Shuttle astronauts will make one final house call to the Hubble Space Telescope as part of a mission to extend and improve the observatory’s capabilities. NASA Administrator Michael Griffin announced plans for a fifth servicing mission to Hubble today during a meeting with agency employees at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The 11-day rehab mission, likely launching early May 2008 using space shuttle Discovery, would keep Hubble working until about 2013. Its batteries and gyroscopes, which are used to point the telescope, are degrading and they will now be replaced. The shuttle crew will also install two new instruments: the Wide Field Camera 3 (WFC3), and the Cosmic Origins Spectrograph (COS). The new instruments will improve significantly Hubble’s ability to probe distant, faint objects in the early Universe. Griffin also announced the astronauts selected for the mission. Veteran astronaut Scott D. Altman will command the final space shuttle mission to Hubble. Navy Reserve Capt. Gregory C. Johnson will serve as pilot. Mission specialists include veteran spacewalkers John M. Grunsfeld and Michael J. Massimino and first-time space fliers Andrew J. Feustel, Michael T. Good and K. Megan McArthur. Altman will be making his fourth spaceflight and his second trip to Hubble. He commanded the STS-109 Hubble servicing mission in 2002. Grunsfeld, an astronomer, will be making his third trip to Hubble and his fifth spaceflight. He performed five spacewalks to service the telescope on STS-103 in 1999 and STS-109 in 2002. Massimino will be making his second trip to Hubble and his second spaceflight. He performed two spacewalks to service the telescope during the STS-109 mission in 2002.
Solscape
Big Bang theory saved
An apparent discrepancy in the Big Bang theory of the universe’s evolution has been reconciled by astrophysicists examining the movement of gases in stars. Professor John Lattanzio from Monash’s School of Mathematical Sciences and Director of the Centre for Stellar and Planetary Astrophysics said the confusion surrounding the Big Bang revolved around the amount of the gas Helium 3 in the universe. „The Big Bang theory predicts a certain amount of Helium 3 in the universe“, Professor Lattanzio said. „The trouble is, low mass stars (about one to two times the size of our sun) also make Helium 3 as a side product of burning the hydrogen in their cores.“ It’s been thought that when the star becomes a giant it mixes the Helium 3 to its surface and, near the end of its life, spews the Helium 3 into space just before it becomes a planetary nebula. But there are inconsistencies with the amount of Helium 3 predicted to be in the universe and the amount that’s actually there; there’s much less than expected. Some scientists have theorised that the rapid rotation of low mass stars destroys the Helium 3 they produce. But computer models that have included this rotation, while showing some destruction of Helium 3, have not been able to reconcile the Big Bang theory. Professor Lattanzio, in collaboration with Dr. Peter Eggleton and Dr. David Dearborn from the Lawrence Livermore National Laboratories in the US, ran 3D computer models of a red giant’s life on some of the world’s fastest computers to investigate whether there was some sort of gaseous mixing occurring in stars that destroyed Helium 3. Their findings have been published in the new issue of the international journal „Science“. Near the end of a star’s life there is a „core flash“ and it was at around this time that the computer models revealed a small instability in the movement of the gases in the star. „When we looked at this in 3D we found this hydrodynamic instability caused mixing and destroyed the Helium 3 so that none was released into space,“ Professor Lattanzio said. „This apparent problem with the Big Bang has been solved – the Helium 3 in the universe comes from the Big Bang and low mass stars, although they produce Helium 3, they do not release any into the universe because they destroy it.“
Scientists crack open stellar evolution
Deep Mixing of He-3: Reconciling Big Bang and Stellar Nucleosynthesis
Oldest Complex Organic Molecules Found in Ancient Fossils
Ohio State University geologists have isolated complex organic molecules from 350-million-year-old fossil sea creatures – the oldest such molecules yet found. The molecules may have functioned as pigments, but the study offers a much bigger finding: an entirely new way to track how species evolved.
