↑ NASA, Jupiter: Moons, NASA Solar System Exploration. ↑ NASA, Jupiter’s Great Red Spot Viewed by Voyager I, NASA, 2014. ↑ NASA, Jupiter: In Depth, NASA Solar System Exploration. ↑ NASA, Planetary Fact Sheet, Planetary Science - NASA. NASA also plans to launch a mission to the Galilean moons in the 2020s, which will focus on looking for evidence for life on Europa. It will then fly by Callisto and Europa, before orbiting Ganymede. The JUICE spacecraft should arrive at Jupiter in 2030. The ESA plan to launch a mission to the Galilean moons in 2022, known as Jupiter Icy Moon Explorer (JUICE). Juno is currently observing Jupiter’s gravitational and magnetic fields and the composition and dynamics of its atmosphere to help explain how planets like Jupiter form. NASA launched Juno in 2011 and it entered into orbit around Jupiter in 2016. The orbiter was deliberately steered into Jupiter and destroyed in 2003 to avoid contaminating any moons that may harbour life. It released an atmospheric probe, which lasted for just under an hour. The Galileo orbiter went into orbit around Jupiter in 1995, after flying by all of the Galilean moons. NASA’s Galileo spacecraft launched in 1989. New Horizons flew within 2 million km of Jupiter and passed all the Galilean moons in 2007, while on its way to Pluto. In 2006, NASA launched the New Horizons spacecraft. Cassini passed within 10 million km of Jupiter on its way to Saturn. NASA, the ESA, and the Italian Space Agency (ASI) launched the Cassini spacecraft in 1997. In 1990, NASA and the European Space Agency (ESA) launched Ulysses, which came within 400,000 km of Jupiter in 1992, and within 120 million km in 2004. Pioneer 11 came closest to Jupiter, flying within 34,000 km, and Voyager 2 was furthest coming within 570,000 km. All of these probes were on their way out of the Solar System (discussed in Chapter 27). This was followed by NASA’s Pioneer 11 in 1974, and Voyager 1 and Voyager 2, both in 1979. The first spacecraft to observe Jupiter, as well as all the Galilean moons, was NASA’s Pioneer 10 probe in 1973. It’s thought to have a small silicate core and a large icy mantle, with an ocean of liquid water between the mantle and the surface. Ĭallisto has a thin atmosphere composed of carbon dioxide. This means that there is nothing to periodically fill in old craters, and so Callisto is the most heavily cratered object in the Solar System. Callisto does not feel Jupiter’s tidal effects as strongly as the other moons, and so it has no active volcanoes. The surface of Callisto is composed of silicate rock and frozen water. It has the second-largest mass of the Galilean moons and is about the same size as Mercury. 21.2.4 CallistoĬallisto is the furthest of the Galilean moons. It’s the only moon in the Solar System known to have a magnetosphere. Ganymede has a thin oxygen atmosphere and a liquid iron core. The surface of Ganymede is covered in dark cratered regions and lighter regions, which are covered in ridges and grooves. Ganymede is primarily composed of silicate rock and frozen water, but a saltwater ocean is thought to exist nearly 200 km below the surface, between two layers of ice. It’s also larger than Mercury, although not as massive. It’s the largest and most massive moon in the Solar System. Ganymede is the third Galilean moon from Jupiter. Īn artist’s impression of Europa with Jupiter and Io in the background. Europa is also expected to contain a salt-water ocean, which extends for about 100 km below its frozen surface. Europa’s interior is mostly composed of silicate rock with an iron core. It has a thin oxygen atmosphere and a surface composed of frozen water. It’s also the least massive of the Galilean moons and has a diameter similar to that of the Earth’s Moon. 21.2.2 EuropaĮuropa is the second Galilean moon from Jupiter. Volcanoes on Io emit plumes of sulfur dioxide, which can reach 500 km, over seven times the diameter of Io and five times the distance to space from the surface of the Earth. The strong gravitational pull of Jupiter causes Io to be geologically active, and it’s thought to be the most geologically active object in the Solar System, with over 500 volcanic centres and over 100 mountains, some almost twice the height of Everest. Its surface is covered with sulfur and sulfur dioxide frost, and it has a molten core made of iron and iron sulfide. Io is the closest Galilean moon to Jupiter and has the third-largest mass of the Galilean moons. A composite image of Jupiter and the Galilean moons (to scale) from left to right: Io, Europa, Ganymede, and Callisto.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |