November 2006 Newsletter

Stockton Astronomical Society

Valley Skies

Valley Skies - November 2006 Issue

Editor's Corner...

"What happened to Pluto?"

Sky & Telescope magazine takes a stance on the new "planet" definition that demotes the ninth planet.

Sky & Telescope Editor-in-Chief Richard Tresch Fienberg doesn't mince words in expressing his opinion of the IAU's new definition of "planet" in the November issue:

"It's stupid and won't last more than three years." (Next General Assembly of the IAU will be in August 2009, in Rio de Janeiro, Brazil).

So what's wrong with the new definition? As Richard sees it, it is "flawed both linguistically and scientifically. By the IAU's wording, a dwarf planet is not a planet, even though a dwarf galaxy is still a galaxy and a dwarf star is still a star. Absurd!"

Also, the requirement that an object is a planet only if it "has cleared the neighborhood around its orbit" is problematic for Earth, Mars, Jupiter and Neptune as well as Pluto because numerous asteroids share or intersect their orbits.

On page 34-39 of the same issue, author Owen Gingerich describes the contentious wrangling that led to the controversial definition at the IAU gathering in August.

Needing a new mnemonic to remember the order of the eight remaining planets, Richard Fienberg suggests:

"Many Very Egotistical Malcontents Just Screwed Up Nomenclature."

Works for me - until, as Richard says, "astronomers have another shot at redemption three years after blowing it in full view of the public."

* * *

November 8 Transit of Mercury

If you are fortunate enough to be free on Wednesday, November 8, you have an opportunity to watch a transit of Mercury across the face of the Sun...all five hours of it!

Here on the West coast, first contact will be around 11:12 a.m. PST. The leading edge of Mercury will contact the Sun's limb at around the seven o'clock position. Almost five hours later, around 4:08 p.m., it will exit the Sun's disk at about the three o'clock position. The black dot of the planet silhouetted against the Sun will be tiny - about 10" of arc (compared with Venus's 58" during its 2004 transit).

Remember, solar viewing should only be done with a safe solar filter over the front of your telescope or binoculars-unless a fried retina and blindness is an acceptable tradeoff. Solar viewing is not something to fool around with unless you know what you are doing. Sky & Telescope has good information at SkyTonight.com/eclipse (see "How to Watch a Partial Solar Eclipse Safely"). Enjoy the ride.

...Trevor Atkinson

The Science Directorate at NASA's Marshall Space Flight Center sponsors the Science@NASA web sites. The mission of Science@NASA is to help the public understand how exciting NASA research is and to help NASA scientists fulfill their outreach responsibilities.

Novarupta

Oct. 3, 2006: In June 1912, Novarupta-one of a chain of volcanoes on the Alaska Peninsula-erupted in what turned out to be the largest blast of the twentieth century. It was so powerful that it drained magma from under another volcano, Mount Katmai, six miles east, causing the summit of Katmai to collapse to form a caldera half a mile deep. Novarupta also expelled three cubic miles of magma and ash into the air, which fell to cover an area of 3,000 square miles more than a foot deep.

An aerial view of the Novarupta Dome in Alaska. USGS photo by Gene Iwatsubo, July 29, 1987.

Despite the fact that the eruption was comparable to that of the far more famous eruption of Krakatau in Indonesia in 1883 and so near the continental United States, it was hardly known at the time because the area was so remote from English-speaking people.

Almost a hundred years later, researchers are paying attention. Novarupta is near the Arctic Circle and its impact on climate appears to be quite different from that of "ordinary" tropical volcanoes, according to recent research by climatologists using a NASA computer model.

When a volcano anywhere erupts, it does more than spew clouds of ash, which can shadow a region from sunlight and cool it for a few days. It also spews sulfur dioxide. If the eruption is strongly vertical, it shoots that sulfur dioxide high into the stratosphere more than 10 miles above Earth.

Up in the stratosphere, sulfur dioxide reacts with water vapor to form sulfate aerosols. Because these aerosols float above the altitude of rain, they don't get washed out. They linger, reflecting sunlight and cooling Earth's surface.

This can create a kind of nuclear winter (a.k.a. "volcanic winter") for a year or more after an eruption. In April 1815, for instance, the Tambora volcano in Indonesia erupted. The following year, 1816, was called "the year without a summer," with snow falling across the United States in July. Even the smaller June 1991 eruption of Pinatubo in the Philippines cooled the average temperature of the northern hemisphere summer of 1992 to well below average.

But both those volcanoes as well as Krakatau were in the tropics.

Novarupta is just south of the Arctic Circle.

Using a NASA computer model at the the Goddard Institute for Space Studies (GISS), Prof. Alan Robock of Rutgers University and colleagues found that Novarupta's effects on the world's climate would have been different. (Their research was funded by the National Science Foundation.)

Robock explains: "The stratosphere's average circulation is from the equator to the poles, so aerosols from tropical volcanoes tend to spread across all latitudes both north and south of the Equator." Aerosols would quickly circulate to all parts of the globe.

But the NASA GISS climate model showed that aerosols from an arctic eruption such as Novarupta tend to stay north of 30°N-that is, no further south than the continental United States or Europe. Indeed, they would mix with the rest of Earth's atmosphere only very slowly.

This bottling up of Novarupta's aerosols in the north would make itself felt, strangely enough, in India. According to the computer model, the Novarupta blast would have weakened India's summer monsoon, producing "an abnormally warm and dry summer over northern India," says Robock.

Why India? Cooling of the northern hemisphere by Novarupta would set in motion a chain of events involving land and sea surface temperatures, the flow of air over the Himalayan mountains and, finally, clouds and rain over India. It's devilishly complex, which is why supercomputers are needed to do the calculations.

