Posted on by Fraser Cain

Boeing Picks Team Leader for JIMO Mission

Image credit: NASA

Boeing has picked Dr. Joe Mills to lead their research into the Jupiter Icy Moons Orbiter program for NASA. This ambitious spacecraft will use a nuclear reactor to power an ion engine – it will be so powerful and efficient that it will be able to put itself into orbit around the various moons of Jupiter. The initial research phase is only a $6 million contract to investigate various technology options for the reactor, ion engine, and power conversion. NASA will choose a primary contractor for the mission in 2004.

Boeing [NYSE: BA] has selected Dr. Joe Mills to lead the company?s effort on the Jupiter Icy Moons Orbiter (JIMO) program, part of a NASA initiative to develop nuclear power and electric propulsion technologies to revolutionize space exploration.

Mills and his team will explore technology options for building the first spacecraft that would use nuclear electric propulsion. Boeing is one of three companies exploring technology options (called a Phase A study contract) for JIMO.

Mills previously headed the International Space Station (ISS) program for Boeing NASA Systems. The company is NASA?s prime contractor for the ISS and is responsible for design, construction, integration and operation of the orbital outpost.

?JIMO, like the International Space Station, is an exciting and groundbreaking mission,? said Mills, Boeing JIMO vice president and program manager. ?I?m looking forward to further challenges as we chart the course of space exploration in the 21st century.?

Mills will be replaced as the Boeing ISS vice president and program manager by John Elbon, who is the Boeing Checkout, Assembly and Payload Processing Services (CAPPS) manager at Kennedy Space Center, Fla.

Mills is an internationally known expert in the nuclear safety field with nearly 40 years experience in the aerospace industry. He received a bachelor of science degree in engineering in 1967, a master of science in nuclear engineering in 1969 and a doctorate in nuclear engineering in 1972, all from the University of California, Los Angeles.

Prior to joining the ISS program, Mills spent 20 years in a variety of project and program management positions with Atomics International, a part of Boeing Rocketdyne Propulsion and Power. From 1987 through 1994, he served as program manager to develop space nuclear power for key military and civilian missions.

Mills devoted his early career to nuclear power systems development. He also specialized in the nuclear safety field of liquid metal fast breeder reactors. He also published numerous papers on nuclear power systems and nuclear power safety.

The JIMO Phase A contract is valued at $6 million, with a $5 million option for further work, and runs through fall 2003. Led in this phase by Boeing Phantom Works, the company?s advanced R&D unit, the JIMO team will study technology options for the reactor, power conversion, electric propulsion and other subsystems of the JIMO spacecraft meant to explore the Jovian moons of Ganymede, Callisto and Europa.

NASA currently plans to select an industry prime contractor in fall 2004 to work with the Jet Propulsion Laboratory (JPL) in Pasadena, Calif., to develop, launch and operate the spacecraft.

Mills is responsible for successful execution of the Phase A trade and concept design study, as well as securing the contract to develop, build and support JPL in operation of the spacecraft. Mills leads the team from the Boeing office in Pasadena, Calif.

Mills reports to Mike Mott, NASA Systems vice president and general manager and Ron Prosser, vice president and general manager for Phantom Works Integrated Defense Advanced Systems.

Original Source: Boeing News Release

Posted on by Fraser Cain

Dinosaurs Killed By Volcanoes and Asteroids?

Image credit: NASA

Most paleontologist believe that a gigantic asteroid struck Mexico 65 million years ago and killed all the dinosaurs; end of story. But a minority believe that the Earth’s environment was already uncomfortable for dinosaurs because of a series of asteroid strikes and volcano eruptions – the asteroid was just the straw that broke the camel’s back. By studying the life spans of colonies of one-celled organisms, paleontologist Gerta Keller has uncovered that the Cretaceous period might have lasted 300,000 years after the asteroid impact.

As a paleontologist, Gerta Keller has studied many aspects of the history of life on Earth. But the question capturing her attention lately is one so basic it has passed the lips of generations of 6-year-olds: What killed the dinosaurs?

The answers she has been uncovering for the last decade have stirred an adult-sized debate that puts Keller at odds with many scientists who study the question. Keller, a professor in Princeton’s Department of Geosciences, is among a minority of scientists who believe that the story of the dinosaurs’ demise is much more complicated than the familiar and dominant theory that a single asteroid hit Earth 65 million years ago and caused the mass extinction known as the Cretacious-Tertiary, or K/T, boundary.

