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December\u2019s Night Sky Notes: Spot the King of Planets<\/h1>\n<\/div>\n<\/div>\n<\/div>\n
by Kat Troche of the Astronomical Society of the Pacific<\/em><\/p>\n Jupiter is our solar system\u2019s undisputed king of the planets! Jupiter is bright and easy to spot from our vantage point on Earth, helped by its massive size and banded, reflective cloud tops. Jupiter even possesses moons the size of planets: Ganymede, its largest, is bigger than the planet Mercury. What\u2019s more, you can easily observe Jupiter and its moons with a modest instrument, just like Galileo did over 400 years ago.<\/p>\n Jupiter\u2019s position as our solar system\u2019s largest planet is truly earned; you could fit 11 Earths along Jupiter\u2019s diameter, and in case you were looking to fill up Jupiter with some Earth-size marbles, you would need over 1300 Earths to fill it up \u2013 and that would still not be quite enough! However, despite its formidable size, Jupiter\u2019s true rule over the outer solar system comes from its enormous mass. If you took all of the planets in our solar system and put them together, they would still only be half as massive as Jupiter all by itself. Jupiter\u2019s mighty mass has shaped the orbits of countless comets and asteroids. Its gravity can fling these tiny objects towards our inner solar system and also draw them into itself, as famously observed in 1994 when Comet Shoemaker-Levy 9, drawn towards Jupiter in previous orbits, smashed into the gas giant\u2019s atmosphere. Its multiple fragments slammed into Jupiter\u2019s cloud tops with such violence that the fireballs and dark impact spots were not only seen by NASA\u2019s orbiting Galileo probe but also by observers back on Earth!\u00a0<\/p>\n Jupiter is easy to observe at night with our unaided eyes, as well-documented by the ancient astronomers who carefully recorded its slow movements from night to night. It can be one of the brightest objects in our nighttime skies, bested only by the Moon, Venus, and occasionally Mars, when the red planet is at opposition. That\u2019s impressive for a planet that, at its closest to Earth, is still over 365 million miles (587 million km) away. It\u2019s even more impressive that the giant world remains very bright to Earthbound observers at its furthest distance: 600 million miles (968 million km)! While the King of Planets has a coterie of 95 known moons, only the four large moons that Galileo originally observed in 1610 \u2013 Io, Europa, Ganymede, and Calisto \u2013 can be easily observed by Earth-based observers with very modest equipment. These are called, appropriately enough, the Galilean moons. Most telescopes will show the moons as faint star-like objects neatly lined up close to bright Jupiter. Most binoculars will show at least one or two moons orbiting the planet. Small telescopes will show all four of the Galilean moons if they are all visible, but sometimes they can pass behind or in front of Jupiter or even each other. Telescopes will also show details like Jupiter\u2019s cloud bands and, if powerful enough, large storms like its famous Great Red Spot, and the shadows of the Galilean moons passing between the Sun and Jupiter. Sketching the positions of Jupiter\u2019s moons during the course of an evening \u2013 and night to night \u2013 can be a rewarding project! You can download an activity guide from the Astronomical Society of the Pacific at\u00a0bit.ly\/drawjupitermoons<\/a><\/p>\n Now in its eighth year, NASA\u2019s Juno mission is one of just nine spacecraft to have visited this impressive world. Juno entered Jupiter\u2019s orbit in 2016 to begin its initial mission to study this giant world\u2019s mysterious interior. The years have proven Juno\u2019s mission a success, with data from the probe revolutionizing our understanding of this gassy world\u2019s guts. Juno\u2019s mission has since been extended to include the study of its large moons, and since 2021 the plucky probe, increasingly battered by Jupiter\u2019s powerful radiation belts, has made close flybys of the icy moons Ganymede and Europa, along with volcanic Io. What else will we potentially learn in 2030 with the Europa Clipper mission?\u00a0<\/p>\n Find the latest discoveries from Juno and NASA\u2019s missions to Jupiter at\u00a0science.nasa.gov\/jupiter\/<\/a><\/p>\n Originally posted by Dave Prosper: February 2023 Powered by WPeMatico<\/a><\/small><\/p>\n Get The Details…<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" by Kat Troche of the Astronomical Society of the Pacific Jupiter is our solar system\u2019s undisputed king of the planets! Jupiter is bright and easy to spot from our vantage point on Earth, helped by its massive size and banded, reflective cloud tops. Jupiter even possesses moons the size of planets: Ganymede, its largest, is [\u2026] Continue reading ![\"Image](\"https:\/\/science.nasa.gov\/wp-content\/uploads\/2023\/04\/do_it_yourself_jupiter-jpg.webp\")
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Last Updated by Kat Troche: November 2024<\/em><\/p>\n