Posted on by Fraser Cain

Icy Extrasolar Planet Discovered

An artist’s illustration shows the extrasolar planet orbiting a dim star. Image credit: NASA Click to enlarge
Using a relatively new planet-hunting technique that can spot worlds one-tenth the mass of our own, researchers have discovered a potentially rocky, icy body that may be the smallest planet yet found orbiting a star outside our solar system.

The discovery suggests the technique, gravitational microlensing, may be an exceptional technology for finding distant planets with traits that could support life.

“This is an important breakthrough in the quest to answer the question ‘Are we alone?'” said Michael Turner, assistant director for the National Science Foundation (NSF) mathematical and physical sciences directorate. “The team has discovered the most Earth-like planet yet, and more importantly, has demonstrated the power of a new technique that is sensitive to detecting habitable planets. It can probe a much greater portion of our galaxy and is complementary to other techniques.”

Located more than 20,000 light years away in the constellation Sagittarius, close to the center of our Milky Way galaxy, planet OGLE-2005-BLG-390Lb is approximately five-and-a-half times the mass of Earth.

Orbiting a star one-fifth the mass of the sun at a distance almost three times that of Earth’s orbit, the newly discovered planet is frigid: the estimated surface temperature is -364 degrees Fahrenheit (-220 degrees Celsius).

Although astronomers doubt this cold body could sustain organisms, researchers believe gravitational microlensing will bring opportunities for observing other rocky planets in the “habitable zones” of stars – regions where temperatures are perfect for maintaining liquid water and spawning life.

The discovery, authored by 73 collaborators from 32 institutions, appears in the Jan. 26 issue of the journal Nature.

OGLE (Optical Gravitational Lensing Experiment) project telescopes first observed the lensing event on July 11, 2005. In an attempt to catch microlensing events as they occur, OGLE scans most of the central Milky Way each night, discovering more than 500 microlensing events per year. But to detect the signature of low-mass planets, astronomers must observe these events much more frequently than OGLE’s one survey per night.

So, when OGLE detected the July 11 lensing, its early warning system alerted fellow astronomers across the globe to microlensing event OGLE-2005-BLG-390 (for the 390th galactic bulge OGLE discovered in 2005). At that point, though, no one knew a planet would emerge.

“The only way to realize the full scientific benefit of our observations is to share the data with our competition,” said co-author Bohdan Paczynski of Princeton University, who along with Andrzej Udalski of Warsaw University Observatory and their colleagues co-founded OGLE in 1997.

The telescopes of PLANET (Probing Lensing Anomalies NETwork) and RoboNet tracked the July 11 episode to completion, providing the data that confirmed the presence of a previously unknown planet. These telescopes collect observations more frequently in an attempt to detect the microlensing signature of planets.

“This discovery was possible because the sun never rises on the PLANET collaboration,” said lead author and PLANET researcher Jean-Philippe Beaulieu of the Institut d’Astrophysique de Paris, France. “The global nature of the PLANET collaboration was crucial for obtaining data throughout the 24-hour planetary signal,” he added.

Ironically, when preparing the final report, the researchers discovered that during its test runs, the new MOA (Microlensing Observations in Astrophysics) telescope, MOA-2, had taken additional measurements of the lensing event. The 6-foot (1.8-meter) aperture telescope has a wider field-of-view than the OGLE telescope, enabling it to observe 100 million stars many times per night. MOA-2 is one of several recent and future advancements that gravitational microlensing proponents hope will greatly increase the number of Earth-like planet discoveries.

OGLE also has plans to increase the field-of-view of its own telescope, and other microlensing groups are proposing to build a new telescope in South Africa. They have also proposed a space mission to see planets as small as Mars as well as free-floating planets that no longer orbit a host star.

“The new discovery provides a strong hint that low-mass planets may be much more common than Jupiters,” said co-author and PLANET researcher David Bennett of the University of Notre Dame. Most extrasolar planets found so far have been Jupiter-sized.

“Microlensing should have discovered dozens of Jupiters by now if they were as common as these five-Earth-mass planets. This illustrates the primary strength of the gravitational microlensing method: its ability to find planets of low-mass,” Bennett said.

Low-mass planets can yield signals that are too weak to detect with other methods. With microlensing, the signals of low-mass planets are rare but not weak. Thus, the rate of low-mass planet discoveries should increase dramatically if more microlensing events can be searched for planetary signals.

