As someone who grew up in Michigan and Wisconsin, I saw plenty of evidence of Earth’s ice ages written in the terrain all around me. There were plenty of moraines and kettle lakes and outwash plains, and I even got to drive through the Driftless Area of SW Wisconsin on occasion when I was traveling outside of Madison. Here in the Southeast, it is much harder to find signs of the ice ages, although there are still a few remnant ecosystems here in Athens that date back that far if you know where to look. That is why I was fascinated by this story describing a recent discovery by scientists that Mars had not one but numerous ice ages in the past. EarthSky describes how the scientists determined that multiple glacial advances and retreats had occurred and shows some images of glaciers that still remain on Mars, covered by dust. You can read the article here.

A well-preserved Martian glacier seen by the HiRISE camera on the Mars Reconnaissance Orbiter spacecraft. Image via NASA/ JPL/ University of Arizona/ Arizona State University.