Towering 'Penitente' Spikes May Exist on the Surface of Europa

   According to new research from scientists at the NASA Ames Research Centre, spikes of ice known as penitentes may tower above the surface of Jupiter's moon Europa. Famous in the media in recent years for its suspected subsurface saltwater ocean, this is a prime location in the solar system for the search for extraterrestrial life.

   In the paper, scientists looked at the sublimation rates of water ice across Europa's surface. By factoring other events that might erode the icy moon's surface, such as asteroid impacts or electrically charged particles hitting the moon from Jupiter, it was found that this model would create a rough surface on Europa. In the equatorial area of the moon, they found that sublimation would be dominant enough to sculpt penitentes up to about 15 metres high and 7 metres across over a span of 50 million years (about the age of Europea's surface)

   These hypothesized areas of jagged ice towers might pose a hazard for any future missions to Europa including NASA's Europa lander concept. This will make reconnaissance key prior to deployal of any probes from orbit.

   However it is just as possible that the penitente model may not apply to Europa. As it was based on penitente formation on Earth, some factors including a lack of atmosphere and Earth ices containing salts and sulfurous compounds could play a role in affecting this model.

   "It is always pleasant to see how rigorous science can help us imagine how the surface of an unknown planet could be at a scale never observed yet," said planetary scientist Cyril Grima at the University of Texas at Austin, who did not take part in this research.

Read more about this fascinating story at:  https://www.popsci.com/ice-spikes-europa

Read the full study here: https://www.nature.com/articles/s41561-018-0235-0

Image: Penitentes in the Atacama desert via ESO/B. Tafreshi