Posted on by Fraser Cain

2004 Astronaut Class Named

Image credit: NASA
Eleven new astronaut candidates are joining the ranks of space explorers. NASA introduced the new class during a Space Day celebration today at the National Air and Space Museum’s Steven F. Udvar-Hazy Center in Chantilly, Va. The class of 2004 will be the first focused from the very beginning on realizing the new Vision for Space Exploration.

NASA Administrator Sean O’Keefe called members of the new astronaut class, “our next generation of explorers, who’ll help blaze a galactic trail through the solar system.

“We are indeed living in an age of heroic potential, as we move forward in the Solar System to explore mysterious new worlds, make important new discoveries and help to expand the sense of possibility for all humans on his planet,” O’Keefe said.

Former Astronaut and U.S. Sen. John Glenn, who introduced O’Keefe, looked back, and ahead. “How far we’ve come in the past few years,” he said, “how far we yet have to go, and how much we have yet to learn. I’m envious of the young people just coming into the space program now for the opportunities that they have.”

The class includes pilots, mission specialists (MS) and three new mission specialist-educator (MS-E) astronauts, teachers who will help ensure there’s always a next generation primed to explore.

The astronaut candidates:

# Mission Specialist-Educator Joe Acaba: A 36-year-old teacher at Dunnellon Middle School in Florida and a former Peace Corps volunteer in the Dominican Republic.

# Mission Specialist-Educator Ricky Arnold: A 40-year-old math and science teacher at the American International School of Bucharest, Romania; he’s also taught in Morocco, Indonesia, and Saudi Arabia.

# Pilot Randy Bresnik: A 36-year-old Marine Corps major, F/A-18 pilot and experimental test pilot who’s getting married this month in a Scottish castle.

# Mission Specialist Chris Cassidy: A 34-year old Navy Seal who has done two tours of duty in Afghanistan.

# Pilot Jim Dutton: A 35-year-old U.S. Air Force major and F/A-22 test pilot who flew combat air patrols over northern Iraq in the 1990s.

# Mission Specialist Jose Hernandez: A 41-year-old engineer at NASA’s Johnson Space Center in Houston; grew up as a migrant farm worker before settling in Stockton, Calif.

# Mission Specialist Shane Kimbrough : A 36-year-old U.S. Army major and flight simulation engineer at NASA’s Johnson Space Center in Houston; served as a platoon leader in an Apache helicopter company during Desert Storm.

# Mission Specialist Tom Marshburn: A 43-year-old flight surgeon at NASA’s Johnson Space Center in Houston; also an avid mountain climber and a private pilot.

# Mission Specialist-Educator Dottie Metcalf-Lindenburger: A 29-year-old science teacher at Hudson’s Bay High School in Vancouver, Wash.; she was a championship runner in college.

# Mission Specialist Bobby Satcher Jr.: A 38-year-old M.D. and orthopedic surgeon at Northwestern Memorial Hospital in Chicago; he’s done charity medical work overseas.

# Mission Specialist Shannon Walker: A 38-year-old Ph.D and manager at NASA’s Johnson Space Center in Houston; she’s lived and worked in Russia, and is an avid private pilot.

After their formal introduction, the new astronaut candidates joined students from NASA’s Earth Crew at an afternoon webcast from NASA Headquarters. The kids introduced the class and showered them with cheers and confetti.

Also at that event, NASA’s Deputy Administrator Fred Gregory read a special Space Day message from President Bush, congratulating the class and praising “America’s spirit of discovery and innovation.”

The candidates will report to NASA’s Johnson Space Center this summer. Once settled in Houston, they will begin the intensive training. Initially, they will undergo land survival training, T-38 jet ground and flight training, Shuttle orbiter systems training, Space Station systems training, science and engineering briefings, and orientation tours at all NASA centers, including the Kennedy Space Center and Marshall Space Flight Center.

“These are the men and women who will help us ‘extend life to there,'” Readdy said. “Naming this new class is an important next step in our exploration goals.”

“Right now, tomorrow’s space explorers are seated in America’s classrooms. As NASA carries out the vision for space exploration, the Education Enterprise remains committed to working closely with our nation’s schools, fostering learning environments that will stimulate students to participate in the journey to go to the Moon, Mars and beyond,” said Dr. Adena Loston, NASA’s Associate Administrator for Education.

Original Source: NASA News Release

Posted on by Fraser Cain

Two Hot Planets Seen Orbiting Very Close to Parent Stars

Image credit: ESO
A European team of astronomers [1] are announcing the discovery and study of two new extra-solar planets (exoplanets). They belong to the OGLE transit candidate objects and could be characterized in detail. This trebles the number of exoplanets discovered by the transit method; three such objects are now known.

