ENCÉLADO [ Ἐγκέλαδος, Enkelados] ▲ Animation of Cassini "E20" Enceladus Flyby - Oct. 14, 2015

Cassini Begins Series of Flybys 

with Close-up of 

Saturn Moon Enceladus

Earlier in Cassini's mission at Saturn, northern terrains on the ocean-bearing icy moon Enceladus were in the shadow of winter.

Credits: NASA/JPL-Caltech

NASA's Cassini spacecraft will wrap up its time in the region of Saturn's large, icy moons with a series of three close encounters with Enceladus starting Wednesday, Oct. 14. Images are expected to begin arriving one to two days after the flyby, which will provide the first opportunity for a close-up look at the north polar region of Enceladus.

Wednesday’s flyby is considered a moderately close approach for Cassini, which will pass at an altitude of 1,142 miles (1,839 kilometers) above the moon's surface. Closest approach to Enceladus will occur at 6:41 a.m. EDT (3:41 a.m. PDT). The spacecraft’s final two approaches will take place in late October and mid-December.

During Cassini’s early-mission encounters with the moon, the northern terrain of Enceladus was masked by wintry darkness. Now that the summer sun is shining on the high northern latitudes, scientists will be looking for signs of ancient geological activity similar to the geyser-spouting, tiger-stripe fractures in the moon's south polar region. Features observed during the flyby could help them understand whether the north also was geologically active at some time in the past.

"We've been following a trail of clues on Enceladus for 10 years now," said Bonnie Buratti, a Cassini science team member and icy moons expert at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "The amount of activity on and beneath this moon's surface has been a huge surprise to us. We're still trying to figure out what its history has been, and how it came to be this way."

Since Cassini's 2005 discovery of continually-erupting fountains of icy material on Enceladus, the Saturn moon has become one of the most promising places in the solar system to search for present-day habitable environments. Mission scientists announced evidence in March that hydrothermal activity may be occurring on the seafloor of the moon's underground ocean. In September they broke news that its ocean -- previously thought to be only a regional sea -- was, in fact, global.

This animation shows NASA's Cassini spacecraft during its Oct. 14, 2015, flyby of Enceladus, which will focus on the Saturnian moon's northern polar region.

Credits: NASA

"The global nature of Enceladus' ocean and the inference that hydrothermal systems might exist at the ocean's base strengthen the case that this small moon of Saturn may have environments similar to those at the bottom of our own ocean," said Jonathan Lunine, an interdisciplinary scientist on the Cassini mission at Cornell University in Ithaca, New York. "It is therefore very tempting to imagine that life could exist in such a habitable realm, a billion miles from our home."

The Oct. 14 encounter will serve as a prelude to the main event, a flyby of Enceladus on Wednesday, Oct. 28, during which Cassini will come dizzyingly close to the icy moon, passing a mere 30 miles (49 kilometers) above the moon's south polar region. During this encounter, Cassini will make its deepest-ever dive through the moon's plume of icy spray, collecting images and valuable data about what's going on beneath the frozen surface. Cassini scientists are hopeful data from that flyby will provide evidence of how much hydrothermal activity is occurring in the moon's ocean, and how the amount of activity impacts the habitability of Enceladus’ ocean.

Cassini's final close flyby on Dec. 19 will examine how much heat is coming from the moon's interior from an altitude of 3,106 miles (4,999 kilometers).

An online toolkit for all three final Enceladus flybys is available at:

http://solarsystem.nasa.gov/finalflybys

Cassini arrived at Saturn in 2004 and still has about two years left on its mission. Beginning in November, mission controllers will begin to slowly raise Cassini's orbit out of the space around the Saturn’s equator, where flybys of the large moons are more common. Coming up are a number of closest-ever brushes with the small moons that huddle near the planet's rings.

"We'll continue observing Enceladus and its remarkable activity for the remainder of our precious time at Saturn," said Linda Spilker, Cassini project scientist at JPL. "But these three encounters will be our last chance to see this fascinating world up close for many years to come."

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington.

For more information about Cassini, visit:

http://www.nasa.gov/cassini

or

http://saturn.jpl.nasa.gov

-end-

Dwayne Brown / Laurie Cantillo
Headquarters, Washington                                                          
202-358-1726 / 202-358-1077
dwayne.c.brown@nasa.gov / laura.l.cantillo@nasa.gov

Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov 

Last Updated: Oct. 13, 2015

Editor: Karen Northon

This artist's concept shows a glowing patch of ultraviolet light near Saturn's north pole that occurs at the "footprint" of the magnetic connection between Saturn and its moon Enceladus. The footprint and magnetic field lines are not visible to the naked eye, but were detected by the ultraviolet imaging spectrograph and the fields and particles instruments on NASA's Cassini spacecraft. The footprint, newly discovered by Cassini, marks the presence of an electrical circuit that connects Saturn with Enceladus and accelerates electrons and ions along the magnetic field lines. In this image, the footprint is in the white box marked on Saturn, with the magnetic field lines in white and purple.

