For my October 2009 diary, go here.

Diary - November 2009

John Baez

November 1, 2009

Lisa dressed up for Halloween, since we were visiting some friends for dinner: Teresa Toscano and John Laursen. Lisa looked quite spooky in her Pierrot mask and a veil, so I took some pictures. We walked over to our friends' house — and when we arrived, Teresa let out a gasp of shock as she opened the door and saw Lisa's masked face.

Much to our delight, our old friends Gene and Barbara Anderson were also there. In 2005 Lisa and I travelled to Turkey with them, visiting Istanbul and Konya. Gene is an anthropologist with prodigious erudition when it comes to recognizing plant and animal species, cooking medieval dishes, and much more. Barbara is a public health specialist whose idea of good time is taking students on public health tours in the poorest parts of Ethiopia or Cambodia. They'd moved up Seattle after Gene retired from the anthropology department here at UCR and Barbara left Loma Linda to become a associate dean at the the College of Nursing at Washington State University. Now she's retired too, and they're back.

We had dinner as kids came by trick-or-treating... but Lisa did not answer the door and scare the wits out of them.

November 7, 2009

We had an AMS conference at UC Riverside this weekend. On Friday: dinner with Scott Carter and also Scott Morrison and his girlfriend and baby. On Saturday: tons of talks, including my talk on the icosahedron. Then dinner at Tio's, with a huge crowd: I ate with Lou Kauffman, David Radford, Scott Carter, Masahico Saito and Seeichi Kamada. Then some of us went on to the Cigar Bar (smoking not allowed!) and Worthington's. At this point the crowd had shrunk to grad students and postdocs (apart from me) such as Aaron Lauda, David Spivak, Alex Hoffnung and John Huerta. I wisely quit at midnight, while some carried on eating pizza and playing pool at Worthington's. Sunday: lots more talks. At lunch I finally met Kevin Walker, and we talked with Justin Roberts, Yael Fregier, Chris Rogers, and also a bit with Vasily Dolgushev.

Categorification is getting really popular.

November 11, 2009

Long hidden in a Swiss bank vault, Carl Jung's Red Book is now available:

Quoting the latter:
He later would compare this period of his life — this "confrontation with the unconscious," as he called it — to a mescaline experiment. He described his visions as coming in an "incessant stream". He likened them to rocks falling on his head, to thunderstorms, to molten lava. "I often had to cling to the table," he recalled, "so as not to fall apart".

Had he been a psychiatric patient, Jung might well have been told he had a nervous disorder and encouraged to ignore the circus going on in his head. But as a psychiatrist, and one with a decidedly maverick streak, he tried instead to tear down the wall between his rational self and his psyche. For about six years, Jung worked to prevent his conscious mind from blocking out what his unconscious mind wanted to show him. Between appointments with patients, after dinner with his wife and children, whenever there was a spare hour or two, Jung sat in a book-lined office on the second floor of his home and actually induced hallucinations — what he called "active imaginations." "In order to grasp the fantasies which were stirring in me 'underground,'" Jung wrote later in his book Memories, Dreams, Reflections, "I knew that I had to let myself plummet down into them". He found himself in a liminal place, as full of creative abundance as it was of potential ruin, believing it to be the same borderlands traveled by both lunatics and great artists.

Jung recorded it all. First taking notes in a series of small, black journals, he then expounded upon and analyzed his fantasies, writing in a regal, prophetic tone in the big red-leather book. The book detailed an unabashedly psychedelic voyage through his own mind, a vaguely Homeric progression of encounters with strange people taking place in a curious, shifting dreamscape. Writing in German, he filled 205 oversize pages with elaborate calligraphy and with richly hued, staggeringly detailed paintings.

November 15, 2009

Jim Stasheff pointed out some really cool images of Mars taken by the High Resolution Imaging Science Experiment, like these sawtooth patterns in the carbon dioxide ice near its south pole.

November 19, 2009

Remember the Uighur uprising in northwest China? One reason: the old town in Kashgar is being levelled. Kashgar has been an important Silk Road city for at least 2000 years, thanks to its location at an oasis at the western end of the Taklamakan Desert, where the northern and southern routes around this incredibly harsh desert meet.

Map of the Tarim River and Taklamakan Desert.
"Kashi" is another name for Kashgar.

