October 19, 2017

13.04.10- Mammoth Extinction vs. Impact Theory.

Woolly Mammoths: hunted to extinction?

  

   An Ice Age extinction mystery has just got more complicated. North America used to be home to some amazing mega-animal life, including wooly mammoths, saber-toothed cats the size of grizzly bears, and armadillos the size of Volkswagens. Then, around the time period known as the Younger Dryas about 12,900 years ago, a mass continent-wide extinction event occurred. Key theories include massive climate change, a large cometary impact, and that greatest of all predators, man. Now, research by Jacuelyn Gill of the University of Wisconsin has dealt a blow (pun intended) to the cometary impact hypothesis. Key evidence for a large airburst over the Laurentide ice sheet comes in the form of an iridium layer seen in the sedimentary deposits laid down at the time, as well as the discovery of minuscule nano-diamonds generated by the heat and blast of the explosion. The problem is, Gill’s studies of fungus spores found in fossilized dung finds the extinction event was already underway well before the impact, around 14,000 years ago. In addition, a mastodon skeleton in the Cincinnati museum has been found to have been dated from circa 10,055 years ago, well after the impact! This seems to put the appearance of Clovis man and overhunting as the key to large mammal extinction in the Ice Age North American scene. Perhaps even a combination of the factors was the cause. The concept of the Early Dryas extinction is unique because it is the most recent extinction event (other than the one we’re currently undergoing!) along a timeline of multiple events throughout the history of life on Earth. Being the most recent, perhaps more evidence for complicating factors is simply lying around for us to find. This debate is thus the hottest topic of all large extinction events. And one has to wonder; what would life in modern U.S. suburbia and camping trips be like if there were still saber-toothed cats around?

31.10.09:Daylight Saving Time: Is it Really Worth it?

Tomorrow, at 2AM, astronomers throughout North America can rejoice; daylight saving time (DST) ends for most areas that observe it in Canada and the U.S. as we revert back to ye ole’ standard time. This means observers will no longer have to undergo the long nightly process of sleep deprivation to await dark skies. Indeed, from northern tier states, it can be well past 10pm in mid-summer before its considerably dark! Ah….bring on the darkness. But this also brings up the following is issue….do we REALLY need daylight savings time at all? Allow us to approach the virtual soapbox, if you will. Daylight saving was first famously proposed by Benjamin Franklin and established in the US after World War I. Benefits sited at the time were energy conservation, as well as optimizing daylight hours to coincide with peak productivity periods. These days, public safety is also noted. In 2005, the Energy Policy Act was signed into law by president George W. Bush, rolling daylight saving back even further, currently spanning from the 2nd Sunday in March to the 1st Sunday in November. Granted, this may be way down some people’s lists of enduring offenses committed by the Bush administration, but the damage has been done. This year’s shift represents the earliest that we can potentially “fall back,” as November 1st is a Sunday. In agrarian times, this curious system might have made sense; each local hamlet set its own time, and primary reliance was on sunlight for human activities. But in a global, 24 hour civilization, is this idiosyncrasy for the past really required? Claims of energy savings are dubious; how about smarter night-time lighting policies? Some states, such as Arizona and parts of Indiana have done away with DST all together, and the Apocalypse has yet to rain down on them. In northern areas such as our native Maine and Alaska, DST is sort of a moot point, as the gathering winter darkness always ultimately wins. Let’s say “Down with DST,” in an effort to bring back sanity and our dark skies. Let’s step forward into the 21st century! Anyway, that’s our 2 cents…we here at Astroguyz would do away with all time-zones as well, but that’s another post…see you in Standard Time-land!