Solar System dynamics discussion thread
Posted: 09 Jun 2018 09:33
THE SOLAR SYSTEM DYNAMICS DISCUSSION THREAD
UNDERSTANDING CELESTIAL MECHANICS
INDEX OF TOPICS
But there's another reason for this thread (one less egoistical) and that is that in the process of learning some of the topics above I've encountered bad explanations (even at University level), filled with terrible misconceptions that I've been fighting against a lot. I would like to tell you some of them as to avoid more and more confusion in these topics, at least for the ones that find the information useful.
GOALS (EFFECT) To gain an in-depth understanding on celestial mechanics in the Solar System. To gain intuition on that understanding and not make it just by "the calculations say so even If I'm unable to comprehend what is going on". To educate ourselves and improve SpaceEngine with accurate suggestions on the matter. RULES (LAWS OF CAUSALITY) I'm going to try to address some topics when I can and explain them the best way I can, but the vast majority of them are to far away from my understanding so I'm also going to ask a lot of questions. I hope to be more or less constant with this (but I would need time). I'm also planning to do some Python programs to try and test some ideas that I have (probably also misconceptions) about how really Laplace resonances work for example. But my main goal here is to have a "low-level" discussion with all the necessary math but above all with real comprehension of what is going on. For that I think is important to use analogies. Let's make a very very difficult topic part of popular science, step by step, for everyone to understand even if the process is long and slow.
You can (and should) also try to address each of the topics. The order is not important.
If we address a topic I'm going to link where we discussed in the index of topic of the main post (this one). If a new topic should be addressed or one of the topics needs to be splittled in two then we can generate a larger index.
I will start soon with the tides (since I think I finally have overcomed some of the largest obstacles in understanding them). See you then.
- Misconceptions on the Universal Law of Gravitation and Newtonian Mechanics.
- The Hill sphere. Is the Moon more strongly atracted to the Sun than to Earth?
- Lunar evection and variation (anisotropic potential dwell around Earth due to the Sun's influence).
- Common misconceptions about tides. What are tides really?
- "The devil is in the detail" of tidal theory (coastlines, resonances, delays, tide-predicting machines, tides caused by planets, etc...).
- The Roche limit. Phobos future destruction and Saturn rings survival.
- The 1:1 spin-orbit resonance. Lunar hemispheres dychotomy, tidal braking and tidal locking in the Earth-Moon and Pluto-Charon systems.
- "The devil is in the detail" of increasing length of days on Earth (fluctuations, tectonics, post-glacial rebound, etc...).
- Why the Moon's semi-mayor axis is getting bigger and that of Phobos is shrinking. Tidal acceleration and angular momentum exchange.
- Precession and nutation on Earth as caused and regulated by Earth's non-sphericity (equatorial buldge) and gravitational interactions.
- Origin of the Moon (impact parameters, synestia, possible mutiple moon system and ring system etc...)
- Evolution of the orbit of the Moon (how it developed high inclination by proto-lunar disk resonances, the evection resonance and the high excentricity peak, 3:2 spin-orbit resonance event, etc...)
- What are the Milankovitch cycles? Axial tilt, precession, orbital eccentricity and orbital inclination cycles for Earth.
- True polar wander (changes in the moment of inertia of Earth, axial tilt of the Moon, cold traps change of location in the Moon etc...)
- Langrange points I: What are they? Gravitational potential in co-rotating reference frames, stability and instability, Horseshoe orbits and Trojan orbits. Description from an inertial reference frame.
- Lagrange points II: Trojans, the Hilda family, Theia formation, Kordylewski clouds, the Tethys-Telesto-Calypso and Dione-Helene-Polydeuces langrange systems etc...
- Mean-motion orbital resonances in the Main Belt (Kirkwood gaps, the story of Rhea Sylvian HED meteorites, the origin of the K/T impactor).
- Resonances in the rings of Saturn. Gaps, Lindblad resonance, Titan ringlet, Daphnis waves, moonlets, spokes and propelers.
- Epimetheus and Janus orbital swaping, Prometheus interactions with the F ring and shepherd moons.
- Tidal heating in Io, Europa and ancient Ganymede (Why is happening if they are tidally locked?)
- Tidal heating in Enceladus by Dione's tidal interaction.
- 1:2:4 Laplace Resonance. How it works? Why is it stable? How the galilean moons arrived to that orbital configuration? Energy distribution.
