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10/23/2008
Commitments
I’ve watched the TV show "Sunday Morning" since its inception many years ago. This long-term relationship has lasted primarily because the show deals mostly with topics that inform and leave one feeling better about the world. This past Sunday’s show was about animals, including animal intelligence. Some of the intelligent animals and scientists on the program were ones I have written about in these columns. The elephant who recognizes itself in the mirror was one of the animals on the program.
Another long-term relationship has been with the Star-Ledger, our New Jersey newspaper that I cite frequently. As with many papers recently, the Star-Ledger has been in financial difficulty and the owners have threatened to sell the paper or cease publication, a most distressing possibility. For example, the October 19 Star-Ledger had two articles dealing with long-term relationships, one of which could be relevant to why I’ve been married to my wife for over 57 years! The other article concerned an 8-year long mapping project of unimaginable scope.
Let’s start with my long-term marriage. Given today’s high divorce rate and even the ignoring of the institution of marriage by many couples, marriages of 50 or 60 years are an endangered species. Could it be that those who stay together do indeed have what’s often called the "right chemistry". The Star-Ledger article by Denise Gellene deals with a recent study of a mouse-like rodent known as the prairie vole. Researcher Larry Young at Emory University and colleagues at Emory and the University of Regensburg in Germany have looked at the behavior and the brain chemistry of voles that have been separated from their mates.
Unlike some other types of voles, which lead quite uncommitted social lives, the prairie voles form lifelong monogamous relationships with their mates. Surprisingly, this formation of a close bond actually changes the chemistry of the vole’s brain. Young and colleagues have previously looked at effects in voles of such chemicals as the well publicized oxytocin. The work described in Gellene’s article concerns the formation of a particular chemical in the brain that fosters loyalty to the mate. This "loyalty" chemical , known as a corticotropin-releasing factor (CRF), is also found in our human brains. While CRF is good in that it promotes loyalty, it seems that too much CRF in the brain leads to depression.
The researchers separated male voles from their mates and found that the males showed signs of depression, acting as if they no longer cared about what happened to them. Placed in a pool of water, for example, they didn’t try to swim but just floated in the water. Or, if they were hung by their tails, they just hung there, not attempting to struggle. There were changes in the brain, as the researchers found when they killed the voles and sampled sections of their brains. Sure enough, in the depressed animals they found elevated levels of CRF.
The researchers also tried giving some males separated from their mates a drug that suppresses the formation of CRF. These voles behaved normally, not depressed. Could the old saying "absence makes the heart grow fonder." just be due to a chemical? OK, we humans are a lot more complex and live more complex lives in a much different culture than the voles. I’m sure our mates would not want to think that our loyalty to them is simply due to a chemical! And I’m positive nobody will want to sacrifice themselves to have their brains analyzed for CRF just to prove a point. Nevertheless, there is some work going on in the pharmaceutical arena on drugs affecting CRF as possibilities for control of depression.
Enough about depression. Let’s turn now to something truly inspiring, that 8-year mapping project, the Sloan Digital Sky Survey (SDSS). certainly one of the most awesome projects ever attempted. I’m sure that I’ve mentioned some results of this survey in some past column or columns. If not, I’ve been remiss. The other Star-Ledger article, by John Johnson Jr., is headlined "A map of the universe, eight years in the making". In essence, the object of the SDSS was to make a three-dimensional map of the visible universe, or at least of a substantial portion of the visible universe. The SDSS was the brainchild of Princeton astrophysicist Jim Gunn. The idea was to locate and pinpoint the distance from Earth of the visible celestial objects in a substantial portion of the sky. With such a "map", one could start here on Earth and take a virtual trip out through space passing stars, galaxies, quasars and even supernovae as you traveled out billions of light-years in space. The SSDS began in 2000 and ended in July of this year, 2008.
