Tropical year

Okay kiddo, have you ever noticed that the days are longer in the summertime and shorter in the wintertime? That's because the Earth goes around the Sun once every 365 and a quarter days, and that's called a tropical year.

Now, a tropical year is how long it takes for the Earth to return to the same position relative to the Sun. But why doesn't it take exactly 365 days? Well, that's because the Earth's orbit around the Sun is not a perfect circle, it's more like an oval or ellipse.

That means that sometimes the Earth is closer to the Sun and sometimes it's farther away. And when the Earth is farther away, it travels a little slower in its orbit, and when it's closer, it travels a little faster.

So even though it takes about 365 and a quarter days for the Earth to go around the Sun, we add an extra day to the calendar every four years (that's called a leap year) to keep everything in sync with the seasons.

And that's basically what a tropical year is, a year that takes into account the Earth's orbit around the Sun and the changing length of the seasons. Hope that makes sense, little one!