A new proof that we have not discovered everything about our solar system : NASA announced this monday that Hubble discovered a new moon of Neptune. It is actually the smallest moon of the planet.
With a diameter of 19 km, S/2004 N 1 (provisional name of the moon) orbits at a distance of more than 105,000 km from Neptune (between the orbits of Larissa and Proteus) and makes a complete revolution in about 23 hours. According to NASA, the moon shines about 100 million times less than the palest of stars which can be seen to the naked eye.
The real name of S/2004 N 1 will be announced in the next days or the next weeks by NASA. And maybe, it won't be the last moon that we can find in our solar system. Who knows ?