Jeanna Bryner
Space.comSun, 16 Sep 2007 15:29 UTC
Wobbles in the rotation of Mars swung the planet into about 40 extreme ice ages in the past 5 million years and allowed thick ice layers to remain far away from the poles, an astronomer says.
Various spacecraft have revealed evidence for ice ages on Mars. Around 4 million to 5 million years ago, precipitation events sent piles of snow and ice that accumulated around the ice caps. Nowadays, the only visible ice on Mars is the pair of polar caps. But in recent years, orbiting probes have found solid evidence for vast sheets of underground ice near the red planet's equator, at what scientists call mid-latitudes.
The extinction of many large mammals at the end of the Ice Age may have packed an even bigger punch than scientists have realized. To the list of victims such as woolly mammoths and saber-toothed cats, a Smithsonian-led team of scientists has added one more: a highly carnivorous form of wolf that lived in Alaska, north of the ice sheets.
Wolves were generally thought to have survived the end-Pleistocene extinction relatively unscathed. But this previously unrecognized type of wolf appears to have vanished without a trace some 12,000 years ago.
The study, which will be published in the June 21 online issue of Current Biology, combined genetic and chemical analyses with more conventional paleontological study of the morphology, or form, of the fossilized skeletal remains. This multifaceted approach allowed the researchers to trace the ancient wolves' genetic relationships with modern-day wolves, as well as understand their role in the ancient ecosystem.
"Being able to say all of those things - having a complete picture - is really unusual," said lead author Jennifer Leonard, a research associate with the Smithsonian Genetics Program, and currently at Uppsala University in Sweden.
In the 1970s, leading scientists claimed that the world was threatened by an era of global cooling.
Based on what we've learned this decade, says George Kukla, those scientists - and he was among them -- had it right. The world is about to enter another Ice Age.
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The eagle screams,
And with pale beak tears corpses. . . .
Mountains dash together,
Heroes go the way to Hel,
And heaven is rent in twain. . . .
All men abandon their homesteads
When the warder of Midgard
In wrath slays the serpent.
The sun grows dark,
The earth sinks into the sea,
The bright stars
From heaven vanish;
Fire rages,
Heat blazes,
And high flames play
'Gainst heaven itself"
R.B. Anderson, "Norse Mythology," 1875
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NASA seems to
spend a lot of time looking for and thinking of ways to divert errant asteroids that might possibly hit earth. However, they keep reassuring the public that the probability of actually being hit by an asteroid is extremely small. So why
all the attention?
When ice ages held Europe in their grip, Africa also felt the pinch - though in a different way.
It has long been suspected that there is a connection between the west African monsoon and climate at higher latitudes - especially over geological timescales, says David Lea at the University of California, Santa Barbara. "But until now, there hasn't been enough supporting evidence." Now Lea, with team leader Syee Weldeab and colleagues, has reconstructed the most detailed history of the monsoon yet, spanning 155,000 years and two ice ages.
A controversial new idea suggests that a large space rock exploded over North America 13,000 years ago.
The blast may have wiped out one of America's first Stone Age cultures as well as the continent's big mammals such as the mammoth and the mastodon.
The blast, from a comet or asteroid, caused a major bout of climatic cooling which may also have affected human cultures emerging in Europe and Asia.
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| A space rock may have exploded in the air over North America
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You may well ask the question, where did the animals and plants of modern day Ireland and Britain come from? Published in the journal, Proceedings of the Royal Society, scientists at Queen's University Belfast have uncovered evidence that stoats survived in Ireland at the coldest point of the last Ice Age, 23,500 years ago.
The research has revealed that despite few animals or plants surviving the millennia of freezing cold and ice, the Irish stoats had real staying power. The Irish lineage of these small carnivores that eat mice, rabbits and birds is unique according to the research.
The scientists reached their conclusions by studying the wiry mammal's DNA collected from museum collections and gamekeepers.
Explaining the research findings, Dr Robbie McDonald, Manager of Quercus at Queen's, explained: "These tenacious carnivores probably survived the extreme cold at the peak of the last Ice Age by living under the snow and eating lemmings, just as they do in Greenland today.
Heavy crop losses have been reported throughout the Southeast after last weekend's frigid temperatures, and farmers are bracing for another expected cold snap next week.
In South Carolina, at least 90 percent of the peach crop was destroyed and officials said Wednesday they would seek federal aid.
"This is comparable to a hurricane," Agriculture Commissioner Hugh Weathers said of the damage to the state's $40 million-a-year industry. "Growers say we'll be fortunate to get 10 percent of a crop."
In Georgia, farmers and agriculture officials were still assessing the damage, but the weekend freeze may have wiped out more than half the state's peach crop.
Courtney Dentch
BloombergTue, 10 Apr 2007 09:35 UTC
The groundhog's prediction for an early spring is proving wrong in New York City, where a cold front has kept temperatures about 7 degrees below the historical average this month, the National Weather Service said.
Just 10 days into April, temperatures have averaged 42 degrees Fahrenheit (5.5 Celsius), about one degree warmer than the average for April 1874, the coldest on record, said Michael Silva, meteorologist with the National Weather Service's Upton, New York, station.
ATLANTA - It may be two weeks into spring, but it's beginning to look a lot like Christmas.
Cold temperatures in much of the country have those celebrating Easter this weekend swapping out frills, bonnets and sandals for coats, scarves and socks. Baseball fans are huddled in blankets, and instead of spring planting, backyard gardeners are bundling their crops.
Comment: And if it happened once, there's no reason why it couldn't happen again. Particularly if these type of events turn out to be cyclic, as the evidence suggests.