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A very interesting essay from Alex Vilenkin on whether the universe has a beginning and what this implies. If you want my opinion, “nothing” does not equal “physical system with zero energy”.

I recently commented on Neil deGrasse Tyson’s chiding of Isaac Newton for failing to anticipate Laplace’s discovery of the stability of the Solar System. He has commented further on this episode and others in this article for Natural History Magazine.

Tyson’s thesis is as follows:

… a careful reading of older texts, particularly those concerned with the universe itself, shows that the authors invoke divinity only when they reach the boundaries of their understanding.

To support this hypothesis, Tyson quotes Newton, 2nd century Alexandrian astronomer Ptolemy and 17th century Dutch astronomer Christiaan Huygens. The remarkable thing about Tyson’s article is that none of the quotes come close to proving his thesis; in fact, they prove the opposite.

Newton and God

Tyson is quotes from Newton’s General Scholium, an essay appended to the end of the second and third editions of the Principia.

But in the absence of data, at the border between what he could explain and what he could only honor—the causes he could identify and those he could not—Newton rapturously invokes God:

“Eternal and Infinite, Omnipotent and Omniscient; … he governs all things, and knows all things that are or can be done. … We know him only by his most wise and excellent contrivances of things, and final causes; we admire him for his perfections; but we reverence and adore him on account of his dominion.”

To be blunt, what part of “he governs all things” doesn’t Tyson understand? God’s “dominion” – the extent of his rule – is “always and everywhere”. Clearly, Newton is not invoking God only at the edge of scientific knowledge, but everywhere and in everything. The Scholium is not long, so I invite you to read it; you will nowhere find Newton saying that God is only found where science has run out of answers. You will find him saying (echoing Paul) that “In him are all things contained and moved.” Continue Reading »

Warning: long post!

Abstract: Neil deGrasse Tyson has argued that Isaac Newton’s religious views stymied his science, preventing him from discovering what Laplace showed a century later – that the planetary orbits are stable against perturbation. This conclusion is highly dubious. Newton did develop perturbation theory, and applied it to the moon’s orbit. His lack of progress is explainable in terms of his inferior geometrical, rather than algebraic, approach. Laplace built on the important work of Clairaut, Euler, d’Alembert and Lagrange, which was not available to Newton. Laplace’s discovery was not definitive – computer simulations have showed that the Solar system is chaotic. And finally, Newton does not give up on science and invoke God at the first sight of ignorance, saying rather “I frame no hypothesis”. His “Reformation” of the Solar System is plausibly not supposed to be miraculous. I conclude that scientists (myself included) are terrible at history. Continue Reading »

I’ll be speaking at the Sutherland Astronomical Society on Thursday 5th November. The meeting is at Green Point Observatory, Oyster Bay at 7:30 pm.

Title: The Fine-Tuning of the Universe for Intelligent Life

Abstract: Let’s make it slightly different from the one that we are familiar with. We could change the laws of nature, just a little bit. We could change how the universe begins, or make it four-dimensional. In the last 30 years, scientists have discovered something astounding: the vast majority of these changes are disastrous. We end up with a universe containing no galaxies, no stars, no planets, no atoms, no molecules, and most importantly, no intelligent life-forms wondering what went wrong. This fact is called the fine-tuning of the universe for life. After explaining the science of what happens when you change the way our universe works, we will ask: what does all this mean?

Deducing the Stars

The following cartoon recently appeared on my Facebook feed, courtesy of Beatrice the Biologist.
Tube worm conversation

This provides a neat illustration of the difference between how a biologist approaches nature and how a physicist approaches nature. Here is perhaps the greatest astrophysicist of the twentieth century, Sir Arthur Stanley Eddington, in his book “The Internal Constitution of the Stars” (1926, pg. 16).

We can imagine a physicist on a cloud-bound planet who has never heard tell of the stars calculating the ratio of radiation pressure to gas pressure for a series of globes of gas of various sizes, starting, say, with a globe of mass 10 gm., then 100 gm., 1000 gm., and so on, so that his nth globe contains 10n gm. Table 2 shows the more interesting part of his results.

Eddington Table

The rest of the table would consist mainly of long strings of 9’s and 0’s. Just for the particular range of mass about the 33rd to 35th globes the table becomes interesting, and then lapses back into 9’s and 0’s again. Regarded as a tussle between matter and aether (gas pressure and radiation pressure) the contest is overwhelmingly one-sided except between Nos. 33-35, where we may expect something interesting to happen.

What “happens” is the stars.

We draw aside the veil of cloud beneath which our physicist has been working and let him look up at the sky. There he will find a thousand million globes of gas nearly all of mass between his 33rd and 35th globes — that is to say, between 1/2 and 50 times the sun’s mass. The lightest known star is about 3 x 1032 gm. and the heaviest about 2 x 1035 gm. The majority are between 1033 and 1034 gm. where the serious challenge of radiation pressure to compete with gas pressure is beginning.

Continue Reading »

My honourable co-author Geraint Lewis has written a short overview of the fine-tuning of the Universe for intelligent life at the Conversation. Go have a read.

Book update: we’re reviewing a contract with a publisher.

I’ll be speaking at the Northern Sydney Astronomical Society on Tuesday 15th September. The meeting at at Regis Hall, Regis Campus, St Ignatius College,Riverview St, Lane Cove at 7:30 pm. I’m on at 8pm.

In November, I’ll be speaking in Sutherland, so stay tuned.

Title: The Fine-Tuning of the Universe for Intelligent Life

Abstract: Let’s make it slightly different from the one that we are familiar with. We could change the laws of nature, just a little bit. We could change how the universe begins, or make it four-dimensional. In the last 30 years, scientists have discovered something astounding: the vast majority of these changes are disastrous. We end up with a universe containing no galaxies, no stars, no planets, no atoms, no molecules, and most importantly, no intelligent life-forms wondering what went wrong. This fact is called the fine-tuning of the universe for life. After explaining the science of what happens when you change the way our universe works, we will ask: what does all this mean?

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