03 agosto 2007

1. It isn't easy to become a fossil



"It isn't easy to become a fossil… Only about one bone in a billion, it is thought, becomes fossilized. If that is so, it means that the complete fossil legacy of all the Americans alive today - that's 270 million people with 206 bones each - will only be about 50 bones, one-quarter of a complete skeleton. That's not to say, of course, that any of these bones will ever actually be found. Bearing in mind that they can be buried anywhere within an area of slighly over 9.3 million square kilometres, little of which will ever be turned over, much less examined, it would be something of a miracle if they ever were”



2. There is more life under the Earth than on top of it



“We now know that there are a lot of microbes living deep within the Earth… Some scientist now think that there could be as 100 trillion tons of bacteria living beneath our feet in what are known as subsurface lithoautotrophic microbial ecosystems… Thomas Gold of Cornell has estimated that if you took all the bacteria out of the Earth’s interior and dumped it on the surface, it would cover the planet to a depth of five feet. If the estimates are correct, there could be more life under the Earth than on top of it.”



3. The most striking thing about our atmosphere



"The most striking thing about our atmosphere is that there isn’t very much of it. It extends upward for about 120 miles, which might seem reasonably bounteous when viewed from ground level, but if you shrank the Earth to the size of a standard desktop globe it would only be about the thickness of a couple of coats of varnish”



4. Men will never reach the edge of the solar system



"Pluto may be the last object marked on schoolroom charts but the solar system doesn’t end there. In fact, it isn’t even close to ending there. We won’t get to the solar system’s edge until we have passed through the Oort cloud, a vast celestial realm of drifting comets… Far from marking the outer edge of the solar system, as those schoolroom maps so cavalierly imply, Pluto is barely one 50,000th of the way. Of course we have no prospect of such a journey. Based on what we know now and can reasonably imagine, there is absolutely no prospect that any human being will ever visit the edge of our own solar system — ever. It is just too far".



5. There is no point trying to hide from your bacteria



"There is no point trying to hide from your bacteria, for they are on you and around you always, in numbers you can't conceive of. If you are in good health and averagely diligent about your hygiene, you will have a herd of about one trillion bacteria grazing on your fleshy plains - about one hundred thousand of them on every square centimetre of skin. And those are just the bacteria that inhabit your skin... Every human body consists of about ten quadrillion cells, but it is host to about a hundred quadrillion bacterial cells. They are, in short, a big part of us. From the bacteria's point of view, of course, we are a rather small part of them… This is their planet, and we are only on it because they allow us to be”.



6. There is nothing we can do about asteroids



“Oh, probably none,” said Anderson breezily. “It wouldn’t be visible to the naked eye until it warmed up, and that wouldn’t happen until it hit the atmosphere, which would be about one second before it hit the Earth. You’re talking about something moving many tens of times faster than the fastest bullet. Unless it had been seen by someone with a telescope, and that’s by no means a certainty, it would take us completely by surprise.”



7. We are energy



“You may not feel outstandingly robust, but if you are an average-sized adult you will contain within your modest frame no less than 7 x 10^18 joules of potential energy -- enough to explode with the force of thirty very large hydrogen bombs, assuming you knew how to liberate it and really wished to make a point. We’re just not very good at taking it out. Even a uranium bomb –the most energetic thing we have produced yet- releases less than 1 percent of the energy it could release if only we were more cunning”.



8. Atom’s nucleus



“Neutrons and protons occupy the atom’s nucleus. The nucleus of an atom is tiny -- only one-millionth of a billionth of the full volume of the atom -- but fantastically dense, since it contains virtually all the atom’s mass. As Cropper has put it, if an atom were expanded to the size of a cathedral, the nucleus would be only about the size of a fly -- but a fly many times heavier than the cathedral”.



9. The center of the Earth



“The distance from the surface of Earth to the center is 3,959 miles, which isn’t so very far. It has been calculated that if you sunk a well to the center and dropped a brick into it, it would take only forty-five minutes for it to hit the bottom… Our own attempts to penetrate toward the middle have been modest indeed. One or two South African gold mines reach to a depth of two miles, but most mines on Earth go no more than about a quarter of a mile beneath the surface. If the planet were an apple, we wouldn’t yet have broken through the skin”.



10. Is there life out there?







Bill Bryson, " “Still, statistically the probability that there are other thinking beings out there is good… Under Drake’s equation you divide the number of stars in a selected portion of the universe by the number of stars that are likely to have planetary systems; divide that by the number of planetary systems that could theoretically support life; divide that by the number on which life, having arisen, advances to a state of intelligence; and so on. At each such division, the number shrinks colossally—yet even with the most conservative inputs the number of advanced civilizations just in the Milky Way always works out to be somewhere in the millions”.Bill Bryson, " A Short History of Nearly Everything