Through Planet Four: Craters, citizen scientists can help planetary scientists identify and measure features on the Martian surface while also helping improve the design of future Zooniverse projects. Citizen scientists use different tools and interfaces that will help Zooniverse learn more about what works best for cratering and similar tasks.
 
Planet Four aims to determine the number of craters on the Martian surface at different scales and resolutions. By counting the craters researchers will be able to figure out how old various geological surfaces are. This will be a big help for the 2016 NASA InSight mission, which will use geophysical techniques such as seismology and heat flow to figure out how Mars has evolved. Knowing the age of the surface will help put a time-scale on that evolution.
 
The craters are not difficult to find. In fact, sometimes there can be hundreds within one image. There simply aren’t enough scientists to do this work, which is where citizen scientists come in. The features are usually circular and often appear darker than the surrounding plain, where they have puffed away the overlying light surface dust. By counting how many craters are on different surfaces (for example a lava flow or an ancient sea bed), researchers can figure out when those features were formed.