While we gear up for the New Year on Earth, Mars scientists are already celebrating an exciting event: the end of the Martian year. Mars completed its orbit around the Sun on November 12, 2024, and as its northern hemisphere transitions from winter to spring, dramatic changes are unfolding across the Red Planet.
Unlike Earth’s gradual spring thaw, Mars experiences a more explosive spring due to its thin atmosphere. The planet’s ice does not melt; instead, it sublimates—turning directly into gas. This transition leads to fascinating, often violent phenomena, reshaping the Martian landscape in unique ways. Here’s a glimpse into some of these awe-inspiring changes:
1. Frost Avalanches
In 2015, NASA’s Mars Reconnaissance Orbiter (MRO) captured a dramatic moment: a 66-foot-wide (20-meter-wide) chunk of carbon dioxide frost falling through the atmosphere. During Martian spring, ice fractures and breaks, resulting in avalanches that tumble down cliffsides. These events highlight the differences between Earth and Mars, where cracks and explosions replace the slow melting of ice.
2. Gas Geysers
Another captivating feature of Martian spring is the eruption of gas geysers. These explosive jets of carbon dioxide ice shoot into the air, creating dark fans of sand and dust on the surface. The phenomenon occurs when sunlight sublimates the lower layers of ice, causing pressure to build up and eventually burst out of the surface, sending debris flying. These geysers are most prominent during the northern hemisphere’s spring, but larger geysers will emerge in the southern hemisphere in December 2025.
3. Spiders on Mars
In the northern hemisphere, once the carbon dioxide ice sublimates, the underlying dirt is left with intricate, spider-like markings. These araneiform terrains look like giant spider legs from space. They are a result of the same gas geysers, which leave behind scour marks that resemble the legs of a spider once the ice melts. This eerie phenomenon is just one of the many ways Martian spring redefines the planet’s surface.
4. Powerful Winds
The Martian north pole is home to a giant ice cap, which becomes increasingly dynamic as spring approaches. As temperatures rise, winds pick up and carve deep troughs into the ice cap, creating spirals reminiscent of milk swirling in a café latte. These winds, much like Earth’s Santa Ana or Chinook winds, increase in speed and temperature as they pass through the troughs, reshaping the Martian landscape. The winds also influence sand dunes, causing them to migrate as the frost melts.
5. Wandering Dunes
As the frost on Martian dunes melts, the sands begin to shift. The winds that shape the north pole also play a role in moving these dunes, causing them to migrate across the landscape. This process is similar to the shifting of dunes on Earth, but with the added twist of frost locking them in place during the winter months.
Conclusion: A Unique Martian Spring
Each year on Mars brings different patterns of sublimation, wind, and ice activity, resulting in variations in how these phenomena unfold. The southern hemisphere of Mars also experiences its own unique springtime effects. Through the observations of NASA’s MRO and the study of these extraordinary processes, scientists continue to unlock the mysteries of the Red Planet’s dynamic surface, offering new insights into the forces that shape this alien world.