Posted on by Fraser Cain

Why is Mars So Dry?

Image credit: NASA/JPL
The MER rovers Spirit and Opportunity, now traveling on the surface of Mars, are exploring a geography drier than the driest desert on Earth. Despite the polar ice caps and suspected pockets of liquid water beneath the martian surface, the amount of water on Mars is but a teaspoon compared to the vast watery reserves of Earth. Why is Mars so dry?

The inner planets of our solar system – Mars, Earth, Venus and Mercury – formed by the accumulation of small rocks and dust that swirled around the sun in its earliest years. If the Earth and Mars are made of the same stardust, they should have been born with about the same ratio of water.

Many scientists think Mars once was very watery, but lost its oceans due to the low mass of the planet. This, combined with a thin atmosphere, allowed most of the water on Mars to evaporate out into space.

But according to a study by Jonathan Lunine of the Lunar and Planetary Laboratory at the University of Arizona, the Red Planet was dry from the very beginning.

Lunine, writing in the journal Icarus in 2003 with colleagues John Chambers, Alessandro Morbidelli, and Laurie Leshin, says that Mars was originally a planetary embryo. In essence, a planetary embryo is a very large asteroid that can be as massive as Mercury or Mars. This pre-Mars embryo existed in the asteroid belt, which at the time was more widely dispersed in the solar system, spread out between 0.5 to 4 AU from the sun. Today the main asteroid belt is roughly at 2 to 4 AU, located between Mars (1.5 AU) and Jupiter (5.2 AU).

Lunine says that Mars grew to its present size from accumulations of smaller asteroids and comets. He says that the more massive Earth, in comparison, mostly formed from large planetary embryos colliding into each other.

“By chance Mars was not struck by giant asteroids while Earth was – the lucky versus unlucky pedestrian,” says Lunine. “But Mars was struck by much smaller bodies because these are so numerous.”

The Earth currently orbits the sun at 1 AU. Lunine says that planetary embryos in this orbit would not have had much water. Early in the sun’s evolution, during planetary formation, the dusty disk that surrounded the young star was very hot. Water-bearing compounds would not have been able to form in this disk at 1 AU.

Since Mars is further away from the sun than Earth, and closer to the cooler, “moist” regions of the asteroid belt, it would seem logical that Mars would have been born with more water. Yet Lunine says that Mars probably acquired only 6 to 27 percent of an Earth’s ocean (1 Earth ocean =1.5 ?1021 kg).

That’s because some of the planetary embryos that eventually constituted the Earth were saturated with water. While 90 percent of the embryos that formed the Earth were from the 1 AU region, and therefore dry, 10 percent were from 2.5 AU and beyond. Embryos coming from this distance would’ve had large supplies of water. Smaller asteroids coming from this distance would’ve contributed to the Earth’s water supply as well. At most, Lunine says that only 15 percent of Earth’s water came from comets.

Mars, meanwhile, had the bad luck to be born as a single dry rock. Mars eventually received some water late in the formation game, after its core had already formed and it had nearly reached its present mass. According to Lunine’s scenario, Jupiter also gained its present day mass around this time. Jupiter’s gravity then either sucked in nearby asteroids or caused them to scatter outwards. The proto-Mars somehow escaped being shifted by Jupiter’s gravity, but was bombarded by the outward-bound asteroids.

“The impacts of small asteroids and comets constituted a “late veneer” which added water to Mars, in contrast to the picture for Earth where water was added through collisions with Mercury-sized embryos throughout a growth period of some tens of millions of years,” the scientists write.

Although Mars doesn’t form in their computer model, the scientists think that may reflect the chaotic nature of planetary formation, where the directions of planetary embryos and asteroids are unpredictable and many outcomes are possible.

“There is a fair amount of randomness involved in building the terrestrial planets, so ending up with a Mars that did not happen to accrete many water-rich planetesimals is a possible occurrence,” says Alan Boss of the Carnegie Institution of Washington. “This may well help explain the paucity of water on modern-day Mars.”

Such differences in planetary formation also could occur among the inner planets of other solar systems. So far, astronomers know of 104 stars that have planets orbiting them. All of the extrasolar planets found so far are gas giants, but it seems likely that terrestrial planets like Mars and the Earth also could orbit distant stars, even though we do not yet have the technology to detect them.

