Tidal heights changes caused by 18.61 years cycle of lunar 'wobbles'

Chiara’s slave

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OK now will l put on my nuclear attack suit, crash helmet and retreat to ..... Mars??

So weather changes / Global warming is solely due to burning fossil fuels - Correct??

So, Dinasaurs etc driving around in supercars and burning coal to keep warm were responsible for global warming and the end of the Ice age , melting the ice that left Morrains in the UK?

I am not saying we have not exacerbated the warming but it is a cycle?

I am but a a mere engineer so do not understand, (History and timescales may be distorted) but some of the theories proposed do not stand scrutiny.

I have now set sail for Greenland ( I should be so lucky) to escape the exocets.
Natural climate change occurs over millennia. Not something humans notice in a lifetime. Btw the dinosaurs were finished off by a meteorite. Not sure whats going on here, I’m not a cimate activist at all. But this is simply conspiracy theory, the wind farm bit, and you, Salty, have indeed failed to grasp the timescales involved. Thousands of years previously to observe change, now a few hundred. There may be natural change too, but dwarfed by man made.
 

johnalison

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I thought that but Prof Brian Cox said it will fly outwards as energy is removed. He is orders of magnitude smarter than I am so I assume he’s right.
While it is true that a satellite such as the Moon orbits slower the further away it is, I think there must be more to it than that. If an artificial satellite fires a retro-rocket to slow itself without changing its course, it will fall back to Earth. However, this does not mean that the Moon will fall towards us if energy is removed by tidal friction (if this actually occurs), but as for why the difference should happen, it is too near my bedtime for such matters. I saw a video some while back about the problem of black holes colliding, when it was proposed that this should be impossible due to the loss of orbital energy as their orbits shrank, if I understood them.
 

franksingleton

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OK now will l put on my nuclear attack suit, crash helmet and retreat to ..... Mars??

So weather changes / Global warming is solely due to burning fossil fuels - Correct??

So, Dinasaurs etc driving around in supercars and burning coal to keep warm were responsible for global warming and the end of the Ice age , melting the ice that left Morrains in the UK?

I am not saying we have not exacerbated the warming but it is a cycle?

I am but a a mere engineer so do not understand, (History and timescales may be distorted) but some of the theories proposed do not stand scrutiny.

I have now set sail for Greenland ( I should be so lucky) to escape the exocets.
If you want to discuss climate change, there is a forum for that purpose. Meanwhile, take a look at Climate Change - Franks-Weather - The Weather Window.

Very briefly, natural climate change occurs over many thousands of years. Use of fossil fuels is creating clime change on a far shorter time frame.
 

LittleSister

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First of all, the 18.6 year cycle is well known and has been since the times of the ancient Babylonians (it affects things like lunar eclipses). Second, the paper in question is about cyclical changes in the growth of mangroves affected by that lunar cycle. In this case, it IS cyclical behaviour, and separate from climate change. Mangroves are not at risk

So, basically, move along there, nothing to see.

Firstly, it wasn't well known here, and I thought it might be of interest, which is why I posted it. The Forum would have rather thin pickings if it were restricted to things no one had known about before. (Why there are so few ancient Babylonians posting on the forum is a question I shall leave for another day. )

Secondly, we'll worry about the mangroves only once we've arranged some sort of prop arrangement to stop the moon crashing into the earth because of wind farms.

Thirdly, scientists should be investigating why forum discussions are not subject to centripetal forces.
 

lustyd

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While it is true that a satellite such as the Moon orbits slower the further away it is, I think there must be more to it than that. If an artificial satellite fires a retro-rocket to slow itself without changing its course, it will fall back to Earth. However, this does not mean that the Moon will fall towards us if energy is removed by tidal friction (if this actually occurs), but as for why the difference should happen, it is too near my bedtime for such matters. I saw a video some while back about the problem of black holes colliding, when it was proposed that this should be impossible due to the loss of orbital energy as their orbits shrank, if I understood them.
PBCox did explain the whole thing at the time, and it did make sense but agree it’s counter intuitive to me too.
 

Sandy

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I find the Tidal Coefficients, as used extensively in France and other places, are really helpful as a simple and objective summary of how big the tides are - eg here La Rochelle-Ville - September tide times - METEO CONSULT MARINE - Free 15-day Marine forecasts - METEO CONSULT MARINE
I find them really confusing as I then need to go and look up the highest spring tide for that location.

When you are faced with a 9 metre range I find it more comfortable to know the predicted height of tide in metres.
 

chrishscorp

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Thats what I suspect is happening, here in Portugal the wind pattern seems to have changed, I note that the Azores high doesnt seem to have settled this year. Is this an indication of what we might be doing by gathering "free" energy? Discuss?

