Hold on to Your Moons! Ice, Atmospheres and the Grand Tack

Hold on to Your Moons! Ice, Atmospheres and the Grand Tack

Among the many ideas proposed to explain the formation of our Solar system, one of the leading theories is the “Grand Tack”. This scenario suggests that, early in their formation, Jupiter and Saturn undertook a sweeping voyage, migrating from the outer Solar System to within the orbit of Mars. The two huge planets then entered an orbital resonance with each other, before their cosmic dance took them back out to their current positions. The model neatly explains, amongst other things, the current locations of Mars, the Asteroid Belt and the outer planets—which are hard to recreate in models assuming a more static Solar System.

Plutonian craters to be named after Star Trek characters

Plutonian craters to be named after Star Trek characters

In July of this year (2015), NASA’s New Horizons mission will fly past Pluto and its moons. It will map the surface of the Plutonian system in unprecedented detail, revealing craters and other surface features for the first time. In preparation for the deluge of newly discovered craters, mountains, crevasses and other surface features, Mamajek et al. discuss a naming system for Pluto and its moons.

Falling stones paint it black

Falling stones paint it black

Mercury is the smallest planet in the Solar System, but some of its properties are a big challenge to explain. Today’s Astrobite presents a solution to one of these issues: The darkening of Mercury is induced by a high abundance of carbon delivered by meteorites.