Original Source: NSF News Release

Posted on by Fraser Cain

Prometheus and Dione

The Saturnian moons Prometheus and Dione. Image credit: NASA/JPL/SSI Click to enlarge
The ring moon Prometheus continues its work shaping the delicate F ring as Dione looks on. It is easy to see how Prometheus has an irregular, oblong shape, while Dione is quite round.

The rings are partly cut off by Saturn’s shadow at right. Prometheus is 102 kilometers (63 miles) wide; Dione is 1,123 kilometers (700 miles) wide.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 20, 2005, at a distance of approximately 2.5 million kilometers (1.6 million miles) from Dione and 2.2 million kilometers (1.4 million miles) from Prometheus. The image scale is 15 kilometers (9 miles) per pixel on Dione and 13 kilometers (8 miles) per pixel on Prometheus.

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 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 imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

NASA/JPL/SSI News Release

Posted on by Mark Mortimer

Book Review: On to Mars 2

Mars is the planet most like Earth. With this accreditation, it has remained one of the likeliest off-world places for people to colonize. There are the usual obstacles; long distance, no water, no infrastructure and a harsh environment. But with any fresh world, there are great opportunities for new technologies, new leadership and new societies. Governments of countries on Earth understandably have no mandate to establish colonies off-world and they’ve shown little progress. However, their constituents do have both the mandate and desire to pursue this captivating goal. Drawing on this desire is the organization called The Mars Society. Within are thousands of people who regularly contribute to our knowledge base on how people can successfully get to and profit from Mars. In their view, combining opportunities and desires into a concerted effort is one means of having that first human footfall on the Martian surface.

Lacking a government’s or business’ mandate to step onto Mars, the Mars Society is a ready outlet for people with this desire. Annual conferences allow individuals and teams to come together to spread the word. This book, and its enclosed CD, collect an expansive selection of contributions apparently from a number of conferences between the years 2000 and 2004. Many contributions are reports in scientific format that result directly from two of the Mars Society’s research encampments; the Mars Desert Research Station in Utah and the Flashline Arctic Research Station on Devon Island. At these sites, people with no astronaut training or experience but lots of desire can emulate the tasks and challenges of a hypothetical Mars site. In so doing, they can actively add knowledge today to contribute to tomorrow’s footfall.

Though the analogue sites are the basis for most of the papers, they don’t constrain the topics. Given the unique conditions of the sites (e.g. bare rock and hostile climate), people can assess particular aspects of a team on Mars. They can simulate and examine group dynamics amongst the participants, construct storage vaults using local material and measure dust ingress before gears grind to a halt. Contributors with other backgrounds and objectives also have reports. For them, sites may be backyards for greenhouse studies, desks and computers for rocket design or purely their own experience, such as with quality management. In essence, as we’re going to have to replicate many of the natural and human contrived processes, the Earth is just one big analogue.

With so much to choose from, there’s no wonder that the reports cover a broad selection of topics. This is the book’s undoing. All topics relate to Mars but this is the only common thread. Some get very technical, such as discussing bit rates and data packets for computer networks. Others are almost dreamy in their visions of leadership and government. Because of this, it is the authors’ passion that rises up to claim the common thread rather than the technical work or the target. As well, a contradiction arises. The book begins by claiming that NASA’s constituency driven mandate makes poor results by being random and entropic. Yet, the perception from reading this book is that these individual’s efforts are equally random and entropic. Organization and focus are lacking.

Nevertheless, if you have any interest in a human presence on Mars, this randomness shouldn’t and indeed won’t trip you up. This book will empower the average person to get off their duff and lend a hand. As is obvious, much work needs doing and there are many ways to contribute. The international range of authors and the many formats (e.g. reports, poetry and song) demonstrate the many possible routes. The annual conference, the thousands of supporters and this book show that volunteers need not work in isolation or without appreciation.

With Mars never leaving its nearby orbit and shimmering down on us at night, we’re always reminded of its proximity. And, we’ve proven our ability to go into space and walk on the surface of other realms. The book On to Mars – Volume 2 is a compilation by Frank Crossman and Robert Zubrin containing reports of ideas and results from people who are more than ready to put people on Mars. Their efforts speak loudly, and when that footfall first strikes, assuredly there will be a great chorus of cheers.

