Alt text: They’re up there with coral islands, lightning, and caterpillars turning into butterflies.
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I get similar feelings about earth when I can see the moon during the daytime. Something about seeing it with clear craters against the blue sky makes it feel much more like we’re just floating in space with a cratered barren partner.
I always wondered how quickly the tides actually change. If the moon is directly overhead, does the tides at the lowest or the highest? Or does it just pushes things around and it’s just different?
Think about the moon like a flashlight beam. Where the center hits the ocean, it keeps a consistent pull upwards, and moves the bulge of water as it orbits. Towards the edges of focus, it’s dropping a bit of water and it’s rippling away as it falls. I am no scientist, but I liked this explanation when I saw it because it was simpler to understand.
It’s because the center of mass between the earth and moon is off center, nearly 3k miles from the core, and constantly moving as the moon orbits.
So it’s not due to a direct pull upwards alone, and the earth’s orbit around the sun technically has a slight wobble due to it.
Edit: For more info, look up info on the barycenter of the earth and moon.
I wonder if life would exist on our planet if there were not tides.
The Sun also creates tides, just not as strong as lunar tides. So we would still have tides, even if we had no Moon.
The Sun also creates tides
The second worst British tabloid? I highly doubt it.
The ol’ Lemmy-roo!
I think it’s more wild that not only are big moons rare, ours is literally the same size as the sun from our point of view.
It also makes almost exactly 13 laps for every lap the earth makes.
And from what I have heard on science podcasts, the moon is, and has been, and still will be, moving away from the earth. Making the perfect solar eclipse only for a segment of the earth’s history.
It honestly makes me feel lucky being born when I was.
We also get to see the after effects of the big bang which won’t be detectable for the majority of the lifetime of our universe.
Which is why a 13 month calendar all having 28 days would have made more sense
Landlords would love it, at least. I personally would hate it, being a renter.
Haha great point. I never thought of that
Landlords would love it, at least.
And I thought you ment because the pubs would be full that week :-(
Your rent right now can be thought of as a large payment split into 12 equal pieces (even though months aren’t actually equal) and your rent payment is just 1/12 of that. If there were 13 months it would just be split into 1/13 so each months payments would be slightly smaller to be the same total
If we transitioned it would take years and for at least some amount of time of overlap they would show both prices so it would be much harder for them to just jack up the price like they would prefer to do
Don’t worry, they ain’t ever gonna replace the Gregorian calendar.
It’s a shame, though. That Jeromian 13 month one sounds like a better fit, whether or not you’re in Vancouver!
It makes 12 months because the lap the Earth makes is deducted from the 13 the moon makes, so effectively it makes 12 cycles around the Earth.
12 is an easier number to work with because of how many factors it has
hmm, how about 12 months each with 30 days, plus 5 days every year that’s not part of any month?
5 days every year that’s not part of any month
Those are called intercalary months. They had them in the ancient egyptian calendar (5 every year, 6 in leap years) and were usually used for rest and religious ceremonies.
I’m pretty sure they’re being cheeky and we’re referencing exactly this ;)
plus 5 days every year that’s not part of any month?
Just add a leap month every six years
You’d have 12 30-day months most years, and an extra in the sixth! While we’re at it, we can redefine a week to be six days, so there’s a perfectly rounded number of weeks per month/year! Days, hours, minutes and seconds are already fine, but maybe we should also replace units shorter than a second with something more dozenal/hexal(?), too…
While a novel idea, a leap month would throw the concept seasons and therefore agriculture off significantly. Relatively predictable seasons and being able to track our place in it with calendars was a great help to agrarian communities, helping them know when to plant and harvest most effectively.
Every 7 or 6 years for a leap week 12 month calendar, it would be four times longer for a leap month, and the formula is a bit too complex for people to do in their heads, but we all refer to computer calendars anyway
A 364 day calendar with 13 even months, or 12 months alternating between 35 and 28 days or whatever would also let you use the same calendar every year (as opposed to my tea towel that has a calendar that is only useful in leap years that start on a Tuesday — the last was 2008 when it was bought, next is 2036)
Though it would be too expensive to change the calendar, and a 364 + leap weeks calendar doesn’t track the seasons as well as 365 + leap day calendar, I really like the symmetry 454 calendar
13*28=364 so even 13 months and 28 days doesn’t work.
If we had 28 days in a month then the week needs to be something other than 7 days. Three out of four times February / March fucks me over by having the same weekday/ day of the month.
There is a calendar that uses 28, 35, 28 day months each quarter for 364 days, with the last quarter having an extra week (or having an intercalary week so they can pretend quarters will be all equal) in leap years
13 is a unlucky superstition number.
