As we travel from Mars’s equator toward the planet’s northern regions, we arrive at Coloe Fossae. This landscape is characterized by long, shallow grooves that cut across an area filled with steep valleys, scattered impact craters, and surface clues left behind by an ancient ice age.

Ice Ages on Earth and Across the Solar System
Earth has gone through several ice ages over the past 2.5 billion years. The most recent one, which reached its peak roughly 20,000 years ago, lowered Earth’s global average temperature to around 7–10 °C (up to 8 °C cooler than today).

These long-term freezes differ completely from today’s human-driven warming trend. Ice ages arise from slow, natural cycles tied to shifts in a planet’s orbit around the Sun and changes in the tilt of its rotational axis. When an ice age begins, glaciers and ice sheets expand, and as temperatures fluctuate, these ice masses repeatedly advance and retreat.

Other planets show similar patterns. Mars carries its own evidence, and the newest views from the High Resolution Stereo Camera on ESA’s Mars Express reveal how strongly these cold periods shaped the planet.