For his article, Johnson interviewed a number of astronomers who actually monitored the images revealed by the SDSS 96-inch telescope at the Apache Point Observatory in Sunspot , New Mexico as it scanned successive patches of the sky night after night. The patches of sky were about the size of 8 full moons. One astronomer, Stephanie Snedden, told of watching fuzzy blobs floating by on the screen and chills going down her spine, realizing these blobs were each galaxies with billions of stars like our own Milky Way galaxy. According to the Ledger article, in the 8 years of operation, SDSS has looked at some 800,000 galaxies!
The SDSS used a 125-Megapixel camera to gather the images and spectroscopes to measure the color of the images. Remember the red shift? Edwin Hubble showed nearly 80 years ago that the farther away a star or galaxy, the more the color shifts towards the red portion of the spectrum. So, measuring the "color" is equivalent to measuring the distance. Jim Gunn has apparently continued to be the guiding light for SSDS since its inception and is rightly proud of the results of SDSS. With over a quarter of the sky covered, he is quoted on the SDSS Web site as saying, "Visible light is where we understand the universe best, but when we began the SDSS, there were no sensitive, well characterized, visible light catalog that covered a large area of the sky. Now we have multi-color images of 300 million celestial objects, 3-dimensional maps and detailed properties of well over a million of them, and it’s all publicly available online. That changes everything." That’s one impressive "map"!
In addition to the huge number of galaxies, SDSS has mapped a hundred thousand quasars, the brightest objects in the universe. Quasars are huge black holes, up to 10 billion times the mass of our sun, sucking in hot gas. The SDSS also includes another very important project, to discover and quickly report the existence of Type 1a supernovae. These supernova explosions are the "standard candles" used to measure distances and expansion of the universe. These supernovae played a key role in the discovery that the universe is speeding up, thanks to the mysterious dark energy. Because their brightness and light decay properties are so alike in their patterns, if one can catch them in the earliest stages, astronomers around the world can zero in on them, make their measurements and get a good idea of the distance from Earth. To catch them, the SSDS focuses on one area of the sky and monitors the same area repeatedly every couple of days to spot any new brightening indicative of a supernova. They’ve found about 500 Type 1a supernovae that have been caught early, in addition to many other supernovae of different types and in more advanced stages of decay. Something’s blowing up all the time in our universe!
I said the SDSS ended in July. But the work is far from over. A new phase of SDSS began almost immediately and work is already underway to understand our own Milky Way in greater detail, to study dark energy, to study galaxy clusters and dark matter and to study the "wobble" of stars looking for evidence of planets. I’m amazed at what this one Earth-bound telescope has been able to achieve. As I’ve been writing this, I’ve become reasonably sure I’ve mentioned in some earlier column a key experimental detail responsible for the success of the SDSS.
The old fashioned way of carrying out such a project would have been to take photos of the night sky and laboriously scan them for the individual objects. I assume these would then be matched up with the spectroscopic data to determine the color and distance of each object. In the SDSS, the astronomers could actually look at up to 640 individual objects at once. They did this by having aluminum plates drilled with holes in a pattern matching the positions of the objects to be studied. The light from the telescope was passed through this aluminum "mask" so the light from each star, galaxy or other object passed through a given hole. Each hole was "plugged" with a light sensitive fiber. In this way, the light from each of the 640 objects was neatly separated out for detection and storage of the individual sets of data and computer analysis.
According to the Ledger article, the procedure went as follows: each morning scientists at the University of Chicago sent out instructions as to which objects they wanted studied. The appropriate holes were drilled at the physics lab of the University of Washington and the aluminum plates then sent to Apache Point in New Mexico to be plugged with the light-sensitive fibers. Some 3,000 aluminum plates were involved. To keep the work manageable, "only" some 1.4 million objects were chosen for this treatment!
Last night we watched Nova and its most interesting program on Hugh Everett’s parallel worlds. If indeed I exist in some other unimaginably distant world, I hope that in that world I decided to become an astrophysicist capable of understanding the complexities of our universe. OK, you’re right, if my twin has the same feeble brain I have, he might not be up to the task. In that case, perhaps he has decided to be a paleontologist studying evolution, fossils and the like. I think he could handle that.
Allen F. Bortrum
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