Word: planetful
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...Mercury only once before, 30 years ago, when Mariner 10 made three flybys. Now NASA is set to try again, with a spacecraft called MESSENGER, which is scheduled to take off as early as this week on a mission to become the first probe to orbit the planet...
Even to astronomers, Mercury is a cosmic oddity. It spins so slowly and scoots around the sun so fast that a Mercury year--just 88 Earth days--is half as long as a Mercury day. On the planet's illuminated side--where the sun looks three times as big as it does from Earth and is 11 times as bright--temperatures climb to 840°F. When that side rotates into darkness, the thermometer plunges to --300°F. Eons of this rotisserie roll have cooked Mercury down to a nub with a metal core that represents three-quarters...
MESSENGER will study these and other Mercurian curiosities when it arrives at the planet in 2011. Completing a full orbit in 12 hours and swooping as close as 124 miles to the surface, it will need just six months to photograph the entire globe. After a three-decade wait for a return visit, that ought to seem like no time at all. --By Jeffrey Kluger...
Mercury is closer to the sun than any other planet, but it is not quite the hottest of the group. That distinction goes to nearby Venus, where the temperature climbs to 900°F (482°C), owing to the planet's dense, heat-trapping atmosphere...
Mercury has a large core of mostly iron, making the planet extraordinarily dense. This means that although Mercury is about 75% the diameter of Mars, it has about the same gravity...