Juno will be only the second human satellite to examine Jupiter while orbiting the gas giant, following Galileo. Other probes have examined it in passing, but they and the Galileo mission have left a bunch of questions. One problem is that we see only the top layer of Jupiter's atmosphere, and that can't really tell us much about anything other than the top layer of Jupiter's atmosphere. Our atmosphere is relatively thin and transparent. But Jupiter's is made up of a whole different mix of gases and is many many times thicker -- its Great Red Spot, for example, is actually a hurricane-like storm that's been going on for several hundred years and is bigger than our entire planet.
Scientists hope that Juno's sophisticated sensors can ferret out Jupiter's secrets. The probe is named after the goddess Juno, who in Roman mythology was the wife of the king of gods, known as Jupiter or Jove. On the one hand, this bodes well for the ability of the probe to snoop through Jupiter's business pretty thoroughly, since husbands are rarely if ever able to keep secrets from wives. On the other hand, we could have a problem if Jupiter forgets something important like an anniversary or when Juno arrived in orbit, because slip-ups like that have been known to block spousal communication for a considerable time.