Posted on by Fraser Cain

Spitzer Sees the Aftermath of a Planetary Collision

Astronomers say a dusty disc swirling around the nearby star Vega is bigger than earlier thought. It was probably caused by collisions of objects, perhaps as big as the planet Pluto, up to 2,000 kilometers (about 1,200 miles) in diameter.

NASA’s Spitzer Space Telescope has seen the dusty aftermath of this “run-in.” Astronomers think embryonic planets smashed together, shattered into pieces and repeatedly crashed into other fragments to create ever-finer debris. Vega’s light heats the debris, and Spitzer’s infrared telescope detects the radiation.

Vega, located 25 light-years away in the constellation Lyra, is the fifth brightest star in the night sky. It is 60 times brighter than our sun. Observations of Vega in 1984, with the Infrared Astronomical Satellite, provided the first evidence for dust particles around a typical star. Because of Vega’s proximity and because its pole faces Earth, it provides a great opportunity for detailed study of the dust cloud around it.

“Vega’s debris disc is another piece of evidence demonstrating the evolution of planetary systems is a pretty chaotic process,” said lead author of the study, Dr. Kate Su of the University of Arizona, Tucson, Ariz. The findings were presented today at the 205th meeting of the American Astronomical Society in San Diego.

Like a drop of ink spreading out in a glass of water, the particles in Vega’s dust cloud don’t stay close to the star long. “The dust we are seeing in the Spitzer images is being blown out by intense light from the star,” Su said. “We are witnessing the aftermath of a relatively recent collision, probably within the last million years,” she explained.

Scientists say this disc event is short-lived. The majority of the detected material is only a few microns in size, 100 times smaller than a grain of Earth sand. These tiny dust grains leave the system and dissipate into interstellar space on a time scale less than 1,000 years. “But there are so many tiny grains,” Su said. “They add up to a total mass equal to one third of the weight of our moon,” she said.

The mass of these short-lived grains implies a high dust-production rate. The Vega disc would have to have an improbably massive reservoir of planet-building material and collisions to maintain this amount of dust production throughout the star’s life (350 million years, 13 times younger than our sun). “We think a transient disc phenomenon is more likely,” Su said.

Su and her colleagues were struck by other characteristics of Vega’s debris disc, including its physical size. It has a radius of at least 815 astronomical units, roughly 20 times larger than our solar system. One astronomical unit is the distance from Earth to the sun, which is 150 million kilometers (93 million miles). A study of the disc’s surface brightness indicates the presence of an inner hole at a radius of 86 astronomical units (twice the distance between Pluto and the sun). Large embryonic planets at the edge of this inner hole may have collided to make the rest of the debris around Vega.

“Spitzer has obtained the first high spatial-resolution infrared images of Vega’s disc,” said Dr. Michael Werner, co-author and project scientist for Spitzer at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. “Its sensitive infrared detectors have allowed us to see that Vega is surrounded by an enormous disc of debris,” he said.

JPL manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology (Caltech) in Pasadena. JPL is a division of Caltech. The multi-band imaging photometer for Spitzer, which made the new disc observations, was built by Ball Aerospace Corporation, Boulder, Colo.; the University of Arizona; and Boeing North American, Canoga Park, Calif.

Imagery and additional information about the Spitzer Space Telescope is available on the Internet, at:

http://www.spitzer.caltech.edu/Media

Original Source: NASA News Release

Posted on by Fraser Cain

Seeing Into the Heart of the Milky Way

The center of our galaxy is hidden behind a “brick wall” of obscuring dust so thick that not even the Hubble Space Telescope can penetrate it. Astronomers Silas Laycock and Josh Grindlay (Harvard-Smithsonian Center for Astrophysics) and colleagues have lifted that veil to reveal a beautiful vista swarming with stars. Moreover, their hunt for specific stars associated with X-ray-emitting sources has ruled out one of two options for the nature of these X-ray sources: most apparently are not associated with massive stars, which would have shown up as bright counterparts in their deep infrared images. This points to the X-ray sources being white dwarfs, not black holes or neutron stars, accreting matter from low-mass binary companion stars.

