Mountkeen wrote:Yes indeed the sun does have an effect on the tides but it is far, far smaller than the moon's.
Carswell appears to think that the sun is dominant and that the moon only plays a part in spring/neap tides.
Thanks; do you have a source for "far, far smaller than the moon's"? I'm aware that Nightingale used the phrase '27m x bigger' but his tweet of course did not/could not due to character limits provide any reputable source backing that up. When I wrote my last comment I was unclear which object's effect on our ocean tides was actually the greater; also the press coverage I mentioned (which did not show all the tweets in full) implied that Carswell was simply arguing with an expert even when the expert was correct because he was 'sticking to his principles'.
Actually, on further checking, I think I can answer my own question (I find Nightingale's tweet a little confusing as I assumed '27m x bigger' was referring to the moon's tidal effect compared to the sun - whereas he was actually referring the the sun's size compared to the moon's):http://oceanservice.noaa.gov/education/ ... cause.html
"If tidal forces were based solely on comparative masses, the sun should have a tide-generating force that is 27 million times greater than that of the moon. However, the sun is 390 times further from the Earth than is the moon. Thus, its tide-generating force is reduced by 390 cubed, or about 59 million times less than the moon. Because of these conditions, the sun’s tide-generating force is about half that of the moon."
Yes - based on the NOAA - Carswell was wrong. But when he tweeted "surprised head of Science research at a university refutes idea sun's gravity causes tides" he was responding to the overly simplistic comment "you've been misinformed. Tides caused by moon not the Sun ... distance matters." Thus - Nightingale APPEARED to refute the idea that the sun’s gravity causes (or contributes to) tides. He should have been clearer, as clearly the sun does play a role which I assume Nightingale would not deny/be ignorant of.
All in all good topic of discussion for the equinox.
Of course the politician Carswell's whole intent was to suggest that we can trade more with BIG but DISTANT (non-EU) China than with SMALL but CLOSE (EU) Ireland ...
(I will be watching UK BBC Two at 9pm this evening.)