The Cassini spacecraft was sent by NASA and ESA to study Saturn and its moons. Two of Saturn’s moons, Enceladus and Tethys, appear in the bottom right of this image. So far, the spacecraft has found new storm systems on Saturn, active geysers on its moon Enceladus, liquid oceans on its moon Titan, and many other unexpected discoveries. Due to its elliptical orbit, Cassini is occasionally able to catch beautyful images of saturn backlit by our sun, as seen above.
Pluto (bottom image) with various other non-planets.
Since everyone has their knickers in a knot over Pluto not being a planet, here are various different celestial objects who are also not classified as planets. You’ll notice, just because it’s not called a “planet” doesn’t mean it isn’t cool.
Let us be reminded, there is no heirarchy of celestial bodies. It wasn’t necessarily “demoted” from planethood, it was simply reclassified as something else. There’s literally no reason to be emotionally attatched to the idea of Pluto’s planetary classifaction.
But what “classifies” a planet anyway?
According to the International Astronomical Union, there are 3 basic requirements that it must meet:
1) It orbits the sun
2) Sufficient mass to assume a “hydrostatic equilibrium” (meaning it’s mostly shaped like a globe)
3) Has “cleared its neighborhood” in its orbit.
The third one is where Pluto fails. What they mean by “clearing the neighborhood” is that the orbital path is good and clear. Every planet will still collide with something now and then but their orbital paths are not occupied by anything that is similar to the size of the planet itself. They’re not really in danger of running into much of anything except maybe an asteroid or a comet that might enter their path and collide.
In addition, here is an image showcasing the dwarf planets of the solar system. Pluto isn’t alone in it’s classification.
So don’t be sad over Pluto not being a planet, you’re just being melodramatic. Wipe your tears away with some scientific literacy. ;)
The Moon of Lakes and Rivers - Saturn’s moon Titan
Saturn’s moon Titan is the only world - other than earth - that we know has liquid’s pooled on its surface. Unlike Earth, Titan has lakes of liquid methane - you wouldn’t want to swim in these lakes.
Titan’s “methane cycle” is analogy to Earth’s water cycle. In the 3rd and 4th images above we can see clouds of methane in Titan’s atmosphere. Ever since NASA’s Voyager 1 spacecraft, we have known that the gases that make up Titan’s brown colored haze were hydrocarbons. The atmosphere of Titan is largely nitrogen; minor components lead to the formation of methane–ethane clouds and nitrogen-rich organic smog.
It is thanks to the Cassini spacecraft that we now understand more about the climate of Titan - though we still understand very little!
The Cassini Space craft has mapped most of the Northern polar region of Titan, this is the region that contains almost all of Titan’s lakes. Cassini is systematically sweeping across Titan and mapping the surface of this strange alien world. The image below is an example of Cassini’s mapping process:
The building blocks of life might be
hanging out on Titan, one of Saturn’s
moons. Cornell University scientists
believe they have proven that life only
requires the existence of one chemical:
hydrogen cyanide, which can be
found all over the universe and is the
most common hydrogen-containing
compound on Titan’s surface. Source
Titan is the largest moon of Saturn. It is the only natural satellite known to have a dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found
Titan is primarily composed of water ice and rocky material. Much as with Venus prior to the Space Age, the dense, opaque atmosphere prevented understanding of Titan’s surface until new information accumulated with the arrival of the Cassini–Huygens mission in 2004, including the discovery of liquid hydrocarbon lakes in Titan’s polar regions.
The atmosphere is largely nitrogen; minor components lead to the formation of methane and ethane clouds and nitrogen-rich organic smog. Titan’s lower gravity means that its atmosphere is far more extended than Earth’s and about 1.19 times as massive. It supports opaque haze layers that block most visible light from the Sun and other sources and renders Titan’s surface features obscure.Atmospheric methane creates a greenhouse effect on Titan’s surface, without which Titan would be far colder. Conversely, haze in Titan’s atmosphere contributes to an anti-greenhouse effect by reflecting sunlight back into space, cancelling a portion of the greenhouse effect warming and making its surface significantly colder than its upper atmosphere.
Titan’s clouds, probably composed of methane, ethane or other simple organics, are scattered and variable, punctuating the overall haze.The findings of the Huygens probe indicate that Titan’s atmosphere periodically rains liquid methane and other organic compounds onto its surface. Clouds typically cover 1% of Titan’s disk, though outburst events have been observed in which the cloud cover rapidly expands to as much as 8%. One hypothesis asserts that the southern clouds are formed when heightened levels of sunlight during the southern summer generate uplift in the atmosphere, resulting in convection. This explanation is complicated by the fact that cloud formation has been observed not only after the southern summer solstice but also during mid-spring.
Saturn’s largest and second largest moons, Titan and Rhea, appear to be stacked on top of each other in this true-color scene from NASA’s Cassini spacecraft.
Titan is likely differentiated into several layers with a 3,400-kilometre (2,100 mi) rocky center surrounded by several layers composed of different crystal forms of ice.Its interior may still be hot and there may be a liquid layer consisting of a “magma” composed of water and ammonia between the ice Ih crust and deeper ice layers made of high-pressure forms of ice.
Rhea is an ice-cold body of weak density (1.236 g/cm3), indicating that the moon consists of a rocky nucleus counting only for a third of the mass of Rhea, the rest being mainly some ice-cold water.
With the sun now shining down over the north pole of Saturn’s moon Titan, a little luck with the weather, and trajectories that put the spacecraft into optimal viewing positions, NASA’s Cassini spacecraft has obtained new pictures of the liquid methane and ethane seas and lakes that…
“Yeah. You know how? When the big bang happened, all the atoms in the universe, they were all smashed together into one little dot that exploded outward. So my atoms and your atoms were certainly together then, and, who knows, probably smashed together several times in the last 13.7 billion years. So my atoms have known your atoms and they’ve always known your atoms. My atoms have always loved your atoms.”