AL VUELO DE UN QUINDE EL BLOG

jueves, 15 de marzo de 2012

Astronomy: Compact Planetary System

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., This artist's concept depicts a planetary system so compact that it's more like Jupiter and its moons than a star and its planets. Astronomers using data from NASA's Kepler mission and ground-based telescopes recently confirmed that the system, called KOI-961, hosts the three smallest exoplanets currently known to orbit a star other than our sun. An exoplanet is a planet that resides outside of our solar system.

Compact Planetary System
This artist's concept depicts a planetary system so compact that it's more like Jupiter and its moons than a star and its planets. Astronomers using data from NASA's Kepler mission and ground-based telescopes recently confirmed that the system, called KOI-961, hosts the three smallest exoplanets currently known to orbit a star other than our sun. An exoplanet is a planet that resides outside of our solar system.

The star, which is located about 130 light-years away in the Cygnus constellation, is a red dwarf that is one-sixth the size of the sun, or just 70 percent bigger than Jupiter. The star is also cooler than our sun, and gives off more red light than yellow.

The smallest of the three planets, called KOI-961.03, is actually located the farthest from the star, and is pictured in the foreground. This planet is about the size of Mars, with a radius of 0.57 times that of Earth. The next planet to the upper right is KOI-961.01, which is 0.78 times the radius of Earth. The planet closest to the star is KOI-961.02, with a radius 0.73 times the Earth's.

All three planets whip around the star in less than two days, with the closest planet taking less than half a day. Their close proximity to the star also means they are scorching hot, with temperatures ranging from 350 to 836 degrees Fahrenheit (176 to 447 degrees Celsius). The star's habitable zone, or the region where liquid water could exist, is located far beyond the planets.

The ground-based observations contributing to these discoveries were made with the Palomar Observatory, near San Diego, Calif., and the W.M. Keck Observatory atop Mauna Kea in Hawaii.

Image Credit: NASA/JPL-Caltech
NASA.

Guillermo Gonzalo Sánchez Achutegui

miércoles, 7 de marzo de 2012

Astronomy: NASA's Twin GRAIL Spacecraft Begin Collecting Lunar Science Data

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., NASA's Gravity Recovery And Interior Laboratory (GRAIL) spacecraft orbiting the moon officially have begun their science collection phase. During the next 84 days, scientists will obtain a high-resolution map of the lunar gravitational field to learn about the moon's internal structure and composition in unprecedented detail. The data also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.

Artist concept of GRAIL mission. GRAIL will fly twin spacecraft in tandem orbits around the moon to measure its gravity field in unprecedented detail. Image credit: NASA/JPL .

PASADENA, Calif. -- NASA's Gravity Recovery And Interior Laboratory (GRAIL) spacecraft orbiting the moon officially have begun their science collection phase. During the next 84 days, scientists will obtain a high-resolution map of the lunar gravitational field to learn about the moon's internal structure and composition in unprecedented detail. The data also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.
"The initiation of science data collection is a time when the team lets out a collective sigh of relief because we are finally doing what we came to do," said Maria Zuber, principal investigator for the GRAIL mission at the Massachusetts Institute of Technology in Cambridge, "but it is also a time where we have to put the coffee pot on, roll up our sleeves and get to work."
The GRAIL mission's twin, washing-machine-sized spacecraft, named Ebb and Flow, entered lunar orbit on New Year's Eve and New Years Day. GRAIL's science phase began yesterday at 5:15 p.m. PST (8:15 p.m. EST). During this mission phase, the spacecraft will transmit radio signals precisely defining the rate of change of distance between the two. The distance between the spacecraft will change slightly as they fly over areas of greater and lesser gravity caused by visible features such as mountains, craters and masses hidden beneath the lunar surface. Science activities are expected to conclude on May 29, after GRAIL maps the gravity field of the moon three times.
"We are in a near-polar, near-circular orbit with an average altitude of about 34 miles (55 kilometers) right now," said David Lehman, GRAIL project manager from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "During the science phase, our spacecraft will orbit the moon as high as 31 miles (51 kilometers) and as low as 10 miles (16 kilometers). They will get as close to each other as 40 miles (65 kilometers) and as far apart as 140 miles (225 kilometers)."
The two spacecraft were previously named GRAIL A and B. The names Ebb and Flow were the result of a nationwide student contest to choose new names for them. The winning entry was submitted by fourth graders from the Emily Dickinson Elementary School in Bozeman, Mont. Nearly 900 classrooms with more than 11,000 students from 45 states, Puerto Rico and the District of Columbia, participated in the contest.
JPL manages the GRAIL mission for NASA's Science Mission Directorate in Washington. The GRAIL mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems in Denver built the spacecraft.
For more information about GRAIL,

visit: http://www.nasa.gov/grail .

Guillermo Gonzalo Sánchez Achutegui

viernes, 17 de febrero de 2012

Science: The Depths of Winter: How Much Snow Is In Fact On the Ground?

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., Transportation crews, water managers and others who make vital safety decisions need precise measurements of how snow depth varies across wide areas.

