by Michael Erlewine
- Star Lives
- StarLives.jpg (90.7 KiB) Viewed 169 times
Over the centuries, astrologers have taken note of a handful of fixed stars and a few other celestial objects. In the 20th Century, the advent of more and more powerful telescopes, made it clear that there are literally billions of objects out there, each with some kind of significance. There is no way each of these objects could be individually studied and their influences (or lack thereof) noted.
In fact, many astrologers find the recent advances in astronomy and astrophysics over the last 40 years complex and difficult to understand. And yet it could be important for us to grasp the significance of what is being discovered out there in deep space. In this article, we will attempt to provide astrologers with a key to unlocking the mysteries of modern astrophysical inquiry.
I have been repeatedly asked to explain what all this deep-space astrology (stars, black holes, etc.) means. My answer is that it is far easier for you to learn to read and interpret the results of scientific astronomers than to look for someone to explain the endless series of newly discovered stellar objects to you, one by one. It should be enough to be told that everything out there has to do with the life and death of stars, just as down here we are concerned with our own life and death. That note plus the age-old maxim "As Above, So Below," should do it for you. Learn to read science in terms of your own self and life. It is not hard and it opens up the world of scientific writing to you, from that moment forward. You don't need an interpreter. You are the interpreter.
Any investigation of our universe becomes the story of the stars. Aside from dust and gas, space contains stars. Even such exotic objects as pulsars, neutron stars and black holes are but the end stages in the lives of stars. Almost all of the information assembled through various branches of astronomical observation, be it visual, infrared, ultraviolet, x-ray or Gamma-ray may best be examined in terms of the following question: What stage in the life history of a star do they describe? Therefore, a grasp of the basic stages in the life history of a star provides the essential framework for astrophysical inquiry.
It is difficult, perhaps impossible, to consider the various stages of a star's life and the sequence of these stages, without being struck by the resemblance to our own life story. Here is our own life story acted out on a grand scale before our very eyes.
It is now considered fact that the birthplace of stars is the womb of vast nebular clouds of dust and gas distributed throughout space. In these relatively cool and dark clouds, proto-stars (new stars) form through a process of gravitational condensation or contraction. It is imagined that perhaps some outside force, maybe in the form of gravitational energy from a passing stellar object, causes a dust cloud to begin the contraction process. These huge clouds are known to be of various densities. They contain spots where the gas and dust is somewhat denser than in the surrounding regions of the cloud. These denser areas attract still more material toward themselves until a huge amount of matter, many times the size of our solar system, is formed. The contraction process becomes critical -- nothing within the protostar can stand up to the crushing weight of gas and dust that continues to accumulate. A crisis is reached.
Through a friction-like process, the ever-increasing pressure and density inside the proto-star causes the temperature to rise in the star's center or core until a thermonuclear reaction is initiated at 10 million degrees. Such a reaction releases enormous radiant energy that pulses out from within and holds back or stops the contraction process. A star is born!
From this point forward, the life story of a particular star is dependent upon the mass of the original protostar. The collapse of the protostar takes a relatively short portion of the star's life, and once the thermonuclear ignition takes place, the star's surface temperature rises rapidly, and then levels off, and the star settles down to about ten billion years of being a star in the common sense of the word. It is important, at this point, to examine the struggle going on within the stellar interior.
Once born, the star must live and die, much like us. The death of stars is inevitable and the life process is often conceived as one of thwarting or putting off of this inescapable death and thus prolonging life. The most fascinating aspect of a star's life is the intense struggle between the forces of gravity and contraction on one hand (so called outer forces) and the internal forces of radiation pressure on the other. As long as there is radiation coming from within, the forces of gravitational contraction are resisted or balanced, and stellar life as we observe it continues. The star shines. In fact, the entire life of the star can be conceived of in terms of a continuous conversion process. Figure B shows how these two archetypical forces form the stellar shell, which is well below the actual surface of the star itself. The thickness of this shell as well as its position near to or far from the inner stellar core suffers continual change and adjustment throughout the life of the star.
The incredible weight of the many layers of gas first initiates and than continues to contain and maintain the radiant process -- a cosmic crucible. This pressure and the inevitable collapse that must occur is forestalled and put off by an incredible series of adjustments and changes going on within the core of the star. First of all, hydrogen burning (initiated at the birth of the star) continues for around ten billion years. This constitutes a healthy chunk of the stellar lifetime. Our sun is about halfway through this stage at present, and we can expect the sun to continue as it is today for another five billion years or so. The exhaustion of hydrogen signals the onset of drastic changes in the life of the star and brings on the next stage of that life.
