens throughout the year to the Sun’s position:
The figure-8 shape that we see happens on some of the other planets, but not on most of them. For example, if we did the same thing on Mars, taking a picture of the Sun at the same exact time every day for a year, we would get a teardrop shape instead of a figure-8:
In fact, if you made a list of what these shapes look like on all the terrestrial planets, here’s what you’d find:
- Mercury: a single point (because a day on Mercury takes exactly two years!)
- Venus: an ellipse
- Earth: figure 8
- Mars: teardrop
- Jupiter: ellipse
- Saturn: teardrop with a teeny-tiny loop at the end
- Uranus: figure 8
- Neptune: figure 8
- Pluto: a very large figure 8
So of all the planets close to the Sun, only Earth sees a figure-8. My question for you is this: why does the Sun trace a figure-8 shaped analemma? If you want to go a little beyond that, I’ll ask you what the significance of April 15th and August 31st are, too.