If some inner terrestrial planets are formed by collisions of several planetary embryos, while others are embryos that only gather up moist comets and asteroids, then planets around these other stars could have very different amounts of water. Lunine suggests that the timing and formation of the gas giant planets in each solar system will play an important role in this process, just as Jupiter has influenced the character of our own solar system.

Lunine currently has a paper in Icarus, with Tom Quinn and Sean Raymond of the University of Washington, on the possible variation in water abundance for terrestrial planets around other stars. In addition, he is carefully watching the data collected by the MER rovers Spirit and Opportunity, as well as the satellites currently orbiting Mars.

“Odyssey, MER, and Mars Express will determine how much water exists at present, hopefully, and provide better constraints on past water abundance,” says Lunine. “I am particularly interested in the MARSIS radar results, and those of its successor – SHARAD.”

MARSIS is a radar device on the Mars Express satellite that can look through the top five kilometers of martian crust to search for layers of water and ice. The Italian space agency is planning to fly a shallow subsurface radar, called SHARAD, on NASA’s Mars Reconnaissance Orbiter to see if water ice is present at depths greater than one meter. While MARSIS has a higher penetration capability, it has much lower resolution than SHARAD will have.

Original Source: Astrobiology Magazine

Posted on by Fraser Cain

Titan Launches Defense Satellite

Image credit: Boeing
On the final mission for the program, a Boeing [NYSE:BA] Inertial Upper Stage (IUS) payload booster vehicle successfully deployed a U.S. Air Force Defense Support Program (DSP) satellite today.

The IUS-10 and its integrated payload, DSP-22, were launched aboard a Titan IV B rocket, which also flew with a Boeing-made fairing. Liftoff occurred at 1:50 p.m. EST from Space Launch Complex 40 at Cape Canaveral Air Force Station, Fla.

Upon separation from the rocket, IUS-10 fired its two stages to propel the spacecraft toward its geosynchronous orbit. Following roll maneuvers, the IUS successfully deployed the spacecraft.

?This last IUS mission added a critical asset to our nation?s military space program with the successful launch of DSP-22,? said Bill Benshoof, Boeing IUS program manager. ?The flight of IUS-10 concludes a 22-year journey for one of the most successful upper stages ever built and flown.?

The Boeing IUS program has supported national security, telecommunications and science missions with successful spacecraft deployments for the U.S. Department of Defense, the original Tracking and Data Relay Satellite constellation, and the Magellan, Galileo, Ulysses and Chandra missions for NASA.

Adding to the celebration of today?s successful last flight of the IUS, the Boeing IUS team received honors this week by the Air Force Association at the AFA?s Air Warfare Symposium in Orlando, Fla., for its significant contributions to the advancement of Air Force space activities in the last 50 years.

The Boeing IUS has been launched from the space shuttle and Titan IV rockets. There have been 24 IUS missions flown to date ? 15 launched from the shuttle and nine launched from the Titan IV.

A typical IUS mission launched from a Titan IV involves IUS separation from the rocket?s second stage booster approximately nine minutes into flight. The IUS takes over responsibility for the remainder of the powered portion of the flight.

For the next six hours and 45 minutes, the IUS autonomously performs all functions to place the spacecraft into its proper orbit.

The first IUS engine burn occurs a little over one hour into the IUS booster?s flight. The second solid rocket motor ignites about six-and-a-half hours into flight followed by a coast phase, and then, separation of the spacecraft.

IUS vehicle production was completed at Boeing in Kent, Wash. Spacecraft integration, checkout, ground operations and launch preparation activities were conducted at Cape Canaveral.

Boeing also produces the payload fairing for the Titan IV program. A 56-foot long fairing was used for the DSP-22 mission. Boeing-built fairings have flown on all 37 Titan IV launches to date and will fly aboard the remaining two Titan IV launches.

?This successful launch continues the 100 percent mission success record for the Titan IV payload fairing,? said Richard Peters, program manager and chief engineer, Boeing Titan fairing program.

The fairing for the DSP-22 mission was produced at Boeing in Huntington Beach, Calif., with the fairing?s thermal protection system applied at Boeing in Pueblo, Colo.

The Boeing IUS and Titan fairing programs are managed by Boeing Expendable Launch Systems in Huntington Beach.

