A Short History of Nearly Everything: Measuring a Meridian

"If you had to select the least convivial scientific field trip of all time, you could certainly do worse than the French royal Academy of Sciences' Peruvian expedition of 1735.   Led by a hydrologist named Pierre Bouguer and a soldier-mathematician named Charles Marie de la Condamine, it was a party of scientists and andvetures and who travelled to Peru with the purpose of triangulating distances through the Andes.

At the time people had lately become infected with a powerful desire to understand the Earth - to determine how old it was, and how massive, where it hung in space, and how it had come to be.   The French party's goal was to help settle the question of the circumference of the planet by measuring the length of one degree of meridian (or one-360th of the distance around the planet) along a line reaching from Yarouqui, near Quito, to just beyond Cuenca in what is now Ecuador, a distance of about 320 kilometres.

Almost at once things began to go wrong, sometimes spectacularly so.   In Quito, the visitors somehow provoked the locals and were chased out of town by a mob armed with stones.   Soon after the expedition's doctor was murdered in a misunderstanding over a woman.   The botanist became derranged.   Otheres died of fevers and falls.   The third most senior member of the party, a man named Jean Godin, ran off with a thirteen-year-old girl and could not be induced to return.

At one point the group had to suspend work for eight months while La Condamine rode off to Lima to sort out a problem with their permits.   Eventually he and Bouguer stopped speaking and refused to work together.   Everywhere the dwindling party went it was met with the deepest suspicions from officals who found it difficult to believe that a group of French scientists would travel halfway around the world to measure the world.   That made no sense at all.  Two and a half centuries later, it still seems a reasonable question.   Why didn't the French make their measurements in France and save themselves the all the bother and discomfort of their Andean adventures?

The answer lies partly with the fact that eighteenth century scientists, the French in particular, seldom did things simply if an absurdly demanding alternative was available, and partly with a practical problem problem that had arisen with the English astronomer Edmond Halley many years before - long before Bouguer and la Condamine dreamed of going to South America, much less had a reason for doing so.

(...)

They chose the Andes because they needed to measure near the equator, to determine if there really was a difference in sphericity there, and because they reasoned that mountains would give them good sightlines.   In fact, the mountains of Peru were so contantly lost in coud that the team often had to wait weeks for an hour's clear surverying.   On top of that, they had selected one of the most nearly impossible terrains on Earth.   Peruvians refer to their landscape as muy accidentado - "much accidented" - and this it most certainly is.   Not only did the French have to scale some of the world's most challenging mountains - mountains that defeated even their mules - but to reach the mountains they had to ford wild rivers, hack their way through jungles, and cross miles of high, stony, desert, nearly all of it uncharted and far from any source of suppplies.   But Bouguer and La Condamine were nothing if not tenacious, and they stuck to the task for nine and a half long, grim, sun-blistered years.   Shortly before concluding the project, word reached them that a second French team, taking measurements in northern Scandinavia (and facing notable discomforts of their own, from squelching bogs to dangerous ice floes), had found that a degree was in fact longer near the poles, as Newton had promised.   The Earth was 43 kilometres stouter when measured equatorially than when measured from top to bottom around the poles.

Bouguer and La Condamine thus had spent nearly a decade working towards a result they didn't wish to find only to learn now that they weren't even the first to find it.   Listlessly they completed their survery, which confirmed that the first French team was correct.   Then, still not speaking, they returned to the coast and took separate ships home."

A Short History of Nearly Everything: Cosmic Background Radiation

"Even the notion of the Big Bang is quite a recent one.   The idea had been kicking around since the 1920s when Georges Lemaitre, a Belgian priest-scholar, first tentatively proposed it, but it didn't really become an active notion in cosmology until the mid-1960s, when two young radioastronomers made an extraordinary and inadvertant discovery.

Their names were Arno Penzias and Robert Wilson.   In 1965, they were trying to make use of a large communications antenna owned by Bell Laboratories at Holmdel, New Jersey, but they were troubled by a persistent background noise - a steady, steamy hiss that made any experimental work impossible.   The noise was unrelenting and unfocused.   It came from every point in the sky, day and night, through every season.   For a year the young astronomers did everything they could think of to track down and eliminate the noise.   They tested every electrical system.   They rebuilt instruments, checked circuits, wiggled wires, dusted plugs.   They climed into the dish and placed duct tape over every seam and rivet.   They climbed back into the dish with brooms and scrubbing brushes and carefully swept it clean of what they referred to in a later paper as "white dielectric material", or what is known more commonly as bird shit.   Nothing they tried worked.

Unknown to them, just 50 kilometres away at Princeton University a team of scientists led by Robert Dicke was working on how to find the very thing they were trying so diligently to get rid of.   The Princeton researchers were persuing an idea that had been suggested in the 1940s by the Russian-born astrophysicist George Gamow: that if you looked deep enough into space you should find some cosmic background radiation left over from the Big Bang.   Gamow calculated that by time it had crossed the the vastness of the cosmos the radiation would reach Earth in the form of microwaves.   In a more recent paper he had even suggested an instrument that might do the job: the Bell antenna at Holmdel.   Unfortunately, neither Penzias and Wilson, nor any of the Princeton team, had read Gamow's paper.

