In the summer of 2018, the planets Mars and Saturn face the earth one after the other. During this event, the planets are relatively close to Earth, so astronomers can observe them more closely. Hubble used this preferred configuration and imaged both planets to continue his long-term observation of the outer planets in the solar system.
Ever since the launch of the NASA / ESA Hubble Space Telescope, the goal has always been to study not only distant astronomical objects but also the planets of our solar system. Hubble's high-resolution images of our planetary neighbors can only be surpassed by images of spacecraft that actually visit these bodies. However, Hubble has an advantage over space probes: it can periodically observe these objects and observe them for much longer periods than any other passing probe.
In recent months, the planets Mars and Saturn have been in opposition to Earth – Saturn on June 27 and Mars on July 27. A contrast occurs when the sun, the earth and an outer planet line up and the earth sits between the sun and the outer planet. During an opposition, a planet is fully illuminated by the sun, as seen from Earth, and it also marks the time when the planet is closest to Earth so that astronomers can see more clearly the features on the planet's surface.
A Month Earlier Saturn's Opposition – June 6 – Hubble was used to observe the ringed planet. At that time, Saturn was about 1.4 billion kilometers from Earth. The captured images show Saturn's excellent ring system near its maximum slope to Earth, allowing a spectacular view of the rings and the gaps between them. Although all gas giants have rings, the Saturn are the largest and most spectacular, reaching up to eight times the radius of the planet.
In addition to a beautiful view of the ring system, Hubble's new image shows a hexagonal pattern in the north pole – a stable and stubborn wind feature discovered in 1981 during the flyby of the Voyager 1 spacecraft. South of it is a series of bright clouds: remnants of a dissolving storm.
Watching the planet Hubble managed to capture images of six of Saturn's currently known moons: Dione, Enceladus, Tethys, Janus, Epimetheus, and Mimas. The scientists assume that a small, unpredictable moon like this one fell apart the Saturn ring system 200 million years ago.
Hubble shot the second portrait of the planet Mars on July 18, just 13 days before Mars reached its closest approach to Earth. This year, Mars will be 57.6 million kilometers from Earth. This is the best approach since 2003, when the red planet came closer to us in almost 60,000 years than any other time.
While earlier images showed detailed surface features of the planet, this new image becomes a giant sandstorm surrounding the entire planet. Still visible are the white polar caps, Terra Meridiani, the Schiaparelli Crater and the Hellas Basin – but all these features are slightly blurred by the dust in the atmosphere.
Comparing these new images of Mars and Saturn with older Hubble data, other telescopes and even space probes enable astronomers to study how cloud patterns and large-scale structures on other planets in our solar system change over time.
Hubble takes close-ups of Jupiter