The Defense Support Program is a satellite surveillance system providing the United States and its allies with ballistic missile early warning and other information related to missile launches, surveillance and the detonation of nuclear weapons.

A unit of The Boeing Company, Integrated Defense Systems is one of the world?s largest space and defense businesses. Headquartered in St. Louis, Boeing Integrated Defense Systems is a $27 billion business. It provides systems solutions to its global military, government and commercial customers. It is a leading provider of intelligence, surveillance and reconnaissance; the world?s largest military aircraft manufacturer; the world?s largest satellite manufacturer and a leading provider of space-based communications; the primary systems integrator for U.S. missile defense; NASA?s largest contractor; and a global leader in launch services.

Original Source: Boeing News Release

Posted on by Fraser Cain

New Galaxy Beats Distance Record

Image credit: Hubble
An international team of astronomers may have set a new record in discovering what is the most distant known galaxy in the universe. Located an estimated 13 billion light-years away, the object is being viewed at a time only 750 million years after the big bang, when the universe was barely 5 percent of its current age.

The primeval galaxy was identified by combining the power of NASA’s Hubble Space Telescope and CARA’s W. M. Keck Telescopes on Mauna Kea in Hawaii. These great observatories got a boost from the added magnification of a natural “cosmic gravitational lens” in space that further amplifies the brightness of the distant object.

The newly discovered galaxy is likely to be a young galaxy shining during the end of the so-called “Dark Ages” ? the period in cosmic history which ended with the first galaxies and quasars transforming opaque, molecular hydrogen into the transparent, ionized universe we see today.

The new galaxy was detected in a long exposure of the nearby cluster of galaxies Abell 2218, taken with the Advanced Camera for Surveys on board the Hubble Space Telescope. This cluster is so massive that the light of distant objects passing through the cluster actually bends and is amplified, much as a magnifying glass bends and magnifies objects seen through it. Such natural gravitational “telescopes” allow astronomers to see extremely distant and faint objects that could otherwise not be seen. The extremely faint galaxy is so far away its visible light has been stretched into infrared wavelengths, making the observations particularly difficult.

“As we were searching for distant galaxies magnified by Abell 2218, we detected a pair of strikingly similar images whose arrangement and color indicate a very distant object,” said astronomer Jean-Paul Kneib (Observatoire Midi-Pyrenees and Caltech), who is lead author reporting the discovery in a forthcoming article in the Astrophysical Journal.

Analysis of a sequence of Hubble images indicate the object lies in between a redshift of 6.6 and 7.1, making it the most distant source currently known. However, long exposures in the optical and infrared taken with spectrographs on the 10-meter Keck telescopes suggest that the object has a redshift towards the upper end of this range, around redshift 7.

Redshift is a measure of how much the wavelengths of light are shifted to longer wavelengths. The greater the shift in wavelength toward the redder regions of the spectrum, the more distant the object is.

“The galaxy we have discovered is extremely faint, and verifying its distance has been an extraordinarily challenging adventure,” said Dr. Kneib. “Without the magnification of 25 afforded by the foreground cluster, this early object could simply not have been identified or studied in any detail at all with the present telescopes available. Even with aid of the cosmic lens, the discovery has only been possible by pushing our current observatories to the limits of their capabilities!”

Using the combination of the high resolution of Hubble and the large magnification of the cosmic lens, the astronomers estimate that this object, although very small ? only 2,000 light-years across ? is forming stars extremely actively. However, two intriguing properties of the new source are the apparent lack of the typically bright hydrogen emission line and its intense ultraviolet light which is much stronger than that seen in star-forming galaxies closer by.

“The properties of this distant source are very exciting because, if verified by further study, they could represent the hallmark of a truly young stellar system that ended the Dark Ages,” added Dr. Richard Ellis, Steele Professor of Astronomy at Caltech, and a co-author in the article.

The team is encouraged by the success of their technique and plans to continue the search for more examples by looking through other cosmic lenses in the sky. Hubble’s exceptional resolution makes it ideally suited for such searches.

“Estimating the abundance and characteristic properties of sources at early times is particularly important in understanding how the universe reionized itself, thus ending the Dark Ages,” said Mike Santos, a former Caltech graduate student, now a postdoctoral researcher at the Institute of Astronomy, Cambridge, UK. “The cosmic lens has given us a first glimpse into this important epoch. We are now eager to learn more by finding further examples, although it will no doubt be challenging.”

