When it comes to finding places in our own solar system where extraterrestrial life might exist, one of the most likely locations is Jupiter’s moon Europa. This ice-covered world is thought to have a subsurface ocean that could harbor life. Europa is a target of future space missions to try and determine if life is present.
Some of those missions want to put a lander on the surface of the moon and the equator where higher temperatures are present was one of the likely targets. New research has revealed that the equatorial location poses some extreme hazards that hadn’t been expected. Scientists have predicted that fields of sharp ice standing nearly 15-meters tall might be scattered across equatorial regions of Europa.
Thanks to these massive spires of ice, the most prime location for landing spacecraft has potentially unsurmountable obstacles. These spires of ice are known as penitents, and they happen on Earth. Penitentes are sharp-edged spikes made of snow and ice that point towards the midday sun. They are formed via a process called sublimation requiring bright and sustained sunshine along with cold and dry air that is very still.
Sublimation turns ice into water vapor directly without having to melt into a liquid first, leaving behind penitents. On Earth, these objects grow to between 1 and 5 meters tall and are only seen in high-altitude tropical and subtropical conditions, such as in the Andes.
Europa has perfect conditions to form penitents with a surface mostly dominated by ice, extreme cold, and little variation in the angle of the sun. Scientists ran the numbers and determined the equators could have the objects standing 15-meters tall and with about 7.5 meters between each one. More detail will be gleaned when the NASA Europa Clipper spacecraft launches in 2022.