They cover a lot of area, many football fields worth--maybe 1/4 to 1/2 a square mile. (I looked it up and the article said 1.5 square kilometers, which is a little more than 1/2 a square mile.)
They cover a lot of area, many football fields worth--maybe 1/4 to 1/2 a square mile. (I looked it up and the article said 1.5 square kilometers, which is a little more than 1/2 a square mile.)