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07/31/2015
Pluto and Plants in your Diet
CHAPTER 59 Pluto and Platonic Poisons
I'm not a fan of "earmarks", typically items slipped into bills by legislators who either want to fund projects benefitting their own districts or to insert an item that they hope will accomplish something other than the main goal of the legislation. However, a front-page article by Kenneth Chang in the Sunday, July 19, New York Times mentioned earmarks proposed by Maryland's Senator Barbara Mikulski and approved by Congress over a decade ago. Those earmarks deserve appreciation for their support of the New Horizons mission that is returning fascinating pictures of Pluto and its moons after flying less than 8,000 miles from the dwarf planet a few weeks ago. Chang's article details the checkered history of the Pluto mission and the Bush administration's attempts to kill the mission by not including money to support it in successive proposed budgets for 2002 and 2003. The earmarks apparently supplied life support for the mission.
Admittedly, Senator Mikulski probably had a "local" reason to propose the earmarks. The Times article described the important contributions to the Pluto mission from the Johns Hopkins Applied Physics Laboratory, located in Maryland. This lab knew how to build spacecraft and worked hard with NASA to come up with a relatively cheap design. I won't go into details of the process but I was intrigued by one obstacle that showed up late in the game. With Pluto being so far away the Sun isn't bright enough to power a spacecraft using solar cells. Instead, the mission would rely on plutonium-generated power, originally set at 220 watts. It turned out Los Alamos had shut down its plutonium oxide production and could only supply 180 watts worth of plutonium. Fortunately, with improved design of the communications equipment and the ultimate delivery of 200 watts worth of plutonium, the mission was set to go and launched in January of 2006. According to Wikipedia, the radioisotope thermoelectric generator (RTG) that generates the power on New Horizons contains 24 pounds of plutonium oxide.
Given my obsession with space-related stuff, I obviously have to write about what New Horizons has reported so far. But wait! Today, July 23, I was having lunch and watching the news when a report came in that NASA had announced that Kepler had found an earth-like planet orbiting a Sun-like star. The New York ABC news commentator jokingly said something to the effect, "Hey, this is just another case of disrespecting Pluto." I didn't catch whether or not the reporter said the planet was in a habitable zone so I've got to disrespect Pluto and check this out now. Excuse me, I'll check my email........ I'm back and, sure enough, there was an email from NASA telling of the finding of the planet Kepler 452b orbiting a G2-type star like our Sun and the planet is indeed in a habitable zone! Kepler 452b is 60 percent larger than Earth but is the smallest exoplanet found to date orbiting in a habitable zone. A year on Kepler 452b is 385 days, not much different from our 365-day year. Its sun is 1.5 billion years older than our Sun and, presumably, any life on 452b has had a much longer time to evolve than here on Earth. Planet 452b is some 1,400 light-years from Earth.
The Kepler data were supplemented by measurements from telescopes in Texas, Arizona and Hawaii to refine the knowledge of the properties of 452b and its star. In addition to the 452b finding, the Kepler team announced an additional 521 exoplanet candidates, bring the total such candidates to 4,696. There are now 1,030 confirmed planets out there beyond our solar system. In the newest batch of candidates there are nine that are between 1 and 2 times the size of Earth that orbit in the habitable zones of stars similar in size and temperature to our Sun. Kepler just keeps on giving and giving.
OK, back to poor upstaged Pluto. It's highly unlikely that there's life on the dwarf planet but that doesn't mean it's not an active place. Look at those mountains some 11 thousand feet high that are thought to be made of water ice. I was most impressed with the mountains but the Pluto scientists seem to be more interested in the relatively smooth plains only a hundred million years old that consist of frozen mix of carbon monoxide, methane and nitrogen. There's geological activity going on in this lonely outpost of our solar system. And the atmosphere surrounding Pluto is rich in nitrogen, as is our own here on Earth.
After writing recently about the odd moons of Pluto, I've been looking forward to some pictures of the critters and was not disappointed. I mentioned that a couple of the moons were shaped like footballs, but the moon Nix is actually more like a jellybean than a football and even has a bit of reddish tint in part of it. Initial speculation is that it might be a crater. The moon Hydra is quite an irregular body, stated by NASA to resemble the state of Michigan!
In another press release on July 24, NASA shows a picture of Pluto backlit by the Sun and wow, there's a bunch of haze! In fact, two distinct layers of haze 50 and 30 miles above the surface. I learned some chemistry from the release. It seems that even out there over three billion miles away, the ultraviolet light from our sun is strong enough to break down methane gas to form such things as ethylene and acetylene plus tholins, compounds that are new to me. Wikipedia tells me that the term tholin was coined by none other than Carl Sagan and a colleague, Bishun Khare, to describe what is termed a "difficult-to-characterize" bunch of compounds that give a reddish tinge to a number of bodies in our solar system. The compounds apparently begin as nitrogen and methane and under conditions reigning in the solar system get reacted and converted in a chain of processes into this bunch of different compounds collectively known as tholins.
