Produced by: Tarun Mishra Designed by: Manoj Kumar
NASA's Juno spacecraft recently identified Jupiter's fifth moon, Amalthea, during its 59th close flyby of the planet earlier this year. This marks a significant observation as Juno provided a rare view of this lesser-known moon.
Image data: NASA/JPL-Caltech/SwRI/MSSS. Image processing by Gerald Eichstädt
Amalthea, discovered in 1892 by Edward Emerson Barnard, is often overshadowed by Jupiter's four Galilean moons: Io, Europa, Ganymede, and Callisto. This recent sighting has brought renewed attention to this intriguing satellite.
During the flyby on March 7, 2024, Juno transited Jupiter's Great Red Spot. According to NASA's blog, the spacecraft was approximately 165,000 miles (265,000 kilometers) above Jupiter's cloud tops, at about 5 degrees north latitude, when Amalthea was observed.
In images released by NASA, Amalthea appeared as a tiny dot against Jupiter's reddish cloud bands. These images offer a rare glimpse of the moon as it transits the Great Red Spot, enhancing our understanding of its position and appearance.
Amalthea has a unique, potato-like shape and is the reddest object in the solar system. Its lack of sufficient mass prevents it from forming a spherical shape. It orbits Jupiter inside Io's path, taking 0.498 Earth days to complete one orbit.
Scientists are intrigued by Amalthea's slight excess heat emission. Theories suggest it receives heat from Jupiter both directly and indirectly, and tidal pressures caused by Jupiter's gravitational pull might also generate internal heat.
Previous missions, such as the Galileo spacecraft, have provided insights into Amalthea's surface, revealing impact craters, hills, and valleys. These features contribute to its unique geological profile.
Despite its fascinating characteristics, Amalthea is often overlooked in scientific discussions, overshadowed by its larger Galilean counterparts. Juno's recent observations help bring this moon back into the spotlight.
The continued study of Amalthea, facilitated by missions like Juno, is crucial for understanding the complex dynamics of Jupiter's moons and their interactions with the giant planet. Future observations will aim to uncover more about this mysterious moon's origins and behaviour.