Their study is being presented today at a press conference at the 205th meeting of the American Astronomical Society in San Diego, Calif.

To peer into the galactic center, Laycock and Grindlay used the unique capabilities of the 6.5-meter-diameter Magellan Telescope in Chile. By gathering infrared light that more easily penetrates dust, the astronomers were able to detect thousands of stars that otherwise would have remained hidden. Their goal was to identify stars that orbit, and feed, X-ray-emitting white dwarfs, neutron stars or black holes – any of which could yield the faint X-ray sources discovered originally with NASA’s Chandra X-ray Observatory.

Chandra previously detected more than 2000 X-ray sources in the central 75 light-years of our galaxy. About four-fifths of the sources emitted mostly hard (high-energy) X-rays. The precise nature of those hard X-ray sources remained a mystery. Two possibilities were suggested by astronomers: 1) high-mass X-ray binary systems, containing a neutron star or black hole with a massive stellar companion; or, 2) cataclysmic variables, containing a highly magnetized white dwarf with a low-mass stellar companion. Determining the nature of the sources can teach us about the star formation history and dynamical evolution of the region near the galactic center.

“If we found that most of the hard X-ray sources were high-mass X-ray binaries, it would tell us that there had been a lot of recent star formation because massive stars don’t live long,” says Laycock. “Instead, we found that most of the X-ray sources are likely to be older systems associated with low-mass stars.”

That conclusion comes from a null result: that is, most of the counterparts to the X-ray sources must be fainter than the brightness expected if the X-ray sources had massive companions. Since massive stars are both rare and bright, an association with the X-ray sources would have been easy to spot. Smaller stars are more common and fainter, making it difficult to match them to a specific X-ray source. Analysis of the infrared images found only a chance number of matches between stars and the locations of X-ray sources. Many of those matches likely were due to the crowded field of view.

“The fact that we found no significant excess of bright infrared counterparts means that the galactic center Chandra sources are probably low-mass binaries. Since by far the most common low-mass binaries with X-ray luminosities, spectra, and variability similar to the galactic center Chandra sources are accreting magnetic white dwarfs, we conclude these are the most likely identification,” says Grindlay.

If the X-ray sources near the galactic center are accreting white dwarfs, the large numbers of compact low-mass binaries required could suggest that they formed in the very dense star cluster around the galactic center or that they have been “deposited” there by the destruction of globular clusters. Deeper infrared observations and spectra of the sources are needed to make actual identifications and constrain the masses of the accreting compact objects.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) 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: CfA News Release

Posted on by Fraser Cain

Iapetus Has a Seam

Images returned by NASA’s Cassini spacecraft cameras during a New Year’s Eve flyby of Saturn’s moon Iapetus (eye-APP-eh-tuss) show startling surface features that are fueling heated scientific discussions about their origin.

One of these features is a long narrow ridge that lies almost exactly on the equator of Iapetus, bisects its entire dark hemisphere and reaches 20 kilometers high (12 miles). It extends over 1,300 kilometers (808 miles) from side to side, along its midsection. No other moon in the solar system has such a striking geological feature. In places, the ridge is comprised of mountains. In height, they rival Olympus Mons on Mars, approximately three times the height of Mt. Everest, which is surprising for such a small body as Iapetus. Mars is nearly five times the size of Iapetus.

Images from the flyby are available at http://saturn.jpl.nasa.gov, http://www.nasa.gov/cassini and http://ciclops.org.

Iapetus is a two-toned moon. The leading hemisphere is as dark as a freshly-tarred street, and the white, trailing hemisphere resembles freshly-fallen snow.

The flyby images, which revealed a region of Iapetus never before seen, show feathery-looking black streaks at the boundary between dark and bright hemispheres that indicate dark material has fallen onto Iapetus. Opinions differ as to whether this dark material originated from within or outside Iapetus. The images also show craters near this boundary with bright walls facing towards the pole and dark walls facing towards the equator.

Cassini’s next close encounter with Iapetus will occur in September 2007. The resolution of images from that flyby should be 100 times better than the ones currently being analyzed. The hope is that the increased detail may shed light on Iapetus’ amazing features and the question of whether it has been volcanically active in the past.