The noise that Penzias and Wilson were hearing was, of course, the noise that Gamow had postulated.   They had found the edge of the universe, or at least the visible part of it, 90 billion trillion miles away.   They were "seeing" the first photons - the most ancient light in the universe - though time and distance had converted them to microwaves, just as Gamow had predicted.   In his book The Inflationary Universe, Alan Guth provides an analogy that helps to put this finding in perspective.   If you think of peering into the depths of the universe as looking down from the hundredth floor of the Empire State Building (with the hundreth floor representing now and the street level representing the moment of the Big Bang), at the time of Wilson and Penzias's discovery the most distant galaxies anyone had ever detected were on about the sixtieth floor and the most distant things - quasars - were on about the twentieth.   Penzias and Wilson's findings pushed our aquaintance with the visible universe to within half an inch of the lobby floor.

Still unaware of what caused the noise, Wilson and Penzias phoned Dicke at Princeton and described their problem to him in the hope that he might suggest a solution.   Dicke realised at once what the two young men had found.   "Well, boys, we've just been scooped," he told his colleagues as he hung up the phone.

Soon afterwards the Astrophysical Journal published two articles: one by Penzias and Wilson describing their experience with the hiss, the other by Dicke's team explaining its nature.   Although Penzias and Wilson had not been looking for cosmic background radiation, didn't know what it was when they found it, and hadn't described or interpreted its character in any paper, they received the 1978 Nobel Prize in Physics.   The Princeton researchers got only sympathy.   According to Dennis Overbye in Lonely Hearts of the Cosmos, neither Penzias nor Wilson altogether understood the significance of what they had found until they read about it in the New York Times.

Incidently, disturbance from cosmic background radiation is something we have all experienced.   Tune your television to any channel it doesn't receive and about 1 per cent of the dancing static you see is accounted for by this ancient remant of the Big Bang.   The next time you complain that there is nothing on, remember that you can always watch the birth of the universe."

A Short History of Nearly Everything: Atoms

From A Short History of Nearly Everything:

"Atoms, in short, are very abundant.

They are also fantastically durable.   Because they are so long-lived, atoms really get around.   Every atom you possess has almost certainly passed through several stars and been part of millions of organisms on its way to becoming you.   We are each so atomically numerous and so vigourously recycled at death that a significant number of our atoms - up to a billion for each of us, it has been suggested - probably once belonged to Shakespeare.   A billion more each came from Buddha and Genghis Khan and Beethoven, and any other historical figure you care to name.   (The personages have to be historical, apparently, as it takes the atoms some decades to become thoroughly redistributed; however much you may wish it, you are not yet at one with Elvis
Presley.)"

A Short History of Nearly Everything: Space

"Now, the first thing you are likely to realize is that space is extremely well named and rather dismayingly uneventful.   Our solar system may be the liveliest thing for trillions of miles, but all the visible stuff in it - the Sun, the planets and their moons, the billion or so tumbling rocks of the asteroid belt, comets and other miscellaneous drifting detritus - fills less than a trillionth of the available space.   You also quickly realize that none of the maps you have ever seen of the solar system was drawn remotely to scale.   Most schoolroom charts show the planets coming one after the other at neighbourly intervals - the outer giants actually cast shadows over each other in many illustrations - but this is a necessary deceit to get them all on the same bit of paper.   Neptune in reality isn't just a little bit beyond Jupiter, it's way beyond Jupiter - five times further from Jupiter than Jupiter is from us, so far out that it receives only 3 per cent as much sunlight as Jupiter.

Such are the distances, in fact, that it isn't possible, in any practical terms, to draw the solar system to scale.   Even if you added lots of fold-out pages to your textbooks or used a really long sheet of poster paper, you wouldn't come close.   On a diagram of the solar system to scale, with the Earth reduced to about the diameter of a pea, Jupiter would be over 300 metres away and Pluto would be two and a half kilometres away (and about the size of a bacterium, so you wouldn't be able to see it anyway).   On the same scale, Proxima Centauri, our nearest star, would be 16,000 kilometres away.   Even if you shrank down everything so that Jupiter was as small as the full stop at the end of this sentence, and Pluto was no bigger than a molecule, Pluto would still be over 10 metres away.  

So the solar system is really quite enormous.   By the time we reach Pluto, we have come so far that the Sun - our dear, warm, skin-tanning, life -giving Sun - has shrunk to the size of a pinhead.   It is little more than a bright star.   In such a lonely void you can begin to understand how even the most significant objects - Pluto's moon, for example -  have escaped attention.   In this respect, Pluto has hardly been alone.   Until the Voyager expeditions, Neptune was thought to have two moons; Voyager found six more.   When I was a boy, the solar system was thought to contain thirty moons.   The total is now at least ninety, about a third of which have been found in just the last ten years.   The point to remember, of course, when considering the universe at large is that we don't actually know what's in our own solar system.  

Now the other thing you will notice as we speed past Pluto is that we are speeding past Pluto.   If you check your itinerary, you will see that this is a trip to the edge of our solar system, and I'm afraid we're not there yet.   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, and we won't reach the Oort cloud for another - I'm so sorry about this - ten thousand years.   Far from marking the edge of the solar system, as those schoolroom maps so cavalierly imply, Pluto is barely one-fifty-thousandth of the way."


A bit out of date now, of course, but still pretty cool.   Science!  :D