https://www.scientificamerican.com/article/signs-of-life-on-europa-may-be-just-beneath-the-surface/

If signs of life exist on Jupiter’s icy moon Europa, they might not be as hard to find as scientists had thought, a new study reports.

The 1,900-mile-wide (3,100 kilometers) Europa harbors a huge ocean beneath its icy shell. What’s more, astronomers think this water is in contact with the moon’s rocky core, making a variety of complex and intriguing chemical reactions possible.