Could support life

“Europa, one of Jupiter’s 69 moons, was discovered by Galileo in 1610,” emails John Cameron of St Andrews.

“Only a quarter of earth’s size, it has more water and its thin atmosphere is mainly composed of oxygen. It also has an iron core, a rocky mantle and a magnetic field.

“It has the smoothest surface of any solid object in the solar system. Heat generated by tidal flexing keeps the ocean in liquid form so it can absorb chemicals from the surface and there’s volcanic or hydrothermal activity on the seabed.

“So it appears to have the necessary nutrients, chemical ingredients and energy sources to support life.

“The Europa Clipper mission will confirm its habitability in the 2020s by orbiting the moon for a total of around 45 flybys.”