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EL CYBERASTRONOMO CENTROAMERICANO

El Informador De La Sociedad Virtual De Astronomia De Centroamerica

NUMERO 12 ANIO 1 AGOSTO 1, 1997 DIRECCION POSTAL: E-MAIL: ecastro@guate.net

14 AV. 39-39 ZONA 8 01008 TELEFONO: (502) 472 1277

GUATEMALA, GUATEMALA, C.A.

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Al pie de la letra

EUGENE M. SHOEMAKER (1928-1997)

Gene Shoemaker, renowned both as a geologist and an astronomer, and a member of the Board of Directors of The Spaceguard Foundation, was killed instantly on the afternoon of July 18, when his car collided head-on with another vehicle on an unpaved road in the Tanami Desert northwest of Alice Springs, in the Northern Territory of Australia. His wife Carolyn, who had closely collaborated with him in both his geological and his astronomical activities for many years, was injured in the accident and is in stable condition in Alice Springs Hospital.

Born in Los Angeles, California, on 1928 April 28, Eugene Merle Shoemaker graduated from the California Institute of Technology in Pasadena at the age of 19. A thesis on the petrology of Precambrian metamorphic rocks earned him a master's degree only a year later, at which point he joined the United States Geological Survey, an organization with which he remained at least partly associated for the rest of his life. His first work for the USGS involved searching for uranium deposits in Colorado and Utah. While doing this, he also became interested in the moon, the possibility of traveling there, and of establishing the relative roles of asteroidal impacts and volcanic eruptions in forming the lunar craters. He then embarked on work for a Ph.D. at Princeton University, intending to continue his study of metamorphic petrology, although this was interrupted when the USGS again sent

him to the field, this time leading him to an investigation of volcanic processes, for it was in the eroded vents of ancient volcanoes that the uranium deposits were often located.

Gene Shoemaker and Carolyn Spellman were married in 1951. A visit to Arizona's Meteor Crater the following year began to set Gene toward the view that both it and the lunar craters were due to asteroidal impacts. In 1956 he tried to interest the USGS in the construction of a geological map of the moon. This work was sidelined, because the national interest in the production of plutonium led him to study of the craters formed in small nuclear explosions under the Yucca Flats in Nevada and invited a comparison

with Meteor Crater. It was then that he did his seminal research on the mechanics of meteorite impacts that included the discovery, with Edward Chao, of coesite, a type of silica produced in a violent impact. Awarded a master's degree in 1954, Gene Shoemaker received his doctorate from Princeton in 1960 with a thesis on Meteor Crater.

In 1961 he took a leading role in the USGS venture, in Flagstaff, Arizona, into the study of "astrogeology", the Ranger missions to the moon and the training of the astronauts. It had long been Gene's dream to go to the moon himself, but in 1963 he was diagnosed as having Addison's disease, a condition that prevented him from becoming an astronaut. When the

USGS Center of Astrogeology was founded in Flagstaff in 1965, he was appointed its chief scientist and organized the geological activities planned for the lunar landings. In 1969 he returned to Caltech as a professor of geology and served for three years as chairman of the Division of Geological and Planetary Sciences there. Until he retired from the professorship in 1985 he divided his time between Pasadena and Flagstaff. He continued to maintain an office in the USGS Astrogeology building after his formal retirement in

1993, while at the same time taking up a position at the Lowell Observatory.

It was shortly after the 1969 arrival in Pasadena that he became interested in extending his geological knowledge of the formation and distribution of terrestrial and lunar impact craters to the study of the astronomical objects that formed them. With Eleanor Helin he developed a plan to search for such objects--the Apollo asteroids--with the 0.46-m Schmidt telescope at Palomar. This search program had its first success in July 1973

and was soon, with the help also of a number of students and of collaborations using other Schmidt telescopes, significantly augmenting the rather meager knowledge that had been accrued on these objects during the previous four decades.

Carolyn became involved with measuring images from the Palomar films in 1980, and in 1982 the Helin and the Shoemaker observing programs with the 0.46-m Schmidt went their separate ways. Carolyn proved to be very adept at scanning the Schmidt films, and this new phase of the search program had its first success with the discovery of (3199) Nefertiti, an Amor asteroid with its perihelion 0.13 astronomical unit outside the earth's orbit.

In 1983 the first of the record 32 comets associated with the Shoemaker name was discovered. By the time the observing program ended, in late 1994, it had produced 40 of the--now--417 known Amor, Apollo and Aten asteroids (the orbits of this last group being smaller than that of the earth). Together with the other observing programs at Palomar, the Shoemakers have ensured that Palomar recently became and is likely to remain the leading site for the discovery of asteroids, with currently more than 13 percent of asteroids that

have been numbered having been found there. A few months before the Shoemaker program was terminated came its "defining moment", with Gene receiving the thrill of his lifetime when some 20 components of one of those 32 comets were observed to crash into the planet Jupiter with astoundingly dramatic results.