The observations were performed in March 2004 with the FLAMES multi-fiber spectrograph on the 8.2-m VLT Kueyen telescope at the ESO Paranal Observatory (Chile). They enabled the astronomers to measure accurate radial velocities for forty-one stars for which a temporary brightness “dip” had been detected by the OGLE survey. This effect might be the signature of the transit in front of the star of an orbiting planet, but may also be caused by a small stellar companion.

For two of the stars (OGLE-TR-113 and OGLE-TR-132), the measured velocity changes revealed the presence of planetary-mass companions in extremely short-period orbits.

This result confirms the existence of a new class of giant planets, designated “very hot Jupiters” because of their size and very high surface temperature. They are extremely close to their host stars, orbiting them in less than 2 (Earth) days.

The transit method for detecting exoplanets will be “demonstrated” for a wide public on June 8, 2004, when planet Venus passes in front of the solar disc, cf. the VT-2004 programme.

Discovering other Worlds
During the past decade, astronomers have learned that our Solar System is not unique, as more than 120 giant planets orbiting other stars were discovered by radial-velocity surveys (cf. ESO PR 13/00, ESO PR 07/01, and ESO PR 03/03).

However, the radial-velocity technique is not the only tool for the detection of exoplanets. When a planet happens to pass in front of its parent star (as seen from the Earth), it blocks a small fraction of the star’s light from our view. The larger the planet is, relative to the star, the larger is the fraction of the light that is blocked.

It is exactly the same effect when Venus transits the Solar disc on June 8, 2004, cf. ESO PR 03/04 and the VT-2004 programme website. In the past centuries such events were used to estimate the Sun-Earth distance, with extremely useful implications for astrophysics and celestial mechanics.

Nowadays, planetary transits are gaining renewed importance. Several surveys are attempting to find the faint signatures of other worlds, by means of stellar photometric measurements, searching for the periodic dimming of a star as a planet passes in front of its disc.

One of these, the OGLE survey, was originally devised to detect microlensing events by monitoring the brightness of a very large number of stars at regular intervals. For the past four years, it has also included a search for periodical shallow “dips” of the brightness of stars, caused by the regular transit of small orbiting objects (small stars, brown dwarfs or Jupiter-size planets). The OGLE team has since announced 137 “planetary transit candidates” from their survey of about 155,000 stars in two southern sky fields, one in the direction of the Galactic Centre, the other within the Carina constellation.

Resolving the nature of the OGLE transits
The OGLE transit candidates were detected by the presence of a periodic decrease of a few percent in brightness of the observed stars. The radius of a Jupiter-size planet is about 10 times smaller than that of a solar-type star [2], i.e. it covers about 1/100 of the surface of that star and hence it blocks about 1 % of the stellar light during the transit.

The presence of a transit event alone, however, does not reveal the nature of the transiting body. This is because a low-mass star or a brown dwarf, as well as the variable brightness of a background eclipsing binary system seen in the same direction, may result in brightness variations that simulate the ones produced by an orbiting giant planet.

However, the nature of the transiting object may be established by radial-velocity observations of the parent star. The size of the velocity variations (the amplitude) are directly related to the mass of the companion object and therefore allow to discriminate between stars and planets as the cause of the observed brightness “dip”.

In this way, photometric transit searches and radial-velocity measurements combine to become a very powerful technique to detect new exoplanets. Moreover, it is particularly useful for elucidating their characteristics. While the detection of a planet by the radial velocity method only yields a lower estimate of its mass, the measurement of the transit makes it possible to determine the exact mass, radius, and density of the planet.

The follow-up radial-velocity observations of the 137 OGLE transit candidates is not an easy task as the stars are comparatively faint (visual magnitudes around 16). This can only be done by using a telescope in the 8-10m class with a high-resolution spectrograph.

The nature of the two new exoplanets
A European team of astronomers [1] therefore made use of the 8.2-m VLT Kueyen telescope. In March 2004, they followed 41 OGLE “top transit candidate stars” during 8 half-nights. They profited from the multiplex capacity of the FLAMES/UVES fiber link facility that permits to obtain high-resolution spectra of 8 objects simultaneously and measures stellar velocities with an accuracy of about 50 m/s.

While the vast majority of OGLE transit candidates turned out to be binary stars (mostly small, cool stars transiting in front of solar-type stars), two of the objects, known as OGLE-TR-113 and OGLE-TR-132, were found to exhibit small velocity variations. When all available observations – light variations, the stellar spectrum and radial-velocity changes – were combined, the astronomers were able to determine that for these two stars, the transiting objects have masses compatible with those of a giant planet like Jupiter.

