What are the details of the motions of the Earth-Sun-Moon system? Why is it that in January the Earth is closer to the Sun? We’ll be learning all about that in this post.

Earth’s Rotation Around the Sun

Earth’s orbit around the Sun is in the shape of an ellipse, which is an imperfect circle. This orbit takes 365.25 days, which is why we have a leap year every 4 years, to make sure that our calendars are up to speed with Earth’s orbit. As Earth orbits around the sun, it also rotates on its axis once every 24 hours.

Since Earth rotates on an axis, each hemisphere of Earth is tilted either toward or away from the sun for nearly half of the year. The tilt of Earth’s rotational axis is the reason Earth experiences seasonal changes. For example, when the Northern Hemisphere is tilted toward the sun, the season is summer. At the same time, the Southern Hemisphere is tilted away from the Sun, making its weather winter. And vice versa as the Southern Hemisphere begins to tilt towards the sun and the Northern Hemisphere tilts away from the sun.

The Resilient Earth

Due to the tilt of Earth’s axis, different regions on Earth have days and nights of different lengths. The variations in the amount of sunlight affect the length of the day and night in our seasons. When a certain hemisphere is tilted towards Earth, that hemisphere experiences summer and longer days and shorter nights. When the hemisphere is tilted away from Earth, it experiences winter and shorter days and longer nights.


Earth and the Moon

Just like the orbit of the Earth around the Sun, the Moon’s orbit around the Earth is in the form of an ellipse. It’s closest to the Earth at its perigee, which is when the moon is closest to the Earth. The apogee is when the moon is the farthest from Earth.


Due to its elliptical orbit, the moon looks 30% bigger during the perigee rather than during the apogee. During the perigee, or when the moon is closes to Earth, astronomers can see characteristics of the moon’s surface in greater detail.


To help you better understand this concept, it’s recommended that you create a model of the earth, sun, and moon. Of course, it will not be to scale, but the imperfect elliptical orbits and the tilted axis will become clear to you. Try building the model as to where the objects will be able to move as you push it, or even install motors and use code to let your model run. An Arduino is recommended for the programming part of the project. Have fun! Let your imagination run wild.


The orbit of the Earth around the sun affects our daily lives, though we may not think much of it. We tend to go on with our normal day-to-day lives, not thinking of what makes the sun shine on our faces. Why is the weather what it is? It’s all science. Science is the basis of what affects us, and why it affects us the way it does. Although, even the best scientists and physicists haven’t even scratched the surface of understanding why we exist. In scientific terms, of course. Religiously, it’s all there, right for the taking.

So, learn! Building a model is exciting and exhilarating for your inner engineer. Plus, you get to learn about science in the end. Sounds like a win-win situation to me.