Carolyn also went along on Gene's annual trips to Australia to examine impact craters, and the tragic irony that his own death should occur there as the instantaneous result of another violent impact would not have been lost on him. Gene lived as he died, active to the hilt, his enquiring mind participating in the adventure of ever learning more over an unusually large range of scientific disciplines. His many honors included the Wetherill Medal of the Franklin Institute in 1965, election to membership in the National Academy of Sciences in 1980, the Gilbert Award of the Geological Society of America in 1983 and the Kuiper Prize of the American Astronomical Society in 1984. Above all, he was truly the

"father" of the science of near-earth objects, to the discovery and study of which The Spaceguard Foundation is dedicated, and his expertise and drive will be sorely missed.

Brian G. Marsden

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TELESCOPIO EN VENTA (GUATEMALA)

Dobsoniano marca Odissey de 8", f/4.5, en perfecto estado, con un ocular de 27mm, incluye mira TELRAD................................................................................US$570.oo

Interesados llamar a Rodrigo Roesch, al tel. 597-2420 (noche) 591-4731(horas habiles)

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Europa tiene ionosfera.

Ha sido anunciado el descubrimiento por parte de la nave Galileo de la NASA de una tenue ionosfera en la luna helada Europa de Jupiter.

Una ionosfera es una capa de particulas atomicas con carga electrica (iones y electrones) que se forma a partir de las moleculas gaseosas en los niveles superiores de una atmosfera. En el caso de Europa puede estar causada tanto por la interaccion con el viento solar como con el campo magnetico de Jupiter.

Esta ionosfera -a pesar de su poca densidad-, junto con el oxigeno detectado por el Hubble el anio pasado, proporcionan fuertes indicios de la existencia de una atmosfera en Europa, lo que supone que la luna no es un cuerpo muerto sino que existe algun tipo de proceso en la superficie.

La ionosfera fue detectada mediante seis ocultaciones de la nave Galileo por Europa producidas entre Diciembre de 1996 y Febrero de 1997. Una ocultacion se produce cuando un cuerpo intercepta las emisiones de radio de la nave impidiendo que lleguen a la Tierra. la refraccion producida en la senial de radio en el momento de su desaparicion y

reaparicion es la que seniala la presencia de electrones o particulas cargadas.

Esta ionosfera se une a la ya conocida en Io, donde se cree que existe una atmosfera influenciada por el dioxido de azufre emitido desde los volcanes activos de su superficie. Los cientificos de la NASA continuan estudiando las otras dos grandes lunas para determinar si poseen o no ionosfera.

Mas informacion: Pagina de la Galileo <http://www.jpl.nasa.gov/galileo/>

Actualizacion esp@cio

Javier Sanchez Portero \_\_ esp@cio. Noticias de astronomia

mailto:sanja@mx2.redestb.es \_\_ http://espacio.home.ml.org

Tenerife, I.Canarias, Espana \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

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Editorial:

LOS PADECIMIENTOS DEL ASTRONOMO AFICIONADO

En nuestros paises practicar astronomia como aficionado es de por si dificil y hasta se puede volver un riesgo si uno no se sabe detener. La astronomia solo se pude hacer en tiempo libre, si se dedica mas tiempo que este se esta arriesgando el trabajo o los estudios. En el trabajo a muchos jefes no les gusta que se hable de astronomia. Unos porque no la entienden y otros porque la entienden. Los periodicos apenas si publican noticias de astronomia. Si envias un articulo no te lo publican o lo publican 3 meses despues, cuando ya no sirve. Encima de esto te dicen "astrologo", porque nadie esta consciente de la diferencia entre astrologia y astronomia, y a la mayor parte de personas no les interesa saberla, incluyendo personas "cultas".

El astronomo solo se vuelve util cuando va a ocurrir un fenomeno extraordinario, como un eclipse o un cometa, y siempre la pregunta es "¿ocurrira alguna desgracia para la Tierra?" en vez de hacer una pregunta mas inteligente.

Con casi nadie se puede hablar de este tema a profundidad, pues aunque muchas personas dicen que les interesa, la verdad es que les interesa solo hasta cierto punto del cual no quieren pasar. Son contadas con los dedos de la mano las personas que verdaderamente se interesan por la astronomia, que sacrifican sus horas de suenio por hacer observaciones serias, o por lo menos observaciones periodicas de astros, de planetas, de galaxias. El colmo es que para muchas personas el pertenecer a un club de astronomia les de un caracter de "snobs", y lo poco que aprenden les sirve para ir a impresionar a su grupo de amigos o vecinos o hasta su propia familia. En estos paises el astronomo es casi un proscrito. La television concede muy poco tiempo a esta ciencia. Si uno quiere explicar sencillamente la rotacion de Venus no les parece interesante.

