I've always been fascinated by the migration of green sea turtles. They are found all over ther world, but the ones which nest on Ascension Island in the mid-atlantic, where there is a major nesting colony, then migrate to their feeding grounds off the coast of Brazil. It's a distance of over 2,000 km and the mother turtles make the return journey every few years to the beaches where they were born.
Ascension Island is located on the mid-atlantic ridge, and the foraging grounds for this colony of turtles is at the Eastern extremity of South America at Recife in Brazil. One rather romantic theory for this extraordinary migration is that when the Atlantic was starting to open up, several hundred million years ago the ancestors of the green turtles were to be found in the place where Recife and Ascension Island were very close together. As the sea floor spreading continued, the turtles evolved a mechanism to find their way back and forth as the two places moved apart (and continue to do so) at a rate of about 2cm per year.
Friday 21 September 2007
Friday 7 September 2007
Laser Nuclear fusion could be the answer
So a British- lead team of scientists has won support from the EU to construct an experimental nuclear fusion reactor - which could make nuclear fusion energy a commercial reality within 20 years.
This is the Physicist's dream - unlimited energy with no harmful waste products, from a freely available unlimited resource - hydrogen (from seawater). The worlds most powerful laser would generate the required temperatures of millions of degrees, at which hydrogen burns to form helium, the process which drives the sun.
The fuel would be the heavy isotopes of hydrogen, known as deuterium and tritium. Deuterium can be made cheaply from seawater, and tritium is produces as a by-product in the reactor. When fusion of these isotopes occurs, helium is produced, and a stream of neutrons which release vast quantities of energy in the form of heat.
At the moment, the energy required to start fusion is greater than the energy released. With laser fusion, a powerful laser is directed at a fuel pellet about 2mm across - the pressure compresses the pellet and generates temperatures of tens of millions of degrees. How cool is that?
This is the Physicist's dream - unlimited energy with no harmful waste products, from a freely available unlimited resource - hydrogen (from seawater). The worlds most powerful laser would generate the required temperatures of millions of degrees, at which hydrogen burns to form helium, the process which drives the sun.
The fuel would be the heavy isotopes of hydrogen, known as deuterium and tritium. Deuterium can be made cheaply from seawater, and tritium is produces as a by-product in the reactor. When fusion of these isotopes occurs, helium is produced, and a stream of neutrons which release vast quantities of energy in the form of heat.
At the moment, the energy required to start fusion is greater than the energy released. With laser fusion, a powerful laser is directed at a fuel pellet about 2mm across - the pressure compresses the pellet and generates temperatures of tens of millions of degrees. How cool is that?
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