A large crater in Meridiani Planum on Mars, about 20 kilometers (12.4 miles) northwest of Opportunity's landing site and 42 kilometers (24.6 miles) northwest of Endeavour Crater, where Opportunity is right now. The crater is older than Victoria Crater (another target of Opportunity's), which is clear because it is more filled in with sediments and eroded. Credit: NASA/JPL/University of Arizona
Mars, that ever-changing and beautiful Red Planet practically next door to us, is one of the most well-studied places humans have in the universe. We’ve sent spacecraft there for about 50 years. Yet there’s still a lot of mysteries out there.
NASA’s Mars Reconnaissance Orbiter is among the investigating spacecraft in the area checking out the planet’s past and looking for any interesting clues to tell us more about how Mars — and the Earth, and the solar system, and planets in general — formed. Mars had a wetter past (as the rovers have showed us), but where the water went and why its atmosphere are so thin are among the things scientists are trying to understand.
Luckily for us, the catalog of the University of Arizona’s High Resolution Imaging Science Experiment (HiRISE) is easily available online for all of us to marvel at. Here are just some of the pictures sent back from across the solar system. To see more, look below and check out this HiRISE web page.
This image from Mars shows a variety of sandy features: ripples, transverse aeolian ridges (which are larger and lighter), dunes (dark) and draa (very large bedforms that are greater than 1 kilometer or 0.62 miles). Credit: NASA/JPL/University of Arizona
A Martian alluvial fan on the floor of a 60-kilometer (38-mile) crater near the equator of Mars. Scientists commonly study these features to learn more about the Red Planet’s wet past. Credit: NASA/JPL/University of Arizona
Shiny dunes on Mars taken by the HiRISE camera on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona
Dunes migrating across the surface of Mars. Picture taken by the HiRISE camera on the Mars Reconnaissance Orbiter. Credit: NASA/JPL/University of Arizona
By Elizabeth Howell
Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.