Last updated October 25, 2018 at 2:39 pm
Hubble took advantage of close passes to capture incredible snaps of Saturn and Mars.
As Saturn and Mars ventured close to Earth, the Hubble Space Telescope captured these exquisite photographs.
Hubble captured Saturn when the ringed world was approximately 2.18 billion kilometres from Earth, and Mars when it was just 59.4 million kilometres from Earth – a mere stones throw in astronomical terms.
The close passes from the planets occur when the planets are in opposition – when the Sun, Earth and the planet form a direct line. Planets in opposition provide an excellent opportunity for astronomers to see features on the planet’s surface in fine detail – not only are the planets at their closest to Earth, but planets in opposition appear fully lit by the Sun when viewed from Earth.
Mars’s close distance gives it its brightest appearance in the night sky since the 2003 opposition.
Click the images below for a zoomable version.
Summertime on Saturn
Saturn has seasonal changes caused by the planet’s 27-degree tilt. The increase in sunlight in Saturn’s northern hemisphere has heated the atmosphere and caused a large storm that is now disintegrating in Saturn’s polar region. Small, mid-latitude puffs of clouds are also visible.
The planet’s spectacular ring system is also on full display, nearing it’s maximum tilt toward Earth. This gives a perfect view of the rings and the gaps between them, and provides the best opportunity to view them stretching out nearly 8 times the radius of the planet.
Springtime for Mars
Mars also has seasons, due in part to its 25-degree axial tilt, which is similar to Earth’s 23.5-degree tilt. However, Mars’ more elliptical orbit has a greater influence on its seasonal changes than Earth’s. Its closest and most distant points from the Sun vary by 19 percent (as opposed to just 3 percent for our own planet).
While we’re used to photographs which show detailed surface features of the planet, Hubble’s new image clearly shows the gigantic sandstorm still covering the entire planet. The white polar caps, Terra Meridiani, the Schiaparelli Crater, and Hellas Basin are still visible, but even they are slightly blurred by the dust in the atmosphere.
Each Martian year, moderately large dust storms cover continent-sized areas and last for weeks at a time. Global dust storms like the one current happening on Mars sometimes last for weeks or months, and tend to happen during the spring and summer in the southern hemisphere, when Mars is closest to the Sun and heating is at a maximum to generate winds.