A team of astronomers using the NASA/ESA Hubble Space Telescope has discovered a fifth moon orbiting the icy dwarf planet Pluto. The green circle marks the newly
discovered moon, designated S/2012 (134340) 1, or P5, as photographed by Hubble’s Wide Field Camera 3 on 7 July 2012. The moon is estimated to be 10 to 25 kilometres across. The darker stripe in the centre of the image is because the picture is constructed from a long exposure designed to capture the comparatively faint satellites
of Nix, Hydra, P4 and S/2012 (134340) 1, and a shorter exposure to capture Pluto and Charon, which are much brighter.
Credit: NASA, ESA, and M. Showalter (SETI Institute)
The solar neighbourhood:
What Hubble has taught us about planets,
asteroids and comets in our own Solar System
Hubble’s high resolution images of the planets and moons in our Solar System can only be surpassed by pictures taken from spacecraft that actually visit
them. Hubble even has one advantage over these probes: it can look at these
objects periodically and so observe them over much longer periods than any
passing probe could. Regular monitoring of planetary surfaces is vital in the
study of planetary atmospheres and geology, where evolving weather patterns
such as dust storms can reveal much about the underlying processes.
In comparison with probes that have to travel vast distances and require
years of planning to visit the planets Hubble is also able to react quickly to sudden dramatic events occurring in the Solar System. This allowed it to witness the
stunning plunge of comet Shoemaker-Levy 9 into Jupiter’s atmosphere during
the period 16-22 July 1994. Hubble followed the comet fragments on their last
journey and delivered incredible high-resolution images of the impact scars.
The consequences of the impact could be seen for several days afterwards,
and by studying the Hubble data astronomers were able to gain fundamental
information about the composition and density of the giant planet’s atmosphere. Since the impact of Shoemaker-Levy 9, Hubble has continued to study
impacts and events on Jupiter, improving our understanding of the Solar System’s largest planet.
Pluto and its surrounding moons have also been the target of Hubble’s observations. Several new moons have been discovered as well as a dwarf planet
beyond Pluto, which led to the discussion of Pluto being a planet.
Hubble also observed the spectacular break up of comet 73P/Schwassmann-Wachmann 3 as it visited the inner Solar System, the asteroid collision
P2010/A2 and a mysterious disintegrating asteroid.