With a diameter of about 1,400 kilometers (890 miles), Iapetus is Saturn’s third largest moon. It was discovered by Jean-Dominique Cassini in 1672. It was Cassini, for whom the Cassini-Huygens mission is named, who correctly deduced that one side of Iapetus was dark, while the other was white.

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 Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The European Space Agency built and manages the development of the Huygens probe and is in charge of the probe operations. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini’s science instruments. The imaging team is based at the Space Science Institute, Boulder, Colo.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Topography Mission Wraps Up With Australia

Culminating more than four years of processing data, NASA and the National Geospatial-Intelligence Agency have completed Earth’s most extensive global topographic map.

The data, extensive enough to fill the U.S. Library of Congress, were gathered during the Shuttle Radar Topography Mission, which flew in February 2000 on the Space Shuttle Endeavour.

The digital elevation maps encompass 80 percent of Earth’s landmass. They reveal for the first time large, detailed swaths of Earth’s topography previously obscured by persistent cloudiness. The data will benefit scientists, engineers, government agencies and the public with an ever-growing array of uses.

“This is among the most significant science missions the Shuttle has ever performed, and it’s probably the most significant mapping mission of any single type ever,” said Dr. Michael Kobrick, mission project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

The final data release covers Australia and New Zealand in unprecedented uniform detail. It also covers more than 1,000 islands comprising much of Polynesia and Melanesia in the South Pacific, as well as islands in the South Indian and Atlantic oceans.

“Many of these islands have never had their topography mapped,” Kobrick said. “Their low topography makes them vulnerable to tidal effects, storm surges and long-term sea level rise. Knowing exactly where rising waters will go is vital to mitigating the effects of future disasters such as the Indian Ocean tsunami.”

Data from the Shuttle Radar Topography Mission are being used for applications ranging from land use planning to “virtual” Earth exploration. “Future missions using similar technology could monitor changes in Earth’s topography over time, and even map the topography of other planets,” said Dr. John LaBrecque, manager of NASA’s Solid Earth and Natural Hazards Program, NASA Headquarters, Washington, D.C.

The mission’s radar system mapped Earth from 56 degrees south to 60 degrees north of the equator. The resolution of the publicly available data is three arc-seconds (1/1,200th of a degree of latitude and longitude, about 295 feet, at Earth’s equator). The mission is a collaboration among NASA, the National Geospatial- Intelligence Agency, and the German and Italian space agencies. The mission’s role in space history was honored with a display of the mission’s canister and mast antenna at the Smithsonian Institution’s Udvar-Hazy Center, Chantilly, Va.

To view a selection of new images from the Shuttle Radar Topography Mission’s latest data set on the Internet, visit http://photojournal.jpl.nasa.gov/mission/SRTM.

To view a new fly-over animation of New Zealand on the Internet, visit http://www2.jpl.nasa.gov/srtm/.

To learn more about this mission, visit http://www.jpl.nasa.gov/srtm . For an interactive multimedia geography quiz using data from the mission, visit http://www.jpl.nasa.gov/multimedia/srtm/.

For information about NASA and agency programs, visit: http://www.nasa.gov.

Original Source: NASA News Release

Posted on by Fraser Cain

New Shuttle Tank Arrives in Florida

NASA marked a major milestone for the Space Shuttle’s Return to Flight, as the redesigned External Tank rolled out today from the barge that carried it to the agency’s Kennedy Space Center (KSC), Fla.

The tank was taken to the Vehicle Assembly Building (VAB) for a final checkout. It will eventually be attached to the twin Solid Rocket Boosters and the Space Shuttle Discovery for its Return to Flight mission, STS-114.

“With the arrival of the External Tank, all of the elements of the Space Shuttle system are in place for Return to Flight,” said Michael Kostelnik, deputy associate administrator for International Space Station and Space Shuttle programs. “This improved tank will be the safest we’ve ever flown. The modifications we have made will ensure the Shuttle completes its long-term mission of assembling the International Space Station,” he said.