Keller and a growing number of colleagues around the world are turning up evidence that, rather than a single event, an intensive period of volcanic eruptions as well as a series of asteroid impacts are likely to have stressed the world ecosystem to the breaking point. Although an asteroid or comet probably struck Earth at the time of the dinosaur extinction, it most likely was, as Keller says, “the straw that broke the camel’s back” and not the sole cause.

Perhaps more controversially, Keller and colleagues contend that the “straw” — that final impact — is probably not what most scientists believe it is. For more than a decade, the prevailing theory has centered on a massive impact crater in Mexico. In 1990, scientists proposed that the Chicxulub crater, as it became known, was the remnant of the fateful dinosaur-killing event and that theory has since become dogma.

Keller has accumulated evidence, including results released this year, suggesting that the Chicxulub crater probably did not coincide with the K/T boundary. Instead, the impact that caused the Chicxulub crater was likely smaller than originally believed and probably occurred 300,000 years before the mass extinction. The final dinosaur-killer probably struck Earth somewhere else and remains undiscovered, said Keller.

These views have not made Keller a popular figure at meteorite impact meetings. “For a long time she’s been in a very uncomfortable minority,” said Vincent Courtillot, a geological physicist at Universit? Paris 7. The view that there was anything more than a single impact at work in the mass extinction of 65 million years ago “has been battered meeting after meeting by a majority of very renowned scientists,” said Courtillot.

The implications of Keller’s ideas extend beyond the downfall of ankylosaurus and company. Reviving an emphasis on volcanism, which was the leading hypothesis before the asteroid theory, could influence the way scientists think about the Earth’s many episodes of greenhouse warming, which mostly have been caused by periods of volcanic eruptions. In addition, if the majority of scientists eventually reduce their estimates of the damage done by a single asteroid, that shift in thinking could influence the current-day debate on how much attention should be given to tracking and diverting Earth-bound asteroids and comets in the future.

Keller does not work with big fossils such as dinosaur bones commonly associated with paleontology. Instead, her expertise is in one-celled organisms, called foraminifera, which pervade the oceans and evolved rapidly through geologic periods. Some species exist for only a couple hundred thousand years before others replace them, so the fossil remains of short-lived species constitute a timeline by which surrounding geologic features can be dated.

In a series of field trips to Mexico and other parts of the world, Keller has accumulated several lines of evidence to support her view of the K/T extinction. She has found, for example, populations of pre-K/T foraminifera that lived on top of the impact fallout from Chicxulub. (The fallout is visible as a layer of glassy beads of molten rock that rained down after the impact.) These fossils indicate that this impact came about 300,000 years before the mass extinction.

The latest evidence came last year from an expedition by an international team of scientists who drilled 1,511 meters into the Chicxulub crater looking for definitive evidence of its size and age. Although interpretations of the drilling samples vary, Keller contends that the results contradict nearly every established assumption about Chicxulub and confirm that the Cretaceous period persisted for 300,000 years after the impact. In addition, the Chicxulub crater appears to be much smaller than originally thought — less than 120 kilometers in diameter compared with the original estimates of 180 to 300 kilometers.

Keller and colleagues are now studying the effects of powerful volcanic eruptions that began more than 500,000 years before the K/T boundary and caused a period of global warming. At sites in the Indian Ocean, Madagascar, Israel and Egypt, they are finding evidence that volcanism caused biotic stress almost as severe as the K/T mass extinction itself. These results suggest that asteroid impacts and volcanism may be hard to distinguish based on their effects on plant and animal life and that the K/T mass extinction could be the result of both, said Keller.

Original Source: Princeton News Release

Posted on by Fraser Cain

Up Next, Mars Reconnaissance Orbiter

Image credit: NASA/JPL

Earth’s closest approach to Mars is past, but it’ll just be another two years until the planets are close together again – time to send more probes. Next up will be NASA’s Mars Reconnaissance Orbiter, which will make a detailed inspection of the Martian surface; imaging objects as small as a coffee table. It will also be able to scan underground layers for evidence of water and ice, and measure the atmosphere above the surface to find vents of water vapour escaping from below the surface. The spacecraft is expected to launch on August 10, 2005.

As Earth pulls away from Mars after last month’s close approach, NASA is developing a spacecraft that will take advantage of the next close encounter in 2005.

That spacecraft, Mars Reconnaissance Orbiter, will make a more comprehensive inspection of our planetary neighbor than any previous mission.