Satellite photo of Taklamakan Desert,
bordered by the Tien Shan range in the north, Kunlun Shan in the south, and Pamir Mountains at west.

Taklamakan Desert

Yak in Kashgar market, photo taken in 1987 by Bernard Gagnon

For more photos of Kashgar, go here, here, and here. I would like to visit the place before it's completely modernized.

I fell in love with the Silk Route and cities in the Taklamakan Desert, like Kashgar, Khotan and Turfan, when I read this book:

You simply must read this you enjoy history, archaeology or adventure stories!

Here are some books by the original European explorers of the Taklaman Desert — the "foreign devils" who dug up and stole the buried archaeological treasures from this land. I'm going to get these, either from the UCR library or interlibrary loan...

I enjoyed Stein's Ruins of Desert Cathay, so I'll probably like these too. You can read a bunch of them online if you click on the links!

Wow — this site is packed with great stuff:

For example, it has a digital archive of rare books including all these books by Aurel Stein: From volume 2 of Stein's Innermost Asia, here's a photo he took of a shrine in Sirkip, which seems to be somewhere in or near the Gobi desert:

November 21, 2009

Together with a number of coauthors, Jacquelyn Gill of the University of Wisconsin in Madison recently uncovered new evidence for the "Pleistocene overkill hypothesis": To help you understand what's at stake here, let me expand a bit on the story I told back in December 1, 2006.

The last Ice Age - the Wisconsin glaciation, began in about 70,000 BC. The glaciers reached their maximum extent about 18,000 BC, with ice sheets down to what are now the Great Lakes. In places the ice was over 1.6 kilometers thick!

Then it started warming up. By 16,000 BC people started cultivating plants and herding animals. Around 12,000 BC, people of the Clovis culture came to the Americas — known by their distinctive and elegant spear tips, called Clovis points:

The culture then broke into several local cultures — the Folsom tradition, Gainey, Suwannee-Simpson, Plainview-Goshen, Cumberland point, and Redstone — roughly around the time of the Younger Dryas cold spell beginning around 10,800 BC. By about 10,000 BC the Ice Age was over, and a warm wet period called the Atlantic began. The first cities in the Old World date to around 7,500 BC; cities in the Americas seem to come much later.

At the time of maximum glaciation, there were three main refuges for life in North America. Biologists call such things "glacial refugia". The first was all the land south of the glaciers, including an "ice-free corridor" just east of the Rocky Mountains. The second was Beringia, a huge region made of what's now Yukon and Alaska, together with eastern Siberia. As you can see, the ocean was lower when more water was frozen up in glacier and the ice caps:

The third was the coastal plain region of eastern America, which is now submerged to form the continental shelf off the coast of New England and Canada. Besides these big refugia, there were also smaller coastal refugia and nunataks - mountains too high for the glaciers to cover them!

What was life like south of the ice sheets near the height of the last ice age? In the eastern half of North America there was tundra and spruce forest. Further west it was drier, except for a belt that got runoff from melting glaciers. West of what is now Minnesota it was too dry for forests - just grasslands. And where the Great Plains now reign supreme, there was a huge area of sand dunes!

There were many large mammals, almost all extinct now — and the mystery of their extinction is what the new paper tackles! Largest of these were the American mastodon and four species of mammoths, only two of which survived to the end of the ice age: the woolly mammoth in the tundra of Beringia, and the much larger Jefferson's mammoth in the central plains and the west. Both these went extinct around 9,000 BC, perhaps killed off by humans. But the ScienceNews article by Sid Perkins says that butchered mammoth bones have been found in Wisconsin archaeological sites dating back to 12,700 BC and 12,100 BC. And bones from butchered mammoths have been found with Clovis spear points in Wyoming and South Dakota.

There were giant beavers, 2.5 meters long and 220 kilograms (485 pounds) in weight. There were also giant ground sloths.

There was also the Mexican horse and western camel, Camelops hesternus:

Recently people have found spearheads dating back to 8,300 BC bearing protein residue from the Mexican horse! Indeed, this horse may have been hunted into extinction. Early Americans also hunted the western camel in Wyoming, as recently as 8,000 BC, which is around when they died out.