Review by Mark Mortimer

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

Posted on by Fraser Cain

Opportunity Begins Its Third Year on Mars

Opportunity rover’s panorama of “Erebus Rim”. Image credit: NASA/JPL Click to enlarge
NASA’s Mars rovers, Spirit and Opportunity, have been working overtime to help scientists better understand ancient environmental conditions on the red planet. The rovers are also generating excitement about the exploration of Mars outlined in NASA’s Vision for Space Exploration.

The rovers continue to find new variations of bedrock in areas they are exploring on opposite sides of Mars. The geological information they have collected adds evidence about ancient Martian environments that included periods of wet, possibly habitable conditions.

“The extended journeys taken by the two rovers across the surface of Mars has allowed the science community to continue to uncover discoveries that will enable new investigations of the red planet far into the future.” said Mary Cleave, associate administrator for the Science Mission Directorate, NASA Headquarters.

NASA’s third mission extension for the rovers lasts through September 2006, if they remain usable that long. During their three-month primary missions, the rovers drove farther and examined more rocks than the prescribed criteria for success.

Opportunity begins its third year on Mars today. It is examining bedrock exposures along a route between “Endurance” and “Victoria” craters. Opportunity found evidence of a long-ago habitat of standing water on Mars.

On Jan. 3, Spirit passed its second anniversary inside the Connecticut-sized Gusev Crater. Initially, Spirit did not find evidence of much water, and hills that might reveal more about Gusev’s past were still mere bumps on the horizon. By operating eight times as long as planned, Spirit was able to climb up those hills, examine a wide assortment of rocks and find mineral fingerprints of ancient water.

While showing signs of wear, Spirit and Opportunity are still being used to their maximum remaining capabilities. On Spirit, the teeth of the rover’s rock abrasion tool are too worn to grind the surface off any more rocks, but its wire-bristle brush can still remove loose coatings. The tool was designed to uncover three rocks, but it exposed interiors of 15 rocks.

On Opportunity, the steering motor for the front right wheel stopped working eight months ago. A motor at the shoulder joint of the rover’s robotic arm shows symptoms of a broken wire in the motor winding. Opportunity can still maneuver with its three other steerable wheels. Its shoulder motor still works when given extra current, and the arm is still useable without that motor.

The rovers are two of five active robotic missions at Mars, which include NASA’s Mars Odyssey and Mars Global Surveyor and the European Space Agency’s Mars Express orbiters. The orbiters and surface missions complement each other in many ways. Observations by the rovers provide ground-level understanding for interpreting global observations by the orbiters. In addition to their own science missions, the orbiters relay data from Mars.

NASA’s Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, manages the Mars Exploration Rover, Odyssey and Global Surveyor projects for NASA’s Science Mission Directorate.

For images and information about the rovers and their discoveries on the Web, visit: http://www.nasa.gov/mars

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

What’s Up This Week – January 23 – January 29, 2006

What's Up 2006

Download our free “What’s Up 2006” ebook, with entries like this for every day of the year.

M1: “The Crab Nebula”. Image credit: R. Jay GaBany. Click to enlarge.
Monday, January 23 – Thanks to dark skies, tonight will be the perfect opportunity to “go crabbing” in Taurus. Although M1 was discovered by John Bevis in 1731, it became the first object on Charles Messier’s astronomical list. He rediscovered M1 while searching for the expected return of Halley’s Comet in late August 1758 and these “comet confusions” prompted Messier to start cataloging. It wasn’t until Lord Rosse gathered enough light from M1 in the mid-1840’s that the faint filamentary structure was noted (although he may not have given the Crab Nebula its name). To have a look for yourself, locate Zeta Tauri and look about a finger-width northwest. You won’t see the “Crab legs” in small scopes – but there’s much more to learn about this famous “supernova remnant” in the future.

Tuesday, January 24 – Today is the birthday of American solar astronomer Harold Babcock. Born in 1882, Babcock proposed that the sunspot cycle was a result of the Sun’s differential rotation and magnetic field in 1961. Would you like to have a look at the Sun? Although solar observing is best done with a proper filter, it is perfectly safe to use the “solar projection method.”

