www.tedturner.com/enterprises/home.asp
Since the early 1970's, Ted Turner has stepped into the international spotlight with one accomplishment after another. Whether in billboard advertisement, cable television, sports team ownership, sailing, environmental initiatives or philanthropy – Turner's vision, determination, generosity and forthrightness have consistently given the world reason to take notice. Turner now dedicates his time and resources to making the world a better, safer place for future generations. His current philanthropic interests include: the Turner Foundation, the United Nations Foundation, the Nuclear Threat Initiative, the Captain Planet Foundation, and the Turner Endangered Species Fund. In addition, he remains actively involved in business with the rapidly expanding Ted’s Montana Grill restaurant chain.
Discover-March 2002
Why is So Much Energy Produced When an Atom is Split or Fused?
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Helen Quinn- Stanford Linear Accelerator Center
When you burn a lump of coal, the energy released comes from the rearrangement of electrical bonds that hold the molecules together. In essence, combustion creates a more efficient arrrangement of atoms and liberates the excess energy.
Following Einstein's equation E=mc² , the loss of energy means the total mass of the system decreases: The waste gases and ash at the end are less massive than the innitial coal plus the oxygen consumed from air.
The binding energy of a molecules, however, is so small that the mass changes by just a few parts per billion. In nuclear processes, the energy again come out of the bonds holding particles together, but the strong nuclear force linking the protons and neutrons in the nucleous of an atom is much more powerful than the electromagnetic forces that hold molecules together.
As with molecules, the nucleus is less massive than the sum of the individual constituents. When light nuclei combine or massive ones split apart, the mass drops by a much greater amount, as much as one part in 10,000.
Again, this mass difference can be liberated in the form of energy. So pound for pound, nuclear fuels liberated nearly a million times as much energy as chemical ones do.
http://wesnerm.blogs.com/net_undocumented/2003/09/asperger_syndro.html
Asperger Syndrome
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I recently wrote about my Myer-Briggs INTJ personality, so I thought I might post this. I have never seen this term before until recently.
I went to a psychiatrist recently for mild depression. I had met a woman earlier, who never believed in depression or that she had it, but she took drugs that were prescribed to her, and the effect was enormous--like night and day.
She suggested that I looked into depression medication if there is a remote chance. Since, for one or two months, I found myself with an unusually low level of energy, being unproductive and unable to get work done for reasons I could not explain, I decided to try it out.
I could not even will myself to do the simplest things. I examined my diet, my level of exercise, and air quality of my house. The psychiatrist (the MD, who prescribes medication) referred me to a psychologist (the PhD) for further testing.
I saw on a note a phrase "Pervasive development disorder." Hmm, that doesn't sound good. I went through a battery of tests, to check my intelligence, my memory, my social skills and so on.
I was asked to define words--ordinary and difficult and asked to pronounce some difficult words, too. The psychologist noted that at few times that I accomplished some puzzles faster than anyone has seen. Doing in 30 seconds, puzzles that ordinarily take a minimum of two minutes; I felt happy about that.
But the final review would be different. The psychiatrist took the test results and told me that I had Asperger's syndrome--a sort of high-functioning autism. Huh? The test results showed that I was highly intelligent.
According to the psychologist, if I took an IQ tests, I would be declared at least superior which is consistent with my education and my background. But, that I have a complete disregard for social matters or anything else non-intellectional. I also miss social cues, and have peculiar mannerisms, such as my "rocking." [....]
www.educatedearth.net/story.php?id=841
About Anti-Matter Propulsion
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Antimatter Introduction
I would guess antimatter rockets are what the majority of people think about when talking of rockets for the future. This is hardly surprising as it is such an attractive word for the writers of science fiction. It is, however, not only interesting in the realm of science fiction.
Make no mistake; antimatter is real. Small amounts, in the order of nanograms, are produced at special facilities every year. It is also the most expensive substance of Earth, in 1999 the estimated cost for 1 gram of antimatter was about $62.5 trillion.
It may surprise you to learn that the reality of antimatter is hardly a modern discovery, its existence was predicted back in 1929 and by 1953 Eugen Sanger (a German rocket scientist) had proposed its use for spacecraft propulsion.
The reason it is so attractive for propulsion is the energy density that it possesses. Consider that the ideal energy density for chemical reactions is 1 x 107 (10^7) J/kg, for nuclear fission it is 8 x 1013 (10^13) J/kg and for nuclear fusion it is 3 x 1014 (10^14) J/kg, but for the matter-antimatter annihilation it is 9 x 1016 (10^16) J/kg. This is 1010 (10 billion) times that of conventional chemical propellants!
This represents the highest energy release per unit mass of any known reaction in physics. The reason for this is that the annihilation is the complete conversion of matter into energy governed by Einstein's famous equation E=mc2, rather than just the part conversion that occurs in fission and fusion.
Antimatter As a Propulsion System
Let us not get carried away here though, this is not some incredible new technology that will power us throughout the galaxy. At the most basic level the antimatter rocket is still a Newtonian rocket, governed by the three laws of motion and it still conforms to Einstein's theory of special relativity, in other words it can not exceed the speed of light.