NASA and Lockheed Martin Corp. spent nearly two years modifying the 15-story, rust-colored tank to make it safer. Among dozens of changes is a redesigned forward bipod fitting to reduce the risk to the Shuttle from falling debris during ascent. Reducing the debris risk was a key recommendation of the Columbia Accident Investigation Board.

“Although we can never completely eliminate insulating foam coming off the External Tank, we have absolute confidence we have eliminated the type of debris that caused the loss of Columbia,” said Bill Parsons, Space Shuttle program manager. “This tank is safe to fly the Return to Flight mission.”

The External Tank arrived at KSC after a 900-mile journey at sea. It departed NASA’s Michoud Assembly Facility in New Orleans on Dec. 31. It was transported via Pegasus, NASA’s specially designed barge. The Solid Rocket Booster retrieval ship Liberty Star brought the barge to Port Canaveral yesterday. The barge was moved by tugs to the KSC Turn Basin, the tank off-loaded and transported to the Vehicle Assembly Building.

“The team here at KSC is tremendously excited to receive the final Shuttle element for the Return to Flight mission,” said Mike Wetmore, director of Shuttle processing at KSC. “We have an experienced team in place that will complete the final checkout and processing of the tank and prepare it for its final journey out to the launch pad before flight.”

In the VAB, the tank will be raised to a vertical position. It will be lifted high up in the transfer aisle into the “checkout cell,” where the tank’s mechanical, electrical and thermal protection systems are inspected. The tank will also undergo new processes resulting from its re-design, including inspection of the bipod heater and External Tank separation camera.

The tank will be prepared for “mating” to the Shuttle’s Solid Rocket Boosters. When preparations are complete, the tank will be lifted from the checkout cell, moved across the transfer aisle and into High Bay 1. It will be lowered and attached to the boosters, which are sitting on the Mobile Launch Platform.

The arrival of the External Tank, the largest element of the Space Shuttle system, follows other recent Return to Flight milestones, including the “stacking” of the Solid Rocket Boosters in the Vehicle Assembly Building and installation of the Space Shuttle Main Engines into Discovery. The External Tank is the only Shuttle component not recovered after launch and reused.

The Return to Flight mission is targeted for a launch window beginning in May. The seven-member Discovery crew will fly to the International Space Station primarily to test and evaluate new procedures for flight safety, Shuttle inspections and repair techniques.

The Space Shuttle Propulsion Office at NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the tank project. Lockheed Martin Space Systems Co., New Orleans, is the primary contractor.

Video b-roll and sound bites of the tank shipment and arrival will be broadcast on NASA TV. Satellite coordinates and NASA TV schedules are available at: http://www.nasa.gov/ntv

For information on NASA’s Return to Flight efforts, including fact sheets and photos about the tank shipment, visit: http://www.nasa.gov/returntoflight

Original Source: NASA News Release

Posted on by Fraser Cain

10 Things to Do in 2005

Image credit: NASA
1.Begin the New Year by observing Saturn. Saturn will be at opposition (i.e. opposite the sun in the sky) on January 13th at 08:00 UTC. Saturn is in the constellation Gemini the Twins, about 6 degrees south east of the star Pollux.

2.Begin learning the names of 20 constellations. The inclination is to start with the brightest, most obvious ones. But sometimes it can be a fun challenge to find a less conspicuous one. Obviously this is a project that could last throughout the entire year. It is also a good chance to learn which constellations are visible during each season.

3.Learn the names of 20 bright stars. While many of us know the names of the constellations, the names of the stars are somewhat less well known. Knowing the star names is a good way to find and learn the constellations as well. Sometimes a constellation will have only one or two bright stars. These can act as guide posts to finding the entire constellation. As with learning the constellations, this is a project that can last all year.

4.Count the stars in the Pleiades, also known as the Seven Sisters. This little star cluster is west of the constellation Taurus the Bull. From a dark location you may see 5 or 6 stars. Then look at them with a pair of binoculars, what do you see?

5.Observe the moon for a month. Notice how much of its surface is illuminated from night to night. Kids can use a calendar and draw what shape the moon is each night (or even day!) Use binoculars or a telescope to observe the lunar features especially near the line that divides day from night (called the terminator).

