Recent Discoveries in Planetary Geology

Mars
- Discovery of Liquid Water: In 2015, NASA announced the discovery of liquid water on Mars. Dark streaks called recurring slope lineae (RSL) were found on the slopes of Martian craters. These RSL are believed to be formed by flowing water during the warm seasons on Mars.
- Confirmation of Methane: Methane, a potential indicator of biological activity, was detected in the Martian atmosphere by the Mars Curiosity rover in 2013. In 2019, NASA confirmed the seasonal variation of methane levels, providing further evidence of its presence on Mars.

Pluto
- Pluto's Geology: The New Horizons spacecraft conducted a flyby of Pluto in 2015, revealing a diverse and geologically active world. The images showed a variety of surface features, including mountains, valleys, and plains. The presence of nitrogen and methane ice was also discovered, suggesting a dynamic and evolving surface.

Europa
- Subsurface Ocean: Europa, one of Jupiter's moons, is believed to have a subsurface ocean beneath its icy crust. In 2020, data from the Hubble Space Telescope confirmed the presence of water vapor plumes erupting from Europa's surface. This discovery supports the possibility of a habitable environment for microbial life.

Enceladus
- Geysers and Ocean: Enceladus, a moon of Saturn, has geysers erupting from its south pole, spewing water vapor and icy particles into space. The Cassini spacecraft detected organic molecules in the plumes, indicating the presence of hydrothermal activity and a subsurface ocean. This finding has increased the potential for finding life beyond Earth.

Mercury
- Volcanism: The MESSENGER mission to Mercury provided detailed images of the planet's surface, revealing evidence of past volcanic activity. The presence of volcanic plains, lava flows, and volcanic vents suggested a dynamic geological history for Mercury, despite being the closest planet to the Sun.

Jupiter
- Great Red Spot: The Juno spacecraft has been studying Jupiter since 2016 and has provided new insights into the planet's massive storm known as the Great Red Spot. Juno's images and data have revealed the intricate structure and dynamics of the storm, helping scientists understand its longevity and behavior.

Summary
Recent discoveries in planetary geology have expanded our understanding of various celestial bodies in our solar system. Liquid water on Mars, the geology of Pluto, the subsurface oceans of Europa and Enceladus, volcanic activity on Mercury, and the detailed study of Jupiter's Great Red Spot are some of the notable findings. These discoveries have deepened our knowledge of planetary processes, potential habitable environments, and the diversity of geological features in our cosmic neighborhood.