A Supercritical Exoplanet

One of the main goals in searching for exoplanets is to find one similar to Earth. Astronomers are beginning to find planets that are roughly the same size and weight as Earth, but are quickly discovering that these planets have few other similarities to Earth.  55 Cancri e is an excellent example. This exoplanet is roughly 8 times the weight of Earth, and a little less than twice the size. The image above shows Earth and the exoplanet to scale, though the drawing of 55 Cancri e is just an artists idea, we have no idea what it really looks like. The two planets are comparable enough to call 55 Cancri e a "Super-Earth". One major difference between Earth and 55 Cancri e is that it sits much closer to its host star than Earth does to our Sun. For comparison, 55 Cancri e is 26 times closer than Mercury is to the sun, and Mercury is 3 times closer to the Sun than Earth! Observations with the Spitzer Space telescope suggest that the planet is not rocky, but actually made of lighter elements, including water! Since the exoplanet is so close to its host star, it is extremely hot. This means that any elements are in a "supercritical" state, or in other words they are in a liquefied gaseous state. Here on Earth we have super critical water near heat vents, and liquid rocket fuel is super critical when ignited. Essentially, this planet is oozing with  super hot material! Definitely not a place I'd want to live!

Image Credit: NASA

Ebb and Flow

GRAIL A and B are lunar satellites launch by NASA that will be studying the gravitational field of the Moon (see GRAIL). The spacecrafts just arrived at the moon on December 31st 2011 and January 1st 2012. To get the general public involved in the mission, NASA decided to hold a competition for elementary school students in which they proposed new, more creative names for GRAIL A and B. The winners are a class of fourth grade students from Montana, who came up with the names "Ebb" and "Flow". Ebb means to move back or away (like a receding tide), where as flow means to move forward, like a flowing stream. The Moon's gravity is what causes the tides to occur, and since GRAILS primary mission is to study the Moon's gravity and how it affects Earth, these names are quite appropriate. Keep an eye out for other space related competitions that you can participate in on the NASA website: www. NASA.gov

Image Credit: NASA