planet

This video explains the difference between a planet, like Earth, and a dwarf planet, like Pluto. 

A Japanese research team of astronomers and planetary scientists has focused their efforts on investigating the atmospheric features of one super-Earth, GJ 1214 b, which is located 40 light years from Earth in the constellation Ophiuchus, northwest of the center of our Milky Way galaxy.

Via NASA:

The sprawling Caloris basin on Mercury is one of the solar system's largest impact basins, created during the early history of the solar system by the impact of a large asteroid-sized body. The multi-featured, fractured basin spans about 1,500 kilometers in this enhanced color mosaic based on image data from the Mercury-orbiting MESSENGER spacecraft. Mercury's youngest large impact basin, Caloris was subsequently filled in by lavas that appear orange in the mosaic. Craters made after the flooding have excavated material from beneath the surface lavas. Seen as contrasting blue hues, they likely offer a glimpse of the original basin floor material. Analysis of these craters suggests the thickness of the covering volcanic lava to be 2.5-3.5 kilometers. Orange splotches around the basin's perimeter are thought to be volcanic vents.

Astronomers studying a newborn star have caught a detailed glimpse of planets forming around it, revealing a never-before seen stage of planetary evolution.

Via: Scientific American:

Whatever you call may call it, Ceres is one of the most geologically interesting and strange objects in the solar system. Its shape, size and composition—round, roughly the size of Texas and at least 20 percent water ice—place it at the poorly understood transition point between rocky worlds like Earth and icy worlds like Jupiter’s Europa, Saturn’s Enceladus, and other large moons of the outer solar system. Other than blurry Hubble Space Telescope images from 2004, its surface had scarcely been glimpsed until Dawn’s approach. As the spacecraft’s ion engines slowly push it toward Ceres, the dwarf planet’s details are now coming into focus, revealing tantalizing new details with practically every new image.

Astronomers have found the first Earth-sized exoplanet within a star's habitable zone. The planet is the closest thing yet to the coveted 'Goldilocks' orb that scientists have long sought — a world roughly the size of Earth orbiting a star at a distance that is just right for liquid water to exist.

"We definitely think it's one step closer to finding a true Sun–Earth analogue," says study co-author Elisa Quintana, an astronomer at the SETI Institute in Mountain View, California, and at the nearby NASA Ames Research Center in Moffett Field. But because the star that the exoplanet orbits is a cool, dim one unlike the Sun, Quintana and her colleagues consider the planet more of a cousin to Earth than a twin.

Scanning the heavens, you might very well miss the star Kepler-62. It's a rather typical star, slightly smaller, cooler, and more orange than the Sun, much like tens of billions of other stars in our galaxy. But it holds a surprise: It's orbited by at least five planets… and two of them are Earth-sized and orbit the star in its habitable zone!