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And this wobble is the reason we have two tides a day - not many people know that!
The wobble is not commonly mentioned in relation to the tides, but it is taken into consideration here:
https://www.sciencefocus.com/planet-earth/why-are-there-two-high-tides-per-day/
Many sources simply say that the water is directed into two bulges by both gravitational pull and "other forces".
Dr. Becky explains the second high tide here:
https://www.sciencefocus.com/planet-earth/why-are-there-two-high-tides-per-day/
Many sources simply say that the water is directed into two bulges by both gravitational pull and "other forces".
Dr. Becky explains the second high tide here:
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yup, that's how I learned it too. It's been used as a question on entrance exams for some universities. I remember another simple question that folk sometimes struggle with:
How do we know the earth's orbit is more or less circular ? - with the only instrument available being our own senses, our own sight, no other instruments are needed of course.
How do we know the earth's orbit is more or less circular ? - with the only instrument available being our own senses, our own sight, no other instruments are needed of course.
It was a very informative, informal tutorial.
but you had to follow the series to, ahem..learn anything.
Nick himself probably should have paid more attention when the tide came in! 😳
I'll look at this from another angle.
By observation only, we can tell that the Earth's orbit is not exactly circular, as proven by this analemma over the Callanish Stones in the Outer Hebrides.
You just have to note the position of the Sun every few days at noon over the course of a year.
The variation in height of the figure of eight shape is due to the tilt of the Earth's axis.
The variation in width of the figure of eight shape results from the ellipticity of the Earth’s orbit.
Problem there, Galu, is how do you define Noon?
Is it when the Sun crosses the Meridian, a straight line space sort of thing, or is it a matter of having a Clock that rings Midday? Which is a time problem.
I am going to bed. Lots to do tomorrow. I have to fix TWO broken stereos belonging to neighbours. I hope my mind is clearer. Usually is after a snooze. 🙂
Is it when the Sun crosses the Meridian, a straight line space sort of thing, or is it a matter of having a Clock that rings Midday? Which is a time problem.
I am going to bed. Lots to do tomorrow. I have to fix TWO broken stereos belonging to neighbours. I hope my mind is clearer. Usually is after a snooze. 🙂
I would define noon (solar noon) as when the Sun reaches its highest position above the horizon on that day and is casting the shortest shadow.
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Pretty good, but there’s a simpler answer… The apparent diameter of the sun remains the same throughout the year.
I would have to project an enlarged image of the Sun onto a screen using my telescope in order to confirm or deny that! 😀
Yeah, to be fair, you should not look at the sun, so you do need more than just your own senses - a simple instrument, a pinhole, would do it but you need something other than your own senses... But nothing sophisticated!
Artemis I and the recent interesting December 8 Mars/Moon occultation astronomical event has sparked great interest in the Mathematical and Orbital Mechanics and Astrological departments of system7 University in Portsmouth, UK, or Pompey as we call it here.
https://en.wikipedia.org/wiki/Moon
My Pompey pub friends are a bit weak on Astronomy, Generally confusing the Moon with the Space Station when quizzed what the big white thing in the night sky is, as we step out for a ciggie on the doorstep of our hostelry. 🙄
Our Maths department has calculated that we shall be watching splashdown on NASA TV at 17.40 UTC aka GMT in Pompey:
https://www.nasa.gov/multimedia/nasatv/index.html#public
"NASA TV coverage of Artemis I’s return to Earth begins at 11 a.m. EST on Sunday, Dec. 11. The Orion spacecraft is scheduled to splash down in the Pacific Ocean at 12:40 p.m. near Guadalupe Island."
Hope it helps. You can adjust for your own time zone accordingly. A simple calculation that even a child of ten should find easy.
Best regards from Steve in Pompey.
https://en.wikipedia.org/wiki/Moon
My Pompey pub friends are a bit weak on Astronomy, Generally confusing the Moon with the Space Station when quizzed what the big white thing in the night sky is, as we step out for a ciggie on the doorstep of our hostelry. 🙄
Our Maths department has calculated that we shall be watching splashdown on NASA TV at 17.40 UTC aka GMT in Pompey:
https://www.nasa.gov/multimedia/nasatv/index.html#public
"NASA TV coverage of Artemis I’s return to Earth begins at 11 a.m. EST on Sunday, Dec. 11. The Orion spacecraft is scheduled to splash down in the Pacific Ocean at 12:40 p.m. near Guadalupe Island."
Hope it helps. You can adjust for your own time zone accordingly. A simple calculation that even a child of ten should find easy.
Best regards from Steve in Pompey.
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See, you should know better at your age. The fact you continue to abuse yourself suggests skepticism of your credentials. 🤐
I'm watching this: https://www.nasa.gov/artemislive/
You see Earth from Orion. Of course, Orion appears motionless but you see the Earth ever so slightly grow and move.
Awesome, think about the technology involved! They must have all hi-end cabling in that thing ;-)
9.000 miles out, 13kMPH
Edit: reminds me of Carl Sagan's phrase 'pale blue dot'.
Jan
You see Earth from Orion. Of course, Orion appears motionless but you see the Earth ever so slightly grow and move.
Awesome, think about the technology involved! They must have all hi-end cabling in that thing ;-)
9.000 miles out, 13kMPH
Edit: reminds me of Carl Sagan's phrase 'pale blue dot'.
Jan
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