Interestingly, both new planets were detected around rather remote stars in the Milky Way galaxy, in the direction of the southern constellation Carina. For OGLE-TR-113, the parent star is of F-type (slightly hotter and more massive than the Sun) and is located at a distance of about 6000 light-years. The orbiting planet is about 35% heavier and its diameter is 10% larger than that of Jupiter, the largest planet in the solar system. It orbits the star once every 1.43 days at a distance of only 3.4 million km (0.0228 AU). In the solar system, Mercury is 17 times farther away from the Sun. The surface temperature of that planet, which like Jupiter is a gaseous giant, is correspondingly higher, probably above 1800 ?C.

The distance to the OGLE-TR-132 system is about 1200 light-years. This planet is about as heavy as Jupiter and about 15% larger (its size is still somewhat uncertain). It orbits a K-dwarf star (cooler and less massive than the Sun) once every 1.69 days at a distance of 4.6 million km (0.0306 AU). Also this planet must be very hot.

A new class of exoplanets
With the previously found planetary transit object OGLE-TR-56 [3], the two new OGLE objects define a new class of exoplanets, still not detected by current radial velocity surveys: planets with extremely short periods and correspondingly small orbits. The distribution of orbital periods for “hot Jupiters” detected from radial velocity surveys seems to drop off below 3 days, and no planet had previously been found with an orbital period shorter than about 2.5 days.

The existence of the three OGLE planets now shows that “very hot Jupiters” do exist, even though they may be quite rare; probably about one such object for every 2500 to 7000 stars. Astronomers are truly puzzled how planetary objects manage to end up in such small orbits, so near their central stars.

Contrary to the radial velocity method which is responsible for the large majority of planet detections around normal stars, the combination of transit and radial-velocity observations makes it possible to determine the true mass, radius and thus the mean density of these planets.

Great expectations
The two new objects double the number of exoplanets with known mass and radius (the three OGLE objects plus HD209458b, which was detected by the radial velocity surveys but for which a photometric transit was later observed). The new information about the exact masses and radii is essential for understanding the internal physics of these planets.

The complementarity of the transit and radial velocity techniques now opens the door towards a detailed study of the true characteristics of exoplanets. Space-based searches for planetary transits – like the COROT and KEPLER missions – together with ground-based radial velocity follow-up observations will in the future lead to the characterization of other worlds as small as our Earth.

Original Source: ESO News Release

Posted on by Fraser Cain

NASA Considers Risking Rover on Dangerous Descent

Image credit: NASA/JPL
Scientists and engineers celebrated when they saw the first pictures NASA’s Opportunity sent from the rim of a stadium- sized crater that the rover reached after a six-week trek across martian flatlands.

Multiple layers of exposed bedrock line much of the inner slope of the impact crater informally called “Endurance.” Such layers and their thicknesses may reveal what the environment on Mars was like before the salty standing body of water evaporated to produce the telltale rocks that were explored in the tiny “Eagle” Crater. That?s where Opportunity spent its first eight weeks on Mars.

“It’s the most spectacular view we’ve seen of the martian surface, for the scientific value of it but also for the sheer beauty of it,” Dr. Steve Squyres of Cornell University, Ithaca, N.Y., said about a color panorama of Endurance Crater released at a news conference today at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. He is the principal investigator for the science instruments on both Opportunity and its twin Mars Exploration Rover, Spirit.

In coming days, Opportunity will circle the rim of Endurance, observing the crater’s interior from various angles. Scientists and engineers have begun to identify interesting science targets and assess how difficult it would be for the rover to descend partway into the crater and climb back out. “We will need to decide whether the science is compelling enough to send the rover into a crater it might never leave, or whether to explore other sites first before entering Endurance,” said Orlando Figueroa, director of the Mars Exploration Program, NASA Headquarters, Washington.

At Eagle Crater, an outcrop of bedrock only about the height of a street curb yielded evidence that the site was once covered by a body of salty water deep enough to splash in. “That was the last dying gasp of a body of water,” Squyres said. “The question that has intrigued us since we left Eagle Crater is what preceded that. Was there a deep body of water for a long time? Was there a shallow, short-lived playa? We don’t know.”

The strategy for seeking answers is to examine older rocks from deeper layers, so Opportunity was sent on drives totaling about 800 meters (half a mile) to reach the deepest crater nearby, Endurance. This crater excavated by the impact of a tiny asteroid or a piece of a comet is about 130 meters (430 feet) wide and, from the highest point on the rim, more than 20 meters (66 feet) deep, 10 times as deep as Eagle. An exposure of outcrop in a cliff high on the inner wall across from the rover’s current position reveals a stack of layers 5 to 10 meters (16 to 33 feet) tall. Other exposures around the inner slope of the crater may be more accessible than the cliff, and chunks from the same layers may have been thrown out onto surrounding ground by the crater-forming impact.

