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

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

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

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

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.

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.

Read more reviews, and find similar books from Amazon.com

Review by Mark Mortimer

New Research Doubts Life in Martian Meteorite

Image credit: NASA
The scientific debate over whether a meteorite contains evidence of past life on Mars continues to intensify, with colleagues of the team that announced the possibility in 1996 revealing new findings that may cast doubt on some of that earlier work.

?These new findings illustrate the excellent scientific process that was ignited by the announcement in 1996 of possible meteorite evidence of past life on Mars,? said Dr. Steven Hawley, Associate Director, Office of Astromaterials Research and Exploration Science at the Johnson Space Center. ?As work on this fundamental question continues, it is quite likely the final answer may not be known until Mars samples can be retrieved for study by scientists there or back on Earth.?

In the recent study, a team of scientists based largely at JSC found that a mineral in Mars meteorite ALH84001 that had been asserted to be most likely caused by an ancient microscopic organism may have been caused by a non-biological process. The team, led by D.C. Golden of Hernandez Engineering Inc. in Houston and including many NASA scientists from the Office of Astromaterials Research and Exploration Science, will have its work published in the May/June issue of American Mineralogist. The same office includes Dave McKay, Everett Gibson and several other scientists who contributed to the 1996 findings.

The new paper reports that magnetite, an iron-bearing mineral found in Martian meteorite ALH84001, was likely caused by inorganic processes, and that those same processes can be recreated in the laboratory, forming magnetite identical to that found in the Mars meteorite.

Magnetite crystals in ALH84001 have been a focus of debate about the possibility of life on Mars. The 1996 study led by McKay suggested that some magnetite crystals associated with carbonate globules in ALH84001 are biogenic because they share many characteristics with those found in bacteria on Earth. A study led by Kathie Thomas-Keprta in 2000 showed that some of the magnetite crystals in ALH84001 carbonate globules are characterized by elongation, a ?unique habit? identical to magnetite grains produced by bacteria on Earth.

Golden and his team first investigated whether an inorganic process can produce magnetite crystals identical to those in ALH84001 claimed by Thomas-Keprta?s team to be biogenic. Then, they sought to replicate the tenet of McKay?s 1996 hypothesis that the purported biogenic magnetite grains in ALH84001 are identical to those produced by a bacterium called MV-1.

Golden?s team concluded that the shapes of the MV-1 and ALH84001 elongated crystals differ. Their study concluded that inorganic processes can make the magnetite crystals in ALH84001, so any claim to a biological source is uncertain. Golden?s team found that decomposition of iron-bearing carbonate under high heat produced magnetite crystals identical to those found in ALH84001.

?The strength of the inorganic process provided here is that not only does it produce elongated magnetite crystals identical to those of the ALH84001 meteorite, but also it produces a whole range of features found in the meteorite,? said Golden, a mineralogist at JSC.

McKay, chief scientist for astrobiology at JSC, stands by his 1996 findings. ?We originally proposed a suite of four lines of evidence which, taken together, were consistent as a package with a possible biological origin,? McKay said. ?The Golden group has singled out one very specific feature, the shape of the magnetite crystals, to try to discredit the whole biogenic hypothesis. Their alternative inorganic hypothesis, thermal decomposition of carbonate, will not explain many of the features described by us in ALH84001. A plausible inorganic model must explain simultaneously all of the properties that we and others have suggested as possible biogenic properties of this meteorite.?

ALH84001 was discovered in 1984 in the Allan Hills region of Antarctica by an annual expedition of the National Science Foundation?s Antarctic Meteorite Program. Its Martian origin was not recognized until 1993. One of about 30 meteorites discovered on Earth thought to be from Mars, it is a softball-sized igneous rock weighing 1.9 kilograms (4.2 pounds). With the exception of ALH84001, all are less than 1.3 billion years old. ALH84001 is 4.5 billion years old.

To view the study on the Internet, visit:

http://www.minsocam.org/MSA/AmMin/AmMineral.html For information about space research on the Internet, visit: http://spaceresearch.nasa.gov/Video to accompany this release will air on the NASA Television Video File at 11 a.m. CDT May 5. NASA TV is on AMC-9, transponder 9C, C-Band, at 85 degrees west longitude, frequency 3880.0 MHz, polarization vertical, audio monaural at 6.80 MHz.

Original Source: NASA News Release

Planetary Society Wants to Aim for Mars

The Planetary Society has come on strong to support the human exploration of the Solar System with a new petition – Aim for Mars – that they intend to deliver to the US Congress. One of the cool things with this petition is that they’ve opened it up to people from other countries as well, as there are ways we can support the initiative (I’m from Canada, remember). They’ve also got lots of other resources to help you understand how to get involved.

Sign the petition!

Fraser Cain
Publisher
Universe Today

Opportunity Reaches Endurance Crater

Image credit: NASA/JPL
This 180-degree view [false-color] from the navigation camera on the Mars Exploration Rover Opportunity is the first look inside “Endurance Crater.” The view is a cylindrical projection constructed from four images. The crater is about 130 meters (about 430 feet) in diameter.

Plans are for the rover first to circumnavigate the 1,350-foot perimeter of the crater, then mission planners will be faced with the tough decision about whether to go into Endurance. One potential hazard that choice might entail stems from the steep walls and fine soil.

Even when exiting the much smaller Eagle Crater (about 1/7th the size of Endurance, the rover eventually ground to a halt. The rover’s wheel traction is generally rated to between 15 and 20 degrees for climbing slopes, but particularly near a crater rim, the soil is through to resemble talcum or powdered cement, rather than sand.