For starters, it will examine landscape details as small as a coffee table with the most powerful telescopic camera ever sent to orbit a foreign planet. Some of its other tools will scan underground layers for water and ice, identify small patches of surface minerals to determine their composition and origins, track changes in atmospheric water and dust, and check global weather every day.

“We’re reaching an important stage in developing the spacecraft,” said James Graf, project manager for Mars Reconnaissance Orbiter at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The primary structure will be completed next month.” The structure weighs 220 kilograms (484 pounds) and stands 3 meters (10 feet) tall. At launch, after gear and fuel are added, it will support over 2 tons.

Also next month, the mission’s avionics test bed will be assembled for the first time and put to use for testing of flight software.

Workers at Lockheed Martin Space Systems, Denver, have already assembled the spacecraft structure and will later add instruments being built for it at the University of Arizona, Tucson; at Johns Hopkins University Applied Physics Laboratory, Laurel, Md.; at the Italian Space Agency, Rome; at Malin Space Science Systems, San Diego, Calif.; and at JPL.

“In several ways, Mars Reconnaissance Orbiter will advance NASA’s follow-the-water strategy for Mars exploration,” said Dr. Richard Zurek, project scientist for the mission.

Current surveys of Mars’ surface composition have found less evidence of water-related minerals than many scientists anticipated after earlier discoveries of plentiful channels that were apparently carved by water flows in the planet’s past. A spectrometer on the Reconnaissance Orbiter is designed to identify some different types of water-related minerals and to see smaller-scale deposits. “Instead of looking for something as big as the Bonneville Salt Flats, we can look for something on the scale of a Yellowstone hot spring,” Zurek said.

Probing below Mars’ surface with penetrating radar, Reconnaissance Orbiter will check whether the frozen water that NASA’s Mars Odyssey spacecraft detected in the top meter or two (yard or two) of soil extends deeper, perhaps as accessible reservoirs of melted water.

Above the surface, an atmosphere-scanning instrument will monitor changes in water vapor at different altitudes and might even locate plumes where water vapor is entering the atmosphere from underground vents, if that’s happening on Mars.

Mars Reconnaissance Orbiter will stream home its pictures and other information using the widest dish antenna and highest power level ever operated at Mars. “The amount of data flowing back to Earth from Mars will be a giant leap over previous missions. It’s like upgrading from a dial-up modem for your computer to a high-speed DSL connection,” Graf said.

The Mars Reconnaissance Orbiter will lay the groundwork for later Mars surface missions in NASA’s plans: a lander called Phoenix selected last month in a competition for a 2007 launch opportunity, and a highly capable rover called Mars Science Laboratory being developed for a 2009 launch opportunity. The orbiter’s high-resolution instruments will help planners evaluate possible landing sites for these missions both in terms of science potential for further discoveries and in terms of landing risks. The orbiter’s communications capabilities will provide a critical transmission relay for the surface missions.

Advantageous opportunities to launch Mars missions come in a rhythm of about every 26 months, shortly before each time Earth overtakes Mars in the two planets’ concentric tracks around the Sun. NASA’s two Mars Exploration Rovers and the European Space Agency’s Mars Express mission were launched during the three months preceding Earth’s most recent passing of Mars on Aug. 27. The Mars Reconnaissance Orbiter team has its work cut out for it to have the spacecraft ready for launch on Aug. 10, 2005, which is about 10 weeks before the next close approach.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Lance Bass Will Join World Space Week

Image credit: World Space Week

He didn’t quite make it up the International Space Station, but Lance Bass, member of the Pop music group NSYNC is still interested in space. He’s going to be visiting schools in the Houston area during World Space Week (October 4-10, 2003) to help promote to children that science and math are “cool”. World Space Week was declared by the United Nations in 1999 and is celebrated in nearly 50 countries around the world. Many other events are planned for the week, including a webcast from the space station, giving people a chance to chat with the astronauts.

One year after completing his spaceflight training here, entertainer, certified cosmonaut and World Space Week 2003 Youth Spokesperson Lance Bass will return to Houston with a new, yet equally challenging mission: to convince young people that space, math and science are “cool.”

Bass will visit several Houston primary and secondary schools during World Space Week, October 4-10, to discuss the importance of science and math. He will review students’ design proposals for “Lance’s Lab,” a global youth competition in which the engineers and explorers of tomorrow design a hypothetical space station module for Bass to live and work in.

