Frank Krygowski writes:

On 1/28/2021 4:54 PM, Radey Shouman wrote:
Ralph Barone writes:

AMuzi wrote:
On 1/28/2021 6:00 AM, Rolf Mantel wrote:
Am 27.01.2021 um 19:19 schrieb Tom Kunich:
On Wednesday, January 27, 2021 at 1:34:38 AM UTC-8, Rolf
Mantel
wrote:
Am 25.01.2021 um 22:44 schrieb Tom Kunich:
On Monday, January 25, 2021 at 10:57:32 AM UTC-8, Frank
Krygowski wrote:

But a warning: Those guys use math.
Why don't you tell us about that math that can measure
the circumference of a oval?
Math does not "measure" but "calculate". Before you can
start
using math, you need a precise description what you mean
by "oval"
(and as soon as you give a precise definition, someboda
can find a
formula for its circumference).

The simplest version of an oval (also called "stadium"
according
to wikipedia) is a circle cut through in the middle where
the
halves are connected by straight lines, so it is defined
by r =
"Radius of each semi-circle" a = "distance between the
two centers
of the semi-circles"

https://en.wikipedia.org/wiki/Stadium_(geometry)

For this oval, the formula is quite simply 2( pi * r + a)

Please do not argue the meanings of words when you know
what is
meant. And do not take a single special case that can be
measured
accurately and pretend that it is fitting for all cases.
Tell us the
perimeter of the orbit of Pluto and then we can see your
accuracies?

Do you understand what is Mathematics and what is not
Mathematics?

The "Orbit of Pluto" is not Mathematics, it's Astronomy, and
it is not an oval by any definition (Wikipedia claims it's
chaotic due to the 2:3 resonance with Neptune; the
Mathematician and Astronomer Pointcare proved in the 1890's
that the Newtonian interaction of three celestrial bodies
usually leads to "chaos", defining for the first time what
chaos is mathematically).

Only when an Astronomer says "Pluto's orbit can be
approximated by an ellipse with long axis 49 AU and short
axis 30 AU for my purposes", the mathematician can start
calculating the perimeter of that ellipse as a meaningful
approximation for the Astronomer.

Rolf






Basically yes but it's not an ellipse. (a figure with two
foci:
https://www.assignmentpoint.com/wp-c.../Ellipse-1.jpg
)

A planet's orbit can be observed and described. It could
probably be measured but probably not calculated given all
of human knowledge to here as the inputs are myriad (not
only Neptune!) and dynamic.



Interestingly enough, even with the theoretical impossibility of predicting
Pluto’s orbit, we still managed to fly a probe past it and take pictures. I
guess it was just a theoretical impossibility, and a little bit of negative
feedback was enough to make it a practical possibility.

https://www.space.com/18377-new-horizons.html

Meteorologists can predict the weather reasonably well a week in
advance. Two years, not so much. Astronomers have a very good idea of
where Pluto will be in a ten years, but figuring out where it will be in
a million years is really hard.

But do we care?

About the weather in two years? Yes, absolutely, think of how many more
outdoor weddings there would be.