Caribou and tundra muskox ranged far further south than they do today. The tundra muskox probably crossed into Beringia around 90,000 BC. There was also a species of woodland muskox, now extinct. The elk, white-tailed deer, mule deer, bison and bighorn sheep that we know today were already widespread. But there were apparently no moose, except in Beringia.

The familiar cougars, bobcats and black bear were already here. Timber wolves were present but uncommon. Grizzly bears reached midlatitude America only after the ice sheets began to melt. But there was also the dire wolf, similar to the modern wolf but bigger and stronger. There was the sabertooth, about the size of a lion, with incredible teeth. There was its smaller relative, the scimatar cat... together with the American cheetah and the American lion, shown here:

All these are gone.

And then, there was the giant short face bear. This was the most powerful predator of the lot: a flesh-eater with powerful jaws, and probably quick on its feet, able to run down prey. It stood 1.6 meters (5.5 feet) at the shoulder. It weighed about 900 kilograms (almost a ton). You would not want to meet one of these:

How did all these animals die out? There are many possible explanations. The most obvious is climate change — until you realize that this latest Ice Age was not the last, and many of these animals seem to have survived through many previous glacial periods and interglacials! On February 13th I mentioned a recently popular theory: a comet collision!

Quoting a bit from the latter:
Something dramatic happened about 12,900 years ago, and the continent of North America was never the same. A thriving culture of Paleo-Americans, known as the Clovis people, vanished seemingly overnight. Gone, too, were most of the largest animals: horses, camels, lions, mammoths, mastodons, saber-toothed cats, ground sloths and giant armadillos.

Scientists have long blamed climate change for the extinctions, for it was 12,900 years ago that the planet's emergence from the Ice Age came to a halt, reverting to glacial conditions for 1,500 years, an epoch known as the Younger Dryas.

In just the last few years, there has arisen a controversial scientific hypothesis to explain this chain of events, and it involves an extraterrestrial calamity: a comet, broken into fragments, turning the sky ablaze, sending a shock wave across the landscape and scorching forests, creatures, people and anything exposed to the heavenly fire.

Now the proponents of this apocalyptic scenario say they have found a new line of evidence: nanodiamonds. They say they have found these tiny structures across North America in sediments from 12,900 years ago, and they argue that the diamonds had to have been formed by a high-temperature, high-pressure event, such as a cometary impact.

However, as you can probably tell from what I wrote above, I consider the most plausible theory to be the Pleistocene overkill hypothesis: namely, that as humans moved into the Americas, they killed off all these large animals. And the new paper by Gill et al seems to support this theory.

Their idea was to look for spores of a fungus called Sporormiella in sediments that accumulated on lake beds in Indiana and New York. This fungus spends part of its life cycle in the dung of large herbivores — for example, these spores have been found in mammoth poop. So, Gill and company argue, the abundance of its spores can be used as a proxy for the abundance of large herbivores!

From this evidence, it looks like their numbers in Indiana began to drop around 12,800 BC. But it wasn't until 11,700 BC that the abundance of Sporormiella had crashed to 2% of its original level. Interestingly, this is when pollen grains from broad-leaved trees such as ash and ironwood began to show up in lake-bottom sediments in substantial numbers. Gill and company argue that this change was a result of the population crash of megafauna that ate the leaves of such trees.

One curious fact is that most sources seem to date the Clovis culture only back to 11,500 BC. According to Gill and company, that seems to be near the end of the collapse of megafauna in America!

Here's one possibility that leaps to my mind: the archaeological record is too sketchy for us to see the Clovis people first showing up around 12,800 BC. And here's another: perhaps the first invading humans belonged to some pre-Clovis culture! There seems to be some evidence for this.

November 25, 2009

Can ants count? Maybe so!

November 29, 2009

Yesterday we had Lisa's friend Lothar over for dinner. He went to Kashgar in October! He said I should go. This got me looking at Taklaman desert tours:

November 30, 2009

Are squares A and B the same color?

Yes! If you don't believe me, look at this, and then read the Wikipedia article about this illusion invented by Edward Adelson of MIT.

For a related illusion, try this.

For my December 2009 diary, go here.

What I see are the current devastation, the frightening disappearances of living species, be they plants or animals. Because of its current density, the human species is living in a type of internally poisonous regime and I think of the present, of the world in which I am ending my days, as this world that I do not love - Claude Levi-Strauss

© 2009 John Baez