Scientists expect to release a spectacular color, high-resolution panorama of Endurance for their next news conference scheduled Thursday.

One characteristic that struck onlookers even from a distance was the layering along the rim and similarity of light colored outcrops thought to represent ancient Martian bedrock. Such stratigraphy reveals a layered history, where the newest sediments deposit on top and the older material is exposed below. By reading this layering like tree rings, scientists hope to read more chapters of their ongoing mystery: what happened to surface water on Mars?

Compared to the most detailed layer at Eagle crater (about 16 inches high), the much older and deeper layers at Endurance appear to be up to 8 feet tall in places. The more layers, the farther back in martian times the bedrock may reveal.

A key scientific objective for this part of Opportunity’s extended mission will be to seek geologic context for the outcrop in the “Eagle” crater by reaching other outcrops in the “Endurance” crater and perhaps elsewhere. Other science objectives are to continue atmospheric studies at both sites to encompass more of Mars’ seasonal cycle and to calibrate and validate data from Mars orbiters for additional types of rocks and soils examined on the ground.

Meanwhile on the opposite side of the planet, the Spirit rover logged another record-breaking day of driving. The last odometer reading turned nearly 100 yards, a goal-to-goal trek traversing the length of a football field.

“We’re going to continue exploring and try to understand the water story at Gusev,” said JPL’s Dr. Mark Adler, deputy mission manager for Spirit. Spirit is in pursuit of geological evidence for an ancient lake thought to have once filled Gusev Crater. Reaching “Columbia Hills,” which could hold geological clues to that water story, is one of several objectives for the extended mission.

New engineering objectives are to traverse more than a kilometer (0.62 mile) to demonstrate mobility technologies; to characterize solar-array performance over long durations of dust deposition at both landing sites; and to demonstrate long-term operation of two mobile science robots on a distant planet. During the past month or so, rover teams at JPL have switched from Mars-clock schedules to Earth-clock schedules designed to be less stressful and more sustainable over a longer period towards what is hoped will be another September mission extension.

Original Source: Astrobiology Magazine

Astronomers Peer Into Our Universe’s Dark Age

Image credit: NASA
Astronomers who want to study the early universe face a fundamental problem. How do you observe what existed during the “dark ages,” before the first stars formed to light it up? Theorists Abraham Loeb and Matias Zaldarriaga (Harvard-Smithsonian Center for Astrophysics) have found a solution. They calculated that astronomers can detect the first atoms in the early universe by looking for the shadows they cast.

To see the shadows, an observer must study the cosmic microwave background (CMB) – radiation left over from the era of recombination. When the universe was about 370,000 years old, it cooled enough for electrons and protons to unite, recombining into neutral hydrogen atoms and allowing the relic CMB radiation from the Big Bang to travel almost unimpeded across the cosmos for the past 13 billion years.

Over time, some of the CMB photons encountered clumps of hydrogen gas and were absorbed. By looking for regions with fewer photons – regions that are shadowed by hydrogen – astronomers can determine the distribution of matter in the very early universe.

“There is an enormous amount of information imprinted on the microwave sky that could teach us about the initial conditions of the universe with exquisite precision,” said Loeb.

Inflation and Dark Matter
To absorb CMB photons, the hydrogen temperature (specifically its excitation temperature) must be lower than the temperature of the CMB radiation – conditions that existed only when the universe was between 20 and 100 million years old (age of Universe: 13.7 billion years). Coincidentally, this is also well before the formation of any stars or galaxies, opening a unique window into the so-called “dark ages.”

Studying CMB shadows also allows astronomers to observe much smaller structures than was possible previously using instruments like the Wilkinson Microwave Anisotropy Probe (WMAP) satellite. The shadow technique can detect hydrogen clumps as small as 30,000 light-years across in the present-day universe, or the equivalent of only 300 light-years across in the primordial universe. (The scale has grown larger as the universe expanded.) Such resolution is a factor of 1000 times better than the resolution of WMAP.

“This method offers a window into the physics of the very early universe, namely the epoch of inflation during which fluctuations in the distribution of matter are believed to have been produced. Moreover, we could determine whether neutrinos or some unknown type of particle contribute substantially to the amount of ‘dark matter’ in the universe. These questions – what happened during the epoch of inflation and what is dark matter – are key problems in modern cosmology whose answers will yield fundamental insights into the nature of the universe,” said Loeb.

An Observational Challenge
Hydrogen atoms absorb CMB photons at a specific wavelength of 21 centimeters (8 inches). The expansion of the universe stretches the wavelength in a phenomenon called redshifting (because a longer wavelength is redder). Therefore, to observe 21-cm absorption from the early universe, astronomers must look at longer wavelengths of 6 to 21 meters (20 to 70 feet), in the radio portion of the electromagnetic spectrum.

Observing CMB shadows at radio wavelengths will be difficult due to interference by foreground sky sources. To gather accurate data, astronomers will have to use the next generation of radio telescopes, such as the Low Frequency Array (LOFAR) and the Square Kilometer Array (SKA). Although the observations will be a challenge, the potential payoff is great.

“There’s a gold mine of information out there waiting to be extracted. While its full detection may be experimentally challenging, it’s rewarding to know that it exists and that we can attempt to measure it in the near future,” said Loeb.

This research will be published in an upcoming issue of Physical Review Letters, and currently is available online at http://arxiv.org/abs/astro-ph/0312134.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

Original Source: Harvard CfA News Release