More pocked with craters than any other object in our solar system, Jupiter's outermost and second-biggest Galilean moon, Callisto, appears geologically unremarkable. In the 1990s, however, NASA's ...

The Sun is slowly setting, it is a beautiful clear sky, and I am in the northern Prague district of Ďáblice inside a long wooded park called Ďáblický háj, which is approximately 60 hectares in size.