July 2005

The San Francisco Chronicle is reporting on a new hypothesis for why the Earth has been subjected to various ice ages in its past. Theorists have proposed that when our solar system passes through a spiral arm, the cosmic rays fall to Earth and knock electrons off atoms in the atmosphere, making them electrically charged, or ionized. Since opposite electrical charges attract each other, the positively charged ionized particles attract the negatively charged portion of water vapor, thus forming large droplets in the form of low-lying clouds. In turn, the clouds cool the climate and trigger an ice age — or so theorists suggest.

I picked this up via MetaFilter. This is a photo gallery titled “Stones of the World” and isn’t so much about geology as it is about the human use of stone in various countries through time. It’s a picture of monuments, temples, statues and carvings. Definitely some interesting pictures and shows how geology has played a part in the development of civilization, whether actively studying geology or not.

Space.com is reporting that a study to be published in the July 22nd issue of Science by Caltech graduate student David Shuster and MIT assistant professor Benjamin Weiss shows that Mars has been a cold planet for much longer than we’ve previously thought. They came to this conclusion by analyzing gas contained in meteorites from Mars. A new study of gas in meteorites suggests Mars was bitterly cold for pretty much all of the past 4 billion years, putting the freeze on hopes that the red planet had any extended wet periods during which life could have flourished. Several rocks that were once near the surface of Mars, and have in the past few million years been kicked up by impacts that sent them to Earth, have been freezing cold for most of the past four billion years, the study concludes. [...] “Our research doesn’t mean that there weren’t pockets of isolated water in geothermal springs for long periods of time, but suggests instead that there haven’t been large areas of freestanding water for four billion years.”

In a new study to be published in the July 21st issue of Nature, researchers from the Carnegie Institution of Washington have discovered that the seismic properties of the mantle aren’t as simplified as originally thought. Experiments show anomalies in waves moving through a region of the lower mantle. “Until this research, scientists have simplified the effects of iron on mantle materials. It is the most abundant transition metal in the planet and our results are not what scientists have predicted,” he continued. “We may have to reconsider what we think is going in that hidden zone. It’s much more complex than we imagined.” The crushing pressures in the lower mantle squeeze atoms and electrons so closely together that they interact differently from under normal conditions, even forcing spinning electrons to pair up in orbits. In theory, seismic-wave behavior at those depths may result from the vice-gripping pressure effect on the electron spin-state of iron in lower-mantle materials.

Another article from back in June, this time posted by New Scientist. Basically, it talks about a concept for astronauts wearing spacesuits with “geology skills built in.” The prototype consists of a hand-held video camera connected to a wearable computer, but later versions may link the camera to a head-up display within an astronaut’s visor [...] the prototype flags up anything a geologist might find interesting, based on its unusual or distinctive appearance [...] The team tested the system in Guadalajara province in central Spain, using it to scout for evidence of sandstone beds deposited by water. The system agreed with human geologists 68 per cent of the time. That’s funny. Sometimes I feel that’s about how often I agree with my geology professors on exams.