Changes are always taking place on Mars, from factors like seasonal variations and wind. But there’s one other aspect that changes the surface of Mar quite often: impacts.
Here’s a new impact crater that was seen by the Mars Reconnaissance Orbiter. Exactly when the crater formed is not known, but this image was taken on July 24, 2020 and in a previous image of this site taken in 2018, the crater is not there.
Is this a closeup look at a tree stump, or an orbital view of an impact crater? At first glance, it might be hard to tell. But this image of a crater on Mars provides planetary scientists almost the same kind of climate history data about the Red Planet as tree rings provide to climate scientists here on Earth.
New research shows that Mars has faced a constant rain of meteors during the last 600 million years. This finding contradicts previous research showing that the impact rate has varied, with prominent activity spikes. Why would anyone care how often meteors rained down on Mars, a planet that’s been dead for billions of years?
Because whatever Mars was subjected to, Earth was also likely subjected to.
While Mars is known as the Red Planet, a variety of colors can be found on the planet’s surface. Just like on Earth, the array of colors we can see in images from Mars comes from the diverse minerals on or just under the surface.
In the case of this picture, subsurface minerals show up in gullies that have eroded down the side of a a giant sand dune.
All across the Martian surface, there are preserved features that tell the story of what Mars once looked like. These include channels that were carved by flowing water, delta fans where water deposited sediment over time, and lakebeds where clay and hydrated minerals are found. In addition to telling us more about Mars’ past, the study of these features can tell us about how Mars made the transition to what it is today.
According to new research led by Brown Ph.D. student Ben Boatwright, an unnamed Martian crater in Mars southern highlands showed features that indicate the presence of water, but there is no indication of how it got there. Along with Brown professor Jim Head (his advisor), they concluded that the crater’s features are likely the result of runoff from a Martian glacier that once occupied the area.
This week we are joined by Dr. Ingrid Daubar, Planetary Scientist from Brown University studying impact cratering within our solar system. Dr. Daubar is part of a team that has been using a new AI classification tool to identify geologic features on planetary surfaces, such as Mars.
Impact craters have been called the “poor geologists’ drill,” since they allow scientists to look beneath to the subsurface of a planet without actually digging down. It’s estimated that Mars has over 600,000 craters, so there’s plenty of opportunity to peer into the Red Planet’s strata – especially with the incredible HiRISE (High Resolution Imaging Science Experiment) camera on board the Mars Reconnaissance Orbiter which has been orbiting and studying Mars from above since 2006.