“I’m very excited about flying in space one day,” said Bass, member of popular band *NSYNC and avid space enthusiast. “What excites me even more is the possibility that eventually, nearly anyone will be able to travel in space just as easily as taking a plane from LA to Houston. But that day will only arrive if today’s young people choose to build an extraordinary future for themselves. The keys to that future are a solid foundation in math and science”

To conclude World Space Week on Friday, Bass will attend a public event that salutes the benefits space exploration brings to education and all aspects of life on Earth. The World Space Week Celebration, starting at 7 p.m. CT on October 10 at the Hyatt Downtown Houston, will support Spaceweek International Association’s programs to excite students about math and science. Celebration-goers will meet Bass, along with Houston Congressman Nick Lampson and other celebrities. Tickets are on sale to the public and can be purchased at www.spaceweek.org.

“Bass’ visits to schools will offer students and teachers the opportunity to create a renewed passion and understanding for the horizons that can be explored with math and science,” said Dennis Stone, president of Spaceweek International Association.

Declared by the United Nations, World Space Week is held October 4 – 10 each year and is marked by celebrations on all seven continents. This year, nearly 50 nations around the world are expected to participate. Events in the United States will focus on the vital role math and science education play in creating tomorrow’s space leaders and pioneers. Highlights include:

  • Teachers across the U.S. will use space in the classroom all week long to excite students about science and math;
  • NASA will host a Web cast from the International Space Station (ISS), October 9 at 12 p.m. CT, with an opportunity to ask questions of an ISS astronaut;
  • Earth & Sky Radio will host World Space Week radio broadcasts on October 7 and 10;
  • The Space Frontier Foundation will hold the “Alt.Space” conference on October 10 in Los Angeles;
  • The Iowa Space Grant Consortium will host a Space Week Science Challenge from October 4-10;
  • The Museum of Texas Tech University will feature a World Space Week celebration on October 4.

For detailed information on events and celebrations across the globe, visit www.spaceweek.org.

About Lance’s Lab
“Lance’s Lab” is a global youth competition, in which K-12 students are asked to design a hypothetical International Space Station module for Bass to live and work in. Lance’s Lab is a worldwide student contest that underscores the fundamental importance of math and science. Winners will meet Bass at an awards ceremony in early 2004.

Special instructional materials are available to schools at no charge, featuring space-related math and science activities for teachers to use during World Space Week. Materials are available in several languages with activities for all grade levels and require little or no teacher preparation. By participating in World Space Week, teachers can excite students about learning and receive cash grants. For details or to download educational materials, visit: www.spaceweek.org/education.html

About World Space Week
From the United States to Bangladesh, from Columbia to China, World Space Week is celebrated annually in some 50 nations, on all seven continents. It serves to celebrate the contributions of space science and technology to the betterment of the human condition.

Declared in 1999 by the UN General Assembly, World Space Week marks the anniversary of two great milestones of humanity’s expansion into space:

  • 4 October 1957 — Date of the launch into outer space of the first human-made Earth satellite, SPUTNIK I, thus opening the way for space exploration;
  • 10 October 1967 — Date of the entry into force of the Treaty on Principles Governing the Activities of States in the Exploration and Peaceful Uses of Outer Space, including the Moon and Other Celestial Bodies

Founded in 1981, Spaceweek International Association (SIA) is non-profit organization that proudly supports the United Nations in the global coordination of World Space Week. SIA works to strengthen the link between space and society through public education, participation, and dialogue on the future of space.

Original Source: World Space Week News Release

Posted on by Fraser Cain

Hoping for a Supernova

Image credit: Hubble

Astronomers from the European Space Agency are tracking hundreds of galaxies with the Hubble Space Telescope, hoping that one or more stars will eventually explode as a supernova. They can then look back through the data and find the individual star that exploded – this would mean it was in the final stages of its life. So far, supernova have only been tracked back to two “mother stars” so far, so astronomers really need more of this data to help understand the conditions that cause a star to go supernova.

A team of European astronomers is using the NASA/ESA Hubble Space Telescope to look back in time. They have imaged the spiral galaxy NGC 3982 and hundreds of other galaxies in the hope that one of the millions of stars in these images will some day explode as a supernova. They can then look back and pinpoint the exact star that has exploded. Only two such supernova ‘mother stars’ have ever been identified.

The fantastic resolution of the Hubble Space Telescope allows individual massive stars in other galaxies to be detected. A team from Cambridge and Trieste have used Hubble and ESO?s Very Large Telescope to image NGC 3982 and several hundred other nearby galaxies in the hope that a few of the stars in these images will explode as supernovae in the future.