“We are looking at the first evidence of our ancestors on the evolutionary tree of the entire universe,” said Dr. Frederic Chaffee, director of the W. M. Keck Observatory, home to the twin 10-meter Keck telescopes that confirmed the discovery. “Telescopes are virtual time machines, allowing our astronomers to look back to the early history of the cosmos, and these marvelous observations are of the earliest time yet.”

The Caltech team reporting on the discovery consists of Drs. Jean-Paul Kneib, Richard S. Ellis, Michael R. Santos and Johan Richard. Drs. Kneib and Richard also serve the Observatoire Midi-Pyrenees of Toulouse, France. Dr. Santos also represents the Institute of Astronomy, Cambridge, UK.

Public funding for this project was provided in part by NASA GSRP grant NGT5-50339 and NASA STScI grant HST-GO-09452.01-A.

The W. M. Keck Observatory is managed by the California Association for Research in Astronomy (CARA), a scientific partnership among the California Institute of Technology (Caltech), the University of California, and the National Aeronautics and Space Administration (NASA). The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

Original Source: Hubble News Release

Posted on by Fraser Cain

Valentine’s Day Greeting from Envisat

Image credit: ESA
Especially for Valentine’s Day, Envisat picks out a heart from the arid landscape of Africa’s Sahara.

This is a multi-temporal Advanced Synthetic Aperture Radar (ASAR) image of the central coast of Mauritania in West Africa, perched on the edge of the Sahara Desert.

The heart-shaped image seen at the centre of the picture is actually a land feature called the Sebkha Te-n-Dghamcha ? a large depression covering an area about 70 by 50 km across. ‘Sebkha’ is the Arabic for dry lake, and it was indeed once covered by water ? the area’s lowest point is more than three metres below sea level.

Most of the water evaporated, leaving behind layers of salt and other minerals including gypsum ? today supporting a thriving mining industry. What remains are shallow ponds of salty water, visible in the image.

While optical images are based on reflected light, radar images like this one show surface roughness, recording how radar pulses were scattered back from the ground towards a space-based detector.

Radar images are ordinarily in black and white. The colours come from combining three different image acquisitions into a single multi-temporal image, useful for highlighting changes occurring over time.

The first acquisition was on 23 November 2002, matching to red; the second on 23 March 2003, corresponding to green; and the last on 24 April 2003, shown as blue. The areas of whiteness in the final image represent areas of high surface reflectivity unchanged between acquisitions.

The saltpan surface of Sebkha Te-n-Dghamcha returns more radar backscatter than surrounding rock and desert sand. In the same way, the roofs and walls of Mauritania’s capital city Nouakchott reflect radar well, and so show up as the white area on the coast at the base of the image.

The different amounts of colours from each acquisition combine in the final image to form other hues that can be interpreted by experienced image processors ? for example, the magenta tint of the Atlantic Ocean shows it was at its calmest during the March acquisition.

Original Source: ESA News Release

Posted on by Fraser Cain

Oldest Quasars Give Clues About Cosmic Dark Age

Image credit: SDSS
The most distant known quasars show that some supermassive black holes formed when the universe was merely 6 percent of its current age, or about 700 million years after the big bang.

How black holes of several billion solar masses formed so rapidly in the very early universe is one mystery raised by astronomers with the Sloan Digital Sky Survey (SDSS). They have discovered 13 of the oldest, most distant quasars yet found.

“We hope to at least double that number in the next three years,” said Xiaohui Fan of the University of Arizona?s Steward Observatory in Tucson.

Fan led the SDSS team that discovered the distant quasars, which are compact but luminous objects thought to be powered by supermassive black holes. The most distant quasar, in the constellation Ursa Major, is roughly 13 billion light years away.

The most ancient quasars raise other tantalizing questions about the early universe. Fan talked about it today (Feb. 13) at the American Association for the Advancement of Science annual meeting in Seattle.

The infant universe was hydrogen and helium.

“But we see a lot of other elements around those early quasars,” Fan said. “We see evidence of carbon, nitrogen, iron and other elements, and it?s not clear how these elements got there. There is as much iron, proportionate to the population of those early systems, as there is in mature galaxies nearby.”