“There is a rock unit below what we saw at Eagle Crater,” Squyres said. “It looks fundamentally different from anything we’ve seen before. It’s big. It’s massive. It has a story to tell us.”

Brian Cooper, leader of JPL’s squad of rover drivers for Spirit and Opportunity, said the initial view of the crater doesn’t settle accessibility questions yet. “The slope right in front of us averages 18 to 20 degrees. Getting into the crater is no problem, but we have a lot more work to do to assess whether we could get back out. That depends on soil properties and slippage, as well as slope.” The planned circuit around the rim will also require careful navigation. “If you don’t go close enough to the lip, you can’t look in, but if you go too far, you could fall in,” he said. “We’re going to have a very interesting few weeks.”

When NASA sent astronauts to the lunar surface more than 30 years ago, it was decided not to allow them to enter craters as fresh and steep as Endurance, but Opportunity may be able to do what no human has done before on another planet.

Scientists and engineers working with the other rover, Spirit, are also examining images of a destination area to identify possible targets of study and to assess how well the rover can get to them. However, that destination area, informally named “Columbia Hills,” still lies several weeks of travel ahead of Spirit. Images and surface-temperature information from the NASA orbiters Mars Global Surveyor and Mars Odyssey are supplementing Spirit’s own increasingly detailed pictures of the hills. Nighttime surface temperatures indicate that some areas within the hills are rockier than others, said Amy Knudson, a rover science team collaborator from Arizona State University, Tempe.

“The hills represent a different rock unit, likely older than the plains we’re on,” Knudson said. “There are intriguing features in the hills and we want to investigate the processes that formed them. We’re especially interested to see if water played any role.”

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA’s Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University at http://athena.cornell.edu.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Canadian Arrow Announces Test Launch Plans

Image credit: Canadian Arrow
Canadian Arrow is pleased to announce that it will begin unmanned test flights of its rocket this summer. The flights, taking place over a period of four months beginning in August, will test the Arrow?s launch pad abort system and escape systems. This testing will be essential before any manned launches are attempted.

The Arrow is currently completing arrangements for the tests at an Ontario location, which will be announced at a future date. The tests will include:

? A launch pad abort test, including testing of the powerful solid rockets that pull the crew cabin to safety in the event of problems while the rocket is on the pad.
? Separation of the nose cone from the crew cabin.
? Deployment of parachutes for safe recovery of the nose cone and crew cabin.
? Testing of aerodynamics to ensure the rocket is able to reach the correct altitude and does not display any flight characteristics that are not normal to flight.
? A mach 1 abort and high altitude abort (application for permission to fly currently being processed)

Specifications of escape system:
? Eight 1,200 lb thrust solid rocket engines that burn for 5 seconds, mounted in a 22-ft tall nose cone
? Two main parachutes 64 ft in diameter
? Onboard computer to record data including acceleration, vibration, pitch, yaw and roll of the rocket.
? Onboard video camera aimed out the same window as the astronauts will use. Video will be available to the media after the flight.
? Vehicle will weigh 2,500lbs at liftoff.
? Crew cabin (space capsule) designed to carry three astronauts 65 inches in diameter and 6 ft tall.

The Canadian Arrow will also fly its first XPOD experiment, produced by students at the Canadian Arrow Science Club at John Dearness School in London. The flight will test the durability of the XPOD. Canadian Arrow is a London-built rocket, competing for the $10 million (US) X PRIZE, which will go to the first team that can launch a passenger space vehicle 100 kilometres into space, land safely and repeat the feat within two weeks.

Original Source: Canadian Arrow News Release

Posted on by Fraser Cain

NASA Announces Two New Earth Observation Satellite Missions

Image credit: NASA/Hampton University
Two NASA missions to explore the boundaries of Earth’s atmosphere with space are scheduled for launch in 2006. Both have recently completed preliminary design phases and are ready to proceed with hardware fabrication, integration and testing.

The Aeronomy of Ice in the Mesosphere (AIM) Small Explorer will determine the causes of Earth’s highest-altitude clouds, which occur on the very edge of space. These clouds form in the coldest part of the atmosphere, about 50 miles above the polar-regions, every summer. Recorded sightings of these silvery-blue, noctilucent or “night-shining” clouds began in the late 1800’s at high latitudes. They have been increasing in frequency and extending to lower latitudes over the past four decades.

Scientists have hypothesized the more frequent occurrences may be an indicator of global warming, but until now they have not been able to test this idea. Since similar thin high altitude clouds have been observed at Mars, what AIM teaches us about Earth’s noctilucent clouds should help us understand the similarities and differences between the martian and terrestrial atmospheres.

