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Martian Spring

March 23, 2019

If you like spring, then you might want to head for Mars about now. That’s because today marks the beginning of spring in the planet’s northern hemisphere. And it’s the longest season of the year, lasting 194 Mars days.

Mars has seasons for the same reason Earth does — the planet is tilted on its axis. So as Mars orbits the Sun, the northern and southern hemispheres take turns receiving more and less sunlight. That creates the cycle of seasons.

The Martian year is almost twice as long as an Earth year. As a result, the seasons are about twice as long as well — on average. Mars’s orbit around the Sun is much more lopsided than Earth’s is, so the planet’s orbital speed varies by quite a bit. That makes the seasons uneven.

Northern spring, for example, occurs when Mars is near its farthest point from the Sun, so Mars is moving slowly. That stretches the season out. Northern autumn, on the other hand, takes place when Mars is close to the Sun, so the season is shorter — just 142 Mars days.

A Mars day, by the way, is about 40 minutes longer than an Earth day. Because of the different length, scientists usually call a Mars day by a different name — a “sol,” for solar — the time it takes the Sun to make one loop across the Martian sky.

And Mars continues to highlight our sky during our own spring season. It’s about a third of the way up the western sky as night falls, and looks like a bright orange star.

Script by Damond Benningfield

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