Archive | March 2020

Launching Planet Four 2.0

Today we have a post by Candy Hansen, principal investigator (PI) of Planet Four and Planet Four: Terrains.  Candy also serves as the Deputy Principal Investigator for HiRISE (the camera providing the images of spiders, fans, and blotches seen on the original Planet Four project).  Additionally she is a  member of the science team for the Juno mission to Jupiter. She is responsible for the development and operation of  JunoCam, an outreach camera that involves the public in planning images of Jupiter.


We are delighted to be back in business with Planet Four on the Zooniverse’s Project Builder platform.  Thanks to all of your previous work the science team has been busy in the hiatus. 

As you know we published our first paper.  It describes the catalog of YOUR measurements that we have compiled, and the statistical analysis applied.  We are now able to query the catalog to get the measurements of fans, directions of fans, assessment of when seasonal activity begins and how it develops, for example.  This is allowing us to address the scientific questions that we laid out when we conceived this citizen science project. 

As a result, the second paper is well underway.  Like wind socks the fans tell us the direction of the wind at the time they emerge.  We are comparing the wind directions predicted by a regional scale atmospheric model with the actual measurements of fan directions.  Sometimes the predictions agree very well (typically in early spring), and sometimes they don’t.  When the predictions don’t agree we are analyzing why – for example, is there local topography affecting the wind direction?  Or is it because it is late in the spring and some areas of ground may be frost-free?  Or, and this is the most important, is the model lacking enough sophistication to reproduce the observed winds?  Your measurements are our guide to the actual on-the-ground environment, so if the results don’t agree, we know we need to improve the model.   

Our third paper is also almost finished.  Particles in the fans land on top of the layer of seasonal dry ice.  As time goes on the dark particles warm up and sink into the ice.  We can use your measurements of fan lengths to quantify this process.   Fan lengths slowly decrease with time as particles gradually sink.

We are looking forward to being back in business with your help, to tackle the next science question on our list:  how do Mars’ dust storms affect seasonal activity?  We will be posting the latest images from Manhattan, Ithaca, Inca City and Giza first because we have the longest time history for those locations.  Then we will add other locations to fill in some of the other longitudes. 

It’s great to be back working with you!  Please know that we value your generous contribution of your time, our most valuable commodity. Check out the new and improved Planet Four at