Only in Western cultures. In East Asia, it’s 4.
They have a different calendar too, no?
Nope, theirs is also the same. Just another same than ours.
Didn’t some cultures do that?
It’s almost like someone put it there on purpose 😉
Exoplanets could have tides too though…
It’s unlikely that there are many exo planets with a moon as big as the Moon. Much more likely to have small ones like Mars. Mercury, Venus and Mars are all great examples of bad shit that can happen to planets: Tidally locked + too close to the sun, rolled over on the side, and finally Mars too small to maintain a molten core and magnetic field. The Moon helps avoid the Venus situation and maybe the Mars problem.
Do you think “big enough moon” is going to be similarly rare to “liquid water”? We’re getting better and better at finding planets. Not sure how we’d find their moons though.
Our planet is scifi as hell. We’ve got natural magnetic shielding to protect our UV-blocking ozone layer from solar winds. This planet is so damn cozy<3
For now
This planet is so damn cozy<3
Oh! Oh! Let’s wreck it by polluting the hell out of it :3
You know it’s too expensive to fix for the people and companies with more wealth than 99.99999% of us, and with the decision maker(s) not valuing any future beyond their expected lifespan, and I don’t think any of them think the previous generation will be the last generation to die
:(
I wish we wouldn’t
but yummy pollutants! :3
Ah btw, this is the gravitational form (geoid) of earth:
The meters is the height difference of orbit.
Damn, now I get why cartographers and the like always try to make it prettier in post!
Never thought I’d be body shaming the Earth, but here we are 🤷
That is pretty severely exaggerated though to emphasize the form.
Lol, but the diff is actually x10000 or something, to make it more visible
That’s just mean! 😉
Its the water that makes the world
go around
Well it’s not near the surface but rather far away in comparison. But also really big a moon.
Can’t forget magnets. How do they work?
Magitech.
Only if Knowledge doesn’t get her way. But considering Travis…
Like other elements, just a bit farther reach with their fields. Fun fact, nothing is solid. When you try and touch something, it’s actually just forces against forces. Atoms are primarily made of nothing.
I feel the (strong) force.
And seahorses! Dont forget them!
Hearts in their head. Males carry the babies.
They’re insane!
The tides are also likely responsible for advanced life on this planet. So there is that.
What’s up with the alt text?
It’s xkcd’s alt text or sub-captions; not accessibility alt text.
It’s your turn Cueball.
At some point I saw a yt science video saying that the water isn’t moving but the dirt bit is the bit moving during tides
and i don’t understand why the tides on the Right Hand coast are like clockwork and the Left Hand side of the country the tides are like “what time is it IDGF HIGHTIDE”
found it “rotating through the tides”
What he’s saying is there is always a bulge of water pointing at the moon (and another pointing away from it) the earth spins so the land sees the bulge coming and retreating as our bit of coast passes under the moon
It’s a bad description because the water also spins with the rest of the world, so though there always is a bulge that is stationary relative to the moon, there is always different water being part of it.
Some of the first mechanical calculators were created to predict tides (~3 centuries ago), because they are a really complex thing that the popular explanations completely paper over and pretend it’s simply the water keeping pace with the Moon.
It’s shown like that because the water is trying to do that, to anthropomorphise it. Though of course that’s not what the water does everywhere because fluid dynamics get pretty nuts when there’s a ton of land in the way.
To expand on the idea, even weather effects the level of the tides rather significantly… For a clear example, look at hurricanes. They can approach double digits in feet of storm swell if they’re severe enough.
Also part of the tide is solar, if you see a highest high tide or lowest low tide, it is very likely it will be at a full or new moon as that is when the moon and sun are aligned, with the moon on one side or the other of Earth (or lagging that by days due to land getting in the way)
I’m not sure what that video said, exactly, but both water and dirt move because they are both affected by tidal forces.
Tide is caused when an object, like Earth, is large enough to experience a difference in the effects of orbital gravity from one end to the other. The center of gravity of an object does not experience tidal forces.
Since most of the Earth’s surface is water, and the water is on top of the dirt, the water should be affected more by tidal forces than the dirt underneath it.
The video may have been talking about how the dirt affected by tidal forces also pushes the water, causing a compounding effect or something.
In the video he’s saying the line between center of moon and center of earth has the most tidal force on the water, while the earht spins through that zone. It was not saying that the water stays 100% stationary and land spins through it, just that the height of water will always be high at that line as the earth rotates
East and west?
yes.
https://www.youtube.com/watch?v=95gsOrr36II
Sunlight moves in from the East, that’s how I remember. (tried to find a gif, but the video is close enough)
