Glossarbegriffe: Galileische Satelliten

Also known as Galileische Monde oder Galileische Trabanten

Description: Die Galileischen Satelliten sind die vier größten und hellsten Satelliten bzw. Monde, die den Planeten Jupiter umkreisen: Io, Europa, Ganymed und Callisto. Io ist dem Jupiter am nächsten und hat Hunderte von aktiven Vulkanen. Das liegt hauptsächlich daran, dass Io durch die Gezeitenwirkung der Schwerkraft des Jupiters "durchgeknetet" wird. Die gesamte Oberfläche von Europa ist mit Eis bedeckt. Unter dem Eis wird ein Ozean aus flüssigem Wasser vermutet, der einer der besten Kandidaten für die Entstehung von Leben außerhalb der Erde im Sonnensystem ist. Ganymed ist der größte Mond in unserem Sonnensystem und auch der Mond mit der größten Masse: Sie ist doppelt so groß wie die des Erdmondes. Kallisto ist fast genau so groß wie der Planet Merkur, hat aber nur etwa ein Drittel der Masse des Merkurs.

Die vier Galileischen Monde wurden von Galileo Galilei im Jahr 1610 entdeckt, als eine von mehreren Entdeckungen im Rahmen seiner Pionierarbeit bei der Verwendung eines Teleskops für astronomische Beobachtungen. Galilei konnte nachweisen, dass die vier Monde den Jupiter im Laufe der Zeit wie ein Miniatur-Sonnensystem umkreisen. Dies war ein klarer Beweis dafür, dass astronomische Objekte einen anderen Mittelpunkt als die Erde umkreisen können. Diese Beobachtung spielte eine wichtige Rolle bei der Verlagerung des wissenschaftlichen Konsenses von der erdzentrierten (geozentrischen) zur sonnenzentrierten (heliozentrischen) Sicht des Sonnensystems.

Zugehörige Glossarbegriffe:

See this term in other languages

Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

Zugehörige Medien

The planet Jupiter with the two of the four Galilean moons (visible as bright dots) orbiting it.

Jupiter's Rotation, by Vishal Sharma, India

Bildunterschriften: Third place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons: Jupiter’s Rotation, by Vishal Sharma, India. This time-lapse beautifully shows the rotation of Jupiter and the passage of two Galilean moons on the right side of the frame. Jupiter completes one rotation in just under 10 hours and we see as the Great Red Spot makes its way from left to right. The two moons travel a noticeable fraction of their orbit in this short time. This image was taken in 2020 in the North of India.
Bildnachweis: Vishal Sharma/IAU OAE

License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons

The planet Jupiter, seen here as a bright disk, is orbited by the four Galilean moons, seen here as bright dots

Jupiter Moons Movie2, by Nicolas Hurez, Paul-Antoine Matrangolo, and Carl Pennypacker, United States of America

Bildunterschriften: Second place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons. This sequence shows the orbit of the four Galilean moons around the planet Jupiter. Almost two entire orbits of the innermost moon, Io, can be seen, with the other moons (Europa and Ganymede, but in particular Callisto) being further away, orbiting noticeably slower. The images were obtained in 2018 with the Las Cumbres Global Observatory at different locations on Earth, allowing a continuous sequence of images over approximately half a week without gaps during the day. With clear skies and over the course of several nights, the motion of the Galilean moons can also be observed with binoculars (ideally steady your elbows on a surface).
Bildnachweis: Nicolas Hurez, Paul-Antoine Matrangolo and Carl Pennypacker/IAU OAE

License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons

Jupiter with coloured horizontal bands of clouds. The shadow of the moon Io is seen as a dark circle in the top left

Jupiter, Io and its shadow, by Ralf Burkart, Germany

Bildunterschriften: First place in the 2021 IAU OAE Astrophotography Contest, category Galilean moons. This time-lapse of Jupiter taken in 2017 from Germany beautifully illustrates the transit of one of the Galilean moons, Io, in front of Jupiter. As this is simply a moon casting a shadow on a planet it is equivalent to a lunar eclipse on Earth observed from further away. While the shadow of the moon is clearly visible from the beginning, it might be difficult to spot the moon itself against the background of the beautiful atmospheric bands of Jupiter the first time the video is seen. Watching it repeatedly allows appreciating the rapid motion and rotation in this fantastic observation.
Bildnachweis: Ralf Burkart/IAU OAE

License: CC-BY-4.0 Creative Commons Namensnennung 4.0 International (CC BY 4.0) icons

Io is roughly spherical. Its surface mostly consists of yellowish sulphuric compounds and rather small darker volcanos.


Bildunterschriften: NASA's Galileo spacecraft acquired its highest resolution images of Jupiter's moon Io on 3 July 1999. Io is one of the four Jovian moons discovered by Galileo Galilei in 1610. Io's colours are witness to its extensive volcanic activity as they stem from sulphuric compounds. Tidal forces from Jupiter and the neighbouring moons are the cause for Io's volcanism.
Bildnachweis: NASA/JPL/University of Arizona credit link

License: PD Public Domain icons

Europa is round with large patches of brown to white colours, covered by numerous crevices, randomly oriented on the surface


Bildunterschriften: This image taken by NASA's Galileo space probe in September 1996 shows Jupiter's ice-covered satellite, Europa, in approximate natural color. Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. The bright feature containing a central dark spot in the lower third of the image is a young impact crater some 50 kilometers (31 miles) in diameter. Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth's moon.
Bildnachweis: NASA/JPL/DLR

License: PD Public Domain icons