Catch Snowball Earth: The Story Of The Great Global Catastrophe That Spawned Life As We Know It Narrated By Gabrielle Walker Expressed As Print

starter but a really interesting story of the science and scientists behind discovering the huge snow ball ice ages, Shows the hard work behind the scientific method and putting forward new theories No seu livro, Terra Bola de Neve, Gabrielle Walker relatanos a odisseia de Paul Hoffman, desde a maratona de Boston deque terminou em nono lugar, com um tempo espetacular para um amador na sua primeira maratona de duas horas vinte e oito minutos e sete segundos.

Podia ter seguido esse trajeto, mas não o fez, Dedicou antes a sua vida à geologia e à defesa de uma teoria em que tropeçou no seu trabalho de campo no deserto da Namíbia.

Paul Hoffman deu seguimento a outros cientistas que desde há muito apontavam para o facto de a terra enquanto planeta não ter tido sempre o mesmo comportamento, aspecto e condições climáticas que as que têm sido observadas por humanos desde há.
anos quando abandonaram as planícies africanas,
Nesta sua história biográfica, de uma ideia e de um homem, Gabrielle Walker contanos como Paul Hoffman soube ler nas investigações de outros que apontavam: para junto ao equador terem surgido “pedras de gelo” a sugestão de ter havido gelo nessas latitudes Brian Hartland e Louis Agassiz nas descobertas de Joe Kirschvink orientação magnética das rochas no momento da sua formação e na teoria da deriva das placas continentais do Meteorologista Alfred Wegner, para nestes ter encontrado substrato para a sua própria teoria a da terra ter sido outrora dominada pelo gelo, num ambiente completamente hostil ao desenvolvimento da vida complexa como a que surgiu no período câmbrico.

Contou para esta teoria com a colaboração outros investigadores e cientistas, dos quais Dan Schrag se revelou dos mais importantes tanto pela sua contribuição científica para teoria abundância de elementos de carbonoe, cuja proporção revelava a existência de vida.
As bactérias consomem o carbono, pelo quando há vida nos vestígios predomina o isótopo de carbono, como pela forma habilidosa como deu consistência à teoria e soube defender conjuntamente com o outro paladino.

Há assim evidencia da geografia da terra e as suas condições ambientais se terem alterado muito ao longo da sua história de,biliões de anos.

Durante a sua vida e desde que a vida surgiu hábiliões de anos, a terra teve vários períodos de glaciação global tendo o mais marcante destes surgido hámilhões de anos, antes da explosão câmbrica e durado alguns milhões de anos.

Esta teoria é apoiada na teoria da deriva das placas, na datação dos estratos geológicos onde as pedras de gelo são encontradas e pelas suas características eletromagnéticas que apontam para terem as mesmas surgido próximo do equador.

Durante estes períodos a terra terseá despojado da quase totalidade da vida e esta só terá retomado o seu desígnio quando as temperaturas globais aqueceram, o que terá surgido como resultado da actividade vulcânica.

A teoria em si é magnifica porque mostranos a terra como um organismo vivo capaz de mudanças que não fogem muito ao que entendemos como “metabolismo”, ainda qua numa outra escala.

Num destes episódios de terra bola de gelo, eventualmente numa das primeiras extinções em massa, ela terá ocorrido fruto do aumento nos níveis de Ono período Ordoviciano hámilhões e que terá surgido fruto da biologia da época que conduziu a um enorme aumento de Ocom redução de COe inerente abaixamento das temperaturas.

Nos períodos descritos por Paul Hoffman não fica claro quais as causas para estes arrefecimentos, Segundo os autores desta teoria, teria sigo o conglomerado de placas continentais junto ao equador que teria criado as condições para o arrefecimento uma vez que as placas continentais têm menos capacidade de reter energia térmica que os oceanos.
Assim quando estas se juntam no equador a terra tem tendência a arrefecer, Talvez Mas tenho as minhas dúvidas se esse arrefecimento não resultou da actividade bacteriana dos estromatólitos anaeróbios e da sua produção de O.
Talvez Mas este é o meu palpite! I liked this book quite a bit and I think Gabrielle Walker is probably a new favorite science writer of mine.
I've also read The Ocean of Air which was really wonderful, That one was a much quicker read than this one, I tried to really remember, focus on and understand the geology being discussed here, Maybe not a good book for a halfhearted science reader, I've seen some reviews that were critical of the focus being on both the scientists AND their work as opposed to JUST on the work, but that's the part I like best.
This is a rollicking tale of exploration, clashes of big egos, travel and discovery, The book proves you need a very thick skin if you want to be a scientist as the whole point of science seems to be to demolish the current theory and build a new or better one.
The good ones stand up to the dynamite, the snowball earth theory appears to be doing just that, Great deep dive into the awful personalities of geologists Made me feel a little better about the awful personalities in my own field they seem less extreme now.
Such a joy to read a really well written and engaging science book, Offers alternative theories to global warming which may or may not hold up but are worth learning either way, Gabrielle does a good job detailing the history behind this idea that the earth has moved from through a cycle of temperate climate regions driven by seasons to a frozen singular global winter snowball state to a volatile hot house environment and back to the seasonal temperate climate we know today.
This theory is playing out in the academic Halls of geology, However, it branches into biology because those geologists determined that the onset and explosion of complex life forms coincided with the last thawing of the snowball.