Before we start, NEVER look at the Sun directly with the eye or with any unfiltered optical device, such as binoculars or a telescope. We’re not joking when we say this will blind you. Exposed film, mylar, and smoked glass are also UNSAFE. But don’t be afraid, because we’re here to tell you how you can enjoy solar viewing. A safe way to observe sunspots is to “project” an image of the Sun through a telescope or binoculars onto a screen. This can be as simple as cardboard, a paper plate, a wall or whatever you have handy. If you’re using a telescope be sure the finderscope is securely capped. If you use binoculars, cover one of the two tubes. By using the shadow method to aim, you will see a bright circle of light on your makeshift screen. This is the solar disc. Adjust the focus by moving the distance of the screen from your optics until it’s about the size of a small plate. If the image is blurry, use manual focus until the edges of the disc become sharp. Even though it might take a little practice, you’ll soon become proficient at this method and be able to see a surprising amount of detail in and around sunspot areas. Happy and SAFE viewing to you!

Today in 1986, the United States Voyager 2 became the first spacecraft to fly by Uranus, providing us with the most outstanding photographs and information on the planet to date. After 10,382 days of successful operation, Voyager 2 still continues on towards the stars carrying “The Sounds of Earth.”

Speaking of stars, turn your scope on brilliant Rigel – Orion’s south-westernmost bright star. Enjoy its cool radiance and look for an 8th magnitude companion just outside the spikes of light caused by the Earth’s atmosphere.

Wednesday, January 25 – This morning before dawn, look for the Moon very near Antares. Many observers in the southern portions of Mexico, Peru and Ecudor will have the opportunity to see it occulted, so please check with the International Occultation Timing Association (IOTA) for details.

Today is the birthday of Joseph Louis Lagrange. Born in 1736, the famed French mathematician made important contributions to the field of celestial mechanics. We’re not talking “wrenches in space,” but how masses interact gravitationally to keep things orderly in the solar system and beyond. If you’re up early this morning, have a look at the lunar crater named for him. You’ll find LaGrange on the southern limb about one-quarter the distance up from the cusp. But, you won’t find the SOHO satellite there. NASA’s “eye on Sol” is parked at Lagrange point one (L1) between the Earth and Sun.

Tonight let’s journey to Orion and have a look at a pair of neighboring open clusters. Found a little less than a hand span northwest of Betelguese, NGC 1807 and NGC 1817 aren’t exactly twins. Both clusters are of similar magnitude and can be seen as faint patches in binoculars. Through a telescope, NGC 1817 appears far more populated with stars than its neighbor. Studies based on stellar motion reveal that NGC 1817 has far more stars than the brighter NGC 1807. Although the two are quite distant from one another in space, we get to see them both as close friends…

Thursday, January 26 – In keeping with our dark sky studies, tonight we’ll explore planetary nebula NGC 1514 in Taurus. Locate it by moving about two finger-width’s south-east of Zeta Perseii. Planetary nebulae were first described as “planetary” by William Herschel in 1785. Before then, all were simply considered “nebulae.” It was once thought they were made of stars, but today we know planetaries are created from material given off by a single star. Many show well-defined rings of one type or another. Others – like M1 – are irregularly shaped supernova remnants. NGC 1514’s material is slowly boiled off over time, rather than caused by a violent explosion.

It would be very hard to find the neutron central star in M1, but almost any scope can make out NGC 1514’s 10th magnitude fueling star as it quietly cooks away gases to feed its nebulous shroud. Because it is so bright, it can easily overwhelm the eye. This makes NGC 1514 similar to the famous “Blinking Planetary” – NGC 6826 – in Cygnus.

Friday, January 27 – The planet Saturn is at opposition tonight, meaning it rises as the Sun sets. Look for it late in the evening moving past M44 – “the Beehive” – cluster in Cancer. The 2006 apparition will continue to feature Saturn’s rings and the planet’s southern hemisphere.

Are you ready for more deep sky? Then let’s head off towards the galaxy NGC 1023 in Perseus. It’s a beautiful example of a slightly tilted “SB0” spiral galaxy. You won’t see any spiral arms on this one – but not because your telescope isn’t large enough. Unlike our own Milky Way, NGC 1023 really doesn’t have any. But, it does have a bright galactic hub bending like a thick lens going outward. At the center of the hub is one of the most massive black holes within a hundred million light-years. Don’t worry about being pulled in, because this galaxy is located 33 million light-years away! You’ll find it a bit closer to home about a fist-width southwest of Algol – Beta Persei.

