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The number of visitors to California's Yosemite National Park has swelled to four million a year. Now scientists think the impact of so many human beings is rippling among the web of organisms in the park, from cougars to mule deer all the way down to the park's signature wildflower, the evening primrose.

Although many of the Yosemite's cougars were shot by park officials in the 1920's, some of these predators remain. Yet they seem to avoid Yosemite Valley, the picturesque main entrance to the park that is home to numerous roads and buildings. The deer recognize this safe haven, says Oregon State University forestry scientist William Ripple. "We think the deer are moving closer to where the humans are." The many mule deer browse heavily on young California black oak and primrose in Yosemite Valley, and the plants are often unable to reach reproductive age. Ripple and his colleagues noticed that oak trees away from the visitor center were taller and more abundant.

By pushing predatory cougars out of the valley, humans have indirectly increased mule deer and reduced oak and primrose populations. This is an example of a trophic cascade—one that appears to be reducing biodiversity in one of the nation's most spectacular landscapes.

NASA's latest space telescope-the Wide Field Infrared Explorer, or WISE-recently took its first images of the sky around Earth in infrared light. In its initial six-month mission, WISE will spot thousands of previously unseen space objects, including asteroids and comets, brown dwarfs, and distant ultraluminous galaxies.

The Northern California coast is home to giant redwoods —the tallest trees in the world. The towering evergreens depend on the region's foggy climate, especially during the hot summer months. When rainfall is insufficient to hydrate the trees from the roots, the trees quench themselves by drawing moisture into their leaves from the fog.

Researchers at the University of California--Berkeley recently analyzed the frequency of coastal fog over the past hundred years. They discovered many fluctuations in fog and an overall decline. Scientists are unsure of what has caused these changes. The team's ongoing research will study how the redwoods will likely respond to variations in the climate they rely on.

China has 20 percent of the world's population but just 7 percent of its arable land. Chinese farmers have, for decades, relied upon artificial fertilizer to boost their crops. These artificial fertilizers, while increasing overall crop yields, can also upset the chemical balance in the soil and cause it to become more acidic. Recently, researchers compared samples of Chinese soil from the 1980's and the 2000's and found that agricultural lands across the country have become considerably more acidic. This chemical imbalance may reduce the farming potential of this land in the future.

In the rock layers of a vast open-pit coal mine in Colombia, paleontologists have uncovered a fossil of the largest snake known to have existed. The massive 60,000,000-year-old vertebrae suggest that the creature was about as long as a bus and three feet thick. The discovery team, composed of researchers from Canada, Panama, and the United States, named the snake Titanoboa cerrejonensis ("titanic boa from Cerrejón") after its size, its close relatives, and the name of the mine. Researchers think Titanoboa would likely have been too large to climb trees like modern boa constrictors. Instead, it probably sought its crocodile prey while swimming through the myriad rivers that cut through its forested coastal habitat.

Beyond being a winning entry in the animal record books, the snake is also a measuring stick for ancient tropical climate. Because the maximum body sizes of some snakes, turtles, crocodiles and other cold-blooded creatures are regulated by the temperature of their surroundings, their size can be used as a temperature gauge. The researchers estimate that the region averaged at least 30-34°C (86 -93°F) 60 million years ago, giving a new data point from which to compare tropical temperature change over time.

Astronomers from the University of California, Berkeley and the Institut de Mécanique Céleste et de Calculs des Éphémérides (IMCCE) in France, recently captured the best view yet of the dog-bone-shaped asteroid Kleopatra. Using the Keck II telescope and a technology known as adaptive optics, which reduces the distortion of light by Earth's atmosphere, the researchers were able to resolve Kleopatra's two small moons—a rare find among asteroids that can provide clues to planet formation.

The new VISTA telescope is taking a fresh survey of the Southern Hemisphere sky by examining infrared radiation. Some of the first images released from the powerful telescope focus on the Orion Nebula. From Earth, the nebula is visible to the naked eye, but cosmic dust blocks much of the view in visible wavelengths of light. VISTA's infrared view has revealed what glows beneath the dark, dusty regions in the famous nebula.