6.In June look for Mercury and Venus in the evening sky between 0:300 and 04:00 UTC. The pair will be only 0.1 degrees apart. At that distance you will probably need binoculars to tell them apart. Venus will be the brightest object in the sky while Mercury will be much fainter. Saturn will be the bright object to the North West.

7.Observe a meteor shower. The famed Perseids is visible from July 17th to August 24th with the peak occurring before dawn on August 12th . Meteor showers get their names from the constellation they appear to radiate from, in this case Perseus the Hero. The best way to observe meteors is lying back on the ground or in a lawn chair. Kids can have fun counting how many they see in an hour.

8.On September 1st, about 03:00 UTC. Jupiter and Venus will be about 1 degree apart in the west just after sunset. No need to use binoculars to find this pair, but it might be fun to see them both through a telescope. Don’t forget to look for Jupiter’s 4 large moons: Ganymede, Callisto, Europa and Io.

9. Hunt for double stars. Many of the stars that we see in the sky have one or more companion stars. In many cases they are not visible to the naked eye. Here is a good opportunity to hone your binocular or telescope skills. Begin with the star Mizar in the constellation Ursa Major (the Big Dipper); it is the middle star in the Dipper’s handle.

10.Share the sky with your children or other young people. Kids love stories, and most never tire of hearing the same ones over and over again. Learn the myths and legends of your favorite constellations and tell them to your kids. Who knows, maybe your love for the sky will spark an interest in them that will last a lifetime.

This list should give even the most timid of beginners a starting point for their celestial quest. And don’t forget, there are lots of other enthusiasts out there, don’t be shy in contacting them and asking questions and sharing your experiences. Enjoy 2005, and clear skies to you all.

Written by Rod Kennedy.

Posted on by Fraser Cain

Map of Dark Matter Developed

Hubble Space Telescope data, analyzed by a Yale astronomer using gravitational lensing techniques, has generated a spatial map demonstrating the clumped substructure of dark matter inside clusters of galaxies.

Clusters of galaxies (about a million, million times the mass of our sun), are typically made up of hundreds of galaxies bound together by gravity. About 90 percent of their mass is darkmatter. The rest is ordinary atoms in the form of hot gas and stars.

Although little is known about it, cold dark matter is thought to have structure at all magnitudes. Theoretical models of the clumping properties were derived from detailed, high resolution simulations of the growth of structure in the Universe. Although previous evidence supported the ?concordance model? of a Universe mostly composed of cold, dark matter, the predicted substructure had never been detected.

In this study, Yale assistant professor of astronomy and physics Priyamvada Natarajan and her colleagues demonstrate that, at least in the mass range of typical galaxies in clusters, there is an excellent agreement between the observations and theoretical predictions of the concordance model.

Using gravitational lensing made it possible for the observers to visualize light from distant galaxies as it bent around mass in its way. This allowed the researchers to measure light deflections that indicated structural clumps in the dark matter.

?We used an innovative technique to pick up the effect of precisely the clumps which might otherwise be obscured by the presence of more massive structures,? said Natarajan. ?When we compared our results with theoretical expectations of the concordance model, we found extremely good agreement, suggesting that the model passes the substructure test for the mass range we are sensitive to with this technique.?

?We think the properties of these clumps hold a key to the nature of dark matter ? which is presently unknown,? said Natarajan. ?The question remains whether these predictions and observations agree for smaller mass clumps that are as yet undetected.?

Co-author on the study, funded by Yale University, is Volker Springel, MPA, Garching, Germany. Other collaborators include. Jean-Paul Kneib, LAM ? OAMP, Marseille, France, Ian Smail, University of Durham, U.K., and Richard Ellis of Caltech.

Original Source: Yale News Release

Posted on by Fraser Cain

Robotic Hubble Servicing Contract Awarded

MacDonald, Dettwiler and Associates Ltd. a provider of essential information solutions, today announced that it has signed a contract worth approximately $154 million U.S. to provide a potential information and robotic servicing solution to NASA to rescue the Hubble Space Telescope. The Hubble mission will follow on the heels of two U.S. military satellite missions that will utilize MDA’s solutions to perform similar tasks.

