Dr Matese reckons it could weigh as little as three jovian masses.

ECONOMIST: X marks the spot

The main source of meteorites, Chinese folklore notwithstanding, is the asteroid belt between Mars and Jupiter, a rough-and-tumble region of our solar system in which would-be planets are upset by Jovian gravity.

FORBES: Hot Rocks

Now the technique used earlier this year to demonstrate the existence of the Europan ocean has been employed to detect an ocean on another Jovian satellite, Ganymede, according to work announced at the recent American Geophysical Union meeting in San Francisco.

ECONOMIST: Blue moon

Galileo's most remarkable discoveries, however, and the ones that dictated that it would eventually follow the probe's fiery fate, were made not about Jupiter itself, but (appropriately) about the four large Jovian moons discovered by Galileo Galilei, the 17th-century astronomer after whom the craft was named.

ECONOMIST: Galileo and Jupiter