Morning frost detected in Mars' ancient volcanoes, found containing 150,000 tons of water ice

In a surprising discovery, scientists have detected early morning frost on the peaks of massive volcanoes on Mars. This finding, which sheds light on the distribution of water on the Red Planet, could be crucial for future human exploration.

The frost was spotted in images taken by the European Space Agency’s (ESA) Trace Gas Orbiter, as reported in a study published in *Nature Geoscience* on Monday.

The frost was found on the calderas of Mars’ massive volcanoes, including Olympus Mons, the tallest volcano in the solar system. The frost appears in the early morning and melts as the sun rises.

Moist air from the Martian surface is carried up the slopes of the volcanoes by thin winds. When this air reaches the colder calderas, it condenses and forms frost, protected from sunlight by the shadows in the craters.

Unlike Earth, where mountaintops are usually colder than plains, Mars’ low atmospheric pressure creates a unique situation. Despite the warm temperatures and thin atmosphere, moist air can still condense into frost on these high altitudes.

The frost, although only as thick as a human hair, covers large areas on the Martian surface. Each day, approximately 150,000 tons of water in the form of frost move between the surface and the atmosphere, highlighting the dynamic nature of water on Mars.

These immense volcanoes are located in the Tharsis plateau, an elevated region nearly 5,000 kilometres (3,100 miles) wide near the Martian equator. These volcanoes have been extinct for millions of years. Among them is Olympus Mons, the largest volcano in the solar system, which is almost three times taller than Mount Everest.

The discovery of frost in this region was unexpected. Plenty of sunshine and a thin atmosphere means the temperature on these peaks is relatively warm compared to Earth, where frosty mountain tops are more common, according to a researcher from Brown University in the United States.

Additionally, the atmosphere near the Martian equator contains very little water, making condensation less likely. However, the European Space Agency’s Trace Gas Orbiter, which has been orbiting Mars since 2018, captured images when the first rays of the Sun illuminated the tops of these volcanoes, revealing a thin layer of ice.

This ice layer, only as thick as human hair, is transient and does not last long. Nevertheless, the daily frost at the summits of volcanoes such as Olympus Mons, Arsia Mons, Ascraeus Mons, and Ceraunius Tholus contains approximately 150,000 tonnes of water, which is equivalent to 60 Olympic swimming pools, according to the ESA. Researchers believe this frost is caused by a microclimate within the calderas of these massive volcanoes.

Mapping the location of water on Mars, which exists only as ice or vapour, is crucial in the quest for signs of extraterrestrial life, as liquid water is considered a fundamental ingredient for life on other planets.