To check the results, Robock and colleagues are examining weather and river flow data from Asia, India, and Africa in 1913, the year after Novarupta. They are also investigating the consequences of other high-latitude eruptions in the last few centuries.

Do Indians need to keep an eye on Arctic volcanoes? The GISS computer says so. Stay tuned to Science@NASA for updates.

Author: Dr. Tony Phillips | Production Editor: Dr. Tony Phillips | Credit: Science@NASA

The Planet in the Machine

By Diane K. Fisher and Tony Phillips

The story goes that a butterfly flapping its wings in Brazil can, over time, cause a tornado in Kansas. The "butterfly effect" is a common term to evoke the complexity of interdependent variables affecting weather around the globe. It alludes to the notion that small changes in initial conditions can cause wildly varying outcomes. Now imagine millions of butterflies flapping their wings. And flies and crickets and birds. Now you understand why weather is so complex.

All kidding aside, insects are not in control. The real "butterfly effect" is driven by, for example, global winds and ocean currents, polar ice (melting and freezing), clouds and rain, and blowing desert dust. All these things interact with one another in bewilderingly complicated ways. And then there's the human race. If a butterfly can cause a tornado, what can humans cause with their boundlessly reckless disturbances of initial conditions?

Understanding how it all fits together is a relatively new field called Earth system science. Earth system scientists work on building and fine-tuning mathematical models (computer programs) that describe the complex inter-relationships of Earth's carbon, water, energy, and trace gases as they are exchanged between the terrestrial biosphere and the atmosphere. Ultimately, they hope to understand Earth as an integrated system, and model changes in climate over the next 50-100 years. The better the models, the more accurate and detailed will be the image in the crystal ball.

CloudSat is one of the Earth observing satellites collecting data that will help develop and refine atmospheric circulation models and other types of weather and climate models. CloudSat's unique radar system reads the vertical structure of clouds, including liquid water and ice content, and how clouds affect the distribution of the Sun's energy in the atmosphere.
(See animation of this data simulation at www.nasa.gov/mission_pages/calipso/ multimedia/cloud_calip_mm.html.)

NASA's Earth System Science program provides real-world data for these models via a swarm of Earth-observing satellites. The satellites, which go by names like Terra and Aqua, keep an eye on Earth's land, biosphere, atmosphere, clouds, ice, and oceans. The data they collect are crucial to the modeling efforts.

Some models aim to predict short-term effects-in other words, weather. They may become part of severe weather warning systems and actually save lives. Other models aim to predict long-term effects-or climate. But, long-term predictions are much more difficult and much less likely to be believed by the general population, since only time can actually prove or disprove their validity. After all, small errors become large errors as the model is left to run into the future. However, as the models are further validated with near- and longer-term data, and as different models converge on a common scenario, they become more and more trustworthy to show us the future while we can still do something about it-we hope.

For a listing and more information on each of NASA's (and their partners') Earth data-gathering missions, visit http://science.hq.nasa.gov/missions/earth.html.

Kids can get an easy introduction to Earth system science and play Earthy word games at http://spaceplace.nasa.gov/en/kids/earth/wordfind

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

The Baldwin Connection

Remember Jeff's 40" telescope project? Several SAS members built up their abs and back muscles, pushing and pulling the grinding tool on that monster mirror. Unfortunately, when Jeff and Glenda decided to move to the Olympic Peninsula, Jeff had to give up on his one-meter light-bucket dream. In 2002, he sold the whole kit and caboodle to the Valley of the Moon Observatory Association (VMOA), a non-profit group of amateur and professional astronomers, most or all of them members of the Sonoma County Astronomical Society.

On a weekend campout with my grandson Skyler and Webelos Pack 186 of Napa on Saturday, October 21^st we camped overnight at Sugarloaf Ridge State Park, near Kenwood in Sonoma County.

Sugarloaf Ridge State Park is home to the Robert Ferguson Observatory (RFO), operated by the volunteers of VMOA in association with California State Parks. Their mission is to provide educational outreach programs about science and astronomy to students and the public. Their program includes monthly public solar and night sky observing, January through November. The Webelos campout (seven kids plus adults) was scheduled to coincide with the October observing session.

We took in the solar observing on Saturday afternoon. I chatted with two of the volunteer docents, Bill Romo and Keith Payea, while the kids toured the observatory.

Sketch of the design for the New Generation 40 inch Telescope Project

I had speculated on the possibility that I would be visiting Jeff's mirror in its new incarnation. Bill explained that the 40 inch project is probably 2-3 years from completion. The Project 40 team has spent a year building a machine to grind the mirror. The design for the one-meter telescope will include a tertiary mirror to enable public viewing without ladders. I look forward to visiting again when the scope is finished. It will be the largest instrument in the western states dedicated to public viewing and education.

The observatory is well worth a visit. There are two sections with retractable roof, one currently housing a 24" f4.5 Dobsonian, the other with three scopes-two used for solar observing, the third a 14" reflector with CCD connected to a 21" monitor. The central dome houses an 8" refractor. The central part of the building also has a lecture room, used for educational programs and slide shows.

The VMOA volunteers do an excellent job of public outreach. On Saturday night, there were seven or eight additional volunteers with telescopes out in front of the observatory. Although our group got scattered amongst the crowd in the darkness of the Moonless evening, I sporadically pointed out constellations with the green laser.

The monthly viewing sessions typically draw 200-300 people. Saturday night was no exception. Everything was very well organized to optimize the visitor experience. Our Webelos left the observatory with their fill of telescopic views of star clusters and galaxies plus a colorful and informative slide presentation.

So guess what they decided unanimously was the highlight of the weekend? The green laser! Ya gotta love it!

For more information about RFO, VMOA, Project 40 and the Baldwin connection, visit the Web site at www.rfo.org

...Trevor Atkinson