Why do the constellations change in the night sky as the seasons shift?
Curious Nature
Adobe stock image/Licensed by Walking Mountains Science Center
Whether you enjoy it or not, the sun is setting earlier but the fading light is not all doom and gloom. Longer nights mean more time to look up at the stars and take in the beauty of the cosmos. As we say goodbye to those warm summer nights and welcome the crisp autumn and winter air, the stars in the night also change, creating a brand-new celestial show. So, why do the constellations change as the seasons shift? Let’s take a celestial journey to find out.
Picture the Earth like a giant spinning top, spinning around the sun. As our home planet orbits the sun, different parts of the sky become visible at night. This is because we’re not just looking out into space — we’re also moving through it. It’s like driving a car and seeing different landscapes through your window as you travel. As we travel in our path, we get different perspectives on the stars. The stars themselves are always there — it’s just our viewpoint that changes. The reason we can predict these shifts is thanks to the work of astronomers and their knowledge of Earth’s orbit and its place in our galaxy.
Astronomers and scientists have been studying these celestial movements for centuries. Many ancient civilizations, like the Babylonians and Greeks, observed and recorded the changing patterns in the night sky. In modern times, astronomers continue to use telescopes, star charts, and computer simulations to track these cosmic changes. With this knowledge of celestial motion, the constellations that appear in the night sky glide into our field of view with regular predictability throughout the year.
During the summer months, we, here in the northern hemisphere, are on the side of the Earth that faces away from the center of our Milky Way galaxy. That’s why we see a specific set of constellations, such as Cygnus the Swan and the Teapot, in the evening sky. Now, as we transition from summer to fall, our Earth keeps spinning. We begin to see the constellations from a different angle. New stars and constellations begin to pop up, like Pegasus the Winged Horse and Andromeda the Princess.
Stargazing is all about our Earth’s position in its orbit and the direction in which we’re looking.
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When winter rolls around, our location in space gives us a fresh set of constellations to admire. Orion the Hunter, Taurus the Bull, and Canis Major with the brightest star in the night sky, Sirius, all become prominent. To help piece together the stars into these constellations consider using an interactive star map such as Stellarium or a phone app such as Night Sky.
The next time you look up at the night sky and notice that the stars in the sky look different than they did a few weeks ago, remember it’s all part of Earth’s cosmic dance. Each season brings its own set of starry wonders, and the universe is always ready to put on a show, all you have to do is look up.
