「dog ear(犬の耳)」とは、本を読んでいるときに気になるところがあったら、ページの端をちょっと折って、印をつけること。
別アカウントのtumblr「辺境の旅」もよろしくどうぞ
Titan’s Hazy History and the Potential for Life
Saturn’s moon Titan is the only moon in our solar system known to possess an atmosphere of any significance.
Ten times thicker than Earth’s, Titan’s atmosphere extends nearly 370 miles (600 km) above its frigid surface. It’s a literal chemical factory, where nitrogen and methane are zapped by the sun’s ultraviolet rays and transformed into organic molecules, some of which descend to the moon’s surface while others rise up above the clouds, creating a bluish high-level haze of hydrocarbons.
Titan’s atmosphere forms an opaque orange shroud that covers it and hides many of its surface features from view, keeping much of its details a mystery until the arrival of the Cassini-Huygens spacecraft in 2004.