Apple | Google | Spotify | Amazon | Participant.FM
Castbox | Stitcher | Podcast Republic | RSS | Patreon
Historical astronomers from virtually each tradition knew of seven issues within the sky that moved. the Solar, the Moon, Mercury, Venus, Mars, and Jupiter.
The seventh and slowest transferring of these was the one named after the Roman god of time: Saturn.
For hundreds of years Saturn was a dot within the sky. Then when telescopes had been invented, our notion of the planet modified dramatically.
Be taught extra about Saturn and what makes it totally different than each different planet within the photo voltaic system on this episode of All the pieces In all places Day by day.
The names of the planets that we use in English got here from the Romans. There was a kind of logic to how the names got out. The planet that moved essentially the most was named after the winged messenger god, Mercury.
The planet that confirmed up at nightfall and daybreak was named after the goddess of magnificence: Venus.
The reddish level of sunshine was named after the god of battle: Mars.
The slowest transferring level of sunshine was named after the Roman god of time: Saturn.
The ancients couldn’t have recognized, but it surely turned out that the rationale why Saturn moved so slowly was as a result of it was the farthest away.
Saturn lies about 1.4 billion kilometers on common away from the Solar. To place that into perspective, it’s a little beneath twice so far as Jupiter is from the solar and about 10x the gap the Earth is from the Solar.
By way of measurement, Saturn is the second largest planet within the photo voltaic system. Jupiter is round 143,000 kilometers in diameter, and Saturn is about 120,000 kilometers in diameter.
Sure, Saturn is fairly large, however that isn’t the defining charistic of the planet. The factor about Saturn, which is de facto totally different, is its density.
To place it in perspective, Saturn has 764x the quantity of the Earth however solely 95x the mass of the Earth.
Meaning its density is simply 12% that of Earth, or to place it in a means that may be a bit extra visceral, assuming you can do it, Saturn may float on water.
The explanation why Saturn has such a low density is that almost all of its environment consists of hydrogen and helium, the 2 lightest parts. It’s believed to have a strong core which is kind of dense, however total, mild parts within the environment scale back its total density.
It takes Saturn 29.5 years to journey across the Solar, but it surely solely takes 10.5 hours for the planet to rotate round its axis.
Our understanding of Saturn modified dramatically with the invention of the telescope. Galileo was the primary one that checked out Saturn with a telescope, however his telescope wasn’t adequate to resolve its main function: its rings.
Galileo simply noticed two blobs on the aspect and figured they had been moons, however they weren’t just like the moons he noticed round Jupiter.
The primary individual to see the rings and who had a telescope sufficiently big to discern them was the Dutch astronomer Christiaan Huygens.
He additionally made the invention of Saturn’s largest moon, Titan. Extra on Titan in a bit.
As telescopes improved, different moons had been found together with Iapetus, Rhea, Tethys, Dione, Mimas, Enceladus, and at last Phoebe in 1899. These are simply the foremost moons that had been found by astronomers on Earth. There are a complete of 83 moons of Saturn which have been found in complete.
The opposite main discovery earlier than the twentieth century was the truth that Saturn’s ring had been, in actual fact, a number of rings with gaps between them.
The assorted rings had been named by letter, however they had been named within the order that they had been found by the gaps between them. Because of this, the sequence makes little sense.
Going outward from the innermost ring, the order is D, C, B, A, F, G, E, with minor rings and gaps getting distinctive names.
The large advance in our understanding of Saturn got here with sending probes to the planet.
The primary probe despatched to Saturn was Pioneer 11. Launched in 1977, it handed inside 21,000 kilometers from the highest of the environment on September 1, 1979.
The pictures it captured had been one of the best ever taken, however they weren’t nice.
Fortunately, it wasn’t lengthy earlier than the subsequent probes arrived. A bit of greater than a 12 months later, Voyager 1 flew by the planet on November 12, 1980, after which Voyager 2 flew by on August 26, 1981.
The pictures captured by these three probes dramatically elevated our understanding of Saturn, its moons, and its rings. Along with the pictures despatched again, they had been additionally capable of take measurements on the planet’s temperature and its magnetic area.
These three probes had been restricted within the quantity of knowledge they may collect as a result of they had been solely fly-bys. There have been just a few days after they may take pictures and gather information.
What was wanted was a probe that would really orbit round Saturn for an prolonged time period. That’s precisely what NASA did with the Cassini–Huygens mission.
The Cassini–Huygens mission had two components. The primary was the Cassini orbiter which was to orbit Saturn to get detailed pictures of the planet and its moons. The second half was the Huygens probe which was despatched into the environment of Titian and landed on the floor.
Right here I most likely want to speak about Titan, which, fairly frankly, is among the most fascinating components of Saturn and the whole photo voltaic system.
Titan is the biggest moon of Saturn and the second largest moon within the photo voltaic system after Jupiter’s moon of Ganymede.