And this might be caused by wind farms harvesting the wind.....

I have checked the date on this forum and its not April the 1st, I have never heard such a crock of utter tosh other than from the lips of the orange umpa lumpa.

The wind systems are driven by the temperatures of our oceans and the currents and tidal streams that these cause, these are changing and that is caused by man made global warming. The waters off the back of the Isle wight have gone up by 1.5 deg C in the last 2 years, local fisherman are catching stray Tuna fish and spotting sea turtles amongst other oddities.
 

Chiara’s slave

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While it is true that a satellite such as the Moon orbits slower the further away it is, I think there must be more to it than that. If an artificial satellite fires a retro-rocket to slow itself without changing its course, it will fall back to Earth. However, this does not mean that the Moon will fall towards us if energy is removed by tidal friction (if this actually occurs), but as for why the difference should happen, it is too near my bedtime for such matters. I saw a video some while back about the problem of black holes colliding, when it was proposed that this should be impossible due to the loss of orbital energy as their orbits shrank, if I understood them.
The ‘more to it’ is that orbiting slower doesn’t gain orbital altitude. If you launch a satellite, you manage it's orbit speed according to the height you attain. Low earth orbit needs just over 17000 mph. At lunar distance, it’s about 2500mph. If you slow down an orbiting body, it doesn’t just crash down though, or at least, not in one go. Slowing it does indeed result in it ‘falling’ but that will cause it to accelerate. What happens is it's orbit becomes more elliptical, it’s speed becomes more variable. Like a comet orbit. If the elliptical orbit touches any atmosphere, further slowing will occur, and in the case of the moon, there may be trouble ahead. Otherwise, with no further slowing, the elliptical orbit might well continue for some time. If, and it's a stupendously big if, capturing tidal energy slowed the moon down, then yes, it would collide with Earth eventually. But, like the wind thing, it’s a conspiracy theory favoured by the insufficiently educated.
 

lustyd

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If, and it's a stupendously big if, capturing tidal energy slowed the moon down
No it’s not, it’s extremely well understood physics. The energy comes from the moon, anything we do to pull energy out of that system has a braking effect. Kids could show you this with magnets.
And no, I didn’t misunderstand his direct answer to the question, so I’ll take the word of the highly qualified astrophysicist. The moon won’t fall out of the sky, it’ll gradually get further away as energy is removed.
 

Chiara’s slave

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One small hole in the theory. Tides speed the moon up, which makes it orbit further out. This is because the earth is rotating, the mass of tides and rotating earth is kind of whipping the moon up. It climbs higher against gravity, and slows to a new equilibrium. Trades speed for height, so to speak. That is what Cox said, you still misunderstand. The slowing is a result of increased height, not the other way around.
 

lustyd

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You have no idea what he said to me, what a weird thing to say. Your understanding of the physics here (it’s not theory, nor up for debate) is lacking and I suggest you stop digging.
 

lustyd

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You’re the one denying science. You have demonstrated my original point though, that it’s a fun subject to use to wind people up both in person and online.
 

dslittle

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I find the Tidal Coefficients, as used extensively in France and other places, are really helpful as a simple and objective summary of how big the tides are - eg here La Rochelle-Ville - September tide times - METEO CONSULT MARINE - Free 15-day Marine forecasts - METEO CONSULT MARINE

Howeve, I dont see any particularly big tides in September (none over 100) and just a single 101 coefficient on 10th October.

We went into the Morbihan last week on a 105 coefficient spring tide. It was certainly interesting…
 

marklucas

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Hi all.

I write this explanation a very long time ago on another (now defunct forum).

Hopefully, this can fill in the gaps for those that are interested enough - some might regard it as somewhat technical, but the devil is always in the detail!

Feedback (polite) is welcome.

Mark

PS And yes the Cherbourg tidal coefficients are very useful and Mr. Reeve- Fawkes deservedly made some money out of it!
 

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webcraft

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I remember being amused by a SciFi story of an Earth where heat pumps were the prevalent energy source. The planet had become an arctic wasteland, with the crisis point being when CO2 began to precipitate.

Seems mass adoption of heat pump technology might be the answer. . .

- W
 

Chiara’s slave

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I remember being amused by a SciFi story of an Earth where heat pumps were the prevalent energy source. The planet had become an arctic wasteland, with the crisis point being when CO2 began to precipitate.

Seems mass adoption of heat pump technology might be the answer. . .

- W
I’ve got a great idea for a perpetual motion machine.
 
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