Blue Martian Dunes
The Mars Reconnaissance Orbiter has imaged these sand dunes five times, watching as they slowly change from the two wind sources converging over them.
![PIA20369.jpg](https://th-thumbnailer.cdn-si-edu.com/fEKYAv9WfmcM9pqq4w_PXyLfDx8=/1000x750/filters:no_upscale()/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/filer/c0/23/c0235b4d-82db-49a6-9b5d-299e521595ed/pia20369.jpg)
The Mars Reconnaissance Orbiter has imaged these sand dunes five times, watching as they slowly change from the two wind sources converging over them.