Do Other Planets Have Seasons? Why Earth's Are Rare

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Tormod Guldvog

Editor & Duowriter

May 6, 2025

Key Takeaways

• Earth's stable seasons depend on the Moon preventing axis wobble.
• Mars's tilt has swung between 10 and 40 degrees over time.
• Uranus sits tilted 98 degrees, creating 42-year polar seasons.

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Gongjie Li studies how planets wobble, and what she found about Earth surprised her.

The Georgia Tech astrophysicist has spent years asking whether other planets have seasons like Earth does, and tracking how their axial tilts shift over time. Her work suggests that Earth's steady four-season rhythm, the predictable cycle that agriculture and ecosystems depend on, is not the cosmic default.

It may be a fortunate anomaly.

Mars Looks Like Earth's Seasonal Twin, But It Isn't

Mars tilts at roughly 25 degrees, strikingly close to Earth's 23.5. Shane Byrne, a planetary science professor at the University of Arizona who studies Martian climate records, sees the resemblance. Both planets have polar regions that alternate between permanent daylight and permanent darkness each half year.

More on Mars

Did Mars Once Have a Tropical Climate With Millions of Years of Rainfall?

Light-colored rocks discovered by NASA's Perseverance rover suggest the Red Planet was far wetter than scientists imagined.

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The winters tell a different story.

Temperatures on Mars drop low enough for the atmosphere itself to freeze, coating the surface in carbon dioxide ice rather than the water ice familiar on Earth. Orbital shape adds another layer of complexity.

Planets with highly elliptical paths, like Mercury and Pluto, experience seasonal heating variations from changing distance to the Sun, independent of any tilt at all.

But the critical difference for Mars is stability. Models published in the journal Earth and Planetary Science Letters in 2018 showed that the planet's tilt has swung between 10 and more than 40 degrees over billions of years.

What looks like a twin of Earth today is a planet whose seasons have been reshuffled repeatedly across geological time.

The current similarity is coincidence.

Earth's Moon Keeps the Seasons Steady

The reason Earth's tilt holds firm comes down to a single companion.

Our Moon is massive enough to pull on Earth's spin axis and force it to precess, or wobble, faster than it otherwise would. That faster wobble prevents a phenomenon called spin-orbit resonance, where gravitational tugs from neighboring planets push a planet's tilt at exactly the wrong frequency, amplifying it over millions of years.

Think of pushing a child on a swing at precisely the right interval. Each push builds the arc higher. Without the Moon acting as a damper, Earth's tilt could have drifted just as wildly as its neighbor's.

Mars has no such protector, and its climate has paid the price across billions of years.

Li considers it fortunate: Earth's spin axis has stayed remarkably steady.

Uranus Reveals the Extreme

At the far end of the spectrum sits Uranus, tilted 98 degrees from vertical.

The planet rolls around the Sun on its side, producing seasonal extremes unlike anything else in the solar system. Each pole receives about 42 years of continuous sunlight followed by 42 years of total darkness, spread across an 84-year orbit. During the brief equinoxes, sunlight strikes the equator, producing rapid 17-hour day-night cycles before the slow roll returns to decades of polar exposure.

When Voyager 2 flew past Uranus in 1986, it caught the planet deep in its southern summer. The spacecraft saw a nearly featureless blue world. In the decades since, as Uranus has moved through its orbit, telescopes have watched dramatic cloud patterns emerge and shift with the changing seasons.

Li argues that Earth's stable spin axis has been essential for complex life to develop here. Scientists searching for habitable exoplanets now recognize that the right distance from a star is not enough.

More On Planets

How Did Planets Form? The Gas Giants Arrived First

Gas giants like Jupiter formed first in our solar system, then shaped Earth's position in the habitable zone through gravitational migration.

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They also need worlds with stable seasonal patterns.

The exoplanet Kepler-186f offers some encouragement, orbiting far enough from its sibling planets that gravitational disturbance stays minimal. Even without a large moon, its obliquity appears to hold steady.

For most worlds, though, the pattern looks more like Mars or Uranus: seasons that drift across geological time or stretch across human lifetimes.

Earth's predictable cycle, maintained by a Moon at just the right mass and distance, may be far rarer than any of us assumed.

Sources

• Primary Source: Do other planets have seasons? (Live Science)
• Additional Context:
  • Earth isn't the only planet with seasons (The Conversation)
  • Seasons on other planets (ESA)
  • The strange seasons of Uranus (EarthSky)

Tormod Guldvog

Editor & Duowriter

Tormod Guldvog is the editor of Science Reader, covering the space where human and artificial intelligence meet. With a background in technology and science communication, he writes about how AI is changing scientific discovery — and what that means for us. More about Science Reader

Cite this article

Tormod Guldvog. (2025, May 6). Do Other Planets Have Seasons? Why Earth's Are Rare. Science Reader. https://sciencereader.com/do-other-planets-have-seasons/