Still if we are enable to develop such a propulsion system in the future it will surely render any other Newtonian rocket obsolete overnight, the system has the highest predicted efficiency, specific impulse and probably the highest thrust to weight ratio.
There does seem to be a serious amount of disagreement over this last point, the general feeling seems to be that the thrust to weight will at least comparable to today's very powerful chemical rockets.
What this means is that only 100 milligrams (1/10 gram) of antimatter would be needed to match the total propulsive energy of the Space Shuttle (all those huge tanks of fuel!). This fact has led to the interesting observation that future advanced spacecraft, such as the antimatter rocket, will not be designed around their propellant tank like conventional craft.
Instead the craft will be designed around the reactors (for nuclear craft) or around the systems and chambers to cause annihilation (for antimatter craft). Radiation shielding will also become a key component of spacecraft design.
So What is This Antimatter Anyway?
Antimatter consists of exactly the same elementary particles as matter, but the electric charge, along with all other quantum numbers, is reversed. For example matter has electrons (negatively charged) and antimatter has positrons (positively charged).
Antimatter does not exist in nature - or at least certainly no where near us, which is just as well. If it did it would immediately annihilate with matter and explode with more force than we have ever experienced. This means we have to manufacture it and then very carefully store it; it is only produced at certain high-energy laboratories around the world (probably most famously at CERN in Geneva).
The actual manufacturing is achieved in a particle accelerator creating extremely high energy collisions, which results in the kinetic energy being converted to matter (subatomic particles), some of which is antimatter.Storage is possible because it may be controlled in magnetic fields, thereby avoiding the obvious problem of trying to store it in structural containers. Production efficiency is extremely poor and collection, storage and handling of antimatter is exceeding complex.
Antimatter Propulsion Systems
Once we have produced and stored the antimatter we can use it in propulsion by releasing it into a chamber and allowing it to annihilate with normal matter which produces its tremendous energy in the form of energetic sub-atomic particles. There are actually two choices for propulsion. Should we choose the proton-antiproton or the electron-positron annihilation?
Well electron-positron annihilation produces high energy gamma rays which are impossible to control, hence useless for propulsion, and on top of this are potentially very dangerous. Whereas the proton-antiproton annihilation produces charged particles (mostly pions moving at velocities close to that of light) that can be directed with magnetic fields, maximising propellant mass.
The fact that there is this mass left over after the annihilation means that the full conversion of mass to energy has not occurred as it does in the electron-positron annihilation, therefore slightly less energy has been produced.
This energy, however, still far exceeds any other method and the resulting particles allow this energy to be harnessed by directing it with magnetic forces.
In other words the perfect reaction does not produce perfect propulsive result. Another important advantage for antimatter rockets over nuclear rockets is that heavy reactors are not required, the reaction is spontaneous. There are four main designs for an antimatter rocket, they are listed here in increasing specific impulse:
- Solid Core - Annihilation occurs inside a solid-core heat exchanger, the reaction superheats hydrogen propellant that is expelled through a nozzle. High efficiency and high thrust, but due to the materials the specific impulse is only 1000secs at best.
- Gas Core - Annihilation occurs in the hydrogen propellant. The charged pions are controlled in magnetic fields and superheat the hydrogen, there is some loss in the form of gamma rays that can not be controlled. specific impulse of 2500secs.
- Plasma Core - Annihilation of larger amounts of antimatter in hydrogen to produce a hot plasma. Plasma contained in magnetic fields, again some loss in form of gamma radiation, the plasma is expelled to produce thrust. There are no material constraints here so higher specific impulse is possible(anywhere from 5,000 to 100,000secs).
- Beam Core - Direct one to one annihilation, magnetic fields focus the energetic charged pions that are used directly as the exhausted propellant mass. These pions travel close to speed of light so the specific impulse could be greater than 10,000,000secs.
The spacecraft will have to be designed to be very long as the annihilation products travel close to the speed of light.
Journey Time
Estimates for travel times to Mars for an advanced antimatter rocket using the beam core approach are anywhere from 24 hours to 2 weeks, it is probable that it will be somewhere inbetween. Compare this to the space shuttle using its conventional chemical propulsion when a trip to Mars would take between 1 and 2 years.
Problems
- Production: we would need at least several milligrams of antimatter to fuel a beam core antimatter engine in local operations and several kilograms for interstellar travel to Alpha Centuri. Given that currently 1-10 nanograms of antiprotons are produced a year at Fermilab (Chicago) and CERN (Geneva), a beamed core engine is not feasible in the near future.
- Storage: the Penning trap has been developed, it is a portable antiproton trap which is capable of storing 1010 (10^10) antiprotons for one week using the superposition of electric and magnetic fields. The next stage is an improvement to 1012 (10^12) antiproton storage. For complete antimatter propulsion it is thought that 1020 (10^20) anti-protons will need to be stored.
Posted by Skywalker on December 31, 2006 at 8:26 am
