Ciencia
Science Illustrated

Science Illustrated Jul-Aug-10

Science Illustrated is an upbeat, visually spectacular gateway to cutting-edge science, which covers a tremendous range of subjects: from paleontology to space exploration, and medical breakthroughs to the latest environmental insights. Science Illustrated aims to report on the world of science in a way that's dynamic, engaging and accessible for all.

País:
United States
Idioma:
English
Editor:
Bonnier Corporation
Periodicidad:
One-off
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1 min.
ruins leave clear traces in plant growth

Italian scientists have found a way to map a city—despite the fact that it's been buried for centuries. The ancient Roman city of Altinum was abandoned between A.D. 400 and 600, when invaders drove out its inhabitants. As the city's residents moved onto the islands of a nearby lagoon, founding the city of Venice, Altinum was covered by floodwaters and soil. Although archaeologists have long known that Altinum existed just north of Venice, they haven't been able to get a good look at the remains of the city until now. In 2007 researchers at the University of Padua took aerial photos of the area during a drought using near-infrared radiation. Healthy plants appeared as a different color than crops struggling in the dry conditions. The photos revealed the outlines of Altinum's…

2 min.
probe to unfurl its sail 500 miles above earth's atmosphere

A nearly century-old dream of space exploration is moving closer to reality as the Planetary Society in Pasadena, California, plans its second attempt to send a spacecraft sailing toward the stars powered entirely by energy from light particles. In the 1920s, Russian scientists Fridrich Tsander and Konstantin Tsiolkovsky first contemplated solar sails. In the 1950s and '60s, a number of researchers theorized that the pressure from light, or photons, reflecting off an ultrathin foil sheet on a spacecraft would push the craft forward. The Planetary Society attempted the world's first launch of a solar sail into space in 2005, but the Russian rocket carrying it exploded over the Barents Sea. Shortly after the failed launch, the Society took over Nanosail, NASA's solar-sail R & D program, which was about to be shut…

2 min.
birds get their colors in three distinct ways

Q What gives bird feathers their colors? A Birds can see a larger spectrum of colors than most of us, and they flaunt a variety of eye-catching plumage. Pigments called melanins, carotenoids and porphyrins made in the birds' skin produce most feather colors. Melanins produce black feathers, but depending on the concentration of the pigment granules, they can also range to reddish browns and pale yellows. Bright red, yellow and orange feathers are produced by carotenoids, which birds generally get from eating plants. These pigments can interact with melanins to produce even more colors, like olive green. The final group, porphyrins, appear as a wide range of colors, including brown, pink, red and green. Certain birds, such as parrots, get their bright colors from less-common pigments produced directly in their feathers. In…

1 min.
who first tried to sail around africa?

A Greek explorer, Eudoxus of Cyzicus, made the first known attempt to sail the entire perimeter of Africa in the 2nd century B.C. His first boat ran ashore, and his second expedition was lost. No one tried again until the late 1400s. Who first used the word “computer”? The word comes from the verb “compute,” meaning to determine, especially by mathematical means. That word comes from the Latin computare. “Computer” was first written in 1646 by English author Thomas Browne to describe a person who computes. Who invented the pocket watch? Peter Henlein, a German locksmith, is thought to have invented the first watches in the early 1500s. Unlike clocks, these used springs instead of drive weights, allowing them to be small and portable.…

2 min.
gigantic carnivores

Q How big can carnivorous land mammals grow? A Theoretically, around 2,425 pounds for terrestrial mammals, according to models developed by researchers at the Institute of Zoology in London. That number takes into account the fact that larger animals need to eat more, and that carnivores spend much more time and energy looking for (and killing) food than herbivores do. Carnivores face energy-based challenges related to their size: The larger a predator becomes, the more difficult it becomes to take in enough calories. Once mammals exceed about 44 pounds, they can generally meet their energy needs only by eating prey of their own size or larger. Large prey provides significant food and energy but also takes more energy to hunt, and this imposes a limit on the maximum size of carnivores. The…

1 min.
how do electric eels generate electricity?

These fish contain special cells called electroplaques that produce electricity through the excitation of nerves. Large numbers of electroplaques in the tail region of the eels form the electric organs, which the animals use to stun their prey. The organs can discharge up to 650 volts, nearly four times the peak voltage produced by a household outlet. How was the speed of light first measured? English astronomer James Bradley calculated the speed of light in 1725 by measuring changes in the position of stars. He correctly concluded that the movement of the Earth along its orbit, and the fact that light had a finite speed, caused the stars' apparent orbital movement. How do squirrels choose which acorns to store for winter? Squirrels favor acorns from red oaks because they last through the winter without…