German Humor Orbital Canon
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1: 365.2425 days per year. Over 71 million years, that adds up to an extra 17.75 million days.
2: It doesn't really matter; the total should be rounded off to 2 significant digits, because the number of years is only known to that precision: 26 billion days.
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We are slowing moving away from the sun, the days are slightly longer now than they were 71 million years ago.
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@Dragoon If Earth is moving away from the sun, the years are getting longer.
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@Zecc said in The Official Funny Stuff Thread™:
@Dragoon If Earth is moving away from the sun, the years are getting longer.
Yes, that's what he said. Unless longer days means something else when un-divided into years....
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@Dragoon said in The Official Funny Stuff Thread™:
We are slowing moving away from the sun, the days are slightly longer now than they were 71 million years ago.You have the effect right, but not the reason. Days are due to rotation of Earth around its own axis, and that is what is slowing down, due to tidal effects.
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@Tsaukpaetra said in The Official Funny Stuff Thread™:
@Zecc said in The Official Funny Stuff Thread™:
@Dragoon If Earth is moving away from the sun, the years are getting longer.
Yes, that's what he said. Unless longer days means something else when un-divided into years....
Not quite. A year is how long it takes to translate around the sun, a day is how long it takes for the Earth to rotate on itself. So for the same duration of rotation and increasing duration of translation, you get shorter days relative to a year.
Unless, of course, I am completely wrong on this because I haven't had my coffee yet.
Anyway, what @Bulb said.
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@Bulb said in The Official Funny Stuff Thread™:
@Dragoon said in The Official Funny Stuff Thread™:
We are slowing moving away from the sun, the days are slightly longer now than they were 71 million years ago.You have the effect right, but not the reason. Days are due to rotation of Earth around its own axis, and that is what is slowing down, due to tidal effects.
And going further from the sun makes (solar) days shorter, assuming unchanged axial rotation
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@kazitor said in The Official Funny Stuff Thread™:
assuming unchanged axial rotation
But tidal interaction with the moon means that's definitely not a precondition that is true. Which means I'm not going to try to work out how the things balance.
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@kazitor said in The Official Funny Stuff Thread™:
@Bulb said in The Official Funny Stuff Thread™:
@Dragoon said in The Official Funny Stuff Thread™:
We are slowing moving away from the sun, the days are slightly longer now than they were 71 million years ago.You have the effect right, but not the reason. Days are due to rotation of Earth around its own axis, and that is what is slowing down, due to tidal effects.
And going further from the sun makes (solar) days shorter, assuming unchanged axial rotation
You sure? A prograde spinning planet (most of them, only Venus and Uranus spin retrograde) will add one synodic (solar) day per synodic orbit (year), making synodic days shorter than sidereal days. Increasing orbital distance increases orbital period, so the one synodic day gets added to more sidereal days, making the difference smaller. Assuming unchanged sidereal day (rotational period), that means slightly longer synodic (solar) day.
Anyway, the whole premise is incorrect. Earth doesn't have a source of energy to increase its orbital distance. What it does is dissipate rotational energy through tides, which slows down the rotation, increasing the length of day, both synodic and sidereal.
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@Tsaukpaetra said in The Official Funny Stuff Thread™:
@Zecc said in The Official Funny Stuff Thread™:
@Dragoon If Earth is moving away from the sun, the years are getting longer.
Yes, that's what he said. Unless longer days means something else when un-divided into years....
A "day" is the earth's rotation on its axis. A "year" is the orbit of the earth around the sun. Two completely different things.
If the earth's rotational speed changed, a day would be longer (or shorter if it sped up) but it would still take the same number of "days" for the earth to make one orbit around the sun. Assuming you continue to use one complete rotation as the definition of a day.
Or, if the earth's orbital speed changed, the length of a day would stay the same but a year would be longer (or shorter if it sped up). Assuming you continue to use one complete orbit of the sun as the definition of a year.
Thought experiment: What if the earth's rotation slowed down and instead of 24 hours it took 29 hours. How would that affect society?
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@Gern_Blaanston said in The Official Funny Stuff Thread™:
Thought experiment: What if the earth's rotation slowed down and instead of 24 hours it took 29 hours. How would that affect society?
I think the coffee industry would die nearly instantly. 🦩
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@Gern_Blaanston said in The Official Funny Stuff Thread™:
What if the earth's rotation slowed down and instead of 24 hours it took 29 hours. How would that affect society?
Yay! More time to
every day!