- Cycloidal fractures in Europa's crust and periodic lava tsunamis in Loki Patera
- 3:2 spin-orbit resonance in Mercury. How it works? Why It didn't fall in a 1:1 spin-orbit resonance? Why Mercury is not tidally heated having an eccentric orbit and not been tidally locked? Where does Mercury's orbital eccentricity comes from?
- 2:3 mean motion resonance between Pluto and Neptune. How it works and why is it stable? Plutinos.
- Other families of resonant TNOs
- 2:4 mean motion resonance between Tethys and Mimas (and the libration of the nodes).
- 3:4 mean motion resonance between Hyperion and Titan.
- TRAPPIST-1 complex chain of 6 mean motion resonances.
- Titius-Bode Law and Kepler's Mysterium Cosmographicum in solar and extrasolar systems as an indicator of to stable resonances.
- Orbital precession resonance. Perihelion secular resonance v[sub]6[/sub] between Saturn and asteroids.
- Saturn-Neptune secular axial-tilt-orbital-tilt resonance. Large Saturn axial tilt motivated by the depletion of the Kuiper Belt by Neptune.
- Uranus tilt in a colisionless scenario. Resonance with large satellite now disappeared.
- Venus slow rotation as a Cassini State. Possible resonance between Earth and Venus. What prevented tidall locking on Venus?
- Lidov-Kozai mechanism for the irregular satellites.
- Triton's retrograde motion and destruction of previous large moons in the Neptunian system.
- How a gravitational slingshot really works?
- The gravitational capture and alternative large impact hypothesis for the formation of the martian moons.
- Yarkovsky effect and how it works
- Poynting–Robertson drag and how it works
- Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effect and how it works
- Tumbling motion in asteroids
- 2015 BZ[sub]509[/sub] retrograde asteroid stability
- Saturn's Hyperion chaotic motion (digression on classical and quantum uncertainty) and Pluto's Nix chaotic rotation (energy transfers, origin and evolution)
- Nice Model, planetary migration and the Late Heavy Bombardment.
- Jumping-Jupiter scenario
- Grand tack scenario
- Long term stability of the Solar System
- Jupiter-Mercury future g[sub]1[/sub] = g[sub]5[/sub] secular resonance and the destruction of the inner solar system (collision with Earth and ejection).
- History of Neptunes discovery (+ Galileo's precovery). How exactly was Neptune's existence theoreticaly predicted using only Newton's Laws and Uranus's residuals? Le Verrier's inverse problem: How Neptune perturbs Uranus's motion?
- Planet 9 and resonant Extreme TNOs
- Extreme TNOs without Planet 9 (mutual interaction hypothesis)
- The Oort cloud and close stellar encounters.
- The Oort cloud and the galactic tide.
- Relativity in the Solar System dynamics. Perihelion precession of Mercury. Where is the energy to perform that change coming or is it even necessary? Anomalous orbital precession for Comet Lovejoy compared to that of Mercury's and how we know planet Vulcan does not exist.
But there's another reason for this thread (one less egoistical) and that is that in the process of learning some of the topics above I've encountered bad explanations (even at University level), filled with terrible misconceptions that I've been fighting against a lot. I would like to tell you some of them as to avoid more and more confusion in these topics, at least for the ones that find the information useful.
GOALS (EFFECT) To gain an in-depth understanding on celestial mechanics in the Solar System. To gain intuition on that understanding and not make it just by "the calculations say so even If I'm unable to comprehend what is going on". To educate ourselves and improve SpaceEngine with accurate suggestions on the matter. RULES (LAWS OF CAUSALITY) I'm going to try to address some topics when I can and explain them the best way I can, but the vast majority of them are to far away from my understanding so I'm also going to ask a lot of questions. I hope to be more or less constant with this (but I would need time). I'm also planning to do some Python programs to try and test some ideas that I have (probably also misconceptions) about how really Laplace resonances work for example. But my main goal here is to have a "low-level" discussion with all the necessary math but above all with real comprehension of what is going on. For that I think is important to use analogies. Let's make a very very difficult topic part of popular science, step by step, for everyone to understand even if the process is long and slow.
You can (and should) also try to address each of the topics. The order is not important.
If we address a topic I'm going to link where we discussed in the index of topic of the main post (this one). If a new topic should be addressed or one of the topics needs to be splittled in two then we can generate a larger index.
I will start soon with the tides (since I think I finally have overcomed some of the largest obstacles in understanding them). See you then.