The atmosphere is about twenty-percent oxygen and eighty percent nitrogen from Earth's surface to where space begins at one-hundred-twenty kilometers up.

VOA: special.2011.04.06

That is the lowest point on the earth's land surface so this dramatic drop in just a very short geographical area.

这是地球陆地表面的最低点,这急剧下降是在很短的地理范围内。

耶鲁公开课 - 旧约导论课程节选

Right. The most famous example is that when things fall near the surface of the Earth, they all have the same acceleration, and the acceleration that's common is called g, and that's 9.8 m/s^.

最有名的例子就是,当物体地球表面附近下落时,它们都拥有相同的加速度,这个普遍的加速度叫做g,大小为9.8m/s^

耶鲁公开课 - 基础物理课程节选

The basic concept is the same as that underpinning the "white roads" idea -- the development of a technology that can reflect a proportion of the sun's radiation away from the earth's surface and back out into space, thereby cooling the atmosphere and slowing, or even reversing the damaging effects of global climate change.

CNN: The shield of Ra: Could solar reflection save the planet?

"Landsat is a centerpiece of NASA's Earth Science program, and today's successful launch will extend the longest continuous data record of Earth's surface as seen from space, " NASA Administrator Charles Bolden said in a statement.

CNN: NASA cheers new Landsat launch

Solar energy can, of course, be gathered on Earth, but only about half of the sun's radiation ever makes it to the Earth's surface--the rest is either absorbed by the atmosphere or reflected back by clouds.

FORBES: Galactic Gold Mine?