Visit the USGS Home Page Go to the Astrogeology Research Program Home Page USGS Astrogeology Research Program

Voyager 2 Detects Odd Shape of Solar System's Edge

Friday, May 26, 2006

VoyagerVoyager 2 could pass beyond the outermost layer of our solar system, called the "termination shock," sometime within the next year. The milestone, which comes about a year after Voyager 1's crossing, comes earlier than expected and suggests to scientists that the edge of the shock is about one billion miles closer to the Sun in the southern region of the solar system than in the north.
This implies that the heliosphere, a spherical bubble of charged low-energy particles created by our Sun's solar wind, is irregularly shaped, bulging in the northern hemisphere and pressed inward in the south.
Scientists determined that Voyager 1 was approaching the termination shock when it began detecting charged particles that were being pushed back toward the Sun by charged particles coming from outside our solar system. This occurred when Voyager 1 was about 85 AU from the Sun.
One AU is the distance between the Earth and the Sun, or 93 million miles.
In contrast, Voyager 2 began detecting returning particles while only 76 AU from the Sun.
"This tells us that the shock down where Voyager 2 is must be closer the sun than where Voyager 1 is," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena.
The researchers think that the heliosphere's asymmetry might be due to a weak interstellar magnetic field pressing inward on the southern hemisphere.
"The [magnetic] field is only 1/100,000 of the field on the Earth's surface, but it's over such a large area and pushing on such a faint gas that it can actually push the shock about a billion miles in," Stone explained.

credit:, Ker Than

8 Worlds Where Life Might Exist

Thursday, May 25, 2006

Earth. Our world is the poster child for solar-powered planets. Most flora and fauna on Earth – with some important exceptions such as the bacteria that live in deep rock – are ultimately animated by the roaring nuclear fusion taking place in the Sun’s heart. On Earth, it’s usually chlorophyll that converts this radiant energy into chemical compounds to energize our existence (or bulge our waistlines).

Venus. Despite the fact that Venus, our sister planet, has been described as purgatory personified, there are some researchers who still hold out hope for life there.

Mars. While Mars’ highly reactive and powder-dry landscape is practically guaranteed to be sterile, there is indirect evidence for watery aquifers a few hundred feet beneath the surface. If these liquid reservoirs exist, life may have found refuge within.

Titan. This large moon of Saturn, revealed in detail by NASA’s Cassini mission, and subject to shameless examination by the Huygens probe, is far too cold for liquid water. But its air is thick with hydrocarbons. David Grinspoon has suggested that the Sun’s weak ultraviolet light might rip apart some of these atmospheric compounds, producing acetylene. Falling into the liquid lakes of methane and ethane below, this gas (best known for firing blowtorches on Earth) could serve as a food for microscopic life. Unlikely? Yes. Impossible? No.

The best known of tidally heated satellites are:

Europa. There’s good evidence, mostly from its changing magnetic field, that this ice-covered world orbiting Jupiter has an ocean lying 10 miles or so beneath its crusty exterior. At the bottom of this vast, cryptic sea, volcanic vents might be spewing nutrients and hot water into a cold, dark abyss, providing both the food and energy for simple life.

Ganymede and Callisto. Both of these jovian moons show magnetic field variations similar to those of Europa, suggesting that they, too, might be hiding large, watery oceans. Given their thicker ice skins, finding that life – if it exists – would be even more daunting than for Europa.

Enceladus. In the news recently, this Saturnian satellite seems to be a giant Slurpee – an icy moon that, thanks to tidal heating, is spouting geysers of water into space. An unexpected entry in the horse race of habitability, Enceladus is the first other world for which we have convincing evidence of liquid

Credit:Seth Shostak,SETI Institute. More: 8 Worlds where life might exist

Wedding Dress For Use In Space

Thursday, May 25, 2006

Wedding Dress

June is almost here and I've been thinking about the brides who will need a dress for their wedding, should they carry out their celebration in space. After all, life will go on there.

Eri Matsui designed these wedding dresses for a Space Couture Design Contest supported by the Japan Aerospace Exploration Agency. The dress to the left can be worn in gravity, and the one on the right in zero gravity; however, both will look exceptional under either condition.

Her design stimulates our dream that we may get married in space soon. Excuse me, I just remembered something. I had better call Eri Matsui. We're going to need a tuxedo to go with that.

