Chapter 3: The Reverend Evans's Universe

Please either use this thread to discuss the above referenced chapter of "A Short History of Nearly Everything" by Bill Bryson.

Bryson tells us that only about 6,000 stars are visible to the naked eye from earth and of these, only about 2,000 can be seen from any one point on the planet. With binoculars one can see 50,000 stars and with a two-inch telescope that number jumps to 300,000. With a sixteen-inch telescope you begin to count not in stars but in galaxies, up to 100,000 galaxies, with each one of those galaxies containing tens of billions of stars!

Returning to earth, Bryson tells us about a quiet and cheerful man, Rev. Robert Evans, who has an amazing special skill - he finds supernovae. A supernova is a dying star that may occur once in two or three hundred years in an average galaxy. Yet, The Rev. Robert Evans, from his home in Australia's Blue Mountains, about 50 miles west of Sydney with a 16-inch telescope discovered 36 supernovas between 1980 and 2003 even though less than 60 supernovae were located by all scientists since the invention of the telescope!
Bryson writes about many such interesting people who made great contributions in science but don't always get the attention they deserve in the regular textbooks.

I'm liking the little bios he gives of the scientists--or, in the case of Evans, I guess non-scientists. But what really is the difference? It's great that a non-specialist can be an important contributor. I've always suspected that scientists must be super-quirky, and Bryson does a great job of confirming my suspicions!

But let me get this straight--supernovas, Bryson tells us, are like blast furnaces that took the existing light gases and forged them into the elements that made possible solid bodies like our own earth.

Is it in this chapter that Bryson reports that the universe is actually so empty--though containing trillions and trillions of massive objects--that our most perfect vacuum can't duplicate its emptiness? Now that truly does seem unbelievable.

I'm relieved to know that we're in no apparent danger of being blasted by a supernova, because unless one is within 8 to 10 light years away, we're out of range.

LevV wrote:Bryson tells us that only about 6,000 stars are visible to the naked eye from earth and of these, only about 2,000 can be seen from any one point on the planet.

Fact check!! http://www.skyandtelescope.com/astronom ... -09172014/ says the number of stars visible from earth down to 6.5 magnitude is over 9000. All stars visible from earth are visible from the equator, by definition, while only half are visible from the poles.

My astronomical interest in this question arose from a religious question, the meaning of the loaves and fishes miracle in the Bible. There are two versions of this story, one with 5000 men in the multitude and one with 4000. Overall the story gets told six times in the New Testament, double the number of any other miracle. My reading sees the feeding of the multitude as a cosmic parable, with the number of men standing for the number of visible stars, and the difference between 5000 and 4000 reflecting conflicting views on how many stars can be seen, or perhaps different sources, 5000 in lower Egypt and 4000 in Babylon, reflecting different latitudes.

Bryson may be using a brighter magnitude limit than Sky and Telescope, since even mag 6 requires keen eyes. Uranus is mag 5.7, and was not detected as moving until just over two centuries ago. Here is a link to observing Uranus http://www.nakedeyeplanets.com/uranus.htm

DWill wrote:I'm liking the little bios he gives of the scientists--or, in the case of Evans, I guess non-scientists. But what really is the difference? It's great that a non-specialist can be an important contributor. I've always suspected that scientists must be super-quirky, and Bryson does a great job of confirming my suspicions!

This dude is certainly quirky - an example. In 1987 a sophisticated system for discovering supernovas was created. It involved computers and very sensitive digital cameras. It automated supernova hunting where one could set up the system and go on to do something else. When Bryson asked Evans (who had been making his discoveries with his sixteen inch telescope in his back yard) if he was tempted to adopt the new technology, he said, "Oh, no, I enjoy my way too much. Besides - he gave a nod at the photo of his latest supernova and smiled - "I can still beat them sometimes".

Evans is the prime example of the amateur scientist who makes an amazing breakthrough. This reminds me of Gregor Mendel, the monk puttering around in his garden who discovered the basic laws of heredity.

These amateurs must have an awesome skill-set, though. That must have been true of Mendel. It was true of Thoreau, who is often credited with founding the science of ecology.

I read this short chapter three times and learn more with each reading. I especially appreciated his manner of describing the formation of our solar system.
First came the Big Bang which created lots of light gases but no heavy elements. Then came the super hot super novas which created the heavier elements such as carbon and iron bringing about the potential for a living world. In our part of the universe it took the form of a great swirl of gas and dust billions of miles wide. Most of this mass - 99.9% of it went into forming the sun with the remainder forming planets, moons and other smaller bits circling the sun.

This is how Bryson describes the likely formation of the planets: "Out of the floating material .... two microscopic grains floated close enough together to be joined by electrostatic forces. This was the moment of conception for our planet. All over the inchoate solar system, the same was happening. Colliding dust grains formed larger and larger clumps. Eventually the clumps grew large enough to be called planetisimals. As these endlessly bumped and collided, they fractured or split or recombined in endless random permutations, but in every encounter there was a winner, and some of the winners grew big enough to dominate the orbit around which they traveled".

Another interesting fact. The greenhouse effect wasn't always bad news for the Earth. The Earth began to form an atmosphere very early on of carbon dioxide, nitrogen, methane and sulphur. The sun was much dimmer then and without the benefit of greenhouse protection from all the carbon dioxide, the Earth might have frozen over permanently with no possibility of life forming!