When a star of more than 10 times the mass of our Sun reaches the end of its nuclear fuel reserve, it can no longer produce enough energy to keep it from collapsing under its own immense weight. The core of the star collapses, and the outer layers are ejected in a fast-moving shock wave. These supernova explosions are at the heart of our understanding of the evolution of galaxies and the formation of the chemical elements in the Universe. Yet astronomers have been able to identify only two stars that later exploded as supernovae with any confidence.

Supernovae have many different characteristics and understanding exactly which type of star produces which kind of supernova is a fundamental challenge. To find these supernova ‘mother stars’, the team has undertaken this intensive study of the nearby Universe and is now playing a waiting game.

It appears that typical spiral galaxies produce one supernova roughly every 100 years and so the team has to study a large number of galaxies to stand a chance of being lucky enough to catch a star before it destroys itself and becomes either a neutron star or a black hole.

By using the most powerful telescopes both in space and on the ground to take images at different optical and infrared wavelengths, the temperature, luminosity, radius and mass of the stars that later explode can be estimated. This will allow astronomers to see exactly which types of stars produce supernovae and to test if their theories for the origins of these cosmic explosions are correct.

The beautiful galaxy NGC 3982 is a typical spiral galaxy and looks just as our own galaxy, the Milky Way, would if we could view it face on. It harbours a huge black hole at its core and has massive regions of star formation in the bright blue knots in the spiral arms. Supernovae are most likely to be found within these energetic regions.

Original Source: ESA News Release

Posted on by Fraser Cain

NASA Safety Panel Resigns

Image credit: NASA

All nine members of NASA’s Aerospace Safety Advisory Panel handed in their resignations on Tuesday in the wake of criticism from the Columbia accident investigation report and Congress. The panel was originally formed after the Apollo 1 accident killed three astronauts in a fire in 1967, and included space engineers, scientists, and aerospace industry experts. NASA is now in the process of evaluating the structure of the safety panel to make it more effective in the future.

NASA Administrator Sean O’Keefe accepted letters of resignation from all 11 members and consultants of the Aerospace Safety Advisory Panel (ASAP). Congress first chartered the Aerospace Safety Advisory Panel in the aftermath of the Apollo 1 fire in 1967 to act as an independent body to advise the NASA Administrator on the safety of operations, facilities, and personnel.

ASAP chair Shirley McCarty said in a cover letter to the Administrator, “This will give you and the Congress the freedom to revitalize the Panel and reshape its charter and mission.”

“Reflecting on the findings of the Columbia Accident Investigation Board and the process failures identified in its report, it’s evident that a wide range of oversight functions should be strengthened within the agency,” said Administrator O’Keefe. “We need to take this opportunity to explore how the original concept for an Aerospace Safety Advisory Panel needs to evolve to best meet the future needs of the agency.”

NASA has already started the initial evaluation process to revise the panel’s charge, based on congressional reaction to the findings of the Columbia Accident Investigation Board. The agency also will review the original 1967 ASAP charter and its amendments.

“I want to send my personal gratitude to the panel members for their work and dedication to NASA,” added Administrator O’Keefe. “We have a lot of hard work ahead of us as we prepare to safely return to flight. A comprehensive review of the panel and its role in our safety objectives will be vital in the coming weeks as we move forward.”

Original Source: NASA News Release

Posted on by Fraser Cain

Smart-1 is Ready for Launch

Image credit: ESA

The European Space Agency’s Smart-1 spacecraft has been mated to the top of its Ariane 5 rocket, and everything is ready to go for its September 27th launch. Smart-1’s primary mission will be to test out new technologies, including solar electric (ion) propulsion and autonomous navigation. Even though it’s launching in just a few days, it will arrive at the Moon in January 2005, where it will begin analyzing the chemical composition of the Moon’s surface. It will also search for evidence of water ice at the Moon’s southern pole.

Europe’s first mission to the Moon will soon be under way, and UK scientists are looking forward to unravelling some of the secrets of our neighbouring world.

SMART-1 – the European Space Agency’s first Small Mission for Advanced Research in Technology -is now expected to lift off from Kourou, French Guiana, just after midnight on Sunday, 28 September.

Although it is primarily intended to demonstrate innovative technologies such as solar-electric (ion) propulsion and autonomous navigation, SMART-1 also carries a number of scientific experiments that will provide new insights into some of the unanswered questions about our nearest celestial neighbour.

