So what are the odds that Europa's vast oceans are empty and devoid of life? I can just imagine what lives under all that ice.
Like our planet, Europa is thought to have an iron core, a rocky mantle and an ocean of salty water. Unlike Earth, however, Europa's ocean lies below a shell of ice probably 10 to 15 miles (15 to 25 kilometers) thick and has an estimated depth of 40 to 100 miles
Scientists think Europa’s ice shell is 10 to 15 miles (15 to 25 kilometers) thick, floating on an ocean 40 to 100 miles (60 to 150 kilometers) deep. So while Europa is only one-fourth the diameter of Earth, its ocean may contain twice as much water as all of Earth’s oceans combined. Europa’s vast and unfathomably deep ocean is widely considered the most promising place to look for life beyond Earth. A passing spacecraft might even be able to sample Europa’s ocean without landing on the moon’s surface because it is possible that Europa’s ocean may be leaking out into space.