Stellar dendrites are tree-like snow crystals that have branches upon branches.
Credit: Kenneth Libbrecht, Caltech

Stellar plate snow crystals have ridges that point to corners between adjacent prism facets.

Credit: Kenneth Libbrecht, Caltech

Plate-like snowflakes form when it's near -2 degrees C (or 28 F), or near -15 C (5 F).

Credit: Kenneth Libbrecht, Caltech

Equipped with specialized lasers and GPS technology, scientists are working to address a critical wintertime weather challenge: how to accurately measure the amount of snow on the ground.
Transportation crews, water managers and others who make vital safety decisions need precise measurements of how snow depth varies across wide areas.
But traditional measuring devices such as snow gauges and yardsticks are often inadequate for capturing snow totals that may vary even within a single field or neighborhood.
Now scientists at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and at other institutions are finding that prototype devices that use light pulses, satellite signals and other technologies offer the potential to almost instantly measure large areas of snow.
In time, such devices might provide a global picture of snow depth.
"We've been measuring rain accurately for centuries, but snow is much harder because of the way it's affected by wind and sun and other factors," says NCAR researcher Ethan Gutmann.
"It looks like new technology, however, will finally give us the ability to say exactly how much snow is on the ground."
NCAR is conducting the effort with several collaborating organizations, including the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado Boulder.
The work is supported by NCAR's sponsor, the National Science Foundation (NSF).
"Snow represents both a hazard and a water resource in the western states," says Thomas Torgersen, NSF program director for hydrologic sciences. "Both require detailed assessments of snow amounts and depth. This technology will provide new and important guidance."
Emergency managers rely on snowfall measurements when mobilizing snow plows or deciding whether to shut down highways and airports during major storms.
They also use snow totals when determining whether a region qualifies for disaster assistance.
In mountainous areas, officials need accurate reports of snowpack depth to assess the threat of avalanches or floods, and to anticipate the amount of water available from spring and summer runoff.
But traditional approaches to measuring snow can greatly underreport or overreport snow totals, especially in severe conditions.
Snow gauges may miss almost a third of the snow in a windy storm, even when they are protected by specialized fencing designed to cut down on the wind's effects.
Snow probes or yardsticks can reveal snow depth within limited areas. But such tools require numerous in-person measurements at different locations, a method that may not keep up with totals during heavy snowfalls.
Weather experts also sometimes monitor the amount of snow that collects on flat, white pieces of wood known as snow boards, but this is a time-intensive approach that requires people to check the boards and clear them off every few hours.
The nation's two largest volunteer efforts--the National Weather Service's Cooperative Observer Program, and the Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS)--each involve thousands of participants nationwide using snow boards, but their reports are usually filed just once a day.
More recently, ultrasonic devices have been deployed in some of the world's most wintry regions.
Much like radar, these devices measure the length of time needed for a pulse of ultrasonic energy to bounce off the surface of the snow and return to the transmitter.
However, the signal may be affected by shifting atmospheric conditions, including temperature, humidity and winds.
The specialized laser instruments under development at NCAR can correct for such problems.
Once set up at a location, they can automatically measure snow depth across large areas. Unlike ultrasonic instruments, lasers rely on light pulses that are not affected by atmospheric conditions.
New tests by Gutmann indicate that a laser instrument installed high above treeline in the Rocky Mountains west of Boulder can measure 10 feet or more of snow with an accuracy as fine as half an inch or better.
In a little more than an hour, the instrument measures snow at more than 1,000 points across an area almost the size of a football field to produce a three-dimensional image of the snowpack and its variations in depth.
Gutmann's next step will be to build and test a laser instrument that can measure snow over several square miles. Tracking such a large area would require a new instrument capable of taking more than 12,000 measurements per second.
"If we're successful, these types of instruments will reveal a continually-updated picture of snow across an entire basin," he says.
One limitation for the lasers, however, is that light pulses cannot penetrate through objects such as trees and buildings.
This could require development of networks of low-cost laser installations that would each record snow depths within a confined area.
Alternatively, future satellites equipped with such lasers might be capable of mapping the entire world from above.
Gutmann and Kristine Larson, a scientist at the University of Colorado, are also exploring how to use GPS sensors for snowfall measurements.
GPS sensors record satellite signals that reach them directly and signals that bounce off the ground.
When there is snow on the ground, the GPS signal bounces off the snow with a different frequency than when it bounces off bare soil, enabling scientists to determine how high the surface of the snow is above the ground.
Such units could be a cost-effective way of measuring snow totals; meteorologists could tap into the existing global network of ground-based GPS receivers.
However, researchers are seeking to fully understand how the density of the snow and the roughness of its surface alter GPS signals.
"Our hope is to develop a set of high-tech tools that will enable officials to continually monitor snow depth, even during an intense storm," Larson says.
"While we still have our work cut out for us, the technology is very promising."
-NSF-
Media Contacts

Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov

David Hosansky, NCAR (303) 497-8611 hosansky@ucar.edu

Guillermo Gonzalo Sínchez Achutegui

jueves, 9 de febrero de 2012

METEOROLOGÍA: Más de la mitad del interior de Francia en alerta por el frío

Hola amigos: AL VUELO DE UN QUINDE EL BLOG., Un total de 52 departamentos del interior de Francia están hoy en alerta por el frío tras otra noche gélida en la que se alcanzó un nuevo récord de consumo eléctrico y se registraron hasta 20 grados bajo cero en el noreste.