AIM will measure all the parameters important to understanding noctilucent cloud formation. This will help determine the connection between the clouds and their environment and serve as a baseline for the study of long-term changes in the upper atmosphere. Dr. James Russell III of Hampton University in Hampton, Va., leads AIM as Principal Investigator.

The second mission is the Time History of Events and Macroscale Interactions during Substorms mission (THEMIS). A Medium Explorer mission, it will fly five small spacecraft through explosive geomagnetic disturbances to solve the mystery of what triggers the colorful eruptions of the Northern and Southern lights. These violent “substorms” reflect major reconfigurations of near-Earth space and have significant implications for space weather, affecting satellites and terrestrial communications.

Over the years several different hypotheses have been proposed to explain this phenomenon. THEMIS will use five probes, strategically placed in different regions of the magnetosphere, to determine which explanation is correct. THEMIS is led by Dr. Vassilis Angelopoulos of the University of California, Berkeley.

The Explorer Program is designed to provide frequent, low-cost access to space for physics and astronomy missions with small to mid-sized spacecraft. NASA’s Goddard Space Flight Center, Greenbelt, Md., manages the Explorer Program for the Office of Space Science, Washington.

For information and artists’ concepts of the AIM mission on the Internet, visit:
http://aim.hamptonu.edu/

For Information and artists’ concepts of the THEMIS mission, visit:
http://sprg.ssl.berkeley.edu/themis/

For information about the Explorer program on the Internet, visit:
NASA News Release

For information about NASA and agency missions on the Internet, visit:
http://www.nasa.gov

Original Source: NASA News Release

Posted on by Fraser Cain

X Prize Gets Investment and New Name

Entrepreneurs Anousheh Ansari and Amir Ansari, today announced a multimillion dollar contribution to the X PRIZE Foundation which runs an international competition among private spaceships designed to fly the general public into space. On this day, the 43rd anniversary of astronaut Alan Shepard’s suborbital flight into space, the X PRIZE competition is being renamed the ANSARI X PRIZE Competition to reflect the newly-established title sponsorship. The ANSARI X PRIZE is modeled after the $25,000 Orteig Prize won by Charles Lindbergh in 1927 for his historic flight from New York to Paris.

The ANSARI X PRIZE will award $10 million to the first private organization to build and fly a ship that can carry three passengers 100 km (62 miles) into space, return safely to Earth and repeat the launch with the same ship within two weeks. Both flights must be completed by January 1st, 2005. The competition has been endorsed by leading space and aviation organizations around the world and includes the vision to jump-start the commercialization of space travel and industry the same way that Orteig Prize opened today’s commercial airways.

Space exploration has always been a childhood dream for both Anousheh and brother-in-law Amir, who were born in Iran. “As a child I looked at the stars and dreamed of being able to travel into space,” said Anousheh, an avid space enthusiast. “As an adult, I understand that the only way this dream will become a reality is with the participation of private industry and the creative passion of smart entrepreneurs. The ANSARI X PRIZE provides the perfect vehicle to ignite the imagination and passion of fellow entrepreneurs, giving them and their courageous pilots a platform for success.”

Currently, 26 teams from seven nations around the world have registered to compete. Several teams have already conducted successful test launches and plan to announce their competition launches within the next few months.

“The vision for the X PRIZE Foundation and the ANSARI X PRIZE competition began in May 1996 with the support of the business leaders from the St. Louis Community,” said Dr. Peter H. Diamandis, X PRIZE Foundation Chairman and Founder. “My dream, along with Anousheh and Amir, has been to open space travel to the public. With profound thanks to the Ansari family, we have created a self-fulfilling prophecy. The ANSARI X PRIZE Teams are creating a multitude of different designs specifically for public access. One of these unique designs will win in the months ahead and many others will go on to offer commercial services.”

In March 2004 the X PRIZE Foundation also announced a Presenting Sponsorship from Champ Car World Series, the leading open-wheel race car series. The competition has room for two remaining major sponsorships which will provide a company with its logo on all the competing spaceships, hospitality and a variety of other benefits.

About Anousheh Ansari
Anousheh Ansari is a co-founder of venture capital firm Prodea, Inc. Mrs. Ansari co-founded telecom technologies, inc. (tti), a supplier of softswitch-based solutions for network and service providers in 1993, which was acquired by Sonus Networks in 2000. She was listed in the Fortune magazine’s “40 Under 40” in 2001, recognized by Working Woman magazine as the winner of the 2000 National Entrepreneurial Excellence award and was chosen as the winner of the 1999 Ernst and Young Entrepreneur of the Year, Southwest Region, for the Technology and Communications category.

