Name: The Biologist and the Scientist
From: Davao City, Philippines, Philippines
About me: We are the students of the most prestigious university, that is, the University of the Philippines - Mindanao. We are the the future Biologists, Marine Biologists, Scientist, Doctors - you name it. And most of all, we opt to receive the Nobel Prize in the near future! XD
May proposition dito, nagtanong raw si Ma'am NOVERO kung meron pa talaga sa atin ang may gustong mag major sa Cell and Molecular Biology aka CELL BIO. She is willing to FIGHT for it para sa atin but she NEEDS our support with a SIGNATURE CAMPAIGN. Kung makaabot ng 8 (as in eight, walo..) Strong CHANCE na raw talaga na matuloy ang Cell Bio, para wala nang dissolve2 ng majors. Kung di mag succeed, Eco pa rin tayong lahat.
What do you say?
posted by The Biologist and the Scientist @ 3:25 AM
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Michael Reilly, Discovery News
Jan. 6, 2009 -- It's a classic image from every youngster's science textbook: a cutaway image of Earth's interior. The brown crust is paper-thin; the warm mantle orange, the seething liquid of the outer core yellow, and at the center the core, a ball of solid, red-hot iron.
Now a new theory aims to rewrite it all by proposing the seemingly impossible: Earth has not one but two inner cores.
The idea stems from an ancient, cataclysmic collision that scientists believe occurred when a Mars-sized object hit Earth about 4.45 billion years ago. The young Earth was still so hot that it was mostly molten, and debris flung from the impact is thought to have formed the moon.
Haluk Cetin and Fugen Ozkirim of Murray State University think the core of the Mars-sized object may have been left behind inside Earth, and that it sank down near the original inner core. There the two may still remain, either separate or as conjoined twins, locked in a tight orbit.
Their case is largely circumstantial and speculative, Cetin admitted.
"We have no solid evidence yet, and we're not saying 100 percent that it still exists," he said. "The interior of Earth is a very hard place to study."
The ancient collision is a widely accepted phenomenon. But most scientists believe the incredible pressure at the center of the planet would've long since pushed the two cores into each other.
Still, the inner core is a mysterious place. Recently, scientists discovered that it rotates faster than the rest of the planet. And a study last year of how seismic waves propagate through the iron showed that the core is split into two distinct regions.
Beyond that, little is known. But Cetin and Ozkirim think a dual inner core can explain the rise of plate tectonics, and help explain why the planet remains hotter today than it should be, given its size.
"If this is true, it would change all Earth models as we know them," Cetin said. "If not, and these two cores coalesced early on, we would have less to say, but it could still be how plate tectonics got started."
Based on models of Earth's interior, Cetin thinks the two cores rotate in opposite directions, like the wheels of a pasta maker. Their motion would suck in magma from behind and spit it out in front. If this motion persisted for long enough, it could set up a giant current of circulation that would push plates of crust apart in front, and suck them down into the mantle in back.
Friction generated by the motion would keep the planet hot.
Scientists asked to comment on this hypothesis were extremely skeptical. Some asked not to be quoted, citing insufficient evidence to make a well-reasoned critique of the study, which the authors presented last month at the fall meeting of the American Geophysical Union in San Francisco.
"In terms of its volume, and even its mass, the Earth's inner core is quite small relative to the whole planet, about 1 percent," Paul Richards of Columbia University said. "I seriously doubt that inner core dynamics could play a significant role in moving the tectonic plates."
posted by The Biologist and the Scientist @ 7:55 PM
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Dec. 12, 2008 -- It was a dying on a scale never seen before or since on Earth. The slaughter was everywhere; the fertile ocean and balmy supercontinent Pangea were transformed into killing fields, littered with the bodies of ancient animals. By the time the dust had settled on the Permian-Triassic mass extinction 250 million years ago, 90 percent of life on the planet had been snuffed out.
Now a new theory suggests the catastrophe was set in motion 15 million years earlier, deep in the Earth. On the edge of the molten outer core, a plume of super-hot material began rising through the mantle, upsetting convection in the core and throwing the planet's magnetic field into disarray.
The weakening of Earth's magnetic field exposed the surface to a shower of cosmic radiation, says Yukio Isozaki of the University of Tokyo. He believes the radiation broke nitrogen in the atmosphere into ions that acted as seeds for clouds enshrouding the planet.
"This would've caused severe cooling and a drop in sea level" as the cool temperatures allowed massive ice sheets to accumulate on the continents, Isozaki said. "If you check the rock record at that time, tropical coral reefs die first. Then you start to see fauna from mid latitudes move into the tropics. It all points to cooling."
The superplume disrupted the magnetic field and put a strain on creatures living on the surface, but it was only the beginning. Five million years later it reached the surface, Isozaki said, and the hot material punched through the crust, erupting as three successive supervolcanoes.
Today the remnants of those volcanoes are scattered through India, China and Norway. On their own they were too small to do much harm, but together Isozaki thinks they cooled the climate even further, launching an extinction as bad as the one that would kill the dinosaurs 185 million years later.
Then, 10 million years later, the Permian-Triassic extinction struck.
"The effects of the superplume were just the first punch of extinction," Isozaki said. "Then came the knockout punch, the Permian-Triassic extinction."
Isozaki thinks both "punches" were caused by the same superplume. Ten million years after the smaller volcanoes blew their tops, a much larger volcano, the Siberian Traps, erupted, launching the worst killing in the planet's history.
Gregory Retallack of the University of Oregon agrees that the late Permian round of extinction was bad -- as much as 67 percent of species were eradicated. But he doesn't think the two events are related. In the 10 million years after the first punch in the late Permian, he said, life recovered.
"The late Permian looks good all over the world," Retallack said. "You've got corals, healthy marine communities, and lots of fossil flora on land."
There's no questioning the severity of the Permian-Triassic crisis -- "We almost lost it there," Retallack said -- but whether the two can be traced a single mantle superplume, or they were unrelated, remains a mystery for now.
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