The Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment, or HiRISE, captured this view of a recent impact crater on the Red Planet. According to a NASA description, “the new crater and its ejecta have distinctive color patterns. Once the colors have faded in a few decades, this new crater will still be distinctive compared to the secondaries by having a deeper cavity compared to its diameter.” North is up.
Vast valley networks on Mars have suggested that water may have flowed there for millions of years. Now a study at Brown University suggests the valleys could have been carved by much less water in as little as a few hundred to 10,000 years. The findings are consistent with the idea that early Mars may have been cold and icy, with surface water flowing sporadically in response to short-term climate changes.