Antartic radioactive dating of meteorites

In the upper atmosphere, exposure to cosmic rays can transform a stable krypton isotope into a slow-decaying radioactive isotope.PHOTOS: Using krypton to gauge the age of ancient ice Scientists say that air bubbles in polar ice will contain some of these radioisotopes.Scientists say they have developed a means of accurately dating Earth's oldest and densest polar ice by analyzing the composition of krypton gas trapped within ancient air bubbles.In a study published Monday in the journal PNAS, researchers used the new dating method, called Atom Trap Trace Analysis, or ATTA, to study ice recovered from the Mc Murdo Dry Valleys in Antarctica."The oldest ice found in drilled cores is around 800,000 years old, and with this new technique we think we can look in other regions and successfully date polar ice back as far as 1.5 million years," lead study author Christo Buizert, an Oregon State University paleoclimatologist, said in a statement."That is very exciting because a lot of interesting things happened with the Earth's climate prior to 80,000 years ago that we currently cannot study in the ice core record," Buizert said.The smallest meteorites, called micrometeorites, range in size from a few hundred micrometres (μm) to as small as about 10 μm and come from the population of tiny particles that fill interplanetary space ( The effect of the final impact with the ground of meteoroids about a kilogram or less in mass is usually an anticlimax.The fall can go unnoticed even by those near the impact site, the impact being signaled only by a whistling sound and a thud.Many meteorites are recovered only because at least one fragment of the meteoroid strikes a house, car, or other object that draws the attention of...

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For instance, meteorite fragments have been found in samples returned from the .Think of air bubbles frozen in an ice cube--the air is prevented from escaping by the solid ice, but will escape when the cube melts because the energy of the system is lower without the bubbles.(Further separation could occur during solidification, due to different crystallizations of the parent and daughter isotopes.) This means that the information about how much decay took place prior to melting is lost.Shouldn't the radioactive elements have been decaying for 8 billion, 12 billion years; ever since they were blasted into existence in ancient supernovae?In the solid state, everything is pretty well locked into place, so that relatively few particles can escape.