Dr. Bortrum
01/03/2018
Looking Back a Year and More
CHAPTER 88 Looking Back
Happy New Year! At this time of year I look forward to Discover magazine's choices for its Top 100 science stories of the past year. I personally thought the choice would and should be the detections of the gravity wave and the gamma ray burst resulting from the merger of two neutron stars over a million years ago as discussed in my column posted November 1, 2017. Detection of the wave and the burst led to visual detcction of the event and spectral observations were a gold mine, literally. They showed that an Earth-sized amount of gold was formed in the neutron star merger.
The January/February 2018 issue of Discover has appeared and I was almost right. Number 3 on the list was "Astronomers See and Hear the Cosmos" and was the neutron star merger. I think Discover's choices were affected by the political climate of the past year or so. The number one choice was "America Looks Up", the solar eclipse that traversed America and, as Discover put it, united America in this period of discontent with about 154 million people gathered across the country to witness an astronomical spectacle. I watched it on TV and was enthralled, especially when skies cleared for Al Roker on a naval vessel and they witnessed the full eclipse during a thunderstorm.
Discover's second choice was "Human Evolution Timeline Topples". Being intensely interested in any evolutionary subject I can't quarrel with Discover's choice of various investigations suggesting that we homo sapiens have been around perhaps 100,000 years earlier than previously thought. Politics certainly entered into Discover's number 4 choice - "Science Under Siege But Surviving". The anti-science actions of the Trump administration, beginning with the Paris Accord exit and month by month actions with an anti science bias are detailed. To my knowledge, Trump still doesn't have a science advisor and he certainly needs one, in my humble opinion.
Enough of politics. I was intrigued by Discover's number 38 and 40 choices and the contrast between them. Number 38 was "The Fastest Fluid". I found it unbelievable that this liquid has been to rotate at a sextillion times a second! That's a billion trillion times a second! Oh, what is this liquid? It's either a melted proton or a melted neutron and is the smallest drop of liquid ever seen. Or has it been "seen"? I tried to find out exactly how all this is done but quickly realized that it's way over my head! Let's get back to basics. In contrast to what I learned in college back in the 1940s, a proton or a neutron is not a fundamental particle but is made up of so-called quarks and gluons that help stick the quarks together. When a neutron or proton is melted in an accelerator the result is a tiny drop of QGP (quark gluon plasma). The workers at Brookhaven National Lab have created what was present just after the Big Bang, when the universe was filled with QGPs!
So much for number 38; let's go from something about as small as you can get to Discover's number 40, "A Titan for the Record Books", something I can understand. Researchers have examined a fossil found in Argentina back in 2014 and estimate that this dinosaur grew to about 122 feet in length and weighed about 69 tons, which is about ten times the weight of 10 adult male African elephants! The pictured animal has an exceedingly long neck and tail and you wonder how it managed to hold them up.
Just one more item from Discover's list, number 70, "When Did Life appear?". It seems that two different teams of scientists have found fossils or traces of life in rocks in Canada dating back in the range of 3.8 to 4.3 billion years ago. The little critters were smaller than half the width of a human hair and are thought to have sprung to life in hydrothermal vents formed when comets and asteroids were bombarding Earth in its early days. If these findings hold up it shows that life can arise under most unlikely conditions.
Whoa! I had forgotten that the journal Science at year's end comes out with its Breakthrough of the Year and the December 22, 2017 issue cites "Cosmic Convergence", the neutron star merger, as its choice for 2017. Now I feel vindicated. The issue of Science also contains several papers by scores of workers laying out their findings on the merger. Personally, of the many hundreds of columns I've written for this site, I was most excited by writing about this merger of two stars. When I think about the tremendous amount of money and effort put into the risky LIGO projects in hopes of measuring a gravitational wave generated millions or billions of years ago, I marvel at the courage of those who supported the effort. And just a couple weeks ago we got a Christmas card from a couple whose son is in Italy working on the LISA project aimed at putting a gravity wave detector in space, which I presume will be even more sensitive than the ground-based detectors.
Ok, let's get down to Earth and look back at how we might have evolved to become so smart. Almost every morning, I start off the day with orange juice mixed with a banana in our blender. Naturally, I was taken with an article by Ferris Jabr titled "Mind Blender" in the Sunday New York Times Magazine section of December 17 of last year. I must say that I was a bit turned off when I found out what it was that Suzana Herculano-Houzel was blending - brains! Yuk! Suzana has made brain soup by liquefying the brains of many different animals, including primates and humans. In the process she has upended many beliefs about the compositions of brains, including our own. For example, texts and research papers have cited our brains as being composed of 100 billion neurons and trillions of glia, cells that have been found to have important functions that allow the neurons to do their communicating with each other. Herculano-Houzel has found that our brains contain some 86 billion neurons and about the same number of glia, not trillions.
Before she began her blending experiments in Brazil, the standard way researchers counted numbers of brain cells was to section brains into very thin slices and microscopically count the number of cells in the thin samples. They would then extrapolate this number to the total volume of the brain section they had sliced. Not only is this a very tedious time consuming task but the brain is highly convoluted and extrapolating the data from one thin section is not that reliable a process. Now consider the blender. Take a brain or section of a brain and perhaps add some chemicals and blend it to make a soup of uniform composition. Now take a very small portion of the soup and count the number of nuclei in the small sample. You may have added a chemical to make the nuclei light up or become colored to make the counting easier. Now, because you've made a uniform soup and know the total volume you can extrapolate with confidence to the number of nuclei in the brain or in that section of the brain that you've liquefied.
Well, you can imagine the skepticism with which the research community greeted the findings of a young female scientist in Brazil blending brains! (She's currently at Vanderbilt University.) However, her work after her initial blendings has embraced all manner of animals and she has published surprising results on the densities of neurons in some 80 species. One thing that she found is that we humans have 16 billion neurons in our cerebral cortex compared to 9 billion in the cerebral cortex of orangutans and gorillas and only 5.6 billion in the cerebral cortex of the elephant. This despite the fact that the elephant's brain is three times larger than our own. The Times article is loaded with interesting stuff but I'll just end with one possible theory for why we became so smart.
I may have written about work by Harvard anthropologist Richard Wrangham, who wrote a book titled "Catch Fire: How Cooking Made Us Human". Herculano-Houzel extended the thesis of this book by analyzing how much time and energy our cousins, the great apes, spend foraging for food and how much energy it takes to nourish a brain every day. In our case, our brain occupies only 2 percent of our body but it requires 20 percent of the energy we consume every day. The gist of her work is that, because cooking makes more energy available in a given food source, we humans did not have to spend as much time and energy searching for food as the apes did. Today the apes spend about 8 hours a day looking for food. This allowed us to have the energy available to support a larger brain with more densely populated cerebral cortex cells and our brains grew larger. The gorillas grew larger in size but did not learn how to cook. It's interesting to speculate on what would have happened if they had. The Times article had lots of other interesting stuff but I'm late and will stop here. This column is late because of my being caught up in activities related to my wife's return home after over a month in the hospital and in rehab.
Next column on or about February 1, 2018, hopefully.
Allen F. Bortrum
