Timeline for Could planets switch orbits like Janus?
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| Apr 13, 2017 at 12:59 | history | edited | CommunityBot |
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| Apr 13, 2017 at 12:52 | history | edited | CommunityBot |
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| Jan 20, 2016 at 2:33 | vote | accept | bowlturner | ||
| Dec 4, 2014 at 0:59 | comment | added | HDE 226868♦ | @Oldcat True, if these two planets formed as near enough to each other (though possibly scaled up) as Janus and Epimetheus did. | |
| Dec 4, 2014 at 0:58 | comment | added | Oldcat | According to Wiki closest approach would be an equivalent of 6 million miles...so likely the moon would come along with us when we switched orbits. | |
| Dec 4, 2014 at 0:52 | comment | added | HDE 226868♦ | @Oldcat Makes sense. | |
| Dec 4, 2014 at 0:44 | comment | added | Oldcat | Recalc gives inner period of 364.28 days rather than 365. | |
| Dec 4, 2014 at 0:38 | comment | added | Oldcat | The difference in orbit distance is 50 km in a 150,000 km orbit, so 1 part in 3000. Energy in goes by square of distance by area of sphere. My calc for the change in orbital period is probably off. It should follow T^2 = R^3 law. | |
| Dec 4, 2014 at 0:21 | comment | added | HDE 226868♦ | @Oldcat Good logic. Out of curiosity, how did you do the calculations (I don't quite follow)? | |
| Dec 4, 2014 at 0:09 | comment | added | Oldcat | I needed to know how often these flips happened. I took the period of Janus' orbit (about .7 days) and the flip period (about 4 years) and came out to a flip about every 2000 orbits - so 2000 years. So a tiny change in incoming solar due to orbit flip every 2k years is a minimal change to life here. | |
| Dec 4, 2014 at 0:05 | comment | added | HDE 226868♦ | @Oldcat I'm probably forgetting something completely obvious, but where did the 2000 come from? I vaguely recall seeing that somewhere besides in your comments. | |
| Dec 4, 2014 at 0:03 | comment | added | Oldcat | The two orbits the moons share are at different distances. Every 2000 orbits "our" Earth gets close to the other Earth and flips to the other orbit...assuming we were the outer orbit, we now move slightly in and run along for 2000 years that way. Next encounter, we move out, the year lengthens and climate cools a tiny bit. The real interesting thing would be how astronomy would be affected by this other earth being virtually motionless relative to the sun, slowly moving and getting brighter. | |
| Dec 4, 2014 at 0:00 | comment | added | HDE 226868♦ | @Oldcat Why would the year get shorter and the climate get warmer? I'm guessing you're thinking about the planets moving further in to the star they're orbiting, but the configuration means that for part of their orbits, they'd also move further back. | |
| Dec 3, 2014 at 23:57 | comment | added | Oldcat | If we assume Earth and Earth2 are in a Janus like orbit about the sun, then the two orbits are 1 part in 3000 apart. So if we flipped over the year would get about 2-3 hours shorter and the climate get about .06 percent warmer...1.000333 squared. The flips would happen every 2000 years or so if it happened exactly as many orbits as the moons do. | |
| Dec 1, 2014 at 23:53 | history | answered | HDE 226868♦ | CC BY-SA 3.0 |