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@Bulb said in The Official Funny Stuff Thread™:
You sure? A prograde spinning planet (most of them, only Venus and Uranus spin retrograde) will add one synodic (solar) day per synodic orbit (year), making synodic days shorter than sidereal days. Increasing orbital distance increases orbital period, so the one synodic day gets added to more sidereal days, making the difference smaller. Assuming unchanged sidereal day (rotational period), that means slightly longer synodic (solar) day.
Yes, I am sure. The solar day is longer than the sidereal and stellar days, so if the effect is spread out across more days, the solar day becomes less long than before.
For Earth, a mean solar day is obviously 24 hours, whereas it spins on its axis every 23 hours 56 minutes and 4 seconds. Move further from t he sun without changing the stellar day, and the reduced orbital angular velocity brings the solar day closer to the stellar day, i.e., shorter.
Here’s some FUNNY STUFF, depending on your frame of mind: I’ve noticed a curious trend where people try to be ‘technical’ by saying days = rotations and years = orbits, even though these are absolutely not the durations of days and years in normal parlance. The FUNNY part is that just saying the obvious thing is 9001% more accurate: a day is the interval from midnight to midnight and a year is the cycle of the seasons. While an axial rotation is 4 minutes shorter than a day and an orbital period is 20 minutes longer than a cycle of seasons.
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@Gern_Blaanston said in The Official Funny Stuff Thread™:
@Tsaukpaetra said in The Official Funny Stuff Thread™:
@Zecc said in The Official Funny Stuff Thread™:
@Dragoon If Earth is moving away from the sun, the years are getting longer.
Yes, that's what he said. Unless longer days means something else when un-divided into years....
A "day" is the earth's rotation on its axis. A "year" is the orbit of the earth around the sun. Two completely different things.
If the earth's rotational speed changed, a day would be longer (or shorter if it sped up) but it would still take the same number of "days" for the earth to make one orbit around the sun. Assuming you continue to use one complete rotation as the definition of a day.
Yes they're different but no. Just take it to the extreme and imagine a tidally locked system where one rotation takes exactly one year. A year would still be a year but last 0 days because a day would be infinitely long.
Mercury is tidally locked in 3:2 resonance soThe resonance makes a single solar day (the length between two meridian transits of the Sun) on Mercury last exactly two Mercury years, or about 176 Earth days.
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@kazitor said in The Official Funny Stuff Thread™:
@Bulb said in The Official Funny Stuff Thread™:
You sure? A prograde spinning planet (most of them, only Venus and Uranus spin retrograde) will add one synodic (solar) day per synodic orbit (year), making synodic days shorter than sidereal days. Increasing orbital distance increases orbital period, so the one synodic day gets added to more sidereal days, making the difference smaller. Assuming unchanged sidereal day (rotational period), that means slightly longer synodic (solar) day.
Yes, I am sure. The solar day is longer than the sidereal and stellar days, so if the effect is spread out across more days, the solar day becomes less long than before.
For Earth, a mean solar day is obviously 24 hours, whereas it spins on its axis every 23 hours 56 minutes and 4 seconds. Move further from t he sun without changing the stellar day, and the reduced orbital angular velocity brings the solar day closer to the stellar day, i.e., shorter.
Here’s some FUNNY STUFF, depending on your frame of mind: I’ve noticed a curious trend where people try to be ‘technical’ by saying days = rotations and years = orbits, even though these are absolutely not the durations of days and years in normal parlance. The FUNNY part is that just saying the obvious thing is 9001% more accurate: a day is the interval from midnight to midnight and a year is the cycle of the seasons. While an axial rotation is 4 minutes shorter than a day and an orbital period is 20 minutes longer than a cycle of seasons.
a second is defined with some atomic property I won't bother to recall, we can bypass all this confusion using seconds
in millions of years I wouldn't be surprised if other weird things like time dilation and the expansion of the universe complicating things
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@sockpuppet7 Until then, the obvious way to count time is the number of some seconds since some benchmark event. Like, say, the first moon landing.
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@PleegWat said in The Official Funny Stuff Thread™:
@sockpuppet7 Until then, the obvious way to count time is the number of some seconds since some benchmark event. Like, say, the first moon landing.
That would at least be sensible but instead we picked an arbitrary time and date because it was convenient.
UNTIL IT WON'T BE AAAAAAAAAAAAAAAAAAAAAAAAA
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@PleegWat said in The Official Funny Stuff Thread™:
@sockpuppet7 Until then, the obvious way to count time is the number of some seconds since some benchmark event. Like, say, the first moon landing.