On arrival in lunar orbit (expected to be in January 2005), these instruments will search for signs of water ice in permanently shaded craters near the Moon’s poles, provide data on the still uncertain origin of the Moon, and reconstruct its evolution by mapping the surface distribution of minerals and key chemical elements.

The main UK contribution is a compact X-ray spectrometer known as D-CIXS (pronounced dee-kicks), which has been developed by Principal Investigator, Professor Manuel Grande, and his team at CCLRC Rutherford Appleton Laboratory. D-CIXS will help to determine the elements that make up the lunar surface and so provide important information about how the Moon was formed.

“Despite decades of research, we have never fully discovered what the Moon is made of,” said Professor Grande. “The Apollo missions only explored the equatorial regions on the Earth-facing side of the Moon, while other spacecraft only investigated surface colour or searched for water and heavy elements. D-CIXS will provide the first global X-ray map of the elements that make up the Moon.

“X-rays from the Sun cause atoms in the lunar surface to fluoresce – rather like the gas in the fluorescent tubes that light our offices and homes – so that they emit X-rays of their own. D-CIXS will measure the Moon’s composition by detecting these X-rays coming from the lunar surface. The precise energy carried by each X-ray tells us the element that is emitting it.

“This information will provide us with vital clues to help us understand the origins of our Moon.”

In order to create an instrument that is the size of a toaster and weighs just 4.5 kilograms, the D-CIXS team had to miniaturise the components and develop new technology such as novel X-ray detectors – based on new swept charge devices (similar to the charged couple devices found in digital cameras) and microfabricated collimators with walls no thicker than a human hair.

Other UK institutions involved in D-CIXS are:- University of Sheffield, Queen Mary University of London, Natural History Museum, Armagh Observatory, University College London, Mullard Space Science Laboratory and the University of Manchester.

Dr. Sarah Dunkin of CCLRC-RAL and University College London is also a Co-Investigator on the SMART-1 Infrared Spectrometer (SIR), which will search for ice and produce a global map of lunar minerals.

The main UK industrial involvement is by SEA Group Ltd, who helped to develop the Ka-band Telemetry and Telecommand Experiment (KaTE) which will test more efficient communication techniques for deep space missions.

Original Source: RAS News Release

Posted on by Fraser Cain

New Map of Debris Around the Milky Way

Image credit: University of Virginia

A new survey of the stars surrounding the Milky Way has produced a detailed map of how streams of stars and debris are being added to our galaxy. Researchers from the University of Virginia used data from the 2MASS sky survey to map out the Sagittarius galaxy which wraps around the Milky Way in a long stream of stars. They were able to distinguish between galaxies because a certain class of stars, called M giants, are much more common in Sagittarius – when they tuned their search to just look for these stars, Sagittarius “popped into view”.

Thousands of stars stripped from the nearby Sagittarius dwarf galaxy are streaming through our vicinity of the Milky Way galaxy, according to a new view of the local universe constructed by a team of astronomers from the University of Virginia and the University of Massachusetts.

Using volumes of data from the Two-Micron All Sky Survey (2MASS), a major project to survey the sky in infrared light led by the University of Massachusetts, the astronomers are answering questions that have baffled scientists for decades and proving that our own Milky Way is consuming one of its neighbors in a dramatic display of ongoing galactic cannibalism. The study, to be published in the Dec. 20 issue of the Astrophysical Journal, is the first to map the full extent of the Sagittarius galaxy and show in visually vivid detail how its debris wraps around and passes through our Milky Way. Sagittarius is 10,000 times smaller in mass than the Milky Way, so it is getting stretched out, torn apart and gobbled up by the bigger Milky Way.

“It’s clear who’s the bully in the interaction,” said Steven Majewski, U.Va. professor of astronomy and lead author on the paper describing the results.

In model images made to show the interaction in 3-D, available at http://www.astro.virginia.edu/~mfs4n/sgr/, the Milky Way appears as a flattened disk with spiral arms, while Sagittarius is visible as a long flourish of stars swirling first under and then over and onto the Milky Way disk.

“If people had infrared-sensitive eyes, the entrails of Sagittarius would be a prominent fixture sweeping across our sky,” Majewski said. “But at human, visual wavelengths, they become buried among countless intervening stars and obscuring dust. The great expanse of the Sagittarius system has been hidden from view.”