There is a much closer supermassive black hole at the center of our own galaxy. It’s a profound gravitational anomaly causing stars to take on strange, highly elliptical orbits at very high speeds – some which have orbits taking far less time than Jupiter does to revolve around the Sun. The stars involved (“S-stars”) appear mysteriously young to astronomers. This might occur because their outer atmospheres are being stripped away by gravitational tidal forces. It’s happening in NGC 1023 as well, but that galaxy is ten times more massive than our own!

Saturday, January 28 – It’s Saturday and New Moon! Many amateurs will be out tonight “partying” beneath the darkest night sky of the month. All that’s needed is a wide-open field well away from glow from artificial lights and a variety of optical instruments – eyes, binoculars, and telescopes. The joy of observing can be multiplied many times over when shared with others!

What should you bring to a “star party?” Start with your favorite scope and a short list of things to observe including both “everybody’s favorites” and at least one “special study” that others may not have observed before! Tonight, the two “Greats” – M31 and M42 – will be on everyone’s list, but what about those “great” unknowns?

Consider NGC 1535 – a fine planetary nebula with central star in Eridanus. At magnitude 10, this 1600 light-year distant beauty has an easy 12th magnitude star providing illumination at its core. Use high power to give “image scale” to this small, subtle study. You’ll find it just about a fist’s width east-northeast of Gamma Eridani. If you find it difficult, you’d be right – but that’s why this aqua blue planetary is not more widely appreciated!

Sunday, January 29 – Today is the birthday of Johannes Hevelius. Born in 1611, Hevelius was the first to publish detailed maps of the Moon. His book, Selenographia, debuted in 1647. That’s 359 years ago – and it’s still accurate! Too bad there’s no Moon to celebrate with… Or is it?

Let’s have a look instead at the Pleiades – M45. We aren’t finished observing the Pleiades yet, because the “Seven Sisters” may not be finished either. On a moonless night, you can see the afterbirth of stellar creation – the faint sheen of nebulosity illuminated by hot stars doing their best to “light up the night.” Most easily spotted is NGC 1435 associated with Merope and NGC 1432 near Maia. To be sure you are seeing the nebulosity, look well away from both stars. From Merope (the southernmost bright star) look due south – away from the brightest stars of the cluster. Compare that to the nebulosity which surrounds all seven major stars – but especially Maia – north of Merope. Be sure not to stare directly. They will appear like a pale smear or a “fog” on your optics. Move your eyes around to activate the sensitive light-receptors in the eye – that’s using your eyes to advantage!

Until next week? May all of your journeys be at… Light Speed! ~Tammy Plotner

Contributing Writer: Jeff Barbour @ astro.geekjoy.com

Posted on by Fraser Cain

Icy Epimetheus

Icy Epimetheus behind Saturn’s rings. Image credit: NASA/JPL/SSI Click to enlarge
The Cassini spacecraft captured this glimpse of icy Epimetheus just before the small moon disappeared behind the bulk of Saturn’s atmosphere.

See Looking Down on Epimetheus for a closer view of Epimetheus (116 kilometers, or 72 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 20, 2005, at a distance of approximately 2.3 million kilometers (1.4 million miles) from Epimetheus and 2.2 million kilometers (1.4 million miles) from Saturn. The image scale is 14 kilometers (9 miles) per pixel on Epimetheus and 13 kilometers (8 miles) per pixel on Saturn.

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 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 imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

Predicting Titan’s Weather

False-colour images of Titan obtained by Cassini-Huygens Visual Infrared Mapping Spectrometer. Image credit: Click to enlarge
Using recent Cassini, Huygens and Earth-based observations, scientists have been able to create a computer model which explains the formation of several types of ethane and methane clouds on Titan.

Clouds have been observed recently on Titan, Saturn’s largest moon, through the thick haze, using near-infrared spectroscopy and images of the south pole and temperate regions near 40? South. Recent observations from Earth-based telescopes and the NASA/ESA/ASI Cassini spacecraft are now providing an insight into cloud climatology.

