Iapetus is a small and one of the most mysterious objects in the solar system. So here i explain what would standing on this weird moon would be like. Intro and outro footage made with Space Engine. Music: Kevin Macleod - Ossuary 5
Iapetus does not have two contrasting sides because of some ancient collision. The true explanation for the different sides is actually far more fascinating. So to explain why it has a dark side and a light side I have to go on a seemingly unrelated tangent. You see Saturn has another moon called Phoebe. Phoebe is a retrograde moon meaning it orbits the opposite direction of the planets spin (and Iapetus' orbit. It has a radius of 106 Kilometers making it rather large for a moon of its type (Phoebe also has a low albedo meaning it looks incredibly dark). And you see Phoebe is constantly getting smashed into by micro-meteorites and even by other small objects in orbit around Saturn. Because the gravity on Phoebe is so weak these impacts kick up material that goes into orbit around Saturn. This material has over time formed a sort of ring of material called "The Phoebe Ring". This ring is invisible to the naked eye but has been imaged with infrared. Now, scientists have done calculations on the ring material and have discovered that material larger than 3 centimeters across will stay in place in the ring, but material smaller than that will spiral inward. And what large moon is just waiting to sweep up that material, material that happens to be much darker than the surfaces of any other moons? Iapetus! Iapetus is the furthest out of the large Saturnian moons so it's in a perfect spot to sweep up the material. As a result the material from the Phoebe ring sort of rains down on the leading hemisphere of Iapetus (AKA THE DARK SIDE) and it causes the surface to darken, the darker surface absorbs more sunlight and so the ice there sublimates and it darkens some more and the ice sublimates even more and it causes a "Run Away Darkening Effect" that has turned the leading hemisphere dark as night. And because the trailing hemisphere doesn't run into any of the Phoebe ring material it has nothing to cause it to darken and so it stays white as snow. And that how you get the Yin-Yang surface of Iapetus! There you go! That's the explanation! Two seemingly unrelated phenomena that actually are related to each other! I honestly think this is a much cooler explanation than some ancient collision anyway! (:
If gravity is less than one-fortieth the amount of gravity on the surface of the Earth, then you would not need to walk up a mountain on Iapetus. You could reach the top through a series of very long jumps! And if you tripped and fell, the falling motion would be in slow-motion, compared to on Earth, and the force of impact would be negligible. The exception would be if you happened to fall into a deep chasm. In that case, though accelerating slowly, you would ultimately achieve a sufficient velocity to cause real damage or death. But the entire fall might last minutes, rather than seconds, so you'd have a bit of time to come up with a plan to save yourself. Perhaps you could call a nearby astronaut to assist you, or maybe activate your jetpack! There is another effect to keep in mind. Since the surface of Iapetus has no atmosphere, falling objects have no terminal velocity. They just keep accelerating at a slow rate until the fall is stopped by an impact, or a countervailing force.
OK, I'm really into this now! The force of gravity on Iapetus is equal to .223 m/s², per a Google search. If we plug this number into the ke!san online calculator, located at URL keisan.casio.com/exec/system/1224835316, it would require an object on Iapetus seven minutes (420 seconds) to fall ~20,000 meters, which is the height of the highest mountain on Iapetus, and the freefall velocity would be 337 km/hour, or approximately 200 MPH. Even if an astronaut weighed four or five pounds on Iapetus, that velocity would very likely be fatal. However, if the astronaut only fell for 30 seconds, his or her freefall velocity would be about fifteen miles, per hour, which might damage the joints, assuming you landed feet-first, but you would likely survive with a great story to regale humans back on Earth!
And back to that scenario of jumping one's way up a mountain on Iapetus. I could not find an exact match, but "Cosmos: The Infographic Book of Space," located at URL cosmos-book.github.io/high-jump/index.html, estimates a 60-foot vertical jump is probable for a human on Ceres, which has a surface gravity slightly higher than the surface gravity on Iapetus. Let us say that a human could jump about seventy feet high on Iapetus, if jumping straight up. If jumping forward, my swag calculator says a person could jump about four times that distance, or cover a horizontal distance of nearly 300 feet, per jump, begun while standing still! If you have a better or more accurate way to come up with this number, please post a reply here.
Those mountains are insane. Iapetus looks like it was unable to pull itself back together into a sphere after a major collision (at least that would be my guess)
Miranda is exactly what I was thinking (Personally I think Miranda deserves more love for being so cool) but I imagine there are many other ways to explain Iapetus.
No it's an ancient mega structure, a space station, that hemispheric line is as artificial as the whole damn thing. It's honeycombed with spaces, for habitation.
The dark material on Iapetus is from the Phoebe ring. Saturn's moon Phoebe releases dust as it orbits and forms a ring. Iapetus orbits through the ring and the dust gets on the surface thus creating the dark surface.
Have a look at my channel for another video about Iapetus. I have also written a free-to-download book called "Secrets in the Solar System" which has a chapter about Iapetus.
The massive mountain ridge almost looks centrifugally formed, if it coincides with the equator then perhaps it rotates super fast? Or maybe if the ridge doesn't coincide with the equator and/or the spin rate is low, perhaps it previously did until it was disturbed by a huge impact, explaining the stark contrast between both sides?
The leading side of Iapetus in its orbit is the dark side. It's quite likely that a dark material from another moon may have settled there. It's also hypothesized that the mountain chain is the result of a ring around Iapetus that settled down on the surface, as it is on the equator. Great video, as always!
Dreksler I know you made a video about what will happen if Earth became half of it's size. I would like to know what will happen if the sun became half it's size. Do you know what would happen if the sun became half of it's size?
Higtex 98 maybe everything on Earth would freeze if sun became half it's size.I also like to know will the planet Venus freeze if the sun became half of it's size?
Perhaps Iapetus' largest crater is the collision point between it and a celestial body perhaps made of ice, that of whatever material(s) were floating around that region of space. Then, the ice shattered and the chunks went flying above Iapetus, later to be pulled down and consolidated by gravity into splatter marks
The geological diversity found among the many moons in each of the gas giants in our solar system is simply startling. And yet, we are not even able to imagine for a moment the mind-boggling, strange geological formations we would find on the rest of trillions of planets and moons orbiting stars within our Milky Way, and beyond.
It depends on Iapetus orbit to determine how is it that far from Saturn and still remain locked. And yes, it's so needed to send robotic probes for a more specific analysis and study of much ignored Iapetus!!
These are the major moons in the solar system: Mercury - no moons Venus - no moons Earth - moon Mars - Deimos, Phobos. Jupiter - Io, Callisto, Europa, Ganymede. Saturn - Iapetus, Enceladus, Titan, Mimas, Rhea, Tethys. Uranus - Oberon, Ariel, Titania, Umbriel, Miranda. Neptune - Triton, Proteus. Earth, and Uranus are my favorite planets in the solar system. Earth is my favorite planet because it has amazing biodiversity, it is our home planet, and it has beautiful scenery. Uranus is also my favorite planet because it was discovered before Antarctica.