About Amir Ansari
Amir Ansari is a co-founder of venture capital firm, Prodea, Inc. Mr. Ansari co-founded telecom technologies, inc. and served as the CTO for the company prior to its acquisition by Sonus Networks. He has filed several patents in the area of Voice over IP and is currently sitting on the Board of Directors of several technology companies.

About the X PRIZE Foundation
The X PRIZE Foundation is a not-for-profit educational organization with headquarters in St. Louis, Missouri. Supported by private donations and the St. Louis community, the Foundation’s mission is to create educational programming for students and space enthusiasts as well as provide incentives in the private sector to make space travel frequent and affordable for the general public. Several additional sponsorships for the ANSARI X PRIZE competition remain available to corporations or individuals who wish to support the X PRIZE Foundation and associate themselves with space, speed and high technology.

Original Source: X PRIZE News Release

Posted on by Fraser Cain

On the Edge of a Supermassive Black Hole

Image credit: ESO
Fulfilling an old dream of astronomers, observations with the Very Large Telescope Interferometer (VLTI) at the ESO Paranal Observatory (Chile) have now made it possible to obtain a clear picture of the immediate surroundings of the black hole at the centre of an active galaxy. The new results concern the spiral galaxy NGC 1068, located at a distance of about 50 million light-years.

They show a configuration of comparatively warm dust (about 50?C) measuring 11 light-years across and 7 light-years thick, with an inner, hotter zone (500?C), about 2 light-years wide.

These imaging and spectral observations confirm the current theory that black holes at the centres of active galaxies are enshrouded in a thick doughnut-shaped structure of gas and dust called a “torus”.

For this trailblazing study, the first of its kind of an extragalactic object by means of long-baseline infrared interferometry, an international team of astronomers [2] used the new MIDI instrument in the VLTI Laboratory. It was designed and constructed in a collaboration between German, Dutch and French research institutes [3].

Combining the light from two 8.2-m VLT Unit Telescopes during two observing runs in June and November 2003, respectively, a maximum resolution of 0.013 arcsec was achieved, corresponding to about 3 light-years at the distance of NGC 1068. Infrared spectra of the central region of this galaxy were obtained that indicate that the heated dust is probably of alumino-silicate composition.

The new results are published in a research paper appearing in the May 6, 2004, issue of the international research journal Nature.

NGC 1068 – a typical active galaxy
Active galaxies are among the most spectacular objects in the sky. Their compact nuclei (AGN = Active Galaxy Nuclei) are so luminous that they can outshine the entire galaxy; “quasars” constitute extreme cases of this phenomenon. These cosmic objects show many interesting observational characteristics over the whole electromagnetic spectrum, ranging from radio to X-ray emission.

There is now much evidence that the ultimate power station of these activities originate in supermassive black holes with masses up to thousands of millions times the mass of our Sun, cf. e.g., ESO PR 04/01. The one in the Milky Way galaxy has only about 3 million solar masses, cf. ESO PR 17/02. The black hole is believed to be fed from a tightly wound accretion disc of gas and dust encircling it. Material that falls towards such black holes will be compressed and heated up to tremendous temperatures. This hot gas radiates an enormous amount of light, causing the active galaxy nucleus to shine so brightly.

NGC 1068 (also known as Messier 77) is among the brightest and most nearby active galaxies. Located in the constellation Cetus (The Whale) at a distance of about 50 million light-years, it looks like a rather normal, barred spiral galaxy. The core of this galaxy, however, is very luminous, not only in optical, but also in ultraviolet and X-ray light. A black hole with a mass equivalent to about 100 million times the mass of our Sun is required to account for the nuclear activity in NGC 1068.

The VLTI observations
On the nights of June 14 to 16, 2003, a team of European astronomers [2] conducted a first series of observations to verify the scientific potential of the newly installed MIDI instrument on the VLTI. They also studied the active galaxy NGC 1068. Already at this first attempt, it was possible to see details near the centre of this object, cf. ESO PR 17/03.

MIDI is sensitive to light of a wavelength near 10 ?m, i.e. in the mid-infrared spectral region (“thermal infrared”). With distances between the contributing telescopes (“baselines”) of up to 200 m, MIDI can reach a maximum angular resolution (image sharpness) of about 0.01 arcsec. Equally important, by combining the light beams from two 8.2-m VLT Unit Telescopes, MIDI now allows, for the first time, to perform infrared interferometry of comparatively faint objects outside our own galaxy, the Milky Way.

With its high sensitivity to thermal radiation, MIDI is ideally suited to study material in the highly obscured regions near a central black hole and heated by its ultraviolet and optical radiation. The energy absorbed by the dust grains is then re-radiated at longer wavelengths in the thermal infrared spectral region between 5 and 100 ?m.
The central region in NGC 1068

Additional interferometric observations were secured in November 2003 at a baseline of 42 m. Following a careful analysis of all data, the achieved spatial resolution (image sharpness) and the detailed spectra have allowed the astronomers to study the structure of the central region of NGC 1068.

