Image: Martian Morse code

Image: Martian Morse code
Credit: NASA/JPL/University of Arizona

This image of dark dunes on Mars was taken on Feb. 6, 2016, at 15:16 local Mars time by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. These dunes are influenced by local topography. The shape and orientation of dunes can usually tell us about wind direction, but in this image, the dune-forms are very complex, so it's difficult to know the wind direction.

However, a circular depression (probably an old and infilled impact crater) has limited the amount of sand available for dune formation and influenced local winds. As a result, the here form distinct dots and dashes.

The "dashes" are linear dunes formed by bi-directional winds, which are not traveling parallel to the dune. Instead, the combined effect of winds from two directions at right angles to the dunes, funnels material into a linear shape.

The smaller "dots" (called "barchanoid dunes") occur where there is some interruption to the process forming those linear dunes. This process is not well understood at present and is one motivation for HiRISE to image this area.


Explore further

Image: Frosted dunes on Mars

Provided by NASA
Citation: Image: Martian Morse code (2016, July 11) retrieved 18 July 2019 from https://phys.org/news/2016-07-image-martian-morse-code.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
22 shares

Feedback to editors

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more