“We are building robotic space solutions that perform critical tasks to meet the requirements of ongoing and future international space missions,” said Dan Friedmann, President and CEO of MDA. “The Hubble mission and our strategic participation in other space missions will demonstrate that robots can cost-effectively complete complex tasks in space, while working together with astronauts on the ground.”

MDA is involved in two other important unmanned U.S. military satellite missions. MDA recently shipped a space-based solution for a classified satellite observation program, and is in the final stages of another previously announced key space servicing mission.

The Hubble award provides MDA with a new major source of long-term revenue. This award also positions MDA as the world leader in extending human reach in hostile environments with great precision and reliability.

The Canadian Commercial Corporation (CCC) is acting as the contracting agency between MDA and NASA and has executed the contract. CCC, a Government of Canada Crown corporation, facilitates over $1 billion in exports each year.

More information on the Hubble servicing mission is available at http://hubble.gsfc.nasa.gov/robotic/index.php

Original Source: MDA News Release

Posted on by Fraser Cain

Swift Sees Bursts Right Away

Image credit: NASA
The NASA-led Swift mission has opened its doors to a flurry of gamma-ray burst action.

Scientists were still calibrating the main instrument, the Burst Alert Telescope (BAT), when the first burst appeared on December 17. Three bursts on December 19, and one on December 20, followed.

Swift’s primary goal is to unravel the mystery of gamma ray bursts. The bursts are random and fleeting explosions, second only to the Big Bang in total energy output. Gamma rays are a type of light millions of times more energetic than light human eyes can detect. Gamma ray bursts last only from a few milliseconds to about one minute. Each burst likely signals the birth of a black hole.

“The optimists among us were hoping to detect two bursts a week, not three in one day just after turning the telescope on,” said Dr. Scott Barthelmy, the BAT lead scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md. “Maybe we got lucky, or maybe we’ve underestimated the true rate of these bursts. Only time will tell,” he added.

Once the BAT, that covers about one-seventh of the sky at any time, detects a gamma ray burst, it quickly relays a location to the ground. Within about one minute, the satellite automatically turns toward the burst. The move brings the burst within view of Swift’s two other telescopes: the X-ray Telescope (XRT) and the Ultraviolet/Optical Telescope (UVOT).

Once all three instruments are turned on and calibrated, Swift will get down to the business of analyzing gamma ray bursts. “The universe kept up its side of the bargain, and we kept up ours,” said Dr. Neil Gehrels, Swift’s Principal Investigator at Goddard. “This is going to be an exciting mission,” he said.

The Swift team tested the BAT by observing Cygnus X-1, a well-known bright source that produces gamma rays in our galaxy. It is thought to be a black hole in orbit around a star. The team called this BAT’s “first light.”

The BAT is the most sensitive gamma ray detector ever flown. The BAT employs a novel technology to image and locate gamma ray bursts. Unlike visible light, gamma rays pass right through telescope mirrors and cannot be reflected onto a detector. The BAT uses a technique called “coded aperture mask” to create a gamma ray shadow on its detectors. The mask contains 52,000 randomly placed lead tiles that block some gamma rays from reaching the detectors. With each burst, some detectors light up while others remain dark, shaded by the lead tiles. The angle of the shadow points back to the gamma ray burst.

“The BAT coded aperture mask is about the size of a pool table, the largest and most intricate ever fabricated,” said Ed Fenimore of Los Alamos National Laboratory, N.M. Los Alamos created the BAT software. “BAT can accurately pinpoint a burst within seconds and detect bursts five times fainter than previous instruments,” he added.

Swift, a medium-class explorer mission managed by Goddard, was launched from Cape Canaveral on November 20, 2004. The mission is in participation with the Italian Space Agency and the Particle Physics and Astronomy Research Council in the United Kingdom.

Swift was built at Goddard in collaboration with General Dynamics, Ariz.; Penn State University, College Station, Pa.; Sonoma State University, Rohnert Park, Calif.; Los Alamos; Mullard Space Science Laboratory, Surrey, England; the University of Leicester, England; the Brera Observatory, Milan, Italy; and ASI Science Data Center, Rome.

