RocketSTEM Issue #13 - September 2016 | Page 73

Credit: NASA/ESA/M/Kornmesser • As Jupiter is always outside the Earth it is always observed as a disk. Planets closer to the Sun can often be seen as crescents, but planets further from the Sun will always be seen as disks. • In our night skies Jupiter is the third brightest object to be seen. The brighter objects are the Moon and Venus. However when Venus is in crescent it is possible that Jupiter will outshine it. Although Jupiter is a long way away it’s clouds are very reflective. • Jupiter does not have seasons like the Earth as the orbital inclination of the pole is about three degrees so only varies a little throughout the 11.9 year orbit. • The storms present themselves in bands whirling around the orbital plane of the planet. We refer to these as zones and belts. The lighter zones are clouds at a higher altitude and are seen to be cooler in the infrared spectrum. The darker belts are warmer and thought to be lower in the atmosphere. Altogether there are 15 defined areas in Jupiter’s atmosphere which are mirrored in the northern and southern hemispheres. • The most famous feature of the Jovian atmosphere is the storm known as the Great Red Spot. It was documented in 1899 in the Monthly Notices of the Royal Astronomical Society, but there were even earlier scientific observations from H Schwabe in September 1831, and it may well have been observed before that. The Great Red Spot is easy to view in a modern small telescope on a night with good visibility when Jupiter is high in the sky. 71 www.RocketSTEM .org 71