Oldest Complex Organic Molecules Found In Ancient Fossils
Janus Poses Above Saturn
A new incredible photograph shows Saturn’s potato-shaped moon Janus posing above the planet’s cloudy atmosphere. Janus is only 181 kilometers across, and it shows the scars of many impacts with other objects. Like Saturn’s other smaller moons, Janus could be covered with a layer of fine, dust-sized icy material. The Cassini spacecraft took the photo on September 25, 2006, when it was only 145.000 kilometers from Janus.
https://photojournal.jpl.nasa.gov/catalog/PIA08296
Amazon River Once Flowed in Opposite Direction
The world’s largest river basin, the Amazon, once flowed from the Atlantic Ocean to the Pacific – opposite to its present direction – according to research by a geology graduate student and his advisor at the University of North Carolina at Chapel Hill. Graduate student Russell Mapes set out in 2004 to study the speed at which sediment in the Amazon travels from the Andes mountains, in the present headwaters of the river, to the Atlantic. While studying sedimentary rocks in the river basin he discovered something else – ancient mineral grains in the central part of South America that could only have originated in now-eroded mountains in the eastern part of the continent. If the Amazon had continuously flowed eastward, as it does now, Mapes would have found much younger mineral grains in the sediments from the Andes. Mapes explains that these sediments of eastern origin were washed down from a highland area that formed in the Cretaceous Period, between 65 million and 145 million years ago, when the South American and African tectonic plates separated and passed each other. That highland tilted the river’s flow westward, sending sediment as old as 2 billion years toward the center of the continent. A relatively low ridge, called the Purus Arch, which still exists, rose in the middle of the continent, running north and south, dividing the Amazon’s flow – eastward toward the Atlantic and westward toward the Andes. Toward the end of the Cretaceous, the Andes started growing, which sent the river back toward the Purus Arch. Eventually, sediment from the mountains, which contained mineral grains younger than 500 million years old, filled in the basin between the mountains and the arch, the river breeched it and started its current flow. Previous research has identified a reverse flow, but only in segments of the river. Mapes traversed about 80 percent of the Amazon basin.
Blick ins Innere von M87
Mit Hilfe der europäischen H.E.S.S.-Teleskope in Namibia entdeckten Forscher hochenergetische Gammastrahlung, die aus dem Zentrum der riesigen Radiogalaxie M87 kommt. Wegen der beobachteten Schwankungen der Strahlung kommt als Ursprung eigentlich nur ein Ort in Frage: ein Schwarzes Loch im Zentrum der Galaxie.
Gamma-Strahlung vom Rand eines supermassiven schwarzen Lochs entdeckt
NASA Satellite Identifies The World’s Most Intense Thunderstorms
A summer thunderstorm often provides much-needed rainfall and heat wave relief, but others bring large hail, destructive winds, and tornadoes. Now with the help of NASA satellite data, scientists are gaining insight into the distribution of such storms around much of the world.
Tropical Rainfall Measuring Mission
Stellar Explosion Has Many Layers
A new photograph from the Spitzer Space Telescope shows how supernova remnant Cassiopeia A evolved over time. The original star contained 15 to 20 times the mass of our Sun, and was made up of concentric shells of elements. The lightest elements, like hydrogen, were in the outermost shell, while the heaviest elements sunk to the centre. The shells of the exploded material match up quite well with the original layers in the star before it detonated as a supernova.
Spectacular views of V838 Monocerotis light echo
New images taken with Hubble’s Advanced Camera for Surveys (ACS) in November 2005 and September 2006 show the evolution of the light echo around the star V838 in the constellation of Monoceros.
Hubble’s Latest Views of Light Echo from Star V838 Monocerotis
Ancient human footprints found in Mexico
Ancient human footprints discovered in the Mexican desert may be among the oldest in the Americas, researchers said on Wednesday. The 13 footprints found in Cuatro Cienegas in the northern state of Coahuila are fossilized in stone less than an inch deep and are around the age of the oldest known footprints in North or South America – they could be between 10.000 and 15.000 years old. The oldest discovered human footprints in the New World are in Monte Verde, Chile and are believed to be around 13.000 years old. The earliest known hominid tread marks are the Laetoli footsteps in Tanzania. At 3.7 million years old, they far predate the advent of homo sapiens.
Source: Reuters