Space holds many mysteries. For the most part, we're stuck here on earth to sit and think about what lies just beyond our reach. But thanks to science (and an orbiter known as Cassini) we're able to learn more about what lies in space, making the great, big, expansive universe just a little bit smaller.
Cassini traveled almost five billion miles to reach Saturn so that we may find out more about our universe. Cassini's journey to and around Saturn lasted for 20 years, and was heralded as a great success. The mission experienced only a few glitches and taught us more than we every thought possible about the sixth planet from the Sun.
NASA, the European Space Agency (ESA) and the Italian Space Agency (ISA) all joined forces in the Cassini orbiter and Huygens probe exploration of Saturn. Both Cassini and the attached Huygens probe were launched from Cape Canaveral in Florida. The probe and the orbiter were launched on October 15, 1997, and they took seven years to finally arrive at Saturn.
Cassini taught us a lot about Saturn and its moons — and their capacity to support life. Thanks to Cassini, we now know that Titan, Saturn's giant moon, has a dense atmosphere and methane seas. While "methane seas" is an inherently unappealing sounding phrase, Titan could one day host life.
Enceladus, another one of Saturn's moons, could also one day see life living upon it. Beneath Enceladus' icy surface lies an ocean of salty liquid water. There's even a geyser, as some of the water shoots up into space, creating a plume.
But after two decades of service, Cassini's mission came to an end. Cassini finally crashed into Saturn. No, it wasn't from the stress of space travel finally getting to it. The orbiter's demise was intentional, planned out by NASA.
Cassini gives us a final look at Enceladus. In addition to discovering water and geysers on the moon, Cassini discovered carbon-based, organic compounds on Saturn's satellite. The compounds were released from "tiger stripes," aka darkened fissures on Enceladus.
Cassini also bid adieu to Titan. Information gleaned from Cassini suggested that the surface of Titan dissolves in a way that's similar to sinkholes on Earth. The surface of Titan is also quite cold, measuring at a frigid minus 292 degrees Fahrenheit.
Cassini, of course, couldn't say goodbye without sending us final shots of Saturn's famous rings. Saturn's rings are composed of particles of ice and rock. The largest ring is quite large, and is 7,000 times the diameter of the planet.
Cassini also grabbed a close up of the northern hemisphere of Saturn. Saturn's magnetic field is 578 times more powerful than the magnetic field of Earth. The gas giant is the second most massive planet in our Solar System (following Jupiter).
This infrared image depicts the site of Cassini's crash. In 2009, scientists realized that Cassini was running out of gas. In order to prevent a crash into Titan or Enceladus (and potentially contaminating the possible life on those moons), Cassini was programed to crash into Saturn.
This artist's rendering shows the many paths Cassini took during its lifetime. The path shown in orange is Cassini's visit to Titan. The path shown in blue is Cassini's preparation of its final crash into Saturn.