Un total de 52 departamentos del interior de Francia están hoy en alerta por el frío tras otra noche gélida en la que se alcanzó un nuevo récord de consumo eléctrico y se registraron hasta 20 grados bajo cero en el noreste. En la foto de archivo, fechada el día 9 de febrero de 2007, la central nuclear de la empresa EDF en Cattenom, Francia. EFE/CHRISTOPHE KARABA

París, 9 feb (EFEverde).- Un total de 52 departamentos del interior de Francia están hoy en alerta por el frío tras otra noche gélida en la que se alcanzó un nuevo récord de consumo eléctrico y se registraron hasta 20 grados bajo cero en el noreste.
Un total de 52 departamentos del interior de Francia están hoy en alerta por el frío tras otra noche gélida en la que se alcanzó un nuevo récord de consumo eléctrico y se registraron hasta 20 grados bajo cero en el noreste. En la foto de archivo, fechada el día 9 de febrero de 2007, la central nuclear de la empresa EDF en Cattenom, Francia. EFE/CHRISTOPHE KARABA
Los servicios meteorológicos de Météo France indicaron que la pasada noche se alcanzaron los 20 grados bajo cero en la localidad de Mouthe, en una zona del macizo del Jura conocida como "la pequeña Siberia francesa".
Pero la situación no sólo fue extrema en zonas rurales, sino que también hubo 17 grados bajo cero en la ciudad de Bergerac y en otras zonas como en la región de Toulouse, donde las temperaturas bajaron hasta 13-14 grados bajo cero.
En el Macizo central también se llegó a los 14 grados bajo cero, mientras que en Normandía se midieron entre 11 y 12 grados negativos.
París 5 grados bajo cero
En París, donde los servicios municipales han utilizado barcos para romper el hielo de los canales y tratar de impedir que la gente intente caminar por la superficie, el termómetro a primera hora de hoy marcaba 5 grados bajo cero.
En todo el interior del país está previsto que las temperaturas de hoy se sitúen bajo cero, pese a que se espera un tiempo despejado hasta última hora de la tarde, cuando llegarán algunas nubes al extremo norte que podrían traer ligeras nevadas.
Las bajas temperaturas hicieron que ayer volviera a registrarse hacia las 19.00 hora local (18.00 GMT) un nuevo récord de consumo eléctrico con 101.700 megavatios, por encima del pico de 100.500 megavatios alcanzado 24 horas antes. EFEverde
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayaabaca@hotmail.com
ayabaca@yahoo.com

ENERGÍA: EE.UU. aprueba los dos primeros reactores nucleares en más 30 años

Hola amigos: AL VUELO DE UN QUINDE EL BLOG., La Comisión Reguladora Nuclear de Estados Unidos aprobó hoy, por primera vez en más de treinta años, las licencias para la construcción de dos nuevos reactores nucleares.

Fotografía de archivo de http://www.lafototeca.com de EFE del lunes 4 de abril de 2011, del Centro Energético Indian Point, una planta de tres unidades nucleares en Buchanan, Nueva York, tomada desde Tomkins Cove (NY, EE.UU.). EFE/Justin Lane

Washington, 9 feb (EFEverde).- La Comisión Reguladora Nuclear de Estados Unidos aprobó hoy, por primera vez en más de treinta años, las licencias para la construcción de dos nuevos reactores nucleares.

Un consorcio de empresas encabezado por Southern construirá los reactores nuevos en la planta nuclear de Votgle, a unos 275 kilómetros al este de Atlanta (Georgia, sur del país), que ya alberga otros dos.

La mayoría de los cinco miembros de la CRN aprobó la construcción de los dos reactores, pero el personal técnico de la comisión debe completar una revisión administrativa antes de que se emitan las licencias.

El único voto disidente fue el del presidente de la Comisión, Gregory Jaczko, quien en la reunión dijo que hubiera preferido el requisito de "mejoras en la seguridad" de Vogtle, a la luz del desastre nuclear del año pasado en los reactores de la planta de Fukushima Daiichi en Japón.

"Yo no puedo apoyar la emisión de esta licencia como si lo de Fukushima jamás hubiese sucedido", declaró Jaczko.

Estados Unidos, el mayor proveedor de energía nuclear del mundo, cuenta con 104 reactores que operan en 65 plantas nucleares y generan, combinados, casi el 20 por ciento de la energía eléctrica del país.

La construcción de todos los reactores que operan en EE.UU. comenzó antes de 1974, y después del desastre en Fukushima la CRN ordenó una revisión exhaustiva de las medidas de protección en las plantas atómicas.

La mayor planta nuclear de Estados Unidos está ubicada en Palo Verde (Arizona) y cuenta con tres reactores que, en conjunto, generan 3.942 megavatios.

La más pequeña, en Fort Calhoum (Nebraska), tiene un reactor que genera 478 megavatios de electricidad. EFE

Guillermo Gonzalo Sánchez Achutegui