En lugares de reunion algunas personas se burlan del astronomo, diciendole que solo vive en la Luna. Muchas veces se convierte en broma. No hay ninguna cultura astronomica. No hay respeto al cientifico por la misma ignorancia. Esto hace que el astronomo se sienta fuera de lugar, y no tenga con quien hablar, a menos que hable de politica, de futbol o que cuente buenos chistes, lo cual, en efecto, hacen algunos habilidosos cientificos. Por todo esto, el astronomo aficionado piensa a veces que es mejor guardar en secreto que le gusta la astronomia y hablar de otras cosas, dejando para otra noche su encuentro con el cielo. Unicamente otro aficionado puede entender sus triunfos y sus pensamientos.

Otra cosa que sucede es que como no le pagan por hacer astronomia (con algunas excepciones) a veces el astronomo no cuenta con todo el apoyo de la familia y se siente solo. Por eso siente la necesidad de pertenecer a un club. A un lugar donde haya personas con intereses similares. Donde haya personas a quienes les preocupe lo que esta pasando en Jupiter, como van los descubrimientos en Marte, que ha visto el Telescopio Espacial Hubble. El corazon le palpita con cada cosa nueva que se sabe del cielo, pero a mucha gente que lo rodea esto la tiene sin cuidado.

Los gobiernos no apoyan a la astronomia porque no da algun resultado practico. Tampoco lo hacen muchas Universidades. Solo algunas han empezado a cambiar su pensamiento, las que apoyan la investigacion en las ciencias del Espacio. ¿Como vamos a avanzar asi?

El astronomo seguira siendo un bicho raro. Un ser que es feliz bajo las estrellas, en la obscuridad y en el silencio, mientras la mayoria prefiere la luz y el bullicio. En el caso de los jovenes, tendran problemas con sus novias o novios, porque no les interesara la astronomia y no los querran acompaniar a las observaciones. Aun asi, el astronomo aficionado se siente feliz cuando esta solo, en su patio, en una noche fria, observando una estrella doble, un Messier o un cumulo estelar. Y toda esa felicidad le parece solo un suenio cuando, desvelado, tiene que ir a trabajar al dia siguiente.

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Astro-Musica:

David Arkenstone "Another star in the sky", musica de constelaciones y galaxias.

Enya "Watermark", la musica del Universo.

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Direcciones de Internet Interesantes para astronomos

http://ccdis.dis.ulpgc.es:8086/AAGC/swifttuttle.html, aqui se encuentra la historia del cometa Swift Tuttle y las perseidas.

http://www.seds.org/messier/hottest.html

Objetos de Messier y detalles de globulos estelares. ¡Muy bueno!

http://nix.nasa.gov, Excelentes imagenes de galaxias, astronautica, etc.

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¿COMO ESTAN SUS CONOCIMIENTOS DE ASTRONOMIA?

1. ¿Cuando ocurrio la ultima conjuncion de 7 cuerpos del sistema solar?

2. ¿Cuantos satelites tiene el Sistema Solar?

3. ¿Cual es el planeta mas frio?

Respuestas a la anterior: 1) G2 2) 8 billones de km2 3) Saturno

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LO QUE ES MEJOR LEER SIN TRADUCIR:

Navajo Wisdom

About 1966 or so, a NASA team doing work for the Apollo moon mission took the

astronauts near Tuba City where the terrain of the Navajo Reservation looks

very much like the Lunar surface. Along with all the trucks and large

vehicles, there were two large figures dressed in full Lunar spacesuits.

Nearby a Navajo sheep herder and his son were watching the strange creatures

walk about, occasionally being tended by personnel. The two Navajo people

were noticed and approached by the NASA personnel. Since the man did not

know English, his son asked for him what the strange creatures were and the

NASA people told them that they are just men that are getting ready to go to

the moon. The man became very excited and asked if he could send a message

to the moon with the astronauts.

The NASA personnel thought this was a great idea so they rustled up a tape

recorder. After the man gave them his message, they asked his son to

translate. His son would not.

Later, they tried a few more people on the reservation to translate and every

person they asked would chuckle and then refuse to translate. Finally, with

cash in hand, someone translated the message, "Watch out for these guys, they

come to take your land."

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SE BUSCA LA RESPUESTA

1. ¿Por que nunca se despeja el cielo en la noche de las Perseidas?

2. ¿Por que los astronomos no reportan "ovnis"?

3. ¿Habrá vida en el oceano de Europa?

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"El Cyberastronomo Centroamericano" es editador por Edgar Castro Bathen en la ciudad de Guatemala, Centroamerica. Sus comentarios y colaboraciones son bienvenidas al

e-mail: ecastro@guate.net o al Apartado Postal 307 "I" 01907 Guatemala, C.A.

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