Final answer:
The sentences should be completed with the correct past conditional and present simple verb forms to describe what ancient sky watchers could have discovered about Saturn and what we can observe today.
Explanation:
Saturn has always been a fascinating planet. If ancient sky watchers (had studied) it the way we are able to today, they (would have been) amazed. They (would have found) that its rings consisted of billions of icy particles. They (would have discovered) that these rings are extremely thin-only 10 m (33 ft.) thick. And they (would have learned) that some of the planet's small moons play an important part in controlling the orbits and spacing of the rings. If you (study) Saturn's moons today, you (can observe) that some of its 62 moons orbit in opposite directions. You (can see) that some moons even exchange orbits. Most importantly you (can learn) that two of the moons have the potential for life!