Titan additionally occurs to be the one different place within the photo voltaic system that has an atmospheric stress similar to Earth. In principle, in the event you had been to stroll on the floor of Titan, you would wish an area go well with, however you wouldn’t want the go well with to be pressurized.
Titan can also be the one different place within the photo voltaic system which is understood to have steady liquids on the floor.
Now earlier than you get excited and suppose that that is like Earth, it’s not. For starters, the temperature on the floor averages ?179 °C or ?290 °F.
The liquid that’s on the floor is definitely liquid methane. So far as we all know, there’s a methane cycle on Titan, which mirrors the water cycle on Earth. Liquid methane will evaporate right into a fuel after which precipitate down as liquid methane rain.
The mission was launched on October 15, 1997, and spent seven years touring to Saturn. It arrived there on June 30, 2004, and put itself into orbit round Saturn by really flying in a niche between two of the rings.
On Christmas Day of that 12 months, Huygens and Cassini separated, and Huygens landed on January 15, 2005.
The pictures returned by the Huygens lander weren’t nice, and there weren’t many. It didn’t have an extended operational life after it landed. However it did return some pictures, the primary ever taken on the floor of the moon of one other planet.
Additional radar observations of Titan by the Cassini orbiter discovered proof of lakes close to the north pole area.
Whereas the Huygens a part of the mission didn’t final very lengthy, the Cassini a part of the mission lasted far longer than initially meant. The unique mission was solely imagined to final 3 years, but it surely really ended up going over 12 years.
The orbiter was lastly destroyed by flying it into the environment of Saturn on September 15, 2017.
Over the 12 years it flew round Saturn, there was an infinite quantity of knowledge that it collected.
One of many issues we didn’t know a lot about earlier than was the hexagon at north pole of Saturn. This was initially found on Voyager 1, but it surely was investigated additional with Cassini.
Scientists aren’t precisely certain what causes the hexagon sample to look within the clouds. One of the best guess at present is that it’s some kind of standing wave. Researchers had been capable of replicate an analogous sample doing exams of rotating fluids.
The hexagon did change shade through the Cassini mission from bluish to a golden shade.
The hexagon form doesn’t seem on the south pole. As a substitute, there seems to be a hurricane-like storm with its personal eye.
It did a flyby of the moon Enceladus which was 50 kilometers from the floor. It really flew by a geyser plume the place it detected water, CO2, and hydrocarbons.
In 2012 it was witness to an occasion often called the Nice White Spot. This was an enormous storm that appeared within the Northern Hemisphere. It appears to happen regularly about each 28.5 years. It’s much like Nice Pink Spot on Jupiter, however it’s non permanent.
One other discovery was studying extra about Saturn’s rings.
For starters, the rings are 99.9% water ice and a small quantity of rocky materials. There isn’t quite a lot of materials within the rings. They’re very skinny, various, from solely 10 meters to 1 kilometer.
The whole mass of ice within the rings is simply about half the mass of the ice present in Antarctica.
The particles which make up the rings are additionally not very massive ranging in measurement from a couple of millimeters to perhaps a most of 10 meters.
One of many present theories is that the rings of Saturn are solely non permanent. We simply occur to be residing at a time after we can observe them.
It seems what is going on is that the ice particles are slowly being pulled into Saturn resulting from its magnetic area. The quantity of ice being misplaced is estimated to fill an Olympic sized swimming pool each half hour.
It implies that the ring would possibly solely be 100 million years outdated and should have lower than 100 million years left. Which may sound like a very long time, however within the age of the photo voltaic system, it’s virtually nothing.
The supply of the ice making up the rings was most likely a comet or moon, which disintegrated in some unspecified time in the future.
The gaps within the rings primarily come from gravitation resonance with the assorted moons of Saturn.
As a result of Saturn is so far-off, it’s a very troublesome place to achieve. With out the planets being within the right alignment to get a gravitational slingshot, it might probably take a few years.
There aren’t as many future proposed missions as there are for planets comparable to Mars, that are a lot simpler to achieve.
One of many solely proposed future missions is NASA’s Titan Saturn System Mission. Among the present concepts being floated for this mission would possibly embody a balloon that may float in Titan’s methane environment in addition to a ship that would sail in one in every of its methane lakes.
The mission hasn’t been accepted but, and no funding has been allotted. If and when that does occur, the launch won’t happen till someday round 2030.
Saturn is an fascinating planet, however the actually fascinating issues to discover will most likely be its moons, particularly Titan.
There’s nothing else within the photo voltaic system like Titan. Its comparatively thick environment and its liquid floor present the one alternative to check such an surroundings.
On a private stage, in the event you ever get the prospect, take part in a star occasion in your space. It’ll often contain some beginner astronomers who convey out their telescopes so the general public can look by them.
I keep in mind taking part in a single on the customer heart on Mount Kilauea in Hawaii. When you occur to go to whereas Saturn is out, you’ll clearly be capable to see the rings of Saturn with your individual eyes, and perhaps even Titan.
When you see Saturn and its rings with your individual eyes, it is possible for you to to see one thing that even Galileo couldn’t.