Ancient Baby Boom Offers Warning
Washington State Univ. researchers have sketched out one of the greatest baby booms in North American history, a centuries-long “growth blip” among southwestern Native Americans between 500 and 1300 A.D.
It was a time when the early features of civilization — including farming and food storage — had matured to where birth rates likely “exceeded the highest in the world today,” the researchers write in PNAS.
A crash followed, says Tim Kohler, WSU Regents professor of anthropology, offering a warning sign to the modern world about the dangers of overpopulation.
Funded by the National Science Foundation, the study looks at the data from thousands of human remains found over the past century at hundreds of sites across the Four Corners region of the Southwest. While many of the remains have been repatriated, the data let Kohler assemble a detailed chronology of the region’s Neolithic Demographic Transition, in which stone tools reflect an agricultural transition from cutting meat to pounding grain.
Maize, which we know as corn, was grown in the region as early as 2000 B.C. At first, populations were slow to respond, probably because of low productivity, says Kohler. But by 400 B.C., he says, the crop provided 80 percent of the region’s calories.
Sunday, April 5, 2015
Tuesday, March 24, 2015
Solo planets may be surprisingly common | Science News
Solo planets may be surprisingly common | Science News
The first actual observations of what appeared to be free-floating planets came in 2000, suggesting that the simulations were on to something. In the last 15 years, astronomers have stumbled upon about 50 of these planetlike worlds. Some have all the characteristics of planets, minus a parent star. Others raise questions about how stars and planets can form. They all appear to challenge the standard definition of a planet.
It’s time to go beyond serendipitous discoveries, says Michael Liu of the University of Hawaii in Honolulu. He would like to see a systematic search for other untethered worlds.
“A census of rogues,” Liu says, “is the only way we are going to fully understand the extent of what’s out there in the Milky Way.”
Tuesday, May 13, 2014
On Line Images
From NASA:
https://saturn.jpl.nasa.gov/resources/7632/
Spaceship near gas giant.
http://www.renderosity.com/mod/gallery/index.php?image_id=1995914§ion_id=&genre_id=3&page=2&np
High port over an airless waterless planet.
http://www.renderosity.com/mod/gallery/index.php?image_id=1995186§ion_id=&genre_id=3&page=4&np
Spaceship in a nebula.
http://www.renderosity.com/mod/gallery/index.php?image_id=1994932§ion_id=&genre_id=3&page=5&np
Mideivel Tavern (empty).
http://www.renderosity.com/mod/gallery/index.php?image_id=1985344§ion_id=&genre_id=6&page=5&np
Celtic Burial Ground (with Stones)
Medieval musician.
http://www.renderosity.com/mod/gallery/index.php?image_id=1979286
http://www.renderosity.com/mod/gallery/full.php?member&image_id=1983949
Roman/Egypitian Scenes
http://www.renderosity.com/mod/gallery/browse.php?user_id=3033
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