Recent content by WHT

I tried recreating this chart I posted using the online NASA JPL Horizons ephemeris program, but couldn't duplicate the 4.53 year modulation cycle that Ian Wilson had managed to find. What I always find is the 4.42 year modulation by multiplying the absolute value of the lunar declination...

What is intriguing about this 4.53 year cycle is in how it gets conflated with the half-8.85 year cycle, which being 4.4 years is close to 4.53. There are many references to extreme tidal cycles being dominated either by (1) the 18.6 year nodal declination cycle or (2) the 4.4 year half-perigean...

Thanks for the clarification as to the origin of satellite subbands, as they do seem to associate with a cyclic "orbit" perturbing a primary cycle. Still don't have an origin story for the unnamed +subband I was asking about. One place it may come up is in long-period tidal excursions. In the...

I have a related question about the lunar declination with respect to celestial latitude, i.e. tracking the moon instead of a satellite. The declination goes from +/- excursions with a period of 27.2122 days and then slowly evolves between maximum excursions (max lunar standstill) at a period of...

"linearization of the predator-prey model used the Lotka-Volterra calculator" In certain cases differential equations may be overrated in explaining the predator-prey dynamics. I've been conversing with an academic ecologist who was able to explain the famous fox-lemming cycles of 3.8 years by...

"torch.mean(output * target)" Shouldn't a loss function be => output - target ?

Yes, there is a name for the analogous case in Tait-Bryan angles. It's called "Steady Turn," also known as "Constant Turn" or "Banked Turn." In this case, the yaw rate is constant, the pitch rate is zero, and the roll rate is constant. The term "banked turn" refers to the fact that the vehicle...

Going back on some of these old threads, I now know of a less obscure application of "cosine of cosine" and that has to do with Mach-Zehnder modulation. See this recent paper and look at equations 2 & 3 Photonic microwave waveforms generation based on two cascaded single-drive MachZehnder...

After looking at her work some more, the cos(cos()) formulation is actually pretty straightforward, as all she is doing is a slight frequency modulation. Take a look at the combined terms cos(A t) × cos( cos(B t)) and that will expand as a main frequency A modulated by B. She is doing this...

Certainly! The sub disciplines of solid state and condensed matter were driven by the rapidly growing use of applied physics, especially in the semiconductor industry. They opened it up again to include condensed matter as liquids and fluid dynamics also became part of applied physics in...

Jim Hardy, Regarding Zharkova's cosine of a cosine formula, the hint is that it comes from the Schmidt&Lipson Science(2009) article . Schmidt came up with a SW tool called Eureqa which does symbolic regression. Eureqa is no longer available but it could easily find cos(cos()) type expressions...

When condensed mattter physics became king Interesting article in this months Physics Today describing the scope of condensed matter and how it grew out of solid state

> "This forum is mostly for answering homework" Thanks, that's the impression I got, that this forum is mainly geared to answering physics homework problems.

Thanks but ... <i>"Due to the contentious nature of the subject of climate change, the following cannot be used as source material: internet blogs unpublished papers papers published in a small number of excluded journals (see below)"</i> This is a recursive limitation. The minute someone...

I was alerted to this post from the Azimuth Project blog. There is some climate science modeling still going on at John's Azimuth Project discussion forum. I get the impression that digging deep into the physics of climate change is discouraged on the Physics Forum. Is that still true ?