Astronomers estimate the current age of the universe at 13.7 billion years. Quasars in the early universe looked as mature as nearby galaxies that, like the Milky Way, formed a couple of billion years after the big bang.

Also, radio astronomers collaborating with SDSS researchers detected carbon monoxide, a key component of molecular clouds, near the ancient quasars.

All this evidence suggests that the first mature galaxies formed right along with the ancient supermassive black holes in the very early universe.

Although cosmologists aren?t panicked, they need to refine theory to clarify what?s going on.

Fan and his colleagues believe the oldest quasars can be used to probe the end of the Cosmic Dark Ages and the beginning of the Cosmic Renaissance.

In so-called Cosmic Dark Ages, the universe was a cold, opaque place without stars. Then came a critical phase where the universe went through a rapid transition. The first galaxies and quasars formed in the Cosmic Renaissance, heating the universe so it became the place we see today.

Fan and his colleagues believe some of their oldest known quasars may span the critical transition.

“Our observations suggest that what we may be seeing during this transition is atomic hydrogen becoming completely ionized. This ionization process was one of the important processes going on during the first one billion years.”

Current observations have just begun to reveal when and how this ionization process occurred. Data from distant quasars combined with other evidence, such as from the cosmic microwave background, which is relict radiation from the big bang, will begin to test theory of how the first galaxies appeared in the universe, Fan said.

It may take the large-aperture space telescope, NASA’s 6.5-meter James Webb Space Telescope, to really explore what happened between the Cosmic Dark Ages and the Cosmic Renaissance, Fan said.

Optical/infrared ground-based telescopes cannot detect objects red-shifted much beyond 6.5, Fan noted. Water vapor in Earth?s atmosphere absorbs longer infrared wavelengths, so it will take a space-based telescope, probably with an aperture larger than that of the NASA Spitzer Telescope now orbiting Earth, to study objects at redshift 7, 8, or 10 in detail, Fan said.

(So-called redshift is a phenomenon proportional to the velocity of a a celestial object speeding away from Earth. The lines in its spectrum shift toward longer, red wavelengths. Astronomers now believe that the most distant objects recede from Earth at the highest velocities, so the farther away an object is, the greater its redishift.)

Original Source: UA News Release

Posted on by Fraser Cain

Interplanetary Network Connects Rovers, Orbiters, Agencies and Earth

Image credit: ESA
A pioneering demonstration of communications between the European Space Agency’s Mars Express orbiter and NASA’s Mars exploration rover, Spirit, has succeeded.

On 6 February, while Mars Express was flying over the area that Spirit is examining, the orbiter transferred commands from Earth to the rover and relayed data from the rover back to Earth.

“This was the first in-orbit communication between ESA and NASA spacecraft, and we have also created the first working international communications network around another planet,” said Rudolf Schmidt, ESA’s Project Manager for Mars Express. “Both are significant achievements, two more ‘firsts’ for Mars Express and the Mars exploration rovers.”

Jennifer Trosper, Spirit Mission Manager at NASA’s Jet Propulsion Laboratory, California, USA, said, “We have an international interplanetary communications network established at Mars.”

ESA and NASA planned this demonstration as part of continuing efforts to cooperate in space.

The commands for the rover were first transferred from Spirit’s operations team at JPL to ESA’s European Space Operations Centre in Darmstadt, Germany, where they were translated into commands for Mars Express. The translated commands were transmitted to Mars Express, which used them to command Spirit. Spirit used its ultra-high-frequency antenna to transmit telemetry information to Mars Express, and the orbiter then relayed the data back to JPL via the European Space Operations Centre.

“This is excellent news,” said JPL’s Richard Horttor, project manager for NASA’s roles in Mars Express. “The communication sessions between Mars Express and Spirit were pristine. Not a single bit of data was missing or added, and there were no duplications.”

This exercise demonstrates the increased flexibility and capabilities of inter-agency cooperation and highlights the close mutual support that is essential when undertaking international space exploration.

More information on the ESA Mars Express mission can be found at http://mars.esa.int

Original Source: ESA News Release

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Spirit Sees Rising Pockets of Warm Air

Image credit: Cornell
An instrument on the NASA rover Spirit in Gusev crater on the surface of Mars has detected billows of warm air — called thermals — which rise from the planet’s surface into the thin atmosphere. Thermal changes create wind, and this was the first time these pockets of warm air have been detected on the planet.