Wedding dress for use in space [Seihin-World]

Map-a-Planet Recognized as Valuable Resource

Tuesday, May 16, 2006

Map-a-PlanetAmerican Scientist Online, 10 April 2006: The U.S. Geolgoical Survey, Branch of Astrogeology's Map-a-Planet was chosen for "Site of the Week," in American Scientist Online. American Scientist is a magazine of SIGMA XI, a scientific research society. Congratulations Patty Garcia, Lisa Gaddis, Chris Isbell, Janet Barrett, Deborah Soltesz, and Annie Bennett. Read what was reported by this web site, verbatim, below:

The U.S. Geological Survey goes far beyond its national ambit with this friendly, intuitive tool. Choosing from a growing array of datasets, visitors can create customized, browsable maps of Venus, Mars or any of six moons, including our own.

The interface offers three levels. The "easy" version assigns default values for size, resolution, format and projection; these values can be customized in the "intermediate" version via a simple control panel (choose a Mercator projection, for example, or assign a specific resolution). The advanced version provides full control of all variables. The completed maps can be panned, zoomed or resized, and are downloadable either directly via the user's browser or via ftp.

Though the interface is not as polished as that in Google's browsable maps of the moon and Mars, the USGS offering goes much farther afield, offering detailed views of Saturn's moon Rhea and Jupiter's Callisto, Europa, Io and Ganymede. It offers hours of fascinating exploration of a solar system that's at once strikingly alien and increasingly familiar.

View the original article on the American Scientist Online

Map-a-Planet was also recognized in the Resource section of the May 2006 issue of The Geological Society of America's online magazine, GSA Connection.

View the original issue of the GSA Connection

Life on Mars

Monday, May 15, 2006


There is life on Mars,

even if,

it's just a mouse.

Missing History of Astrogeology Saved

Monday, May 15, 2006

Gerald G. Schaber (left) and dad at the launch of Apollo 15 (July, 1971). Schaber helped to develop a geologic field training program for Apollo astronauts. He was also involved in the traverse planning and production (in Flagstaff) of the Lunar Surface Exploration Map Data Package for Apollo 15.

A "must read" Open File Report that is a comprehensive account of the USGS participation in the Apollo era, from its conception through the end of Project Apollo, has been completed by Gerald G. “Jerry” Schaber during the time he was with the U.S. Geological Survey, Branch of Astrogeology, working as a Scientist Emeritis. The work was encouraged and suported by former and current Program Chiefs of Astrogeology, Wes Ward and Lisa Gaddis respectively.

The Open File Report, The U.S. Geological Survey, Branch of Astrogeology-- A Chronology of Activities from Conception though the End of Project Apollo, covers the period of the 1960s-1970s capturing the roles of geoscientist and support personnel working for the U.S. Geological Survey (USGS), Branch of Astrogeology, in Flagstaff, and elsewhere, in support of expeditions to the Moon. Although there are books written by Don Wilhelms that include accounts of Astrogeology’s research and support of NASA’s unmanned lunar spacecraft missions during the Apollo era, they lack detail regarding Astrogeology’s concurrent activities of the “Manned Lunar Exploration Group.” Jerry Schaber has filled that significant gap of history with regard to the participation of the USGS. Astrogeology celebrates this accomplishment.

“This work has been a true labor of love, taking place over many years and requiring much labor and perseverance to get into ‘print’,” says Lisa Gaddis.

The report reveals intimate details such as Astrogeology’s origin and working conditions during these times, studies at Meteor Crater, involvement in telescopic Moon mapping, planning for NASA’s Lunar Missions activities, Flagstaff in the media “Spotlight” during Apollo 11, and also one of the Branch’s own Harrison H. “Jack” Schmitt's walk on the moon during Apollo 17. It captures Eugene M. Shoemaker’s, the Father of Astrogeology, dream of doing field mapping on the surface of the Moon, and recounts how he reaches the lunar surface. There is a wealth of information filled with warmth, humor, struggles, failures and successes-- viewpoints of various participants telling rich and complex stories that leave the reader proud to be an American.

Jerry conducted interviews with sixty-six current and past employees of the U.S. Geological Survey’s Branch of Astrogeology and Branch of Surface Planetary Exploration (the latter in existence from 1967 to 1973). He cited many texts, accessed Astrogeology's personal daily logs and monthly reports, consulted unpublished memoirs of Astrogeology’s geologist John F. “Jack” McCauley's transcripts, and NASA’s Apollo Journal web site which is noted as an excellent resource to capture these fine moments in history, and many other references to bring this valuable information to our fingertips.

This is a highly readable account. It is serious scholarship, suitable for the general public, and those with an interest in science, in the rich culture of history in the making. It is for those who’d like to celebrate their hometown’s (Flagstaff) contribution to space history in familiar locations such as Meteor Crater, where astronaut training took place, use of the Cinder Lakes volcanic field to create Moon-like terrain, where Apollo 15 astronauts James Irwin and David Scott test-drove a geologic rover, and much more.

