Newton Versus Einstein: The Way of Newton

When we wish to understand how the universe works, we need to start from the very beginning from the Greeks up through Newton, who gave us his magnum opus on motion and gravity. However, while it was a triumph, there were clouds on the horizon. Here, we learn all about Newton's formulation of Gravity.
This is the seventh of the videos in my new series of Cosmology. I'm going through Dr. Barbara Ryden's textbook "Introduction to Cosmology". If you follow along, you'll get a full upper-division undergraduate course in Cosmology. I used this textbook at William Paterson University.
This course will cover the current state of the science of Cosmology. To follow along, it'll be a good idea for you to ge to know your calculus. Here are the topics of this video:
Introductory Cosmology
Chapter 03: Newton versus Einstein
Section 01: The Way of Newton
Some things covered:
The History of Gravity.
What Exactly are the Forces of Nature?
Euclidean Space and Time.
I feign no hypotheses....
Testing the Equivalence Principle.
Gauss' Law of Gravity.
Deriving the Poisson Equation.
Gravity's Formulation and Usage.
Textbook: / introduction-to-cosmology
Supplementary links:
physicscourses...
labman.phys.utk...
nssdc.gsfc.nas...
arxiv.org/pdf/...
iopscience.iop...
archive.org/de...
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/ @jasonkendallastronomer

[@Truth_Teller_101]

Glad to see you back, Mr. Kendall. Hope all is well.

[@Flash-sr8hm]

Theres a book called "murdered by isaac newton" which is an eye-opening look at how newton treated his fellow scientists. Newtons ego was larger than his sizable intellect.

[@NicholsonNeisler-fz3gi]

No need to coddle lessers

[@viole649]

As a guy who struggles to understand the concepts Newton discovered centuries ago, I feel calling his intellect ‘sizable’ is very offensive lol.

[@rchas1023]

How long would it take Newton to comprehend the mathematics underlying relativity? First Special, and then General?

[@NicholsonNeisler-fz3gi]

@@rchas1023 not too long ago- the physics are deeper than the math . Would be amazing to introduce them!!

[@JesseWRIGHT-th8mw]

He was Isaac Newton. He'd probably only need to know that the speed on light is a finite universal constant and learn how fields resolve the problem of action at a distance.

[@JerehmiaBoaz]

@@JesseWRIGHT-th8mw Fields don't resolve the problem of action at a distance at all, fields are just a convenient way to model action at a distance. In fact Newtonian gravity is usually taught as a field model (instead of the point attraction that Newton used).

[@Truth_Teller_101]

Probably a few minutes, and then he'd spend the weekend developing a "grand unified theory". Remember that this is the guy who, when encountering a problem he couldn't solve, would just invent a new type of mathematics to solve it. He makes Einstein look like Bill Nye the Science Guy.

[@mikev4621]

@@JesseWRIGHT-th8mw The speed of light was known quite accurately while he was alive

[@graham2105]

Thankyou..Mr kendall, I always enjoy your videos..

[@JasonKendallAstronomer]

You are very welcome

[@Dragonblaster1]

I have a copy of Newton's _Opticks,_ with a foreword by Albert Einstein, in which he acknowledges his debt to Newton.

[@tonibat59]

Very nice lecture Dr Kendall. I enjoyed every bit of it, took notes like at the classroom.
I find however that your last statement about Einstein providing an 'explanation' of gravity, unlike Newtonian gravity (NG), looks a little optimistic.
GR is a necessary improvement and correction to NG, and a big step forward toward an eventual complete explanation. But does not yet provide the full picture.
When Nobel laureate David Gross was asked by Richard Panek 'What is gravity?', his answer was blunt and clear: 'I wish we knew' (See 2017 YT vid "Coming to grips with gravity" (2:40) ).
The rationale for the connection of mass to SPCT curvature is not provided by GR. Why does SPCT curve by the exact amount at every point, depending on the amount of mass, we still ignore.
The point is subtle, but significant.

[@JasonKendallAstronomer]

Thanks for the note. It’s an excellent comment.

[@garysnewjob]

27:35 In other words, "Shut up and calculate. " 😂 🎉

[@NicholsonNeisler-fz3gi]

People are still trying to figure it out

[@desdenova1]

He would probably think that he was a blasphemous heathen who was shockingly lax in his alchemy and bible studies.

[@JerehmiaBoaz]

Newton's discovery that gravity was universal and it was the same gravity that causes the planets to move in ellipses in the sky, causes things to fall down on earth, and that it was a kind of mysterious action at a distance, had its parallel in hermeticism which was directly linked to alchemy and astrology. The Emerald tablet states"That which is below is like that which is above and that which is above is like that which is below to do the miracle of one only thing." (translation by Isaac Newton.)
My personal opinion is that Newton believed he had disproved astrology by identifying its astral influence on earth as the rather mundane gravity. I think it's hard to explain why a hermeticist would almost completely ignore astrology while spending so much time on alchemy, kabbalah/bible studies and hermetic philosophy otherwise.

[@cosmosaic8117]

@@JerehmiaBoaz Keen insight. Why indeed did he hardly ever mention astrology? You may be onto something.

[@peterwexler5737]

It's pronounced "prinnkippeeah. "C," in the middle of a Latin word, is pronounced as a K.

[@whlewis9164]

@@peterwexler5737 as in Julius Kaiser

[@NicholsonNeisler-fz3gi]

We don’t pronounce it that way these days

[@mikev4621]

@@whlewis9164 Eee-oolius

[@cosmosaic8117]

@@NicholsonNeisler-fz3gilol yes we do

[@markhughes7927]

I think he might say ‘hey Albie - gravity’s an effect - not a thing…’

[@truthpopup]

Newton was no dummy. I think he would understand relativity if it had been explained to him.

[@JasonKendallAstronomer]

Agree!