The Voyager, Galileo, and Cassini missions contributed a significant amount of information that has bolstered our understanding of the outer solar system. When Voyager 1 and 2 were released from our atmosphere in 1977, their main goal was to explore Jupiter and Saturn; after a successful mission there, the two spacecrafts continued on to examine Jupiter’s moon and Saturn’s rings (Chaisson, 2011). Although planets like Jupiter have been observed using telescopes from earth, the Voyager was able to reveal many exciting features on the planet, the most important of which is the “Great Red Spot”, a complex storm moving in a counterclockwise direction. In addition to this discovery, Voyager found volcanic activity throughout the Jovian system and was able to determine that Ganymede is the largest moon in our solar system. Without Voyager’s excursion to the outer solar system, we would have never been able to detect any of this. Since the Voyager mission was successful, Galileo was sent out to pick up where the Voyager had left off. This craft deployed a probe into Jupiter’s atmosphere, and although it was eventually destroyed, it was used to study the ice on Jupiter’s moons.
Cassini was sent to Saturn and also aimed to test the theory of relativity. After this exploration, scientists were fully able to understand the rotational pattern of Saturn. We were unable to do this remotely from Earth because there are no fixed features on this planet that could be used to determine the period of rotation; therefore, Cassini was used to emit radio waves that allowed us to make note of this movement. This rotational period has changed over time; it is now six minutes greater than it was when initially measured by Voyager.
Although we have been able to learn many things by observing our solar system with the naked eye and telescopes, we haven’t been able to achieve as great detail as we can when we release spacecrafts to conduct close recordings of faraway planets. Hopefully spacecrafts like Voyager, Galileo, and Cassini continue to be dispatched on missions that will help us understand more about our universe.
Chaisson, E., & McMillan, S. (2011). Astronomy, a beginner\’s guide to the universe. (6th ed.). Benjamin-Cummings Pub Co.