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NASAKepler: How big is the sun? This small. .@ThatsEarth: Perspective of how small we really are.. http://pic.twitter.com/izZtvg1AJW
いい比較図だけどこんなん紹介してる場合かケプラー…

HiRISE: When Mars was wet: How snow melt might have carved valleys http://rss.csmonitor.com/~r/feeds/science/~3/fjo3fM_zEcM/When-Mars-was-wet-How-snow-melt-might-have-carved-valleys …
でも昔の話なのでしょう？