العتمة في الليل: سر من أسرار الكون

by Edward Harrison, حاتم النجدي (Translator)

Why is the sky dark at night? The answer to this ancient and celebrated riddle, says Edward Harrison, seems relatively the sun has set and is now shining on the other side of the earth. But suppose we were space travelers and far from any star. Out in the depths of space the heavens would be dark, even darker than the sky seen from the earth on cloudless and moonless nights. For more than four centuries, astronomers and other investigators have pondered the enigma of a dark sky and proposed many provocative but incorrect answers. Darkness at Night eloquently describes the misleading trails of inquiry and strange ideas that have abounded in the quest for a solution. In tracing this story of discovery--one of the most intriguing in the history of science--the astronomer and physicist Edward Harrison explores the concept of infinite space, the structure and age of the universe, the nature of light, and other subjects that once were so perplexing. He introduces a range of stellar intellects, from Democritus in the ancient world to Digges in the reign of Queen Elizabeth, followed by Kepler, Newton, Halley, Chéseaux, Olbers, Poe, Kelvin, and Bondi. Harrison's style is engaging, incisive yet poetic, and his strong grasp of history--from the Greeks to the twentieth century--adds perspective, depth, and scope to the narrative. Richly illustrated and annotated, this book will delight and enlighten both the casual reader and the serious inquirer.

Genres: Science, Physics, Nonfiction

272 pages

First published January 1, 1987

Reviews

[Rowan · Rating 4 out of 5]

A few months ago I used the word "dark" in a poem, and brought it into my workshop. I knew it was a risk, there are a number of words that are more or less off limits to 'serious' poets. In fact, there are so many words that are off limits to poets that it's hard to categorize them, or say generally what makes them off limits. For the most part it's overuse - which gives an easiness to the word that belies the harder work a 'serious' poet is supposed to be doing with language. When used without a hipster-esque self-conscious irony, these words are unacceptable - we're not allowed to take them seriously. Words like "good" and "bad" and "pretty" and "ugly" - easy and not extremely specific - are these kinds of words. Dark and light, like good and bad, have this doubleness working against them as well: they aren't specific enough to be interesting, and are at the same time poetic cliches. The invested emotional resonance is called up so often that it becomes overly sentimental, a kind of fullness that results in the depletion of meaning. Of course, many many wonderful poets use the word "dark" in any of its variants, in some great poems. So these words can be "saved" to some degree by careful use. I've been thinking a lot about that, that part of the work I'm interested in doing with language is saving, or proving possible, the use of depleted, exhausted words.

I've also been long interested in astrophysics, and the words dark and light clearly have significant importance in discussing the observable universe. It was all of this that came together to interest me in the 1987 work Darkness at Night that poses and then treats historically Olber's paradox: why, in an infinite universe filled with stars, are the night skies dark? If the universe is infinite, shouldn't any line of sight from Earth into the universe eventually be intercepted by a star, making the night sky fully bright?

The book provides, in chronological order, a number of proposed solutions to this riddle, and the corresponding understandings of the universe that inform them. So more than merely answering the question for a contemporary reader with a contemporary understanding of the universe, it lays out in fascinating ways a number of historical ways of viewing the universe and our place within it. Its written with a minimum of technical language and mathematical formulas, so that someone like me with little to no formal scientific training can understand the principles of the models of the universe, and the proposed solutions to cosmic darkness. Of course, as he moves into more contemporary models, the concepts get significantly more complicated and harder to understand.

[Read the whole review: www.alluringlyshort.com]

[Greg Morrison · Rating 3 out of 5]

I read Darkness at Night because it appeared in the footnotes of Edgar A. Poe: Mournful and Never-ending Remembrance. Silverman was discussing Poe's Eureka, a "poem" that Poe claimed would explain the universe, revolutionize the world of science & philosophy, etc.

Among many other riddles, Poe takes on the question of why the night sky is dark.

Here's the basic question. Whenever you look up at the sky, your eye is meeting a star - somewhere, no matter how distant. And if there's millions, billions, trillions of stars, it's all the more likely that anywhere you look, your gaze connects to a star. So, with all those pinpricks of light in the sky, why don't they act like pixels, and create a bright sky at night? Why aren't the skies filled with starlight?

Harrison answers this question very thoroughly, by reviewing all the previous theories and explanations. It turns out that in order to answer this question, you need to talk about the nature of light, of space, whether the universe is expanding, and twenty or so other cosmological questions. He starts far back, with the Pre-Socratics, and goes all the way into the second half of the 20th century.

All this is interesting, but for me, it suffers from a problem common to a lot of science writing. If you already know the current answer to these questions, then hearing ancient Greek or 17th century theories about light has a piquant thrill - kind of like correcting an inaccurate rumor. But if you don't, then it gets rather confusing, and it becomes a succession of odd analogies ("Let's say you have a lightbulb in a box") and theologies.

Overall, I would recommend this book to those curious about the history of science, and the ways imagination confronts a paradox over time.

[A · Rating 4 out of 5]

Harrison gives detailed descriptions of multiple theories that were proposed to answer the question, "Why is it dark at night?" Each theory is dealt with in detail, and the fallacies they include are laid bare.

[Akwany · Rating 5 out of 5]

so intriguing to read, and I would be so lost without the diagrams! Thabk you and well done Edward Harrison!