A larger white square above Enceladus shows a cross-section of the magnetic field line between the moon and the planet. This pattern of energetic protons was detected by Cassini's magnetospheric imaging instrument (MIMI) on Aug. 11, 2008.

The patch near Saturn's north pole glows because of the same phenomenon that makes Saturn's well-known north and south polar auroras glow: energetic electrons diving into the planet's atmosphere. However, the "footprint" is not connected to the rings of auroras around Saturn's poles (shown as an orange ring around the north pole in this image).

The Cassini plasma spectrometer complemented the MIMI data, with detection of field-aligned electron beams in the area. A team of scientists analyzed the charged particle data and concluded that the electron beams had sufficient energy flux to generate a detectable level of auroral emission at Saturn. Target locations were provided to Cassini's ultraviolet imaging spectrograph team. On Aug. 26, 2008, the spectrograph obtained images of an auroral footprint in Saturn's northern hemisphere.

The newly discovered auroral footprint measured about 1,200 kilometers (750 miles) in the longitude direction and less than 400 kilometers (250 miles) in latitude, covering an area comparable to that of California or Sweden. It was located at about 65 degrees north latitude.

In the brightest image the footprint shone with an ultraviolet light intensity of about 1.6 kilorayleighs, far less than the Saturnian polar auroral rings. This is comparable to the faintest aurora visible at Earth without a telescope in the visible light spectrum. Scientists have not yet found a matching footprint at the southern end of the magnetic field line.

The background star field and false color images of Saturn and Enceladus were obtained by Cassini's imaging science subsystem.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif. manages the mission for NASA's Science Mission Directorate, Washington, D.C. The ultraviolet imaging spectrograph team is based at the University of Colorado, Boulder. The magnetospheric imaging team is based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md. The Cassini plasma spectrometer team is based at the Southwest Research Institute, San Antonio, Texas.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .

Image credit: NASA/JPL/JHUAPL/University of Colorado/Central Arizona College/SSI

Last Updated: July 31, 2015

Editor: NASA Administrator

el dispensador anota en tu margen ► 

En la mitología griega, Encélado (en griego Ἐγκέλαδος, Enkelados; en latín Enceladus) era uno de los Gigantes de cien brazos, hijo deUrano: brotó de su sangre cuando fue castrado por Crono. Otra versión afirma que nació de la Tierra, que lo engendró por sí misma o con el Tártaro, airada contra los dioses.

Fue derrotado en la guerra con los dioses del Olimpo por los rayos de Zeus y enterrado bajo el monte Etna por Atenea. Sin embargoEurípides afirma que fue Sileno quien le mató con su lanza (si bien podría tratarse de una más de sus bravuconadas), y Pausanias que fue aplastado por Atenea cuando la diosa le lanzó la isla de Sicilia. Las llamas del Etna se suponía que eran la respiración de Encélado, y sus erupciones se producían al restregar su lado herido en el interior del volcán como escribe el poeta Lucilo.

Algunos creen que Encélado es el mismo que Tifón.

el dispensador anota, una vez más, en tu margen ► 

Encélado es un satélite de Saturno, descubierto en 1789 por William Herschel. A pesar de su pequeño tamaño, tiene una gran variedad de características superficiales como, por ejemplo, superficies viejas y craterizadas, y también superficies jóvenes y muy lisas. Dada su posición en el anillo E, la joven apariencia de parte de su superficie y el descubrimiento reciente de una tenue atmósfera, es muy probable que esté geológicamente activo. Encélado se encuentra en una resonancia orbital 2:1 con Dione, situación similar al caso de Io y Europa, lo cual pudiera proveer la energía necesaria para calentar levemente este satélite, aunque la causa (o causas) del calentamiento de Encélado es actualmente un tema de investigación; de hecho, la producción de calor en el polo sur de esta luna es mucho mayor de lo que se preveía (de casi 16 megavatios, más de 10 veces más de lo que se pensaba, algo cuyo origen es desconocido por ahora)⁹

Debajo de la superficie del satélite existe un océano de agua líquida global, como una capa entre el hielo de la superficie y el núcleo rocoso. Probablemente es calentado por muchas fuentes hidrotermales, lo que despierta gran interés al existir las condiciones necesarias para la vida.

el dispensador dice:

hay agua... hay vida...
hay atmósfera... señales de existencias, todavía...
hay energías conducidas,
¿qué más necesitas,
para darte cuenta que allí hay inteligencias,
que habitan?...
acaso,
¿la soberbia te ciega en tu día?,
acaso,
¿no reconoces de otros su utopía?,
¿hasta donde llega el cinismo que niegas,
pero que tu espíritu no evita?...
evidencias sobran... todavía...
y cada vez son más las señales,
que se te envían,
avisando que lo ajeno no te pertenece,
ni en tus sueños,
ni en tus noches,
ni en tus días...
ten cuidado humano,
porque la Tierra no te pertenece,
y así está escrito en la eternidad,
que niegas y que olvidas...

lo que pretendes como propio,
puede determinar el final de tus días...

¿tienes consciencia de la memoria de los dioses?...
si no la tienes,
no hagas de la paradoja,
el quiebre de tu risa.
OCTUBRE 14, 2015.-