They detect the presence of an innermost, comparatively “hot” cloud of dust, heated to about 500?C and with a diameter equal to or smaller than the achieved image sharpness, i.e. about 3 light-years. It is surrounded by a cooler, dusty region, with a temperature of about 50?C, measuring 11 light-years across and about 7 light-years thick. This is most likely the predicted central, disc-shaped cloud that rotates around the black hole.

The comparative thickness of the observed structure (the thickness is ~ 65% of the diameter) is of particular relevance in that it can only remain stable if subjected to a continuous injection of motion (“kinetic”) energy. However, none of the current models of central regions in active galaxies provide a convincing explanation of this.

The MIDI spectra, covering the wavelength interval from 8 – 13.5 ?m, also provide information about the possible composition of the dust grains. The most likely constituent is calcium aluminum-silicate (Ca2Al2SiO7), a high-temperature species that is also found in the outer atmospheres of some super-giant stars. Still, these pilot observations cannot conclusively rule out other types of non-olivine dust.

Original Source: ESO News Release

Posted on by Fraser Cain

Cassini’s First Detailed Look at Titan

Image credit: NASA/JPL/Space Sciences
The veils of Saturn’s most mysterious moon have begun to lift in Cassini’s eagerly awaited, first glimpse of the surface of Titan, a world where scientists believe organic matter rains from hazy skies and seas of liquid hydrocarbons dot a frigid surface.

Surface features previously observed only from Earth-based telescopes are now visible in images of Titan taken in mid-April through one of the narrow angle camera’s spectral filters specifically designed to penetrate the thick atmosphere. The image scale is 230 kilometers (143 miles) per pixel, and rivals the best Earth-based images.

The two narrow angle camea images displayed here show Titan from a vantage point 17 degrees below its equator, yielding a view from approximately 50 degrees north latitude all the way to its south pole. The image on the left was taken four days after the image on the right. Titan rotated 90 degrees in that time. The two images combined cover a region extending halfway around the moon. The observed brightness variations suggest a heterogenous surface, with variations in average reflectivity on scales of a couple hundred kilometers.

The images were taken through a narrow filter centered at 938 nanometers, a spectral region in which the only obstacle to the transmission of light through the molecular nitrogen atmosphere is the ubiquitous carbon-based, organic haze. Despite the rather long 38-second exposure times, there is no perceptible smear due to spacecraft motion. The images have been magnified 10 times using a procedure which smoothly interpolates between pixels to create intermediate pixel values, and have been enhanced in contrast to bring out details. No further processing to remove the effects of the overlying atmosphere has been performed.

The superimposed coordinate system grid in the accompanying images illustrates the geographical regions of the moon that are illuminated and visible, as well as the orientation of Titan — north is up and rotated 25 degrees to the left. The yellow curve marks the position of the terminator, the boundary between day and night on Titan. The enhanced image contrast makes the sunlit region within 20 degrees of the terminator darker than usual. The Sun illuminates Titan from the right at a phase (ie, Sun-Titan-Cassini) angle of 66 degrees. Because the Sun is in the southern hemisphere as seen from Titan, the north pole is canted relative to the terminator by 25 degrees.

Also shown here is a map of relative surface brightness variations on Titan as measured in images taken in the 1080-nanometer spectral region in 1997 and 1998 by the Near Infrared Camera (NICMOS) on Hubble Space Telescope (Meier, Smith, Owen and Terrile, Icarus 145: 462-473, 2000). NICMOS images have scales of about 300 kilometers (186 miles) per pixel. The map colors indicate different surface reflectivities. From darkest to brightest, the color progression is: deep blue (darkest), light blue, green, yellow, red, and deep red (brightest). The large, continent-sized, red feature extending from 60 degrees to 150 degrees West longitude is called Xanadu. It is unclear whether Xanadu is a mountain range, giant basin, smooth plain, or a combination of all three. It may be dotted with hydrocarbon lakes, but that is also unknown. All that is presently known is that in Earth-based images, it is the brightest region on Titan.

A comparison between the Cassini images and the Hubble map indicates that Xanadu is visible as a bright region in the Cassini image on the right. The dark blue northwest-southeast trending feature from 210 degrees to 250 degrees West longitude, and the bright yellow/green region to the east (right) and southeast of it at -50 degrees latitude and 180 to 230 degrees West longitude on the Hubble map, can both be seen in the image on the left.