“We now can see them (thermals) on Mars and learn how quickly they rise, giving us a better understanding of the wind dynamics there,” said Donald Banfield, Cornell senior research associate in space sciences, at a press briefing today (Feb. 12) at the Jet Propulsion Laboratory in Pasadena, Calif.

Atmospheric science is critical to understanding the complete Martian environment, explained Banfield. Before this mission, planetary scientists had scarce information on the planet’s surface-temperature structure. Satellites orbiting Mars provided temperature information for the upper portions of the planet’s atmosphere. Until now, the temperatures on the surface could not be measured.

Banfield said that wind is sculpting the geological features on Mars. “Wind is the issue. It creates dunes, dust devils and dust storms, and understanding it is important,” he said.

Before the rover Spirit experienced memory malfunctions in January, its Mini-Thermal Emission Spectrometer device, or MiniTES, gathered one eight-minute block of spectral data by staring at the Martian sky. The data, examined by Michael Smith of NASA’s Goddard Space Flight Center and Banfield, showed pockets of warm air rising every few minutes. Both are members of the Mars Exploration Rover mission’s science team.

The MiniTES instrument can read the temperature by analyzing the infrared spectrum in the lower atmosphere. Banfield explained that since the Martian atmosphere is mostly carbon dioxide, the instrument perceives the infrared light wavelength and translates it into temperature.

“We saw warmer and cooler places in the Mars atmosphere,” Banfield told the media. “There were warm blobs and cold blobs passing over the rover.”

As the sun rises each day on Mars, the surface temperature climbs much like on Earth. “There is an upward trend of warm air, convection,” said Banfield. “This is exciting data?this is novel data.”

Meanwhile on the other side of Mars, the rover Opportunity, now at the rock outcrop Stone Mountain on the Meridiani plain, obtained an extreme close-up of round, blueberry-shaped formations in the soil. The spherically shaped formations are about the size of BB pellets and the mission scientists have begun to study them for clues about the soil’s development.

Original Source: Cornell News Release

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Astronomers Find a Huge Diamond in Space

Image credit: CfA
When choosing a Valentine’s Day gift for a wife or girlfriend, you can’t go wrong with diamonds. If you really want to impress your favorite lady this Valentine’s Day, get her the galaxy’s largest diamond. But you’d better carry a deep wallet, because this 10 billion trillion trillion carat monster has a cost that’s literally astronomical!

“You would need a jeweler’s loupe the size of the Sun to grade this diamond!” says astronomer Travis Metcalfe (Harvard-Smithsonian Center for Astrophysics), who leads a team of researchers that discovered the giant gem. “Bill Gates and Donald Trump together couldn’t begin to afford it.”

When asked to estimate the value of the cosmic jewel, Ronald Winston, CEO of Harry Winston Inc., indicated that such a large diamond probably would depress the value of the market, stating, “Who knows? It may be a self-deflating prophecy because there is so much of it.” He added, “It is definitely too big to wear!”

The newly discovered cosmic diamond is a chunk of crystallized carbon 50 light-years from the Earth in the constellation Centaurus. (A light-year is the distance light travels in a year, or about 6 trillion miles.) It is 2,500 miles across and weighs 5 million trillion trillion pounds, which translates to approximately 10 billion trillion trillion carats, or a one followed by 34 zeros.

“It’s the mother of all diamonds!” says Metcalfe. “Some people refer to it as ‘Lucy’ in a tribute to the Beatles song ‘Lucy In The Sky With Diamonds.'”

The diamond star completely outclasses the largest diamond on Earth, the 530-carat Star of Africa which resides in the Crown Jewels of England. The Star of Africa was cut from the largest diamond ever found on Earth, a 3,100-carat gem.

The huge cosmic gem (technically known as BPM 37093) is actually a crystallized white dwarf. A white dwarf is the hot core of a star, left over after the star uses up its nuclear fuel and dies. It is made mostly of carbon and is coated by a thin layer of hydrogen and helium gases.

For more than four decades, astronomers have thought that the interiors of white dwarfs crystallized, but obtaining direct evidence became possible only recently.

