Feb. 24th, 2006

rfmcdonald: (Default)
Advances in radiocarbon dating means, among other things, that the age fossils dating back to the Ice Age has been significantly underestimated.

Two Neandertal fossils excavated from Vindija Cave in Croatia in 1998, believed to be the last surviving Neandertals, may be 3,000-4,000 years older than originally thought.

An international team of researchers, including Erik Trinkaus, Ph.D., the Mary Tileston Hemenway Professor of Anthropology in Arts & Sciences, has redated the two Neandertals from Vindija Cave. The results were published in the Jan. 2-6 early edition of the journal Proceedings of the National Academy of Sciences (PNAS).

Other scientists involved were Tom Higham and Christopher Bronk Ramsey of the Oxford University radiocarbon laboratory, Ivor Karavanic of the University of Zagreb and Fred Smith of Loyola University.

The resultant ages are between 32,000-33,000 years old, and perhaps slightly older.

In 1998, the fossils had been radiocarbon dated to 28,000-29,000 years ago.

As points out, this advance has certain implications for the coexistences of homo sapiens sapiens and homo sapiens neandertalensis, i.e. that there might not have been much coexistence.

Rather than taking some 7,000 years to colonize Europe from Africa, the reinterpreted data shows the process may only have taken 5,000 years, scientist Paul Mellars from Cambridge University said in the science journal Nature on Wednesday.

"The same chronological pattern points to a substantially shorter period of chronological and demographic overlap between the earliest ... modern humans and the last survivors of the preceding Neanderthal populations," he wrote.

The reassessment is based on advances in eliminating modern carbon contamination from ancient bone fragments and recalibration of fluctuations in the pattern of the earth's original carbon 14 content.

Populations of anatomically and behaviorally modern humans first appeared in the near eastern region some 45,000 years ago and slowly expanded into southeastern Europe.

Previously it was thought that this spread took place between 43,000 and 36,000 years ago, but the re-evaluated data suggests that it actually happened between 46,000 and 41,000 years ago -- starting earlier and moving faster.

We didn't co-exist for long, it seems.
rfmcdonald: (Default)
Tau Ceti is a star some 11.9 light years away from our Solar System, one of the twenty closest star systems excluding undiscovered solitary brown dwarves. A solitary yellow dwarf--indeed, a prototype of this class of star--Tau Ceti has long featured prominently as a potential home for life, whether human colonial or indigenous. The fact that Tau Ceti is substantially older than our Sol does mean that it has fewer of the heavy elements needed to produce rocky worlds like our own, but conversely the age of the star gives life more time to develop. Tau Ceti seemed attractive.

This changed when astronomers discovered that Tau Ceti's Oort cometary cloud is ten times denser than Sol's. Even if everything was equal, this would suggest that any hypothetical rocky planets orbiting Tau Ceti would be substantially more likely to be targets of devastating cometary impacts. As [livejournal.com profile] james_nicoll has pointed out in two postings (1, 2), things are not equal, with two stars--UV Ceti and YZ Ceti--bordering on the fringes of Tau Ceti's Oort cloud, ready to nudge comets into collision courses with planets at a high frequency. Best look elsewhere for the aliens, it seems.
rfmcdonald: (Default)
I couldn't help but notice the construction last year that built Ginger (546 Church Street), since this new Vietnamese restaurant took over the location of the famous but now-closed Second Cup at Church and Wellesley, including "The Steps" and all. It wasn't until this evening, hungry and flush with cash, that I actually managed to eat there.

Although Ginger has a large sit-down area, it seems to be geared towards take-out. When I sat down at five o'clock to enjoy my pho oxtail and halved beef balls, I was the only one. The $6.95 price tag was pricy, typical of the items on their menu, but I can't complain about the size of the serving, or of the quality of the fresh pho full of meat and mint. It's just embarrassing that it took me so long for me to figure out that my chopstick skills still aren't good enough to let me strain noodles out of soup without significant splashage.
rfmcdonald: (Default)

Ronald H. Lee's New Oxford Review essay "The Truth About the Homosexual Rights Movement" is one of the saddest essays I've read in a while. My personal experience doesn't match his at all, quite the contrary in fact. Without said movement, the odds that I'd have made it from my 22nd to my 23rd birthday would have been rather disturbingly low.
Page generated Sep. 24th, 2017 10:24 am
Powered by Dreamwidth Studios