A European team, led by Pascal Rannou of the Service d?Aeronomie, IPSL Universite de Versailles-St-Quentin, France, has developed a general circulation model which couples dynamics, haze and cloud physics to study Titan climate and enables us to understand how the major cloud features which are observed, are produced.

This climate model also allows scientists to predict the cloud distribution for the complete Titan year (30 terrestrial years), and especially in the next years of Cassini observations.

The Voyager missions of the early 1980s gave the first indications of condensate clouds on Titan. Because of the cold temperatures in the moon?s atmosphere (tropopause), it was assumed that most of the organic chemicals formed in the upper atmosphere by photochemistry would condense into clouds while sinking. Methane would also condense at high altitudes, it was believed, having been transported from the surface.

Since then, several one-dimensional models of Titan’s atmosphere including sophisticated microphysics models were created to predict the formation of drops of ethane and methane. Similarly, the methane cycle had been studied separately in a circulation model, but without cloud microphysics.

These studies generally found that methane clouds could be triggered when air parcels cooled while moving upward or from equator to pole. However, these models hardly captured the fine details of the methane and ethane cloud cycles.

What Rannou’s team has done is to combine a cloud microphysical model into a general circulation model. The team can now identify and explain the formation of several types of ethane and methane clouds, including the south polar and sporadic clouds in the temperate regions, especially at 40? S in the summer hemisphere.

The scientists found that the predicted physical properties of the clouds in their model matched well with recent observations. Methane clouds that have been observed to date appear in locations where ascending air motions are predicted in their model.

The observed south polar cloud appears at the top of a particular ‘Hadley cell’, or mass of vertically circulating air, exactly where predicted at the south pole at an altitude of around 20-30 kilometres.

The recurrent large zonal (longitudinal direction) clouds at 40? S and the linear and discrete clouds that appear in the lower latitudes are also correlated with the ascending part of similar circulation cell in the troposphere, whereas smaller clouds at low latitudes, similar to the linear and discrete clouds already observed by Cassini are rather produced by mixing processes.

“Clouds in our circulation model are necessarily simplified relative to the real clouds, however the main cloud features predicted find a counterpart in reality.

“Consistently, our model produces clouds at places where clouds are actually observed, but it also predicts clouds that have not, or not yet, been observed,” said Pascal Rannou.

Titan’s cloud pattern appears to be similar to that of the main cloud patterns on Earth and Mars. The puzzling clouds at 40? S are produced by the ascending branch of a Hadley cell, exactly like tropical clouds are in the Intertropical Convergence Zone (ITCZ), as on Earth and Mars.

Polar clouds – produced by ‘polar cells’ – are similar to those produced at mid-latitudes on Earth. On other hand, clouds only appears at some longitudes. This is a specific feature of Titan clouds, and may be due to a Saturn tidal effect. The dynamical origin of cloud distribution on Titan is easy to test.

Cloudiness prediction for the coming years will be compared to observations made by Cassini and ground-based telescopes. Specific events will definitely prove the role of the circulation on the cloud distribution.

Original Source: ESA Portal

Posted on by Fraser Cain

NASA’s IMAGE Mission Ends

IMAGE launch on March, 2000. Image credit: NASA Click to enlarge
NASA’s Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite recently ceased operations, bringing to a close a successful six-year mission. IMAGE was the premier producer of new discoveries on the structure and dynamics of the Earth’s external magnetic field (magnetosphere) and its contents.

“The IMAGE mission showed us space around the Earth is anything but empty, and that plasma clouds can be imaged and tracked just as we do from space for Earth’s surface weather,” said Barbara Giles, IMAGE Program Scientist at NASA headquarters.

Prior to the launch of IMAGE, the energetic particles and electrically charged gas (plasma) surrounding the Earth were completely invisible to human observers. IMAGE enabled researchers to study the global structure and dynamics of the Earth’s inner magnetosphere as it responded to energy from solar winds.

“Nearly six years of imagery by the pioneering cameras on IMAGE revolutionized our understanding of geospace and our knowledge of its space weather,” said James Burch, IMAGE principal investigator at the Southwest Research Institute, San Antonio.

IMAGE was launched on March 25, 2000. It successfully completed its two-year primary mission and continued providing data into December 2005, when it stopped responding to commands from ground controllers. Preliminary analysis indicated the craft’s power supply subsystems failed, rendering it lifeless. The satellite is in an extended elliptical orbit and poses no threat to the planet.

