Skip to main content

Giant asteroid hits Jupiter's moon Ganymede, changing its rotation 4 billion years ago

NEWS - About 4 billion years ago, an asteroid slammed into Jupiter’s moon Ganymede, shifting the axis of the largest moon in the solar system. The asteroid was about 20 times larger than the one that ended the age of dinosaurs on Earth, causing one of the largest impacts with a visible footprint in the solar system.

Giant asteroid hits Jupiter's moon Ganymede, changing its rotation 4 billion years ago

“Jupiter’s moons Io, Europa, Ganymede and Callisto all have interesting features, but what caught my attention were the grooves on Ganymede,” said planetary scientist Hirata Naoyuki of Kobe University.

“We know that these features were formed by an asteroid impact about 4 billion years ago, but we weren’t sure how big the impact was and what impact it had on the moon,” Naoyuki said.

Ganymede is the largest moon in the solar system, even larger than the planet Mercury, and harbors an ocean of liquid water beneath its icy surface. The moon is tidally locked, meaning it always shows the same side to the planet in orbit.

Much of the surface is covered with concentric circles of grooves around a single point, leading researchers in the 1980s to conclude that the grooves were the result of a major impact event. .

Researchers have struggled with this and Hirata was the first to recognize the impact site, which is thought to be almost exactly on the meridian farthest from Jupiter. A similar impact event on Pluto caused the dwarf planet's axis of rotation to shift, and data from the New Horizons spacecraft suggests Ganymede may have undergone a similar change in orientation.

The asteroid that struck Ganymede was probably 300 kilometers (180 miles) across, or 20 times larger than the asteroid that hit Earth 65 million years ago, ending the age of the dinosaurs and creating craters 1,400 to 1,600 kilometers (750 to 1,000 miles) across.

"I want to understand the evolutionary origins of Ganymede and other Jupiter moons. The massive impact must have had a significant impact on their early evolution, but the thermal and structural effects of the impact have not been investigated at all. I believe that further research into the internal evolution of icy moons is possible," Hirata said.

Such a large impact would have changed the mass distribution and caused the rotation axis to shift to its current position. Ganymede is the final destination for ESA’s JUICE spacecraft. If all goes well, it will enter orbit in 2034 and conduct six months of observations to send back data that will help answer many questions.

Original research

Hirata, N. Giant impact on early Ganymede and its subsequent reorientation. Scientific Reports 14, 19982 (2024), DOI:10.1038/s41598-024-69914-2

Popular Posts

Liverwort (Marchantia)

Liverwort ( Marchantia ) is a genus of plants in the Marchantiaceae, growing vines and attached to the soil surface, soft, dark green, upright phallus like a cup, grows in colonies on slopes and vertical soil that is moist and shady. Marchantia has elongated strands, rounded ends, branched, flat margins and a black vein in the middle. The strands formed a circular formation, growing widely and forming new formations around it. Sexual reproduction involves sperm from antheridia in male plants to fertilize ova in archegonia in female plants. The zygote develops into a small sporophyte which remains attached to the larger gametophyte. The sporophyte produces spores which develop into free-living male and female gametophytes. Asexual reproduction via gemmae in the cup-like structures on the upper surface of the plant. Asexual reproduction can also occur when older plant parts die and new, surviving branches develop into separate plants. Kingdom: Plantae Phylum: Marchantiophyta Class: ...

Black potato (Coleus rotundifolius)

Black potato ( Coleus rotundifolius ) is a species of plant in Lamiaceae, herbaceous, fibrous roots and tubers, erect and slightly creeping stems, quadrangular, thick, and slightly odorous. Single leaves, thick, membranous, opposite and alternate. Leaves are oval, dark green and shiny on the upper side, bright green on the lower side. Up to 5 cm long, up to 4 cm wide, slightly hairy and pinnate leaf veins. Leaf stalks up to 4 cm long. Small, purple flowers. Star-shaped petals, lip-shaped crown, dark to light purple with a slightly curved tube shape. Flowering from February-August. Small tubers, brown and white flesh and tuber length 2-4 cm. Kingdom: Plantae Phylum: Tracheophyta Subphylum: Angiospermae Class: Magnoliopsida Order: Lamiales Family: Lamiaceae Subfamily: Nepetoideae Tribe: Ocimeae Subtribe: Plectranthinae Genus: Coleus Species: Coleus rotundifolius

Wild durian (Cullenia exarillata)

Wild durian ( Cullenia exarillata ) is a species of plant in the Malvaceae, a tall tree with smooth, greyish-white bark, peeling on older trees, a straight trunk, horizontal branches and often with a series of knob-like tubercles for flower and fruit attachment. C. exarillata has young branches and the underside of the leaves is covered with golden brown peltate or shield-like scales. The leaves are single, alternate, glabrous, glossy green on the upper side and covered with silvery or orange peltate scales on the underside. Hermaphroditic flowers are tubular and also covered with golden brown scales, 4-5 cm long and cream or reddish brown in color. Flowers have no petals, formed of tubular bracteoles and tubular calyxes, 5-lobed. Fruit is round, 10-13 cm in diameter, covered with thorns and clustered along the branches. Many seeds, reddish brown, 4-5 cm long and 2-3 cm wide. The seeds are enclosed by a fleshy, whitish aril. The fruit splits open when ripe and dries to release the s...