The publications consists of text, figures, tables, appendixes, and many photographs from the branch history photo collection. This report has a total of 1,162 pages; there are links to separate files, tables, and appendix files that are listed on the web pages. Gerald G. Schaber's Open File Report is available on the World Wide Web at URL .

Coming in June: an interview with Gerald G. Schaber.

Bridge Progress on Cedar Hill

Thursday, May 11, 2006

Ped/Bike Bridge – Cedar Ave Photo Credit: Vincent H. Richie of Arizona Historical Society

Those of us who work at USGS in Flagstaff have probably noticed progress of the bridge, on Cedar Hill. Tiffin Miller, Project Manager, says the Contractor continues to work on falsework for the bridge span, and plans on forming & pouring the soffit and web through the week of May 8, 2006. On May 16th, they plan on closing Cedar Avenue at night, at around 10:00 P.M. and work until 6:00 A.M. to set beams for the bridge.
Cedar Avenue has been narrowed and restricted to two lanes throughout the project vicinity. Lane restrictions will remain in place through project completion, anticipated for the end of July of 2006. On May 16th, Cedar Avenue will be closed between Turquoise and West Street from 10 p.m. to 6 a.m. Signs will be installed to detour traffic around the closure. Emergency vehicles will be accommodated through the work zone if necessary. On the 26th of May, the contractors plan to pour concrete. Conservatively, the bridge should be done before or by the end of July.
For current information on the progress of the bridge, visit flagstaff Urban Trails System Project at .


Wednesday, May 10, 2006

More than 60 fragments of dying comet 73P/Schwassmann-Wachmann 3 are racing toward Earth. There's no danger of a collision. At closest approach on May 12th through 16th, the mini-comets will be 6 million miles away.

That is close enough, however, for a marvelous view through backyard telescopes. Many of the fragments are themselves crumbling, producing clouds of gas and dust mixed with boulder-sized debris. As some fragments fade, others brighten, surprising onlookers. It's an amazing display. More: Sky maps, updates and images from around the world.

Mini-Comets Approaching Earth in May

Wednesday, May 10, 2006

In 1995, Comet 73P/Schwassmann-Wachmann 3 did something unexpected: it fell apart. For no apparent reason, the comet's nucleus split into at least three "mini-comets" flying single file through space. Astronomers watched with interest, but the view was blurry even through large telescopes. "73P" was a hundred and fifty million miles away.

We're about to get a much closer look. In May 2006 the fragments are going to fly past Earth closer than any comet has come in more than twenty years.

Comet 73P
Comet 73P breaking up in 1995. Photo credit: Jim V. Scotti 250X145

"This is a rare opportunity to watch a comet in its death throes—from very close range," says Don Yeomans, head of NASA's Near Earth Object Program at JPL.

There's no danger of a collision. "Goodness, no," says Yeomans. "The closest fragment will be about six million miles away--or twenty-five times farther than the Moon." That's close without actually being scary.

Credit: NASA-Full Story: Mini_Comets Approaching Earth

Lunar Outpost Design Challenge

Wednesday, May 10, 2006

Mark your calendars: Coming this fall, students will be challenged to design systems that will support living and working on the Moon. The challenge will be to design a combination of facilities that support arriving precisely, living adaptively and working efficiently that will make exploration possible on the Moon and can protect both the explorers and the Moon from contamination. As usual with Quest Challenges, students will work on these authentic problems under the watchful eye of NASA experts.

Join us as we begin with registration in September and finish with a webcast in early December. A website is available at with a growing list of reading material that will help you get started. If you have any questions, please write to:

NASA to BLast the Moon in Search of Water

Tuesday, May 9, 2006


In this artist's rendering, the satellite and the launcher's second stage approach the moon. Meanwhile, the Lunar Reconnaissance Orbiter is orbiting the moon.
Credit: NASA/John Frassanito and Associates

NASA will send an impactor spacecraft to the moon with liftoff of the Lunar Reconnaissance Orbiter, scheduled for October 2008. The Lunar Crater Observation and Sensing Satellite (LCROSS) will travel independently of the orbiter and crash violently into the lunar surface, at a speed of 5,592 miles per hour (or about 2.5 kilometers per second) to search for water. It should blast out a crater about a hundred feet wide and 15 feet deep.

First, the craft will direct the upper stage used to leave Earth orbit to crash into a permanently-shadowed crater at the lunar south pole, creating a plume visible on Earth through a telescope. Next, the satellite will observe the plume and fly through it using several instruments to look for water. At the end of its mission, the satellite will itself become an impactor, creating a second plume visible to lunar-orbiting spacecraft and Earth-based observants.

Continue reading "NASA to BLast the Moon in Search of Water"