Not any more. By using infrared maps, the astronomers filtered away millions of foreground stars to focus on a type of star called an M giant. These large, infrared-bright stars are populous in the Sagittarius galaxy but uncommon in the outer Milky Way. The 2MASS infrared map of M giant stars analyzed by Majewski and collaborators is the first to give a complete view of our galaxy’s meal of Sagittarius stars, now wrapping like a spaghetti noodle around the Milky Way. Prior to this work, astronomers had detected only a few scattered pieces of the disrupted Sagittarius dwarf. Even the existence of Sagittarius was unknown until the heart of this nearest satellite galaxy of the Milky Way was discovered by a British team of astronomers in 1994.

“We sifted several thousand interesting stars from a catalog of half a billion,” said co-author Michael Skrutskie, U.Va. professor of astronomy and principal investigator for the 2MASS project. “By tuning our maps of the sky to the ‘right’ kind of star, the Sagittarius system jumped into view.”

“This first full-sky map of Sagittarius shows its extensive interaction with the Milky Way,” Majewski said. “Both stars and star clusters now in the outer parts of the Milky Way have been ‘stolen’ from Sagittarius as the gravitational forces of the Milky Way nibbled away at its dwarf companion. This one vivid example shows that the Milky Way grows by eating its smaller neighbors.”

“Astronomers used to view galaxy formation as an event that happened in the distant past,” noted David Spergel, a professor of astrophysics at Princeton University after viewing the new finding. “These observations reinforce the idea that galaxy formation is not an event, but an ongoing process.”

The study’s map of M giants depicts 2 billion years of Sagittarius stripping by the Milky Way, and suggests that Sagittarius has reached a critical phase in what had been a slow dance of death.

“After slow, continuous gnawing by the Milky Way, Sagittarius has been whittled down to the point that it cannot hold itself together much longer,” said 2MASS Science Team member and study co-author Martin Weinberg of the University of Massachusetts. “We are seeing Sagittarius at the very end of its life as an intact system.”

Does this mean we are at a unique moment in the life of our galaxy? Yes and no.

“Whenever possible, astronomers appeal to the principle that we are not at a special time or place in the universe,” Majewski said. “Because over the 14 billion-year history of the Milky Way it is unlikely that we would just happen to catch a brief event like the death of Sagittarius, we infer that such events must be common in the life of big spiral galaxies like our own. The Milky Way probably dined on a number of dwarf galaxy snacks in the past.”

On the other hand, Majewski and his colleagues have been surprised by the Earth’s proximity to a portion of the Sagittarius debris.

“For only a few percent of its 240 million-year orbit around the Milky Way galaxy does our Solar System pass through the path of Sagittarius debris,” Majewski said. “Remarkably, stars from Sagittarius are now raining down onto our present position in the Milky Way. Stars from an alien galaxy are relatively near us. We have to re-think our assumptions about the Milky Way galaxy to account for this contamination.”

The new findings will help astronomers measure the total mass of the Milky Way and Sagittarius galaxies, and probe the quantity and distribution of the invisible dark matter in these systems.

“The shape of the Sagittarius debris trail shows us that the Milky Way’s unseen dark matter is in a spherical distribution, a result that is quite unexpected,” Weinberg said.

“The observations provide new insights into the nature of the mysterious dark matter,” said Princeton’s Spergel. “Either our galaxy is unusual or the dark matter has richer properties than postulated by conventional models.”

2MASS was a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology. The National Aeronautics and Space Administration, and the National Science Foundation funded the project. Additional funding for the Sagittarius study with 2MASS came from the David and Lucile Packard Foundation and the Research Corporation.

Original Source: University of Virginia News Release

Posted on by Fraser Cain

A Few Small Changes

I made a couple of improvements to Universe Today yesterday, including “Printer-friendly pages”. At the bottom of any article on the site now is a link to a printer version of the article. I’ve done a couple of tests and it looks pretty good on my laser printer. Please let me know if you have any problems with it.

A bigger change, however, is that I’m going to be moving the site to a dedicated server in the next few days. It’s a pretty big time commitment, so there might be some delays.

Oh, and I removed that black background on the newsletter – it was making it difficult for people to just reply to the newsletter if they wanted to send me an email. And I like to receive email. 🙂

Thanks!