“The hunt for the crystal core of this white dwarf has been like the search for the Lost Dutchman’s Mine. It was thought to exist for decades, but only now has it been located,” says co-author Michael Montgomery (University of Cambridge).

The white dwarf studied by Metcalfe, Montgomery, and Antonio Kanaan (UFSC Brazil), is not only radiant but also harmonious. It rings like a gigantic gong, undergoing constant pulsations.

“By measuring those pulsations, we were able to study the hidden interior of the white dwarf, just like seismograph measurements of earthquakes allow geologists to study the interior of the Earth. We figured out that the carbon interior of this white dwarf has solidified to form the galaxy’s largest diamond,” says Metcalfe.

Our Sun will become a white dwarf when it dies 5 billion years from now. Some two billion years after that, the Sun’s ember core will crystallize as well, leaving a giant diamond in the center of our solar system.

“Our Sun will become a diamond that truly is forever,” says Metcalfe.

A paper announcing this discovery has been submitted to The Astrophysical Journal Letters for publication.

Original Source: CfA News Release

Posted on by Fraser Cain

Space Exploration Commission Holds First Hearing

The commission appointed to investigate the feasibility of US President’s Bush’s new space initiative held its first public hearing on Wednesday, and heard testimony from five aerospace experts. The testimony from Norman Augustine, retired chairman of Lockheed Martin Corp, said that a human mission to Mars would be very expensive, probably on the order of $150 billion over the next 10 years. He urged the commission to make sure this doesn’t get done “on the cheap”; and pointed to NASA’s history of underestimating the costs for major new projects. The commission is expected to deliver its report in approximately 120 days.

Posted on by Fraser Cain

Wallpaper: Spitzer’s Valentine Rose

Image credit: NASA/JPL
Out of the dark and dusty cosmos comes an unusual valentine ? a stellar nursery resembling a shimmering pink rosebud. This cluster of newborn stars, called a reflection nebula, was captured by state-of-the-art infrared detectors onboard NASA’s new Spitzer Space Telescope, formerly known as the Space Infrared Telescope Facility.

The Valentine’s Day image is available online at http://www.spitzer.caltech.edu and http://photojournal.jpl.nasa.gov/catalog/PIA05266.

“The picture is more than just pretty,” said Dr. Thomas Megeath, principal investigator for the latest observations and an astronomer at the Harvard Smithsonian Center for Astrophysics, Cambridge, Mass. “It helps us understand how stars form in the crowded environments of stellar nurseries.”

Located 3,330 light-years away in the constellation Cepheus and spanning 10 light-years across, the rosebud-shaped nebula, numbered NGC 7129, is home to some 130 young stars. Our own Sun is believed to have grown up in a similar family setting.

Previous images of NGC 7129 taken by visible telescopes show a smattering of hazy stars spotted against a luminescent cloud. Spitzer, by sensing the infrared radiation or heat of the cluster, produces a much more detailed snapshot. Highlighted in false colors are the hot dust particles and gases, respectively, which form a nest around the stars. The pink rosebud contains adolescent stars that blew away blankets of hot dust, while the green stem holds newborn stars whose jets torched surrounding gases.

Outside of the primary nebula, younger proto-stars can also be seen for the first time. “We can now see a few stars beyond the nebula that were previously hidden in the dark cloud,” said Megeath.

In addition, the findings go beyond what can be seen in the image. By analyzing the amount and type of infrared light emitted by nearly every star in the cluster, scientists were able to determine which ones support the swirling rings of debris, called circumstellar discs, which eventually coalesce to form planets. Roughly half of the stars observed were found to harbor discs.

These observations will ultimately help astronomers determine how stellar nurseries shape the development of planetary systems similar to our own.

Launched on August 25, 2003, from Cape Canaveral Air Force Station, Florida, the Spitzer Space Telescope is the fourth of NASA?s Great Observatories, a program that also includes the Compton Gamma Ray Observatory, Chandra X-ray Observatory and Hubble Space Telescope.

JPL manages the Spitzer Space Telescope mission for NASA’s Office of Space Science, Washington, D.C. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. JPL is a division of Caltech.

Additional information about the Spitzer Space Telescope is available at http://www.spitzer.caltech.edu.

Original Source: NASA/JPL News Release