IMAGE discoveries have been reported in more than 400 peer-reviewed publications. More than 20 Ph.D. theses were based on data from the mission. Science highlights include:

– Confirmations: plasma plume creation, post-midnight peak in storm plasmas, the neutral solar wind, terrestrial origin of geospace storm plasmas and continuous nature of magnetic reconnection.

– Discoveries: plasmaspheric shoulders and notches, proton auroras in unexpected places, surprisingly slow plasmasphere rotation, a hot oxygen geocorona and a secondary interstellar neutral atom stream.

– Resolutions: the source of kilometric continuum radiation, solar- wind and auroral intensity effects on ionospheric out flow and the relationship between proton and electron auroras during geospace storms.

The IMAGE education and public outreach program received numerous awards for videos, books, primary and secondary school curricula, teacher training, museum exhibits, planetarium shows, student workbooks and web-based information.

The extensive archival database generated by IMAGE promises to yield new discoveries and will support investigations by other spacecraft and ground-based observatories for many years.

IMAGE was a Medium Explorer mission sponsored by NASA’s Sun-Earth Connections Program and managed by NASA’s Goddard Space Flight Center, Greenbelt, Md. The Southwest Research Institute conducts IMAGE science operations. James Burch is the mission principal Investigator, and Thomas Moore at Goddard is the Mission Scientist.

For information about the IMAGE mission on the Web, visit:

http://image.gsfc.nasa.gov/

Original Source: NASA News Release

Posted on by Mark Mortimer

Book Review: Return to the Moon

The Apollo program of the 1960’s successfully placed a few military men and one geologist on the Moon’s surface. The goal of the program was to showcase the technology of the US. The result aimed for people around the world to believe that their style of government was better than communism. Since this propaganda event, the US, and indeed the rest of the world has, at best, placed a few more people in low earth orbit. Though a number of programs and concepts were dreamed of and even broadcasted, no funds were ever sent their way. Hence, since the highwater mark of landing on the Moon, people have remained in the relatively safe environs within the Earth’s radiation belt. Only a few robots and probes have gone farther to learn more. With over 30 years accumulated knowledge, many expect that it’s time to use this knowledge and get some return from our investment in space.

The desire to return comes out clear and strong in this book. There are twenty eight articles, each written by a motivated specialist. The common theme addresses the how and why of having people return to the Moon. With so many contributors, particular topics can get quite esoteric. Routine thoughts about launch vehicles are followed by more expansive articles on land ownership, rocket sleds, nanobot proving grounds and conscious evolution. As varied as the topics are, none reside in the realm of science fiction. Each has a sound basis in reason. And each, at least according to the author, would make a valuable contribution to this new program. Judicious editing by Tumlinson and Medlicott keep the articles clear, concise and relevant.

Given that both editors are board members of the Space Frontier Foundation, there is no surprise that the underlying theme of the book is for a greater frontier like attitude to Moon exploration. Given this viewpoint, there’s lots of NASA bashing and suggestions for improvements. The articles aren’t necessarily anti-establishment, the authors just believe that their ideas can improve that which has gone before. But, the authors can be overly optimistic. They seem to forget that during the frontier days there was lots of experimentation together with many accidental and purposeful deaths. This downside is never mentioned. Rather, the typical expectation shown in the articles is for the government to build the transportation infrastructure, as the railways in the old west. Once done, rich people or well funded corporations would use it in the time honoured practise of making profit. Maybe this approach will occur and succeed, maybe it won’t. However, this frontier approach is the only one supported within the book.

By having many different authors and many different angles, each article has its own style and flavour. Like an ice cream stand, there should be something for everyone. Also, the authors make convincing arguments. This leaves the impression is that they’ve argued their cases often and can support their reasoning. This robustness lends credence to individual theories and the underlying theme. Also, the topics flow with little repetition, aside from the berating of NASA though these can easily be skipped over. A preamble presumably written by one of the editors effectively places each article in the flow of the arguments. The editors did however miss a fair number of errors which takes some of the polish off. Nevertheless, if you’re interested in alternative options in getting people working on the Moon, this book has many articles which might strike your fancy.

