Timeline for How is this possible: a moon with A) large apparent size B) that spins C) spins in a 5:1 spin-orbit resonance?
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Apr 2 at 19:31 | answer | added | bobsbeenjamin | timeline score: 0 | |
| Apr 2 at 4:24 | answer | added | geometrian | timeline score: 4 | |
| Apr 2 at 4:02 | comment | added | Ben | @wokopa Or to frame the same question another way: if you're happy simply declaring that in your fictional world the year and month just happen to be exact multiples of the planet's current day (or because aliens made it that way), why are you not happy declaring the same thing of the week/month ratio? | |
| Apr 2 at 3:58 | comment | added | Ben | Earth has days, months, and years that could be based on celestial cycles. But none of them are in integer ratios with each other. They're all caused by things that are essentially independent, so it would be an astonishing coincidence if they were. And it doesn't take much imprecision in the ratios for people to notice; believing a year to be perfectly 365 days rather than around 365.24 is only 0.07% off, but it didn't take modern science to notice that. So if the month and the year don't need to be an exact number of days, why does the month need to be an exact number of weeks? | |
| Apr 2 at 1:33 | history | became hot network question | |||
| Apr 1 at 23:34 | comment | added | Mary | In English, all the planets are named after the planets. They just used the German equivalents: Mars=Tyr, Mercury=Woden, Jupiter=Thor, Venus=Freya | |
| Apr 1 at 21:59 | comment | added | Christopher James Huff | Note that even if it just happened by chance (like, say, the moon being just big enough to cover up the sun in a total eclipse), the moon will be experiencing a lot of tidal heating, likely leading to active volcanism. Not a problem, just a pretty significant side effect. | |
| Apr 1 at 19:29 | history | edited | L.Dutch♦ |
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| Apr 1 at 19:11 | answer | added | AlexP | timeline score: 9 | |
| Apr 1 at 18:50 | comment | added | JBH | All that aside, it appears that if you delete everything that's causing us to comment... all of the Earth-centric stuff that isn't relevant to your question at all, what's left is, "can I have a moon the size of Earth's moon that's still rotating more than once per orbit?" I believe it's believed that all moons (celestial objects) rotated and slowly became tidally locked. I believe it's also believed that this takes long enough that life didn't begin until after tidal locking. But is it really necessary to duplicate what happened on Earth? Why not spin the moon and move forward? | |
| Apr 1 at 18:43 | comment | added | JBH | "Our use of the seven-day week can be traced back to the astronomically gifted Babylonians and the decree of King Sargon I of Akkad around 2300 BCE. They venerated the number seven, and before telescopes the key celestial bodies numbered seven (the Sun, the Moon and the five planets visible to the naked eye)." (Source) The article also credits the Jewish Genisis account, but it's unlikely a lot of other cultures would have picked that up. The Babylonians, on the other hand... | |
| Apr 1 at 18:39 | comment | added | JBH | A tidally locked object rotates once per orbit. That's how the locked object keeps the same face toward the locking object. | |
| Apr 1 at 18:08 | comment | added | AlexP | @L.Dutch: In Romance languages five of them are, indeed, named for lights in the sky. (Only five because Saturday is "Sabbath Day" and Sunday is "Lord's Day" in Romance.) But in English only three of them are (Saturday, Sunday and Monday) with the other four named for old pagan gods and goddesses, in German only two of them are (Sonntag and Montag), and in Russian none of them are (the Russian week goes "Day after Holy Day", "Second Day", "Mid Week", "Fourth Day", "Fifth Day", "Sabbath Day", "Holy Day"). | |
| Apr 1 at 17:34 | comment | added | L.Dutch♦ | The 7 days are associated to the 7 shiny and oddly moving things one can see in the sky: Sun, Moon, Mercury, Mars, Venus, Jupiter, Saturn. I would say they are celestial as well. | |
| Apr 1 at 17:29 | history | asked | wokopa | CC BY-SA 4.0 |