All earth science stories

Researchers observe ozone killer

70652986 — Mon, 26 Mar 2007 05:35:41 -0400

Harvard researchers have implicated a particular molecule in the destruction of Earth's ozone layer. The molecule, made up of two chlorine atoms and two oxygen atoms, is called a chlorine monoxide dimer or chlorine peroxide, Cl-O-O-Cl. It has a crucial role in the process by which chlorine destroys atmospheric ozone. Though a variety of chemicals are implicated in ozone loss in the polar winter stratosphere, chlorine is thought to dominate, with a large contribution from bromine radicals. Scientists have been concerned about the impact of man-made processes on the Earth's ozone layer for decades. The ozone layer, a thin band high in the stratosphere, is responsible for shielding the Earth from harmful ultraviolet rays.

Did life originally spring from clay?

70652986 — Mon, 26 Mar 2007 05:21:48 -0400

While the research is a far cry from proving that humans sprang from clay, as some creation myths assert, it does provide a possible mechanism for explaining how life initially arose from nonliving molecules. Researchers at the Howard Hughes Medical Institute and Massachusetts General Hospital showed that the presence of clay aids naturally occurring reactions that result in the formation of fatty sacks called vesicles, similar to what scientists expect the first living cells to have looked like. Further, the clay helps RNA form. The RNA can stick to the clay and move with it into the vesicles. This provides a method for RNA's critical genetic information to move inside a primitive cell.

Earth's birth date turned back

70652986 — Mon, 26 Mar 2007 05:30:43 -0400

Radioactive elements in rocks decay in a predictable way, like the ticking of a well-made clock that can run for millions of years. The decay marks a change in character of the elements; one type of uranium, for example, decays into lead. To measure the age of meteorites, and thereby deteremine the age of Earth itself, Harvard researcher Stein Jacobsen and his colleagues used a radioactive type of hafnium, a rare heavy metal, which decays into tungsten, a more familiar gray-white metal. The ratio of this type of tungsten to a stable variety of the same metal reveals how much hafnium decayed away, or how long the clock has ticked. According to new evidence found in meteorites, our planet is 50 to 90 million years older than previously thought.

Earth's new center

70652986 — Mon, 26 Mar 2007 05:23:50 -0400

The outer core is liquid, the inner core is solid. That's the way Earth has been depicted in textbooks for the past 66 years. But the work of Adam Dziewonski, Frank B. Baird Jr. Professor of Science, and graduate student Miaki Ishii shows that this picture doesn't get to the bottom of things. Engulfed in the inner core, like a pit in a peach, lies a 360-mile-wide inner inner core. This core within a core within a core makes up one ten-thousandth of the Earth's volume. Dziewonski and Ishii patiently examined records of hundreds of thousands of earthquake waves that passed through the center of the planet in the past 30 years to make the discovery. "It may be the oldest fossil left from the formation of Earth," says Dziewonski.