Science & Space
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Mars Cloud Forms Via Never-Before-Seen Ice Physics
A 1,100-mile cloud on Mars forms through a unique process where water vapor freezes without dust particles, a phenomenon previously unobserved in any planetary atmosphere.
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THE PRIMARY BRIEF
- 01 · The primary finding
A new study reports that Mars's 1,100-mile-long Arsia Mons Elongated Cloud forms through homogeneous nucleation, a process where water vapor freezes into ice without dust particles, marking the first observation of this phenomenon in a planetary atmosphere.
- 02 · The primary evidence
Research led by Jorge Hernández-Bernal, published in Nature Geoscience on October 7, 2026, utilized data from the European Space Agency's Mars Express orbiter to simulate extreme temperature drops and humidity spikes that enable this type of ice formation.
- 03 · Why it matters
This discovery challenges existing assumptions about cloud formation on other planets and could inform future exploration by revealing unique atmospheric physics not previously observed in nature.
A study published on October 7, 2026, in Nature Geoscience revealed that the 1,100-mile-long Arsia Mons Elongated Cloud (AMEC) on Mars forms through a process called homogeneous nucleation, marking the first observation of this phenomenon in a planetary atmosphere. The research, led by Jorge Hernández-Bernal of LMD/CNRS/Sorbonne Université in Paris, explains how water vapor directly freezes into ice crystals without requiring dust particles as seeds.
This discovery changes scientific understanding of cloud formation beyond Earth. It highlights how drastically atmospheric processes can differ between planets, offering new insights for future studies of extraterrestrial environments and challenging existing assumptions about how clouds form.
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