Government programs are one of the few places where you can get away with spending other people’s money. Fun as it is, everyone from program managers on up the line must be able to substantiate the investment. Rick Tumlinson and Erin Medlicott in their book Return to the Moon bring together articles from many experts to add some options for the US government’s current program to place people again on the Moon and then on to Mars. The many ideas can bring a fresh new perspective to spending money and realizing profit from setting up a work place for humans off of Earth.

Review by Mark Mortimer

Read more reviews online, or purchase a copy from Countdown Creations.

Posted on by Fraser Cain

Icy Martian Glaciers

Perspective view of ‘hourglass’ shaped craters. Image credit: ESA Click to enlarge
The spectacular features visible today on the surface of the Red Planet indicate the past existence of Martian glaciers, but where did the ice come from?

An international team of scientists have produced sophisticated climate simulations suggesting that geologically recent glaciers at low latitudes (that is near the present-day equator) may have formed through atmospheric precipitation of water-ice particles.

Moreover, the results of the simulations show for the first time that the predicted locations for these glaciers match extensively with many of the glacier remnants observed today at these latitudes on Mars.

For several years, the presence, age and shape of these glacier remnants have raised numerous questions in the scientific community about their formation, and about the conditions on the planet when this happened.

To start narrowing down the rising number of hypotheses, a team led by Francois Forget, University of Paris 6 (France) and interdisciplinary scientist for ESA’s Mars Express mission, decided to ‘turn back the clock’ in their Martian global climate computer model, a tool usually applied to simulate the detail of present-day Mars meteorology.

As a starting point, Forget and colleagues had to make some assumptions – that the north polar cap was still the ice reservoir of the planet, and that the rotation axis was tilted by 45? with respect to the planet?s orbital plane.

“This makes the axis much more oblique than it is today (about 25?), but such an obliquity has probably been very common throughout Mars?s history. Actually, it last occurred only five and a half million years ago,” says Forget.

As expected with such a tilt, the greater solar illumination in the north polar summer increased the sublimation of the polar ice and led to a water cycle much more intense than today.

The simulations showed water ice being accumulated at a rate of 30 to 70 millimetres per year in a few localised areas on the flanks of the Elysium Mons, Olympus Mons and the three Tharsis Montes volcanoes.

After a few thousand years, the accumulated ice would form glaciers up to several hundreds of metres thick.

When the team compared the location and shape of the ‘simulated’ glaciers with the actual glacier-related deposits of Tharsis – one of the three main regions on the planet where signs of glaciers are seen – they found an excellent agreement.

In particular, the maximum deposition is predicted on the western flanks of the Arsia and Pavonis Montes of the Tharsis region, where the largest deposits in this area are actually observed.

In their simulations, the team could even ‘read’ why and how ice was accumulated on the flanks of these mountains in the Tharsis region millions of years ago.

Back then, constant year-long winds similar to monsoons on Earth would favour the upslope movement of water-rich air around Arsia and Pavonis Montes.

While being cooled down by tens of degrees, water would condense and form ice particles (larger than those we observe today in the Tharsis region’s clouds) that settled on the surface.

Other mountains like Olympus Mons show smaller-scale deposits because, according to the simulations, they were exposed to the monsoon-type strong winds and water-rich air only during the northern summer.

“The north polar cap may not have always been the only source of water during the planet’s high obliquity periods,” adds Forget.

“So we ran simulations assuming that ice was available in the south polar cap. We could still see ice accumulation in the Tharsis region, but this time also on the east of the Hellas Basin, a six-kilometre deep crater.”

This would explain the origins of another major area where ice-related landforms are observed today, the eastern Hellas Basin. indeed.

“The Hellas basin is in fact so deep as to induce the generation of a northward wind flow on its eastern side that would carry most of the water vapour sublimating from the south polar cap during summer. When the water-rich air meet colder air mass over eastern Hellas, water condense, precipitate, and form glaciers,” said Forget.

However, the team could not predict ice deposition in the Deuterolinus-Protonilus Mensae region, where glaciers could have been formed by other mechanisms. The scientists are considering several other hypotheses on the formation of recent glaciers.

For instance, observations of Olympus Mons by the High Resolution Stereo Camera on board Mars Express suggest that movement of water from the subsurface to the surface due to hydrothermal activity may have led to the development of glaciers on the cold surface.

Original Source: ESA Mars Express