Oct 042009

The following excerpts are taken from the book, “A Short History of Nearly Everything”. These are truly awesome statements.


The Measure of Things

Astronomers these days can do the most amazing things. If someone struck a match on the Moon, they could spot the flare.

With their radio telescopes they can capture wisps of radiation so preposterously faint that the TOTAL amount of energy collected from outside the solar system by all of them together since collecting began in 1951 is “less than the energy of a single snowflake striking the ground,” in the words of Carl Sagan.

Weighing the Earth

Henry Cavendish is often credited with being the first person to use Newton’s law of gravitation to calculate the mass of the earth, but he did so with a machine developed by a man named John Michell, who died before he could use it.

Delicacy was the key word. Not a whisper of disturbance could be allowed into the room containing the apparatus, so Cavendish took up a position in an adjoining room and made his observations with a telescope aimed through a peephole. The work was incredibly exacting and involved seventeen delicate, interconnected measurements, which together took nearly a year to complete…

Today, scientists have at their disposal machines so precise they can detect the weight of a single bacterium and so sensitive that readings be disturbed by someone yawning seventy-five feet away, but they have not significantly improved on Cavendish’s measurements of 1979.

The Rise of Life – the Big Birth

Whatever prompted life to begin, it happened just once. That is the most extraordinary fact in biology, perhaps the most extraordinary fact we know. Everything that has ever lived, plant or animal, dates its beginnings from the same primordial twitch. At some point in an unimaginably distant past some little bag of chemicals fidgeted to life. It absorbed some nutrients, gently pushed, had a brief existence. This much my have happened before, perhaps many times. But this ancestral packet did something additional and extraordinary: it cleaved itself and produced an heir. A tiny bundle of genetic material passed from one living entity to another, and has never stopped moving since. It was the moment of creation for us all. Biologists sometimes call it the Big Birth.

“Wherever you go in the world, whatever animal, plant, bug, or blob you look at, if it is alive, it will us the same dictionary and know the same code. All life is one,” says Matt Ridley. We are all the result of a single genetic trick handed down from generation to generation nearly four billion years, to such an extent that you can take a fragment of human genetic instruction, patch it into a faulty yeast cell, and the yeast cell will put it to work as if it were its own. In a very real sense, it is its own.

– “Humans are here today because our particular line never fractured – never once at any of the billion points that could have erased us from history.”

Small World

Bacteria may not build cities or have interesting social lives, but they will be here when the Sun explodes. This is their planet, and we are on it only because they allow us to be.

Bacteria, never forget, got along for billions of years without us. We couldn’t survive a day without them. they process our wastes and make them usable again; without their diligent munching nothing would rot. They purify our water and keep our soils productive. Bacteria synthesize vitamins in our gut, convert the things we eat into useful sugars and polysaccharides, and go to war on alien microbes that slip down our gullet.

We depend totally on bacteria to pluck nitrogen from the air and convert it into useful nucleotides and amino acids for us. It is a prodigious and gratifying feat. As Margulis and Sagan note, to do the same thing industrially (as when making fertilizers) manufacturers must heat the source material to 500 degrees centigrade and squeeze them to three hundred times normal pressures. Bacteria do it all the time without fuss, and thank goodness, for no larger organism could survive without the nitrogen the pass on. Above all, microbes continue to provide us with the air we breathe and to keep the atmosphere stable. Microbes, including the modern versions of cyanobacteria, supply the greater part of the planet’s breathable oxygen. Algae and other tiny organisms bubbling away in the sea blow out about 150 billion kilos of the stuff every year.

And they are amazingly prolific. The more frantic of them can yield a new generation in less than ten minutes; Clostridium perfringens, the disagreeable little organism that causes gangrene, can reproduce in nine minutes. At such a rate, a single bacterium could theoretically produce more offspring in two days than there are protons in the universe.

… Bacteria share information. Any bacterium can take pieces of genetic coding from any other. Essentially, as Margulis and Sagan put it, all bacteria swim in a single gene pool. Any adaptive change that occurs in one area of the bacterial universe can spread to any other. […it’s important to remember that one bacteria is as different from its neighbors as animals are from plants]. It’s rather as if a human could go to an insect to get the necessary genetic coding to sprout wings or walk on ceilings. It means that from a genetic point of view bacteria have become a single superorganism – tiny, dispersed, but invincible.

They will live and thrive on almost anything you spill, dribble, or shake loose. Just give them a little moisture – as when you run a damp cloth over a counter and they will bloom as if created from nothing. They will eat wood, the glue in wallpaper, the metals in hardened paint. Scientists in Australia found microbes … that live in – indeed, could not live without – concentrations of sulfuric acid strong enough to dissolve metal. A species called Micrococcus radiophilus was found living happily in the waste tanks of nuclear reactors, gorging itself on plutonium and whatever else was there.

…Some of them seem to be practically indestructible. Deinococcus radiodurans is, according to the Economist, “almost immune to radioactivity.” Blast its DNA with radiation, and the pieces immediately reform “like the scuttling limbs of an undead creature from a horror movie.”

…Slime molds are, make no mistake, among the most interesting  organisms in nature. When times are good, they exist as one-celled individuals, much like amoebas. But when conditions grow tough, they crawl to a central gathering place and beceome, almost miraculously, a slug. The slug is not a thing of beauty and it doesn’t go terribly far – usually just from the bottom of a pile of leaf litter to the top, where it is in a slightly more exposed position – but for millions of years this may have been the niftiest trick in the universe.

And it doesn’t stop there. Having hauled itself up to a more favorable locale, the slime mold transforms itself yet again, taking on the form of a plant. By some curious orderly process the cells reconfigure, like the members of a tiny marching band, to make a stalk atop of which forms a bulb known as a fruiting body. Inside the fruiting body are millions of spores, that, at the appropriate moment, are released to the wind to blow away and become single-celled organisms that can start the process again.

Life Goes on

It is almost impossible for us whose time on Earth is limited to a breezy few decades to appreciate how remote in time from us the Cambrian outburst was. If you could fly backwards into the past at the rate of one year per second, it would take you about half an hour to reach the time of Christ, and a little over three weeks to get back to the beginnings of human life. But it would take you twenty years to reach the dawn of the Cambrian period. It was, in other words, an extremely long time ago, and the world was a very different place.


Good-Bye To All That

So why, out of all the thousands of impacts Earth has endured, was the KT event so singularly devastating? Well, first it was positively enormous. It struck with the force of 100 million megatons. Such an outburst is not easily imagined, but as James Lawrence Powell has pointed out, if you exploded one Hiroshima-sized bomb for every person alive on earth today you would still be about a billion bombs short of the size of the KT impact.



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