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The northern and southern hemispheres of Mars are topographically distinct. Crustal thickness analyses and numerical simulations suggest a giant impact just after the crust differentiated 4.4 billion years ago as a plausible cause for this dichotomy.
International Polar Year 2007–2009 had three predecessors 125, 75 and 50 years ago. These international research efforts were not free from geopolitical interests.
Geoscientists explain women's under-representation in our field along three dominant themes: the structure of academia, historically low numbers of women, and women's views and choices. Which factor they perceive as most important depends overwhelmingly on their gender.
