Bulge Found on Ganymede

Planetary scientists have discovered a previously unknown 3-km-high equatorial bulge on Jupiter's moon Ganymede, suggesting it formed at the poles and once massive enough rotated on a hidden global ocean separated from the rocky crust of the moon.

Planet's Giant Ring System

Astronomers have detected the first exoplanet (J1407b) with an extensive ring system similar to Saturn but about 200 times larger than those of our own ringed planet, possibly a young planetary system in an early transient phase of satellite formation.

Lunar Plain Not Impact Crater

The latest analysis of the Oceanus Procellarum, the large, dark plain on the near side of the Moon, shows it is rimmed by structures that form straight lines and angles, implying formation due to tectonic activity and not as the result of an impact.

Small Asteroids May Be Clusters

Using data from the Spitzer Space Telescope, researchers have found small asteroids that are up to 65% empty space and that many smaller bodies may be clusters of rubble or a dust cloud with a solid nucleus instead of solid rocky bodies.

Dark Side of the Moon Mystery

Astrophysicists have solved the Lunar Farside Highlands Problem, the question dating from 1959 as to why the far side of the Moon has no maria like the near side, the explanation being that the Moon was tidally locked with Earth's orbit soon after its formation resulting in a temperature gradient and thicker crust on the side facing away from Earth.

Two Rings around Asteroid

Astronomers have found two sharply defined rings surrounding the asteroid Chariklo, at 250 km in diameter the largest centaur orbiting between Saturn and Uranus in the outer solar system and the smallest object yet seen to host a stable ring system.

Most Distant in Solar System

Astronomers have discovered a new distant dwarf planet (2012 VP113) that is the most distant known object in our solar system, part of the inner Oort cloud with an elliptical orbit of 80 AU at its closest point to the Sun and perturbed enough to suggest the existence of a further large, planet-sized massive body.

"Zebra Stripes" in Van Allen Belt

NASA's Van Allen probes have detected a persistent pattern in the inner radiation belt surrounding Earth similar to "zebra stripes," a distortion caused by the rotation of the planet that was previously thought incapable of affecting the high-energy electrons of the belts with velocities near the speed of light.

Gaseous Earth-Mass Exoplanet

The recent discovery of an exoplanet (KOI-314c) with a mass comparable to Earth yet covered with a thick atmosphere of hydrogen and helium like a gas giant challenges theories on planetary formation and the assumption that Earth-mass planets necessarily be of a rocky composition.

Low-Density Kuiper Belt Object

Astronomers have identified an intermediate-sized body of rock and ice (2002 UX25) in the Kuiper belt with a measured density significantly less than liquid water, challenging present planetary formation theories.

First Tilted Solar System

NASA's Kepler spacecraft has detected the first known star system with two large planets that orbit on a plane at a steep 45-degree angle relative to the stellar equator, the gas giant Kepler-56 about 2800 light years distant.

Pluto's Moons Named

After a membership vote, the International Astronomical Union (IAU) has formally adopted the names Kerberos and Styx for the recently discovered fourth (P4) and fifth (P5) moons, respectively, of Pluto.

New Stage of Planet Birth

Astronomers have spotted gaps or filaments of material in the dust ring surrounding the forming star HD 142527, a feature caused by orbiting planetesimals that helps the star to grow and a byproduct of planetary formation previously theorized but never before detected.

Ice Found on Mercury

NASA's Messenger spacecraft has discovered evidence of abundant surface water ice on Mercury located in its permanently shadowed polar regions.

Earth's Magnetic Poles Flipped

Analyzing sediment from the floor of the Black Sea, scientists have determined the Earth's magnetic poles reversed and then reversed again relatively quickly about 41,000 years ago, with the process that normally takes millennia completing its cycle in only about 200 years and during which the magnetic field strength was only one-twentieth what it is today.

Cold Layer Around Venus

The European Space Agency's Venus Express has discovered an unexpected cold layer in Venus' atmosphere 77 miles above the planet's surface with temperatures reaching −283°F, much colder than anything in Earth's atmosphere and able to form carbon dioxide ice.

Helium in Moon's Atmosphere

NASA's Lunar Reconnaissance Orbiter has detected helium in the thin atmosphere of the Moon, with scientists uncertain if the helium originates from the surface itself via radioactive decay or is captured from external sources such as the solar wind.

Plate Tectonics on Mars

Previously thought to exist nowhere else in the solar system but Earth, scientists have discovered evidence of plate tectonics on Mars in about a dozen satellite images of surface fault systems collected from orbiting spacecraft.

Moons of Uranus Will Collide

Running thousands of computer simulations varying the masses and known orbits of Uranus' moons Cupid and Belinda, researchers find the orbits of the two moons always intersect on relatively short time scales, implying a collision in the planetary system is inevitable sometime between 1000 and 10 million years from now.

Fifth Moon of Pluto Found

Astronomers working with NASA's Hubble Space Telescope and its Wide Field Camera 3 have discovered a fifth moon orbiting the dwarf planet Pluto, temporarily designated "P5" and with an estimated diameter between 10 and 25 km.