Category Astronomy/Space

Hydrogen Peroxide found on Jupiter’s Moon Ganymede in Higher Latitudes

Hydrogen peroxide found on Jupiter's moon Ganymede only in higher latitudes
Maps of Ganymede’s 3.5 μm H2O2 absorption compared to those of the 3.1 μm Fresnel peaks of water ice and corresponding projections of the U.S. Geological Survey VoyagerGalileo imaging mosaic. H2O2 appears constrained to the upper latitudes, particularly on the leading hemisphere, which exhibits sharp boundaries at approximately ±30° to 35° latitude. These boundaries are roughly coincident with the onset of Ganymede’s polar frost caps and with the latitudes at which most of the impinging Jovian magnetospheric particles can access the surface. Maps of the Fresnel reflection peak of water ice, which generally track the distribution of ice deduced from shorter-wavelength water bands, also show the areas of greatest H2O2 on the leading hemisphere to be enriched in water ice...
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To Stick or to Bounce: Size determines the Stickiness of Cosmic Dust Aggregates

Micrometer-scale dust particles from protoplanetary disks, or sites around stars with particles and hydrogen and/or other gasses, aggregate to form planetesimals, or kilometer-scale building blocks of planets. Planetesimals, in turn, merge due to mutual gravity. ©JAMSTEC

Microparticle dust aggregates, which are thought to play a role in the formation of new planets, are less likely to stick together after a collision when the aggregates are larger.

Current evidence suggests that microparticles of cosmic dust collide and stick together to form larger dust aggregates that may eventually combine and develop into planets...

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Ancient, High-Energy Impacts could have Fueled Venus Volcanism

Model showing Venus' high-energy impacts
An SwRI-led team compared the early impact history of Venus and Earth, determining that Venus experienced higher-energy impacts creating a superheated core. Models show these conditions could create Venus’ extended volcanism and younger surface.

Models show Venus’ superheated core could produce extended volcanism, long-lived resurfacing. A Southwest Research Institute-led team has modeled the early impact history of Venus to explain how Earth’s sister planet has maintained a youthful surface despite lacking plate tectonics. The team compared the early collision histories of the two bodies and determined that Venus likely experienced higher-speed, higher-energy impacts creating a superheated core that promoted extended volcanism and resurfaced the planet.

“One of the mysteries of t...

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Unusual White Dwarf Star is made of Hydrogen on one side and -Helium on the other

This artist's animation shows the two-faced white dwarf nicknamed Janus rotating on its axis. Janus is about 1,300 light-years away in the constellation Cygnus.

In a first for white dwarfs, the burnt-out cores of dead stars, astronomers have discovered that at least one member of this cosmic family is two faced. One side of the white dwarf is composed of hydrogen, while the other is made up of helium.

“The surface of the white dwarf completely changes from one side to the other,” says Ilaria Caiazzo, a postdoctoral scholar at Caltech who leads a new study on the findings in the journal Nature. “When I show the observations to people, they are blown away.”

White dwarfs are the scalding remains of stars that were once like our sun. As the stars age, they puff up into red giants; eventually, their outer fluffy material is blown away and their cores contract into dense, fiery-hot white dwarfs...

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