"A liquid water layer or pocket in contact with the rock, which is deep below Enceladus' surface, will acquire sodium from the rock - essentially leaching the rock," he says.
Rivers clean themselves quickly when pollution is not too great, so long as the water is moving and in contact with plants, soil and rock.
在污染不太严重时，河水只要是流动的而且能接触植物、土壤、岩石，自身很快就会变清洁。
3
“Once you go from football to basketball, the contact doesn’t really bother you, ” says Rock, who didn’t cross over from pigskin to roundball until he got to high school.