My only concern with this chronicle is that it was published in, I haven't found a sequel bringing the reader up to date with the events over the pastyears,

The proponents of this theory feel there were somesnowball events covering's of thousands of years apiece in this timeframe ofmillion years ago.
An extension to the theory suggests there was one other snowball somebillion years ago, What the author fails to do is demonstrate that this kind of timing in the,billion year history of the Earth is actually a strong argument for the need and presence of black swans in any description of climate on Earth.


I really enjoyed this book, Boy are the geologists, biologists, scientists and others who do the reseach on this event dedicated, . . they are all in on this issue, I never knew that the idea had been proffered that Earth has been completely covered in ice on more than one occasion, The science behind the ice covering is fascinating, Even more so, how life developed/exploded as the last Snowball disappeared, Dr. Walker does an excellent job of weaving the various scientists and their complex relationships together along with each of their scientific disciplines, This book was a real eye opener for me, . . which is the point of a good book, . . right As is often the case, with me at least, the last book I've read leads me to the next one, In this case it was sitelinkSupercontinent: Ten Billion Years in the Life of Our Planet about plate tectonics that led me to read this book.
The former had a section about how it might have been the supercontinent of Rodinia, which is believed to have existed prior tomillion years ago, that was the partial cause of the socalled Snowball Earth.


I was a little put off by the author's flowery, adjective and adverb loaded bio's of the various scientists involved, but overall she does a good job of telling the evolving story of the genesis of the Snowball Earth theory, which posits that the Earth was completely covered with ice not long before complex, multicellular life first appears in the fossil record close tomillion years ago.


I have to admit that there is some morbid fascination to be had from reading how brutally the various scientific factions attack each other as they attempt to promote and prove or denegrate and disprove a major new theory.
For a lay person like myself it quickly dispenses any notion that the whole process is very cordial and diplomatic, Nope. Let the mud and spit fly,

Like plate tectonics and continental drift theory before it, the Snowball Earth theory is going through an intense period of testing and criticism and is far from being as accepted as plate tectonics is today.
So, it's an interesting time to sit on the sidelines and watch the science equivalent of a mixed martial arts tournament take place, While, as usual, I was a bit irked by the tendency of scientific authors to personify "Earth" and evolutionary processes and plate techtonics, in this case as a sort of substitute for God, this was an excellent story of how science is done how theories are made, how the personalities of the scientists involved affect the making of theories in addition to the science itself being fascinating.
It's also a wellwritten book by a good storyteller, Quite ok, the science and scientist of this story are a bit overhyped, but it's still a fun read, I had this book on my toread shelf for years, after I read about another book by the same author, The other book is on my toread shelf, too, but I am now not sure I want to start it ever, . .

It's not that I hated the book but I just got bored with about a third way in, I am not a geologist and have no special interest in the details of how a theory was attempted, then disproved, then proved again over time had hoped the story would be about the phenomenon of "snowball earth" rather than the personal life stories of the geologists involved in proving and disproving different theories in connection with snowball earth.
Also the tone of the book grated on me every story seemed to be told with overly dramatic effect like a bad TV documentary.
I enjoyed this read about the early life of Planet Earth which focuses on geology and geologists, The primary scientist featured, Paul Hoffman, is first shown running his first marathon in a great time, He then has to choose between concentrating on his running and going back to study, The author is showing readers that theories and discoveries are made by real people, with real choices, The facts may be embedded in the rocks under our feet, but unless and until sufficient work is done and science is sufficiently developed, the answers cannot be proven.


Stromatalites, very early forms of plant life, took carbon from the air and replaced it with oxygen, These are still found in a bay in Australia, Before them the fossil record shows glaciation, But samples of rock proved, due to the way magnetised particles had lined up at the time the rocks formed, that the ice covered rocks were near the equator, not the poles.
Through work by many geologists over many years, these rocks were found all around the world, Namibia, Canada, Australia, Svalbard were all part of land masses which due to continental drift then lay around the

equator, And they bore ice.

Drop stones are rocks embedded in icebergs that break off glaciers and are dropped to the sea floor as the ice melts.
Geologists learn to spot them in the rock record, These, moraines, icescraped rocks, oolites, volcanic glass, pillow lava and more are all part of the picture, But geologists pick a spot and return to it year after year, building up a detailed study, jealous of their patch, So we have to follow different people almost all male, but not all, Science works by one team presenting a hypothesis which is challenged by others who try to prove or disprove it, So we learn what challenges were presented, why this broke up many friendships and created friction, when Paul took up a previous theory that Earth had been solidly covered in ice.


Since ice reflects heat, a white Earth should stay frozen, The solution presented was volcanic activity which threw carbon dioxide and other greenhouse gases into the air, until the hothouse effect melted the ice.
This appeared to have occurred more than once, Then proof of this had to be found in the rock record, This hunt and struggle occupies most of the book, with only a final chapter or two left to see what caused advanced life to form once the ice melted for the last time.
I found the book easily readable but I know a lot of the terms and background,

If you are interested in geology you will love this book if you are interested in biology you should also read it as background.
A geology student may already be familiar with much of the basic content but still find the concentrated presentation useful, Anyone reading up on continental drift will also be fascinated, What I found many times over to be lacking was photos and maps, Photos of the mountain ranges, stromatalites and fossil tracks of early creatures, Photos, surely, of some of the geology professors, Maps of where the continents used to lie and how they might have girdled the equator, Instead we get a couple of contrasting expeditions the author undertook with professors one in African bush where she got lost and one on a cold, rainy sea peninsula cliff where she huddled with a group to look for fossils.
We have to thank the universities for funding this research by so many people over so many years, I don't want to mark down the rating for the lack of maps and photos, which can probably be hunted for on the net, but if a future edition is being published they would be a big help.
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