Geophysics

After studying the works of French intellectuals and others, Christopher Columbus was convinced that the world was not flat but a perfect sphere when he set off on his courageous but clumsy effort to prove it by sailing to Asia. However, he badly miscalculated the globe's circumference--an error that led him to mistake Cuba for Japan--and erroneously concluded after his third voyage to the New World that Earth actually resembled a pear, according to UCLA Professor Norman J. Thrower.

It was welcome news to Earthlings: The Voyager 1 spacecraft had seemingly crossed a momentous threshold and become the first man-made object to enter interstellar space. "Voyager 1 has left the solar system," the American Geophysical Union declared Wednesday in a news release. An accompanying study published online in the organization's journal, Geophysical Research Letters, also contained an unusually sentimental end note declaring that "we did it. Bon Voyage!" Alas, the elation that spread through news and social media was short-lived.

Scientists piecing together the geological history of the Earth have added another important piece to the mosaic: More than half a billion years ago, North America's Pacific Southwest bordered the east coast of Antarctica. This represents the first real evidence of the origins of the North American continent, according to scientists who presented their findings Tuesday to the Geological Society of America and the Seismological Society of America.

Faced with rising political attacks, hundreds of climate scientists are joining a broad campaign to push back against congressional conservatives who have threatened prominent researchers with investigations and vowed to kill regulations to rein in man-made greenhouse gas emissions. FOR THE RECORD: Climate scientists: An article in the Nov. 8 Section A about a campaign by scientists to push back against congressional conservatives who have attacked the concept of global warming reported that the American Geophysical Union is mobilizing 700 scientists to provide information on climate change.

The earthquake that leveled an unknown number of villages in northern Iran on Thursday, causing devastating loss of life, caught experts by surprise because it struck off the beaten path for major earthquakes in that part of the globe. "We haven't had such a strong earthquake in that region for at least the past 500 years," said Mdansour Niazi, an Iranian geophysicist who is now an earthquake consultant in Berkeley.

A UCLA geochemist analyzing a rock sample drilled from the deep ocean muck has discovered what appears to be the first known piece of the massive meteorite that is widely believed to have wiped out the dinosaurs about 65 million years ago. The tiny fossil meteorite--less than a 10th of an inch across--is the only surviving piece found so far of a six-mile wide cosmic fist that smashed into Mexico's Yucatan Peninsula at the time the dinosaurs died off.

"Hiroo Kanamori knows more about earthquakes than anyone . . . although he probably says, 'I don't understand' more than any other geophysicist," read the citation when the Seismological Society of America gave its annual medal to the Caltech scientist two years ago. This probably captured as well as anything the essence of Kanamori, 57, director of the Caltech Seismological Laboratory.

"The sun rose at night," Chinese philosopher Motze wrote in the 4th century BC in an account of an epic battle that had occurred about 1,500 years earlier. Pasadena geologist Kevin Pang, paging through Chinese texts at the UCLA library, immediately realized that those five words were not poetic allusion to fiery combat, but rather a description of a total eclipse. For the ancient observers, the moon passing in front of the sun marked passage into night.

Ranching, mining, energy exploration and other activities that raise dust in the West are helping diminish the snowpack that supplies much of the region's water, researchers reported Tuesday in the journal Geophysical Research Letters. University of Colorado scientists said dust was blowing from the deserts onto the state's snowcapped mountains, absorbing more of the sun's warmth because of its darker color and melting the snow earlier and more quickly than in the past.

The landscape, wandering with a mind of its own, travels today at the speed at which fingernails grow. Los Angeles creeps toward San Francisco; the Palos Verdes Peninsula squeezes toward Pasadena; and the Ventura basin is slipping shut by a centimeter or so every year, geodetic satellite studies show. California's mobility is hardly unique. Texas was part of Argentina 535 million years ago, new studies suggest.

Ranching, mining, energy exploration and other activities that raise dust in the West are helping diminish the snowpack that supplies much of the region's water, researchers reported Tuesday in the journal Geophysical Research Letters. University of Colorado scientists said dust was blowing from the deserts onto the state's snowcapped mountains, absorbing more of the sun's warmth because of its darker color and melting the snow earlier and more quickly than in the past.

The rock and dust kicked up by an asteroid impact 65 million years ago was not enough to kill the dinosaurs, according to researchers--but the debris might have sparked a deadly chemical reaction in the atmosphere. New studies show that the Chicxulub impact crater on the coast of Mexico's Yucatan Peninsula is smaller than once thought, making dinosaur extinction difficult to explain completely. Researchers presented those findings Sunday at the American Geophysical Union's fall meeting.

Geophysicist Richard S. Gross of the Jet Propulsion Laboratory has solved the mystery of the Earth's "Chandler wobble," a minute oscillation that has tantalized researchers for more than a century. Discovered in 1891 by Seth Carlo Chandler Jr., the wobble is a displacement of about 20 feet at the North Pole with a period of 433 days. Using oceanic data that has only recently become available, Gross reports in the Aug.

Subtle changes in the Earth's orbit may have been responsible for the abrupt transformation of a large region of North Africa from a lush garden into the Sahara Desert. Radiocarbon dating shows that the changes occurred in two phases, one beginning 6,700 years ago and a sharper change beginning 4,000 years ago. During those periods, temperatures rose and precipitation dropped sharply, German researchers report in the July 15 Geophysical Research Letters.

A UCLA geochemist analyzing a rock sample drilled from the deep ocean muck has discovered what appears to be the first known piece of the massive meteorite that is widely believed to have wiped out the dinosaurs about 65 million years ago. The tiny fossil meteorite--less than a 10th of an inch across--is the only surviving piece found so far of a six-mile wide cosmic fist that smashed into Mexico's Yucatan Peninsula at the time the dinosaurs died off.

The landscape, wandering with a mind of its own, travels today at the speed at which fingernails grow. Los Angeles creeps toward San Francisco; the Palos Verdes Peninsula squeezes toward Pasadena; and the Ventura basin is slipping shut by a centimeter or so every year, geodetic satellite studies show. California's mobility is hardly unique. Texas was part of Argentina 535 million years ago, new studies suggest.

Subtle changes in the Earth's orbit may have been responsible for the abrupt transformation of a large region of North Africa from a lush garden into the Sahara Desert. Radiocarbon dating shows that the changes occurred in two phases, one beginning 6,700 years ago and a sharper change beginning 4,000 years ago. During those periods, temperatures rose and precipitation dropped sharply, German researchers report in the July 15 Geophysical Research Letters.

It comes as no surprise to Southern Californians that solid Earth moves. But until recently, geologists believed that these periodic rumblings were mostly skin-deep. Outbreaks such as earthquakes, volcanoes and violent weather were confined to the surface, like a bad complexion. Hidden beneath the layers of crust and mantle, they felt, the planet had an inner serenity.

In what is being hailed as a new window on the inner workings of the Earth, scientists have gotten their first-ever look at our planet's rotating core, a glimpse they say should open up new vistas into realms previously accessible only in theory and science fiction. "It curls your toes that they could do this," said UC Santa Cruz seismologist Thorne Lay.

It comes as no surprise to Southern Californians that solid Earth moves. But until recently, geologists believed that these periodic rumblings were mostly skin-deep. Outbreaks such as earthquakes, volcanoes and violent weather were confined to the surface, like a bad complexion. Hidden beneath the layers of crust and mantle, they felt, the planet had an inner serenity.