1) Impact crater on Mars 
[crater] Oudemans is a crater on Mars named after Jean Abraham Chrétien Oudemans (December 16, 1827 – December 14, 1906), a Dutch astronomer. Oudemans Crater is an example of very pristine morphology since small features in its ejecta and on its floor are preserved. Being young, it does not display water erosion on its rim. Unlike some c...