Apr 4 2013

From The Space Library

RELEASE: 13-086 - HUBBLE BREAKS RECORD IN SEARCH FOR FARTHEST SUPERNOVA --WASHINGTON -- NASA's Hubble Space Telescope has found the farthest supernova so far of the type used to measure cosmic distances. Supernova UDS10Wil, nicknamed SN Wilson after American President Woodrow Wilson, exploded more than 10 billion years ago. SN Wilson belongs to a special class called Type 1a supernovae. These bright beacons are prized by astronomers because they provide a consistent level of brightness that can be used to measure the expansion of space. They also yield clues to the nature of dark energy, the mysterious force accelerating the rate of expansion. This new distance record holder opens a window into the early universe, offering important new insights into how these stars explode, said David O. Jones of Johns Hopkins University in Baltimore, Md., an astronomer and lead author on the paper detailing the discovery. "We can test theories about how reliable these detonations are for understanding the evolution of the universe and its expansion." The discovery was part of a three-year Hubble program, begun in 2010, to survey faraway Type Ia supernovae and determine whether they have changed during the 13.8 billion years since the explosive birth of the universe. Astronomers took advantage of the sharpness and versatility of Hubble's Wide Field Camera 3 to search for supernovae in near-infrared light and verify their distance with spectroscopy. Leading the work is Adam Riess of the Space Telescope Science Institute in Baltimore, Md., and Johns Hopkins University. Finding remote supernovae provides a powerful method to measure the universe's accelerating expansion. So far, Riess's team has uncovered more than 100 supernovae of all types and distances, looking back in time from 2.4 billion years to more than 10 billion years. Of those new discoveries, the team has identified eight Type Ia supernovae, including SN Wilson, that exploded more than 9 billion years ago. The Type Ia supernovae give us the most precise yardstick ever built, but we're not quite sure if it always measures exactly a yard, said team member Steve Rodney of Johns Hopkins University. "The more we understand these supernovae, the more precise our cosmic yardstick will become." Although SN Wilson is only 4 percent more distant than the previous record holder, it pushes roughly 350 million years farther back in time. A separate team led by David Rubin of the U.S. Energy Department's Lawrence Berkeley National Laboratory in California announced the previous record just three months ago. Astronomers still have much to learn about the nature of dark energy and how Type Ia supernovae explode. By finding Type Ia supernovae so early in the universe, astronomers can distinguish between two competing explosion models. In one model the explosion is caused by a merger between two white dwarfs. In another model, a white dwarf gradually feeds off its partner, a normal star, and explodes when it accretes too much mass. The team's preliminary evidence shows a sharp decline in the rate of Type 1a supernova blasts between roughly 7.5 billion years ago and more than 10 billion years ago. The steep drop-off favors the merger of two white dwarfs because it predicts that most stars in the early universe are too young to become Type Ia supernovae. If supernovae were popcorn, the question is how long before they start popping? Riess said. "You may have different theories about what is going on in the kernel. If you see when the first kernels popped and how often they popped, it tells you something important about the process of popping corn." Knowing the type of trigger for Type 1a supernovae also will show how quickly the universe enriched itself with heavier elements such as iron. These exploding stars produce about half of the iron in the universe, the raw material for building planets, and life. The team's results have been accepted for publication in an upcoming issue of The Astrophysical Journal. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. The Association of Universities for Research in Astronomy Inc., in Washington operates STScI.

RELEASE: 13-087 - REGISTRATION OPENS FOR NASA NIGHT ROVER ENERGY CHALLENGE --WASHINGTON -- Registration is open for teams seeking to compete in the $1.5 million energy storage competition known as the Night Rover Challenge, sponsored by NASA and the Cleantech Open of Palo Alto, Calif. To win, a team must demonstrate a stored energy system that can power a simulated solar-powered exploration vehicle that can operate through multiple cycles of daylight and extended periods of darkness. "The goal of the Night Rover Challenge is to stimulate innovations in energy storage technologies of value in extreme space environments, such as the surface of the moon, or for electric vehicles and renewable energy systems here on Earth," said Michael Gazarik, NASA's associate administrator for Space Technology at NASA Headquarters in Washington. "NASA wants this challenge to generate new ideas that will allow planetary rovers the ability to take on a night shift, and possibly create new energy storage technologies for applications of benefit here on our home planet." This is a Centennial Challenge in which NASA provides the prize purse for technological achievements by independent teams while the Cleantech Open manages the competition as NASA's allied organization. The challenge is extended to individuals, groups and companies working outside the traditional aerospace industry. Unlike most contracts or grants, awards will be made only after solutions are demonstrated successfully. During the Night Rover Challenge energy storage systems will receive electrical energy from a simulated solar collector during daylight hours. During darkness, the stored energy will be used for simulated thermal management, scientific experimentation, communications and rover movement. A winning system must exceed the performance of an existing state-of-the-art system by a pre-determined margin. The winning system will be the one that has the highest energy storage density. The partnership NASA has with the Cleantech Open allows us to leverage taxpayer dollars in advancing technology development in this critical area, said Larry Cooper, Centennial Challenges program executive at NASA Headquarters. "Technology development is a priority for NASA; we push technology development effectively by partnering with industry and academia to advance our nation's space exploration and science goals while maintaining America's technology edge." Since the program's inception in 2005, NASA's Centennial Challenges has awarded more than $6 million to 15 different competition-winning teams through 23 events. Competitors have included private companies, citizen inventors and academia working outside the traditional aerospace industry. The competitions are managed by nonprofit organizations that cover the cost of operations through commercial or private sponsorships. The Cleantech Open bills itself as the world's largest accelerator for renewable, or clean, energy technology development. Its mission is to find, fund and foster entrepreneurs with big ideas that address today's most urgent energy, environmental, and economic challenges. A not-for-profit organization, the Cleantech Open provides the infrastructure, expertise and strategic relationships that turn clever ideas into successful global clean-technology companies.