Comments on: Snowball Earth

By: Nemo

Nemo — Wed, 06 Jun 2012 02:33:58 +0000

I hope that Walker doesn’t claim that description of ‘deep time’, it’s from John McPhee. He’s restated that many times in books and lectures. Actually he’s kind of famous for it. Check the wiki page on ‘Deep Time’.

By: Martin Vermeer

Martin Vermeer — Tue, 20 Jul 2010 17:25:29 +0000

Snowball Earth is quite the story, isn’ it? I remember hearing about it, on some meeting between sessions, from Dick Peltier, who also has been involved in its study, producing one possible mechanism (involving CO2!) for producing a “slushball Earth” where patches of ocean water called “refugia” remain open for life.

I had to ask “are they really sure that such a thing happened?” and do my own reading up before really believing it… it sounded incredible.

Whether Snowball Earth really was instrumental in the rise of multicellular organisms, remains speculative as I understand. There could be other such coincidences, like our large Moon, and a Venus nearby that was apparently an ocean planet for the first two Gyrs of her history…

By: Byron Smith

Byron Smith — Mon, 19 Jul 2010 14:01:18 +0000

Fascinating book. Thanks for the review.

By: The Ville

The Ville — Mon, 19 Jul 2010 09:50:31 +0000

I knew that it was possible to detect when the magnetic field switched poles, but didn’t know that the direction of the field in the rocks could give an indication where the rocks were formed.

The fingerprints for the switching polarity of the magnetic poles are found on the deep sea beds where the tectonic plates part and result in volcanoes (undersea fault lines). At these locations there are strips of rock formed by the magma like a ‘magnetic’ zebra pattern, each stripe alternates between the two polarities.

eg. when the magma is expelled and the magnetic field is ‘north-south’ a strip of rock with that polarity is produced, then when the polarity changes to ‘south-north’ the next strip of rock has a similar ‘reversed’ polarity, and so on each time it changes.

By: Ken

Ken — Mon, 19 Jul 2010 00:06:10 +0000

That quote from the book sounded familiar but I hadn’t read the book (yet). Turns out Bill Bryson in A Short History of Nearly Everything paraphrased it. I just reread it last week so it was fresh in my mind. I will have to put Snowball Earth on my reading list.

Another book well worth reading is After the Ice Age by E.C. Pielou. Think I’ve read it 4 times now and it is still fascinating. Pielou is another example of a scientist who can communicate well. The book doesn’t deal with climate specifically but deals with what North America looked like as the glaciers retreated, and how we know what it looked like, and how the ecology of the landscape changed over time. It is like a time-travel historical detective story.

By: Colin Reynolds

Colin Reynolds — Sun, 18 Jul 2010 23:04:26 +0000

Makes me feel small, and humble, too. And yet what does Humanity do with this aeons-old legacy? It blows it all away on junk food and go-faster-stripe gizmos. That part makes me feel kind of sick.