NASA’s Juno mission took the images as it swayed within 1,038 kilometers of the surface of Ganymede during a flyby, the closest spacecraft to the moon since the Galileo spacecraft made it. its approach in May 2000.
“It is the closest spacecraft it is to this gigantic moon in a generation,” said Scott Bolton, senior researcher for Juno, of the Southwest Research Institute in San Antonio, Texas.
“We’re going to take our time before drawing any scientific conclusions, but until then we can just marvel at this heavenly wonder.”
At 3,270 miles in diameter (5,262.4 kilometers), this giant moon is larger than the planet Mercury.
The photos – taken by two of the spacecraft’s three cameras – show the surface in incredible detail, complete with craters, distinct dark and bright terrain, and long structural features, which NASA said may have been linked to tectonic faults.
The spacecraft has been observing Jupiter and its moons since July 2016.
The moon is named after a cupbearer of the ancient Greek gods. In addition to being the largest natural satellite in our solar system, Ganymede is also the only moon to have a magnetic field. This makes the aurora shine around the north and south poles of the moon.
Ganymede has an iron core covered with a layer of rock topped with a thick shell of ice. It is possible that there is an underground ocean, and astronomers discovered evidence of a thin oxygen atmosphere on the moon in 1996 using the Hubble Space Telescope. This atmosphere is too thin to support life.
Dark side of Ganymede
Using its green filter, the spacecraft’s JunoCam visible light imager captured almost an entire side of the moon, which is encrusted with water ice, NASA said.
NASA said it hoped to provide a “color portrait” later when it had versions of the same image taken with the camera’s red and blue filters.
Additionally, Juno’s Stellar Reference Unit, a navigation camera that maintains the spacecraft’s heading, took a black-and-white image of Ganymede’s dark side (the side opposite the sun).
“The conditions under which we collected the dark side image of Ganymede were ideal for a low-light camera like our stellar reference unit,” said Heidi Becker, head of Juno’s radiation monitoring at the Propulsion Lab by NASA reaction. “So that’s a different part of the surface than what JunoCam sees in direct sunlight. It’ll be fun to see what the two teams can put together.”
The solar-powered spacecraft’s encounter with the moon should shed light on its makeup, magnetic field, and icy shell.