NASA Dawn Spacecraft Captures First Image Of Nearing Asteroid

NASA's Dawn spacecraft has obtained its first image of the giant asteroid Vesta, which will help fine-tune navigation during its approach. Dawn expects to achieve orbit around Vesta on July 16, when the asteroid is about 117 million miles from Earth. The image from Dawn's framing cameras was taken on May 3 when the spacecraft began its approach and was approximately 752,000 miles (1.21 million km) from Vesta. The asteroid appears as a small, bright pearl against a background of stars. Vesta also is known as a protoplanet, because it is a large body that almost formed into a planet. "After plying the seas of space for more than a billion miles, the Dawn team finally spotted its target," said Carol Raymond, Dawn's deputy principal investigator at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "This first image hints of detailed portraits to come from Dawn's upcoming visit."

Vesta is 330 miles (530 km) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes obtained images of the bright orb for about two centuries, but with little surface detail. Mission managers expect Vesta's gravity to capture Dawn in orbit on July 16. To enter orbit, Dawn must match the asteroid's path around the sun, which requires very precise knowledge of the body's location and speed. By analyzing where Vesta appears relative to stars in framing camera images, navigators will pin down its location and enable engineers to refine the spacecraft's trajectory. Dawn will start collecting science data in early August at an altitude of approximately 1,700 miles (2,700 km) above the asteroid's surface. As the spacecraft gets closer, it will snap multi-angle images allowing scientists to produce topographic maps.

Dawn will later orbit at approximately 120 miles (200 km) to perform other measurements and obtain closer shots of parts of the surface. Dawn will remain in orbit around Vesta for one year. After another long cruise phase, Dawn will arrive in 2015 at its second destination, Ceres, an even more massive body in the asteroid belt. Gathering information about these two icons of the asteroid belt will help scientists unlock the secrets of our solar system's early history. The mission will compare and contrast the two giant asteroids shaped by different forces. Dawn's science instruments will measure surface composition, topography and texture. Dawn also will measure the tug of gravity from Vesta and Ceres to learn more about their internal structures. The spacecraft's full odyssey will take it on a 3-billion-mile (5-billion-km) journey, which began with its launch in September 2007.

So you Think you can Solve a Cosmology Puzzle?

Cosmologists have come up with a new way to solve their problems. They are inviting scientists, including those from totally unrelated fields, to participate in a grand competition. The idea is to spur outside interest in one of cosmology's trickiest problems measuring the invisible dark matter and dark energy that permeate our universe. The results will help in the development of new space missions, designed to answer fundamental questions about the history and fate of our universe. "We're hoping to get more computer scientists interested in our work," said cosmologist Jason Rhodes of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who is helping to organize the challenge, which begins on Dec. 3, 2010.

"Some of the mathematical problems in our field are the same as those in machine-learning applications for example facial recognition software." JPL and several European Universities, including The University of Edinburgh and University College London in the United Kingdom, are helping to support the event, which is funded by a European Union group called Pattern Analysis, Statistical Modelling and Computation Learning. The principal investigator is Thomas Kitching of the University of Edinburgh. This year, the competition, which has operated since 2008, is called GREAT 2010, after GRavitational lEnsing Accuracy Testing. The challenge is to solve a series of puzzles involving distorted images of galaxies. Occasionally in nature, a galaxy is situated behind a clump of matter that is causing the light from the galaxy to bend.

The result is a magnified and skewed image of the galaxy. In the most extreme cases, the warping results in multiple images and even a perfect ring, called an Einstein Ring after Albert Einstein, who predicted the effect. But most of the time, the results are more subtle and a galaxy image is distorted just a tiny bit not even enough to be perceived by eye. This is called weak gravitational lensing, or just weak lensing for short. Weak lensing is a powerful tool for unlocking the fabric of our universe. Only four percent of our universe consists of the stuff that makes up people, stars and anything with atoms. Twenty-four percent is dark matter a mysterious substance that we can't see but which tugs on the regular matter we can see. Most of our universe, 72 percent, consists of dark energy, which is even more baffling than dark matter.

NASA Demonstrates Tsunami Prediction System

A NASA-led research team has successfully demonstrated for the first time elements of a prototype tsunami prediction system that quickly and accurately assesses large earthquakes and estimates the size of resulting tsunamis.After the magnitude 8.8 Chilean earthquake on Feb. 27, a team led by Y. Tony Song of NASA's Jet Propulsion Laboratory in Pasadena, Calif., used real-time data from the agency's Global Differential GPS (GDGPS) network to successfully predict the size of the resulting tsunami.

The network, managed by JPL, combines global and regional real-time data from hundreds of GPS sites and estimates their positions every second. It can detect ground motions as small as a few centimeters. "This successful test demonstrates that coastal GPS systems can effectively be used to predict the size of tsunamis," said Song. "This could allow responsible agencies to issue better warnings that can save lives and reduce false alarms that can unnecessarily disturb the lives of coastal residents."

Song's team concluded that the Chilean earthquake, the fifth largest ever recorded by instruments, would generate a moderate, or local, tsunami unlikely to cause significant destruction in the Pacific. The tsunami's effect was relatively small outside of Chile.