In the 219th meeting of the american astronomical society, what planet's borders were said to be recognizable from space? hint:

In the 219th meeting of the American Astronomical Society, it was said that "Earth" is the plant that's borders were recognizable from space. 
Former NASA astronaut John Grunsfeld said that these are visible in the form of environmental differences.

He busted a myth also that The Great Wall of China is visible from space, he denied it.

answer; certification; plz check first, i believe this is correct. good luck;