Fraser Cain
Publisher
Universe Today

Posted on by Fraser Cain

Small Telescope Helps Make Observations on Titan

Image credit: NASA

Sarah Horst, a planetary sciences major at Caltech, helped astronomers track cloud formations on Saturn’s moon Titan using only a fourteen inch telescope – in Los Angeles. Researchers needed a way to track Titan night after night for several months, but no large observatory could provide this much time to carry out detailed observations. Horst set up an old teaching telescope to track the intensity of light coming from Titan. Whenever something unusual happened, her associates would contact Keck for detailed photographs.

Meet Sarah Horst, throwback. The planetary science major, a senior at the California Institute of Technology, spent six months engaged in a bit of old-time telescope observing. The work led to some breakthrough research about Saturn’s moon Titan, and indirectly led to funding for a new telescope at Caltech’s Palomar Observatory.

Horst, 21, was looking for a part-time job in the summer of her sophomore year, and was hired by Mike Brown, an associate professor of planetary astronomy. Brown and graduate student Antonin Bouchez knew there had been previous evidence of “weather” on Titan in the form of clouds. But that evidence was elusive. “Someone would look one year and think they saw a cloud, then look the next year and not see a cloud,” explains Brown. “What we were after was a way to look at Titan, night after night after night.”

The problem, of course, is that all of the large telescopes like Keck are incredibly busy, booked by astronomers from around the world who use the precious time for their own line of research. So Brown and Bouchez knew that obtaining large amounts of time for a single project like this was not going to happen.

The solution: Use an old teaching telescope–the hoary 14-inch Celestron telescope located on top of Caltech’s Robinson Lab–to do cutting edge science that couldn’t be done at the largest telescopes in the world, in Hawaii.

Though the power of the Robinson telescope is weak, and light pollution from Pasadena strong, which prevents imaging the actual clouds, the light reflecting from clouds could be imaged (the more clouds, the more light that’s reflected). All that was needed was someone who could come night after night and take multiple images.

Enter Horst, the self-described “lowly undergraduate.” For months, Horst spent her evenings in Robinson. “I did the setup, which involved a wheel that contained four light filters,” she explains. Each filter would capture a different wavelength of light. Software switched the filters; all she had to do, says Horst, was to orientate and focus the telescope.

Now, modern-day astronomers have it relatively easy when using their telescope time. Sure they’re up all night, but they sit on a comfortable chair in a warm room, hot coffee close at hand, and do their observing through a computer monitor that’s connected to a telescope.

Not Horst. She did it the old way, in discomfort. “A lot of times in December or January I’d go in late at night, and it would be freezing,” says Horst, who runs the 800-meter for the Caltech track team. “I’d wrap myself up in blankets.” Horst spent hours in the dark, since the old dome itself had to be dark. “I couldn’t even study,” she says, “although sometimes I tried to read by the light of the moon.”

A software program written by Bouchez plotted the light intensity from each image on a graph. When a particular image looked promising, Bouchez contacted Brown. As a frequent user of the Keck Observatory, which is powerful enough to take an image of the actual clouds, Brown was able to call colleagues who were using the Keck that night and quickly convince them that something exciting was going on. “It only took about ten minutes to get a quick image of Titan,” says Brown. “The funny part was having to explain to them that we knew there were clouds because we had seen the evidence in our 14-inch telescope in the middle of the L.A. basin.”

The result was “Direct Detection of Variable Tropospheric Clouds Near Titan’s South Pole,” which appeared in the December 19 journal Nature. It included this acknowledgement: “We thank . . . S. Horst for many nights of monitoring Titan in the cold.”

The paper has helped Brown obtain the funding to build a new 24-inch custom-built telescope. It will be placed in its own building atop Palomar Mountain, on the grounds of Caltech’s existing observatory. It’s also roboticized; Brown will control the scope from Pasadena via a computer program he has written.

He’ll use it for further observation of Titan and for other imaging, as well, such as fast-moving comets. “Most astronomy is big,” notes Brown; “big scopes looking at big, unchanging things, like galaxies. I like to look at changing things, which led to this telescope.”

What really made this project unique, though, according to Brown, is the Robinson scope. “Sarah was able to do something with this little telescope in Pasadena that no one in the world, on any of their larger professional telescopes on high, dark mountaintops, had been able to do,” he says. “Sometimes a good idea and stubbornness are better than the largest telescope in town.”

For Horst, while the work wasn’t intellectually challenging–“a trained monkey could have done it,” she says with a laugh–it was, nonetheless, “a cool project. Everything here is so theoretical and tedious, and so classroom orientated. So in that way it was a nice experience and reminded me what real science was about.”

Original Source: Caltech News Release