It is impossible to overstate how much more we can learn about other worlds when we visit them. Even from Earth’s orbit, where the atmosphere doesn’t interfere with picture quality, we just can’t see the same details.  I’m going to put some numbers on this. When the Europa Clipper mission reaches Juno in 2030, it will begin a series of flybys that bring it as close as 25 km from Europa’s surface. From a distance of 100km, a 1km feature on Europa’s surface will be half a degree across and appear as wide as the moon does from Earth. From Earth … that 1km feature appears 400 million times...