The radiant pressure of burning Hydrogen within was all that held back the initial contraction of the protostar, and when this is gone, the star's core continues to contract. It then has no material strong enough to stop this contraction and the core again shrinks, causing increased pressure, density and temperature. When the temperature at the center of the star reaches l00 million degrees, the nuclei of helium atoms (products of the Hydrogen burning stage) are violently fused together to form carbon. The fusion of this helium burning at the stellar core again produces a furious outpouring of radiant energy, and this energy release inside the star's core (as the star contracts) pushes the surface far out into space in all directions. The sudden expansion creates an enormous star with a diameter of a quarter of a billion miles and a low surface temperature between 3,000-4,000 degrees -- a red giant.
In about five billion years, the core of our sun will collapse while its surface expands. This expansion will swallow the earth and our planet will vanish in a puff of smoke. Figure C. shows a red giant. The red stars like Antares and Arcturus are examples of this stage and this kind of star.
This helium burning stage (red giant) continues for several hundred million years before exhaustion. With the helium gone, the contraction process again resumes and still greater temperatures, densities, and pressures result. At this point, the size or mass of the star begins to dictate the final course of the life. For very massive stars, the ignition of such thermonuclear reactions as carbon, oxygen, and silicon fusion may take place, creating all of the heavier elements. These later stages in stellar evolution produce stars that are very unstable. These stars can vary or pulsate in size and luminosity. In certain cases this can lead to a total stellar detonation, a supernova.
A star may end its life in one of several ways. When all the possible nuclear fuels have been exhausted, all conversions or adjustments made, the inexorable force of gravity (the grave) asserts itself and the remaining stellar material becomes a white dwarf. As the star continues to contract, having no internal radiation pressure left, the pressures and densities reach such strength that the very atoms are torn to pieces and the result is a sea of electrons in which are scattered atomic nuclei. This mass of electrons is squeezed until there is no possible room for contraction. The resulting white dwarf begins the long process of cooling off.
Becoming a white dwarf is only possible for stars with a mass of less than 1.25 solar masses. If the dying star has a mass that is greater than this limit, the electron pressure cannot withstand the gravitational pressure and the contraction continues. This critical limit of l.25 solar masses is termed the Chandrasekhar Limit after the famous Indian scientist by that name.
To avoid this further contraction, it is believed that many stars unload or blow off enough excess mass to get within the Chandrasekhar Limit. The nova is an example of an attempt of this kind. In recent years it has become clear that not all stars are successful in discarding their excess mass, and for them a very different state results than what we find in the white dwarf. We have seen that the electron pressure is not strong enough to halt the contraction process and the star gets smaller and tighter. The pressure and density increase until the electrons are squeezed into the nuclei of the atoms out of which the star is made. At this point the negatively charged electrons combine with the positively charged protons and the resulting neutron force is strong enough to again halt the contraction process and we have another type of stellar corpse: a neutron star.
We have one further kind of `dead' star. There is a limit to the size of star that can become a neutron star. Beyond a limit in mass of 2.25 solar masses, the degenerate neutron pressure cannot withstand the forces of gravity. If the dying star is not able to eject enough matter through a nova or supernova explosion and the remaining stellar core contains more than three solar masses, it cannot become a white dwarf or a neutron star. In this case there are no forces strong enough to hold up the star and the stellar core continues to shrink infinitely! The gravitational field surrounding the star gets so strong that space-time begins to warp and when the star has collapsed to only a few miles in diameter, space-time folds in upon itself and the star vanishes from the physical universe. What remains is termed a black hole.
It should be clear at this point that all of the many kinds of stars and objects in space could be ordered in terms of the evolutionary stage they represent in the life of the star. Just as each of us face what has been called the "personal equation" in our lives, so each star's life is made possible by the opposing internal and external forces. In the end, it appears, the forces of gravity dominate the internal process of adjustment and conversion that is taking place, just as in our own lives the aging of our personal bodies is a fact. And yet fresh stars are forming and being born, even now. The process of life or self is somehow larger than the physical ends to the personal life of a star or a man and our larger life is a whole or continuum and continuing process that we are just beginning to appreciate. Some of the ideas that are emerging in regard to the black hole phenomenon are most profound and perhaps are the closest indicators we have of how the eternal process of our life, in fact, functions.
In conclusion, a very useful way to approach the fixed stars, as we pointed out above, is to determine what stage in stellar evolution a particular star may be. Is the star a young, energetic newly formed star in the blue part of the spectrum or an old dying (red colored) star? Are we talking about a white dwarf or a super dense neutron star? I have found this approach to the endless millions of stars to much more helpful than ascribing particular characteristics to existing stars and objects, most of which are too new to have any history in astrology anyway. As mentioned earlier, learn to read the writings of science from a personal or astrological perspective. It is very instructive.
