by Chris Peterson » Sun Jun 19, 2022 2:58 pm
APOD Robot wrote: ↑Sun Jun 19, 2022 4:05 am
Game: Super Planet Crash
Explanation: Can you create a planetary system that lasts for 1000 years?
Super Planet Crash, the featured game, allows you to try. To create up to ten
planets, just click anywhere near the central star. Planet types can be selected on the left in order of increasing mass:
Earth,
Super-Earth,
Ice giant,
Giant planet,
Brown dwarf, or
Dwarf star. Each planet is gravitationally attracted not only to the central Sun-like star, but to other planets. Points are awarded, with
bonus factors applied for increasingly crowded and
habitable systems. The game ends after 1000 years or when a planet is gravitationally expelled.
Many exoplanetary systems are being discovered in recent years, and
Super Planet Crash demonstrates why some remain stable. As you might suspect after playing
Super Planet Crash a few times, there is reason to believe that our own
Solar System has
lost planets during its formation.
In physics, this is known as the n-body problem. It goes back to the 3-body problem... the effort to mathematically describe the dynamics of three bodies in mutual orbits. Turns out there is no solution. The 2-body problem is well understood, with solutions going back to Kepler and Newton. But outside of special contrived cases, there is no formulaic solution to any system with more than two bodies. Such systems can only be analyzed numerically- that is, by simulations like the one implemented in today's APOD. And from such simulations (and other theory) we understand that any system with more than two bodies will not be perfectly stable. It will exhibit chaotic behavior, and given enough time, will radically change. Luckily for us, all the dozens or hundreds of other bodies of significant mass were thrown out of the Solar System early on, leaving just a few bodies, with orbits well separated, such that our system exhibits a high degree of stability. But not perfect. And if a rogue star, planet, or black hole decides to pass too close to the Solar System, or through it (which will eventually happen), all of our planetary orbits could be scrambled.
[quote="APOD Robot" post_id=323473 time=1655611534 user_id=128559]
[url=https://apod.nasa.gov/apod/ap220619.html] [img]https://apod.nasa.gov/apod/calendar/S_220619.jpg[/img] [size=150]Game: Super Planet Crash[/size][/url]
[b] Explanation: [/b] Can you create a planetary system that lasts for 1000 years? [url=https://stefanom.org/spc/]Super Planet Crash[/url], the featured game, allows you to try. To create up to ten [url=https://solarsystem.nasa.gov/resources/313/what-is-a-planet/]planets[/url], just click anywhere near the central star. Planet types can be selected on the left in order of increasing mass: [url=https://apod.nasa.gov/apod/ap100713.html]Earth[/url], [url=http://en.wikipedia.org/wiki/Super-Earth]Super-Earth[/url], [url=http://en.wikipedia.org/wiki/Ice_giant]Ice giant[/url], [url=https://exoplanets.nasa.gov/what-is-an-exoplanet/planet-types/gas-giant/]Giant planet[/url], [url=http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question62.html]Brown dwarf[/url], or [url=https://www.universetoday.com/138338/wheres-line-massive-planet-brown-dwarf-star/]Dwarf star[/url]. Each planet is gravitationally attracted not only to the central Sun-like star, but to other planets. Points are awarded, with [url=https://pictures-of-cats.org/wp-content/uploads/2020/07/happy-cat_edited.jpg]bonus factors[/url] applied for increasingly crowded and [url=https://seec.gsfc.nasa.gov/what_makes_a_planet_habitable.html]habitable systems[/url]. The game ends after 1000 years or when a planet is gravitationally expelled. [url=https://apod.nasa.gov/apod/ap190710.html]Many exoplanetary systems[/url] are being discovered in recent years, and [url=https://news.ycombinator.com/item?id=7591094]Super Planet Crash[/url] demonstrates why some remain stable. As you might suspect after playing [url=http://www.space.com/25402-super-planet-crash-video-game.html]Super Planet Crash[/url] a few times, there is reason to believe that our own [url=https://solarsystem.nasa.gov/solar-system/our-solar-system/overview/]Solar System[/url] has [url=http://www.newscientist.com/article/dn20952-missing-planet-explains-solar-systems-structure.html]lost planets[/url] during its formation.
[/quote]
In physics, this is known as the n-body problem. It goes back to the 3-body problem... the effort to mathematically describe the dynamics of three bodies in mutual orbits. Turns out there is no solution. The 2-body problem is well understood, with solutions going back to Kepler and Newton. But outside of special contrived cases, there is no formulaic solution to any system with more than two bodies. Such systems can only be analyzed numerically- that is, by simulations like the one implemented in today's APOD. And from such simulations (and other theory) we understand that any system with more than two bodies will not be perfectly stable. It will exhibit chaotic behavior, and given enough time, will radically change. Luckily for us, all the dozens or hundreds of other bodies of significant mass were thrown out of the Solar System early on, leaving just a few bodies, with orbits well separated, such that our system exhibits a high degree of stability. But not perfect. And if a rogue star, planet, or black hole decides to pass too close to the Solar System, or through it (which will eventually happen), all of our planetary orbits could be scrambled.