Miles
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According to Science mag, there are particular genes that code for various mental illnesses, including schizophrenia, depression, and bipolar disorders. These disorders appear to come down to the encoding of particular neuron receptor sites for various hormones and neurotransmitters in various parts of the brain.
The genes associated with clinical depression, turn out to require an external activation. The gene codes for particular neuron receptor sites, which are the same as those targeted by anti-depressant drugs. But the recent key finding was that these sites must be activated in order for the symptoms of depression to be expressed. This activation is accomplished by the overload of hormones and neuro-transmitters associated with prolonged high stress!
The most likely age for this activation by stress is in the early twenties. So there are all the ingredients of both genes and environment: a physical or genetic predisposition that is activated by social conditions.
The above finding scored number two on the most exciting discoveries of 2003 (See Science 19 December 2003, 2038-39p).
Numero Uno, however goes to astronomy where there was a convergence of different projects (cosmic background and super nova studies) that reveal: first of all the universe is flat, meaning there is no global general relativistic curve to space-time; second, the universe is 13.7 billion years old; third, the visible matter and energy composed only 4% of the total matter and energy; fourth, most of the universe is composed of dark matter, and has an anti-gravity like force called dark energy; and fifth, most stunningly, the expansion is accelerating under the influence of dark energy.
The dark matter mentioned here is NOT the ordinary dark matter like intergalactic gas, neutrinos, and other usual suspects that have been proposed for decades. This is a new sort of dark matter whose identity is unknown. So dark matter makes up 23% of the universe and dark energy fills up 73%, leaving us with 4%.
The only description I could find of the mysterious dark energy was that is was supposedly intrinsic to vacuum (duh!), and inversely proportional to matter density per unit volume. In other words the more empty, the more it expands. This is parameterized into a quantity w (value of the equation of state) which if it is a constant proportion will equal -1. If not constant, then w will be somewhere between 0 and -1. At quantities smaller than -1, say -1.1, the universe goes into the Big Rip, where everything flies apart catastrophically at some later period.
If 96% of the universe is made up of dark mass and dark energy about which we know nothing, then one alternate conclusion is that current theory and observation gives us 4% of what we need to know. That seems about right.
The proposals (Science 20 June 2003) for dark matter come mainly from the survey studies that capture everything in a very small window (1/5 degree of arc, about the size of a full moon, containing ~20,000 galaxies!) and show non-uniform bubble like distortions due to weak gravitational lensing of everything in the patch. The proposed cause of this bubbling or weak lens effect is dark matter clumps between each source and us.
The proposals for dark energy come mainly from the super nova surveys that compare redshifts at different age-distances to find that older more distant SNs are less redshifted than expected, while newer and closer SNs are more redshifted than expected. The focus now is on isolating the transition period between a decelerated inflation as gravitational attraction degrades, and the take over of the dark energy era of accelerated expansion. The era of interest is about 4 billion after the BB, or 9 billion years ago.
At the risk of sounding like Mr. Crank Science, it is tempting to say this is all bullshit and reveals profound and unresolvable problems with the entire big-bang cosmology of the Friedman model (non-curved, expanding gas sphere). When it can be shown that 96% of everything is not covered by a theory, isn't it about time to question the theory?
Beyond that intuitive disbelief, there is this. The oldest quasar known (according to google search) has a redshift of z = 6.4, and its light is presumed to be about 13 billion years old. That gives the universe after the big bang less than one billion years to get up and running, and evolved to the state of generating a galaxy with a supermassive black hole and quasar at its center.
Chuck Grimes