LONDON-With telescopes becoming even more sensitive, astronomers have managed to spot two tiny new moons orbiting Jupiter.

The moons, which are being referred to as ‘moonlets’ due to their small size, measure just one mile across each.

The discovery brings the gas giant’s total number of moons to 69.

The two new moons were discovered by researchers from the Carnegie Institution for Science in Washington DC, using the Magellan-Baade reflector at Las Campanas Observatory in Chile.

The moons are yet to be named, and are currently being referred to as S/2016 J 1 and S/2017 J 1 – where S stands for Satellite, and J stands for Jupiter.

Their discovery came as a surprise to the astronomers, who were looking for objects in the outer solar system when they spotted the moonlets.

Speaking to Sky and Telescope, Dr Scott Sheppard, who led the team, said: ‘We were continuing our survey looking for very distant objects in the outer solar system, which includes looking for Planet X, and Jupiter just happened to be in the area we were looking in 2016 and 2017.’ Both the new moons appear to be in a retrograde orbit, in which they move in the opposite direction to Jupiter around its axis.

They both also have a high degree of inclination off the orbital plane of Jupiter, which suggests that they were probably captured by Jupiter when they drifted too close to the gravitational pull of the planet, according to the researchers.

The orbits of both moons are highly elongated, and take them far away from Jupiter, with S/2016 J 1 orbiting at an average distance of 12,800,246 miles (20,600,000 km) and S/2017 J 1 at a distance of 14,602,223 miles (23,500,000 km) from the host planet.

While the findings have helped planetary scientists to locate some of Jupiter’s ‘lost moons’, the team believes there are still more to be found. Dr Sheppard added: ‘We have for sure recovered five of the lost moons. ‘We have several more Jupiter moons in our new 2017 observations and likely have all of the lost moons in our new observations.’