Cassini Spacecraft: Top Discoveries
Our Cassini spacecraft has been exploring Saturn, its stunning rings and its strange and beautiful moons for more than a decade.
Having expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturnās moons will remain pristine for future exploration ā in particular, the ice-covered, ocean-bearing moon Enceladus, but also Titan, with its intriguing pre-biotic chemistry.
Letās take a look back at some of Cassiniās top discoveries: Ā
Under its shroud of haze, Saturnās planet-sized moon Titan hides dunes, mountains of water ice and rivers and seas of liquid methane. Of the hundreds of moons in our solar system, Titan is the only one with a dense atmosphere and large liquid reservoirs on its surface, making it in some ways more like a terrestrial planet.
Both Earth and Titan have nitrogen-dominated atmospheres ā over 95% nitrogen in Titanās case. However, unlike Earth, Titan has very little oxygen; the rest of the atmosphere is mostly methane and traced amounts of other gases, including ethane.
There are three large seas, all located close to the moonās north pole, surrounded by numerous smaller lakes in the northern hemisphere. Just one large lake has been found in the southern hemisphere.
The moon Enceladus conceals a global ocean of salty liquid water beneath its icy surface. Some of that water even shoots out into space, creating an immense plume!
For decades, scientists didnāt know why Enceladus was the brightest world in the solar system, or how it related to Saturnās E ring. Cassini found that both the fresh coating on its surface, and icy material in the E ring originate from vents connected to a global subsurface saltwater ocean that might host hydrothermal vents.
With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist.
Saturnās two-toned moon Iapetus gets its odd coloring from reddish dust in its orbital path that is swept up and lands on the leading face of the moon.
The most unique, and perhaps most remarkable feature discovered on Iapetus in Cassini images is a topographic ridge that coincides almost exactly with the geographic equator. The physical origin of the ridge has yet to be explainedā¦
It is not yet year whether the ridge is a mountain belt that has folded upward, or an extensional crack in the surface through which material from inside Iapetus erupted onto the surface and accumulated locally.
Saturnās rings are made of countless particles of ice and dust, which Saturnās moons push and tug, creating gaps and waves.
Scientists have never before studied the size, temperature, composition and distribution of Saturnās rings from Saturn obit. Cassini has captured extraordinary ring-moon interactions, observed the lowest ring-temperature ever recorded at Saturn, discovered that the moon Enceladus is the source for Saturnās E ring, and viewed the rings at equinox when sunlight strikes the rings edge-on, revealing never-before-seen ring features and details.
Cassini also studied features in Saturnās rings called āspokes,ā which can be longer than the diameter of Earth. Scientists think theyāre made of thin icy particles that are lifted by an electrostatic charge and only last a few hours. Ā
The powerful magnetic field that permeates Saturn is strange because it lines up with the planetās poles. But just like Earthās field, it all creates shimmering auroras.
Auroras on Saturn occur in a process similar to Earthās northern and southern lights. Particles from the solar wind are channeled by Saturnās magnetic field toward the planetās poles, where they interact with electrically charged gas (plasma) in the upper atmosphere and emit light. Ā
Saturnās turbulent atmosphere churns with immense storms and a striking, six-sided jet stream near its north pole.
Saturnās north and south poles are also each beautifully (and violently) decorated by a colossal swirling storm. Cassini got an up-close look at the north polar storm and scientists found that the stormās eye was about 50 times wider than an Earth hurricaneās eye.
Unlike the Earth hurricanes that are driven by warm ocean waters, Saturnās polar vortexes arenāt actually hurricanes. Theyāre hurricane-like though, and even contain lightning. Cassiniās instruments have āheardā lightning ever since entering Saturn orbit in 2004, in the form of radio waves. But it wasnāt until 2009 that Cassiniās cameras captured images of Saturnian lighting for the first time.
Cassini scientists assembled a short video of it, the first video of lightning discharging on a planet other than Earth.
Cassiniās adventure will end soon because itās almost out of fuel. So to avoid possibly ever contaminating moons like Enceladus or Titan, on Sept. 15 it will intentionally dive into Saturnās atmosphere.
The spacecraft is expected to lose radio contact with Earth within about one to two minutes after beginning its decent into Saturnās upper atmosphere. But on the way down, before contact is lost, eight of Cassiniās 12 science instruments will be operating! More details on the spacecraftās final decent can be found HERE.
Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com
pixelskylines
2087
germansingergirl
amandla
snowghoul
