Destaque para a coluna What's New do físico Robert Park:
HELIUM CRISIS: THE WORLD IS RUNNING OUT OF HELIUM.
Physicists, it must be acknowledged, have a certain reverence for "helium," the second element in the periodic table, without which the 20th century revolution in physics would never have taken place. There is no substitute and the supply is nonrenewable. Helium exists on Earth today only as a product of radioactive decay of heavy nuclei in the crust of our nascent planet. It accumulated in the same underground geologic formations that trap natural gas (methane). At a maximum concentration of 2.7%, natural-gas wells represent the only practical large-scale source of helium. North America has more helium than any other region of the world, but is also by far the biggest consumer. When it's gone, it will be gone forever – unless we succeed in generating power by deuterium fusion. In that case helium may again be abundant, but that day is a long way off. In 1925 a Federal Helium Reserve was created in Amarillo, TX as a strategic supply of gas for airships. By the 1950s helium had become essential to electronics development but huge amounts were being squandered by NASA on low priority tasks such as purging the fuel tanks of shuttle rockets. However, most members of Congress remain unaware of its use for anything other than inflating party balloons. Over the objections of the American Physical Society, which urged an increase in the helium reserve, the 1996 Helium Preservation Act ordered the Interior Department to liquidate the Federal Helium Reserve by 2015. What then?
Robert Park
Sem comentários:
Enviar um comentário