New Horizons will be joining Kepler in that the data gathered from both missions will be the subjects of analyses for years to come. The stored data from the Pluto mission will take a year or so to transmit back to Earth so I'm expecting many more exciting images and findings of activity on that disrespected body and its moons.
In my old age, I'm encountering a plethora of terms that I've either forgotten or that are new to me. Tholins, for example. Another one I met recently is "hormesis", the subject of an article titled "What Doesn't Kill You ..." by Mark Mattson in the July issue of Scientific American. Mattson is chief of the Laboratory of Neuroscience at the National Institute on Aging and is a professor of neuroscience at Johns Hopkins University School of Medicine. (As noted above, Johns Hopkins played a big role in the Pluto mission.) My spellchecker doesn't recognize "hormesis" but I found a definition on the Web site of the Merriam Webster Medical Dictionary: hormesis - "a theoretical phenomenon of dose-response relationships in which something (as a heavy metal or ionizing radiation) that produces harmful biological effects at moderate to high doses may produce beneficial effects at low doses." Many years ago, I was on jury duty with a fellow from Bell Labs who was in the nuclear/radiation area. I don't remember his name but I do remember him saying that there was some evidence that we had evolved to be adapted to a small dose of background radiation. Obviously, a large dose will kill us. Hormesis?
Given the above definition, you might be surprised to find that the main thrust of Mattson's article concerns the health effects of eating fruits and vegetables! If you subscribe to as many health-related publications as I do (way too many), you're bombarded with advice to eat lots of fruits and vegetables, with their loads of antioxidants, to counter the effects of free radicals causing all sorts of maladies such as cancer and heart disease. Yet, as Mattson points out, controlled studies of both humans and animals on antioxidants such as vitamins E, C and A have shown that, taken individually, they don't prevent disease or improve health. I recall a study years ago showing smokers who took vitamin E actually were more prone to cancer than smokers who didn't take the vitamin.
Could something other than antioxidants account for the beneficial effects of eating fruits and vegetables? That's precisely what Mattson is saying and, surprisingly, pesticides might be promoting a healthy lifestyle! Over millions of years of evolution, plants have learned to manufacture compounds that are in essence pesticides that discourage insects from eating the plants. Just as we humans have learned not to eat various bitter tasting plants that could do us in, so are insects and other pests turned off by bad tasting stuff that plants have evolved to secrete in their own defense.
Mattson proposes that when we eat fruits and vegetables we eat small amounts of plant-generated pesticides and these small amounts of bad stuff stresses our cells, say in the brain, which is a key subject of Mattson and colleagues' work. We're often told stress is bad but how do we build up muscles? By exercising, stressing our muscle cells, and the muscles respond by becoming stronger. Similarly, if small amounts of pesticides in plants stress our brain cells, for example, these cells become stronger and this hormesis has a beneficial effect. However, if you should isolate this particular "pesticide" and take too much of it, you could harm and might even kill yourself! It's a challenge to determine the optimum amount of the particular chemical and the amount at which the chemical actually does one harm. Can it be that both we and the plants we eat have evolved together to arrive at levels of "poison" that serve both of us well?
I've only touched on the subject matter in the article, which I recommend wholeheartedly. The role of rest after stressing cells by eating fruits and vegetables is also something to consider. You can overdo that exercise and harm those muscles if you don't work in an appropriate amount of rest. After being stressed by the hormetic compounds in the fruits and vegetables, stressed cells need a chance to recover and manufacture proteins that, in the brain for example, can lead to the formation of new neurons with the possibility of increased learning or memory capacity. There are many promising findings on positive hormesis effects but the author points out there is controversy about hormesis and there is need for much more work on the subject. Hormesis could be the wave of the future in fighting such things as Alzheimer's and other diseases.
Finally, in my previous column, I noted the passing of two individuals, Chris Riddleberger and Alvin Salkind, who played significant roles in my transition from life at Bell Labs to retirement and consulting in academia. A few weeks ago, Benjamin James, a professor at Dickinson College, died at the ripe old age of 102. Back in January in my first column of 2015, I wrote at length about Ben James and his significant role in allowing me to enter college without graduating from high school. Another passing of an individual who played an important role in a transition point of my life.
Finally, I want to once again call your attention to an effort by our StocksandNews editor Brian Trumbore to raise funds to help him keep this site afloat. If you wish to contribute, there's a GoFundMe link on the stocksandnews.com site or at the top of this column if you're reading it on a PC. You may also send a contribution to Brian Trumbore, P.O. Box 990, New Providence, NJ 07974.
Next column, hopefully, on or about September 1.
Allen F. Bortrum
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