Well.... give or take six months or so; and in a few thousand years how much is that going to matter?
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@Bulb said in The Official Funny Stuff Thread™:
A prograde spinning planet (most of them, only Venus and Uranus spin retrograde) will add one synodic (solar) day per synodic orbit (year), making synodic days shorter than sidereal days. Increasing orbital distance increases orbital period, so the one synodic day gets added to more sidereal days, making the difference smaller. Assuming unchanged sidereal day (rotational period),
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@kazitor said in The Official Funny Stuff Thread™:
@Bulb said in The Official Funny Stuff Thread™:
You sure? A prograde spinning planet (most of them, only Venus and Uranus spin retrograde) will add one synodic (solar) day per synodic orbit (year), making synodic days shorter than sidereal days. Increasing orbital distance increases orbital period, so the one synodic day gets added to more sidereal days, making the difference smaller. Assuming unchanged sidereal day (rotational period), that means slightly longer synodic (solar) day.
Yes, I am sure. The solar day is longer than the sidereal and stellar days
Oh, you are right. I got it mixed up. Of course if the planet spins prograde, from its point of view the star orbits it retrograde, so it is one synodic day less, not more, per year. After all, tidally locked planet has one sidereal day per year and zero synodic days.
Here’s some FUNNY STUFF, depending on your frame of mind: I’ve noticed a curious trend where people try to be ‘technical’ by saying days = rotations and years = orbits, even though these are absolutely not the durations of days and years in normal parlance.
That's because day and year are also units of time, and in that use, they refer to the day and year on Earth specifically. So when talking about other planets than Earth, saying orbit and rotation is less ambiguous.
The FUNNY part is that just saying the obvious thing is 9001% more accurate: a day is the interval from midnight to midnight
From mean midnight to mean midnight.
and a year is the cycle of the seasons.
Seasons don't have accurate-enough definitions. Astronomically, the year is defined from the sun passing the cusp of Aries to the next passing the cusp of Aries, where cusp of Aries is the intersection between the equatorial and orbital planes (in one direction).
While an axial rotation is 4 minutes shorter than a day
That's because “rotation” defaults to sidereal and “day” defaults to synodic. But you can say sidereal day and synodic rotation and it will still be clear what you mean.
and an orbital period is 20 minutes longer than a cycle of seasons.
There are actually two ways to define complete orbit—from periapsis to next periapsis or tracing complete circle in a non-rotating frame of reference, which are different due to precession, and … neither of them matches the definition of year due to precession of the rotational axis (and with it the equatorial plane).
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@Bulb said in The Official Funny Stuff Thread™:
from periapsis to next periapsis
At first I read periapis, andapisis the botanical name of the bee...
Anyways, the perihel and ahel are moving through the year, currently earth is closest to the sun in early January, and in some 10,000 years it will be inmidst of Northern summer. Which means more insolation in the Northern half of earth with many effects on the climate. Think of Milankovich cycles (or whatever they are called).
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@BernieTheBernie said in The Official Funny Stuff Thread™:
perihel and ahel are moving through the year
That's the precession of the periapsis.
Anyway, there are more changes that contribute to Milankovich cycles than just precession of perihelion.
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@Bulb said in The Official Funny Stuff Thread™:
Earth doesn't have a source of energy to increase its orbital distance.
...Solar winds?
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@acrow You get more, many orders of magnitude more, from slowing down the rate at which the Earth rotates, at least at the moment. But IIRC, the way solar winds increase the orbital distance gradually by reducing the mass of the sun. I believe the process should speed up as the sun ages; it's currently not a fast process, but it's a
constantcontinuous factor.
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@topspin It's more like how prestigious a dog's brand and model are.
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@Bulb said in German Humor Orbital Canon:
Earth doesn't have a source of energy to increase its orbital distance.
Shouldn't there be an effect similar to the one increasing the orbit of the Moon, where tidal forces transfer rotational energy of Earth onto the Moon?
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@ixvedeusi (moon radius/moon orbit radius) is far larger than (earth radius/earth orbit radius) so the effect will be far smaller.
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@Zerosquare said in German Humor Orbital Canon:
@Gern_Blaanston said in The Official Funny Stuff Thread™:
What if the earth's rotation slowed down and instead of 24 hours it took 29 hours. How would that affect society?
Yay! More time to
every day!Unlikely. You'd now get 9.67 hours of work per day instead of 8h. If you're on an hourly contract, great. If you're on a fixed contract, you'll be screwed over.
Filed under: However, I do want a 54.4 minute lunch break. up from 45 minutes
