The Week: Looking for Lincoln, and an Early Fish Fossil

Brian Choo

An artist's interpretation of a 420-million-year-old bony fish that is challenging what we know about the evolution of jaws.

Last year, moviegoers saw our 16th president star in two different films. This year, two software-wielding history buffs are seeing Abraham Lincoln in different spots in the same photograph.

Forensics

Peek-a-Boo President

The Gettysburg Address may have been an oratorical triumph for Lincoln, but pictures of him at the ceremony are exceedingly rare. Enter Christopher Oakley, a former Disney animator who said he has found the president's blurry visage in a stereoscopic photograph of the event.

In March, while working on a 3-D animation of the speech, Mr. Oakley thought he recognized Lincoln's beard and stovepipe hat in the picture. To verify his hunch, he superimposed a clear picture of the president (taken in a studio 11 days before the address) over the stereoscopic photo, and used Photoshop to line up the two faces.

"All the landmarks — jaw line, beard, hair, cheekbones, heavy brow, ears, line up perfectly," Mr. Oakley told Smithsonian magazine.

If he is right, that means John Richter, a Civil War hobbyist who claimed in 2007 to have spotted Lincoln at a different location in the same picture, is wrong. Historians are split, but Mr. Oakley is convinced. "I've been looking at his face for nearly 50 years," he said, "and last March, at 3 a.m. in my studio, he looked back."

Climate Change

U.N. Sounds a Warning

Human activity is the main cause of global warming, and there is a limit to how much greenhouse gas we can spew into the air before we damage the planet badly, the world's top climate scientists said on Friday. Gathered in Stockholm to release the latest United Nations assessment of climate change, the group for the first time embraced an upper limit on carbon emissions. For the best chance of limiting the warming to an internationally agreed target, the total emissions cannot exceed one trillion tons of carbon burned, a figure that will be reached by 2040 at the current rate of emissions growth.

Paleontology

Jaws, the Early Years

A newly discovered fish fossil is challenging what we know about the evolution of jaws. The 420-million-year-old fossil, found by scientists in Yunnan, China, appears to have the kind of bony jaw associated with modern fish, according to a study in Nature. This suggests that jaws as we now know them may have evolved much earlier than previously thought. What remains unclear is whether this is the jaw that humans eventually inherited.

Nanotechnology

Smaller, Lighter, Slower

Silicon has long been the standard material in computer circuits. But as demand for cheap computing power increases, microchips must get smaller and lighter, leaving scientists in need of materials better suited to the task. Researchers at Stanford took a step in that direction last week by building the first working computer using transistors fashioned from carbon nanotubes, promising cylinder-shaped molecules that have so far proved difficult to work with. The transistors that power the computer are huge by industry standards — one micron — but the computer is Turing complete, which means it can perform any computation, though it's not fast.

"This is not the most efficient computer," said Supratik Guha, director of physical sciences at I.B.M.'s Thomas J. Watson Research Center, "but that wasn't the point. "

Conservation

Guess Who'll Inherit the Earth

It has been 26 years since the government of Thailand built a dam across the Khlong Saeng river, creating a series of islands within a 60-square-mile reservoir that were ideal for studying the speed of mammal extinctions.

Last week, biologists from the National University of Singapore reported their findings: On most of the islands, all the native species were gone, replaced by Malayan field rats. But the diversity of the animals on the nearby mainland remained more or less consistent.

"Our results should be a warning," said Dr. Luke Gibson, who published his study in the journal Science. "This is the trend that the world is going in."

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