Original Source: NASA News Release

Posted on by Mark Mortimer

Book Review: Mars: A Warmer Wetter Planet

This book is an in-depth, technically precise narrative on the geology of Mars. The wealth of provided satellite imagery makes it easily understood by the layman. Images mostly come from Mars Global Surveyor’s MOC system and the Mars Odyssey THEMIS system. Comparisons to the author’s own photographs of Earth’s geological magic magnify the similarities. Yet this is not a picture book. Rather, Kargel does a magnificent job of tying the features into appropriate geological processes. For example, size, frequency and quantity of craters indicate age and tectonics. Crater rim condition demonstrates weathering. Alluvial fans, valleys, and moraines indicate fluid flow. All together these and others lead Kargel to believe and to show us that, at times, the surface of Mars must have had significant amounts of liquid flowing and pooling on its surface. That is, Mars was a much wetter planet than it is today.

But where has this liquid come from and gone to? We don’t know for sure, but Kargel believes the liquid was and still is present on Mars. Warmer equatorial regions have liquid frozen at great depth; mid-latitude regions have this material close to or at the surface; while the polar ice caps and their glaciers act as high density fluid moving at an amazingly slow pace. Kargel’s supposition is that Mars began with a comparatively homogeneous mantle but transitions occurred via ‘MEGAOUTFLO’ events. These episodes of internal geologic activity, such as volcanism, together with cycles of changing orbital eccentricity and obliquity, led to climatic oscillations. Hence, he concludes that though today Mars is very dry, it must have been, at least once before, both a warmer and wetter planet.

The shear breadth of this book can be daunting. Rock types and their personalities abound. Chemical compounds, their formations and their significance also get a solid billing. This is not surprising as after all, Kargel is a pre-eminent geologist and the forward by Harrison Schmitt leaves no doubt whatsoever about the subject. Topics within the text include active outgassing of juvenile volatiles from the mantle, glaciers that flow like condensed laminar fluid down an inclined plane and the forming of the mineral jarosite which requires many times its mass of water.

However this book is not a dry technical treatise. Kargel uses everyday language to discuss what is seen on Mars today, why it came to be, and what use can be made of this new knowledge. He considers the views of Cydonia Clanists and Percival Lowell and how unique life may exist on Mars and where it may be hiding. A very high level view presents the planet’s life cycle starting with accretion and concluding with the charring of its surface during our sun’s final explosion and subsequent collapse into a white dwarf star. He also discusses optimal landing locations for explorers and colonists of Mars, together with processes and techniques for power generation, water provisioning and infrastructure build-out. Still, the focus of this book is Mars’ surface geology and the deductions that result.

And in keeping with the progress of scientific investigation, Kargel is quick to point out that much is needed before any scientific advance is considered valid. This must be kept in mind throughout the book as the phraseology continually changes between observed fact and speculation. Also, given the complexity of the subject, the breadth of discussion is perhaps too broad. This is reminiscent of a wedding guest who waxes too eloquently when they get in front of the microphone. Still, for those who want to know what those amazing pictures of Mars are telling us, this is an excellent book.

Further, just as the proof of this book was nearing completion, the two Martian probes Opportunity and Spirit landed. Some of their early images appear but certainly much is left out. However, the book focuses on planet wide issues as seen through expansive satellite views so the probes’ information would likely be complementary to rather than a replacement of the supposition.

Some people say that we already know that Mars has a lot of rocks on it so why do we keep sending probes to see more rocks? Well a diamond on a wedding band can equally be considered just a rock and isn’t of great value, only don’t tell that to the wearer. Each picture of Martian rocks is much more than just another picture. Jeffrey Kargel in his book Mars: A Warmer Wetter Planet, provides us with the information and background to interpret the pictures and be thankful for their provision. Then, by placing these images into a geologic context, he gives a whole lot of understanding of the planet Mars and its rock formations.

Read more reviews, or order a copy online from Amazon.com.

Review by Mark Mortimer