It is noteworthy that the surface is visible to Cassini from its present approach geometry, which is not the most favorable for surface viewing. The success of these early Cassini observations portends success for upcoming imaging sequences of Titan in which the resolution improves by a factor of five over the next two months. These results are also encouraging for future, in-orbit observations of Titan that will be acquired from lower, more favorable phase angles.

The first opportunity to view small-scale features (2 kilometers or 1.2 miles) on the surface comes during a 350,000 kilometer (217,500 mile) flyby over Titan’s south pole on July 2, 2004, only 30 hours after Cassini’s insertion into orbit around the ringed planet.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

The Results of the Venus Challenge

Thanks to everyone who participated in my little Venus challenge. About two dozen of you took it on to head outside and snap a picture of Venus in your night sky. I love the international aspect of astronomy. No matter where on Earth you are right now, Venus is blazing in the night sky when the Sun goes down. How cool is that? I got photos from six continents, and many different countries. So, wherever you are, get out there and enjoy the night sky. Share your enthusiasm for space and astronomy with your friends.

Posted on by Mark Mortimer

Book Review: Comm Check

The seven-member crew of space shuttle Columbia was a picture perfect cross section of humanity. It included a range of ages, both sexes, a number of ethnicities and several nationalities. Each person was a very talented individual who was excelling in their chosen vocation. Almost all were living out a childhood fantasy of travelling in space. However, their goal was not that of personal glorification but rather of being a participant of the much larger space exploration effort undertaken by NASA, the United States and other world governments. These astronauts realized that they were a beacon for young and old alike; a symbol of what cooperation and skill can achieve. Their hopes, as well as the hopes of their families who were waiting at the landing site, were dealt a serious blow when Columbia didn’t return.

Of course, the shuttle relies on more than just the seven astronauts. Its related workforce totalled about 17,500 people of whom over 90% were contractors. These people were responsible for processing the shuttle before each flight and ensuring that the flight went smoothly. Here is where the main cause of Columbia’s failure arose. The people who were making these decisions were becoming over confident with every successful flight. In particular they were neglecting the fact that the shuttles were still designated as experimental. The mindset appeared to change from proving that the shuttle was ready to fly to one of proving that there was an anomaly that would make the shuttle unflyable. For example standing requirements for meeting readiness to flight were being challenged due to semantics rather than considering the safety implications. Expediency was replacing safety as the mantra of the day and this was a dark foreboding for the experimental shuttle.

Though the CAIB and this book share many of the same concerns about the accident, the authors raise a more fundamental one regarding NASA’s very existence. This concern centres on the political climate that now engages NASA. In the beginning, NASA was a political instrument with the very singular task of landing people on the moon and safely returning them to earth before the year 1970. Yes, in their time they had trials and disasters, but they were focussed and, more importantly, they had the support of the politicians words and especially the budget allocations. NASA succeeded in their task and deserved all the accolades given them.

Today NASA is drastically different. It has no singular goal and it seems to drift from one purpose to the next, as depending on the whim of the party in power. Further, most politicians happily vouch their support for space exploration yet almost yearly force a decrease in NASA’s budget. On top of this, NASA has gotten itself into a program bind. The shuttle’s reason for existence is to build the International Space Station (ISS). Yet the goal of the station itself appears to be mostly to provide rationale for the shuttle’s existence. Neither have strong justification for existence on their own nor do either have an apparent succession plan other than complete replacement. Through an executive order the shuttle is forbidden from launching commercial satellites and when flown for experiments, as Columbia was, there is precious little justification for the $500 million launch cost. NASA is unfocused and unsupported and needs to pull together to define a goal which would clearly places a value on programs, schedules and safety.

Cabbage and Harwood have written an engaging text that strongly focuses on the people directly involved with Columbia’s final flight. Part of it is like a testimonial to the crew and clearly we see the sacrifice made by the crew. I like the chronological narration particular in the rendition of what happened while Columbia was flying in orbit and the ground crew thought there was a problem but couldn’t prove it.

However though there was a lot of personal information sometimes it was excessive. The text contains the complete academic background and most of the career progression of the main individuals. Further, this information appears to be copied straight from a dossier rather than determined from personal interviews. I would have preferred more insight into the person’s feelings than their work accomplishments.

In Comm Check… The Final Flight of Shuttle Columbia, Michael Cabbage and William Harwood co-author an easy to read book that portrays the main people involved with the Columbia accident and the events surrounding it. Though there is no vilification of any person, and none appears to be due, there is a sense that something is not quite right at NASA. Reading this book will remind you of the sorrows of the second loss of a shuttle and will also give you a feeling of how close the United States is to cancelling any future human space flight. This would be a significant decision and reading this book may help you decide where you want to vote on this issue.

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Review by Mark Mortimer