Wednesday, April 26, 2017
CASSINI’S FIRST GRAND FINALE DIVE: MILESTONES THIS ARTIST'S RENDERING SHOWS NASA'S CASSINI SPACECRAFT ABOVE SATURN'S NORTHERN HEMISPHERE THIS ARTIST'S RENDERING SHOWS NASA'S CASSINI SPACECRAFT ABOVE SATURN'S NORTHERN HEMISPHERE, HEADING TOWARD ITS FIRST DIVE BETWEEN SATURN AND ITS RINGS ON APRIL 26, 2017. CREDITS: NASA/JPL-CALTECH
This artist's rendering shows NASA's Cassini spacecraft above Saturn's northern hemisphere
This artist's rendering shows NASA's Cassini spacecraft above Saturn's northern hemisphere, heading toward its first dive between Saturn and its rings on April 26, 2017.
NASA's Cassini spacecraft is set to make its first dive through the narrow gap between Saturn and its rings on April 26, 2017. Because that gap is a region no spacecraft has ever explored, Cassini will use its dish-shaped high-gain antenna (13 feet or 4 meters across) as a protective shield while passing through the ring plane. No particles larger than smoke particles are expected, but the precautionary measure is being taken on the first dive. The Cassini team will use data collected by one of the spacecraft’s science instruments (the Radio and Plasma Wave Subsystem, or RPWS) to ascertain the size and density of ring particles in the gap in advance of future dives. As a result of its antenna-forward orientation, the spacecraft will be out of contact with Earth during the dive.
Below is a list of milestones expected to occur during the event, if all goes as planned:
-- 5 p.m. PDT (8 p.m. EDT) on April 25: Cassini is approaching Saturn over the planet’s northern hemisphere in advance of its first of 22 planned dives through the gap between the planet and its rings.
-- 1:34 a.m. PDT (4:34 a.m. EDT) on April 26: As it passes from north to south over Saturn, Cassini begins a 14-minute turn to point its high-gain antenna into the direction of oncoming ring particles. In this orientation, the antenna acts as a protective shield for Cassini’s instruments and engineering systems.
-- 2 a.m. PDT (5 a.m. EDT) on April 26: Cassini crosses the ring plane during its dive between the rings and Saturn. The spacecraft’s science instruments are collecting data, but Cassini is not in contact with Earth at this time.
-- No earlier than around midnight PDT on April 26 (3 a.m. EDT on April 27): Earth has its first opportunity to regain contact with Cassini as the giant, 230-foot (70-meter) Deep Space Network antenna at Goldstone, California, listens for the spacecraft’s radio signal.
-- Likely no earlier than 12:30 a.m. PDT (3:30 a.m. EDT) on April 27: Images are scheduled to become available from the spacecraft.
As Cassini engineers monitor the status of the spacecraft, updates to these milestones will be added at:
Updates will also be posted on social media at:
More information about Cassini is at:
The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, California, manages the mission for NASA's Science Mission Directorate. JPL designed, developed and assembled the Cassini orbiter.
Jet Propulsion Laboratory, Pasadena, Calif.
Tuesday, April 25, 2017
" CONSTELACIÓN DE LA GRULLA " ( CRANE ) DESDE ROSARIO - ARGENTINA //// FOTO: ESMERALDA SOSA 25-04-2017
.. 5am ..
.. horizonte ESTE ..
" Constelación de La Grulla " - PROYECTOR PLANETARIO ZEISS
PARA VER FOTO EN HD ABRIR SIGUIENTE LINK
" COLLINDER 399 " ( CÚMULO DE LA PERCHA ) DESDE ROSARIO - ARGENTINA /// FOTO: ESMERALDA SOSA 25-04-2017
.. 5am ..
.. en Constelación de SAGITTA ( LA FLECHA )
.. horizonte NORTE ..
PARA VER FOTO EN HD ABRIR SIGUIENTE LINK
Took this photo a couple days ago a few min. after 6:00 am of Sun rising over Lake Superior looking East. Thought it interesting that the gull got into the picture
That’s how I witnessed the Sunrise today in Mataro above waters of the Mediterranean Sea, near Barcelona. The strange shape of the sun, known as Omega Sun, is an atmospheric phenomena in the category of sun mirages. The lower sun is not a reflection from the water. It is an inferior mirage. The lower sun is an inverted image produced by refraction by a layer of warmer and less dense air close to the ocean surface. The current sunspot (2652) is also seen on the face of the sun.
" VENUS & LA LUNA " DESDE ROSARIO - ARGENTINA //// FOTOS: ESMERALDA SOSA --- LUNA ILUMINADA EN 1.2 % --- 25-04-2017
.. desde las 5am hasta las 7.20am ..
.. noche mágica como pocas ..
.. frio, viento y MUCHO rocio .. horizonte SUR con tormenta ..
.. porcentaje de Luna iluminada 1.2 % ..
PARA VER IMAGENES EN HD ABRIR SIGUIENTE LINK
Monday, April 24, 2017
Enceladus’ sea floor has hydrothermal vents like ours
Where there’s heat and water on Earth, there’s life.
By John Wenz
Cassini Imaging Team, SSI, JPL, ESA, NASA
In 1977, a group of marine researchers discovered something they’d only before theorized: cracks in the ocean floor releasing heat, warming up (and often boiling) the ocean around it. They also found mollusks in them, and subsequent vents have yielded heat resistant microbes, giant tube worms, and more fantastic creatures living in what are essentially small, underwater volcanoes.
Now, NASA has announced that they have indirect evidence for hydrothermal vents beyond Earth. In its encounters with Saturn’s moon Enceladus, the Cassini craft found chemicals associated with these events. The results were published today in Science. It adds to the body of evidence that Enceladus could be ripe for life.
"Enceladus is too small to have retained the hydrogen from when it formed, so the hydrogen we see today is coming from inside Enceladus," Linda Spilker, project scientist on the Cassini mission, said in a press conference.
Enceladus, which is a tiny moon, took Cassini researchers by surprise when they discovered what seemed to be geysers of water emitting from the south pole in 2005. Subsequent investigations built a picture of the origin: liquid water under the surface of Enceladus, which led to the idea of an entire ocean under the surface. The heating mechanism, to date, has not been discovered.
The Ion Neutral Mass Spectrometer on the craft made the observation of molecular hydrogen in the ejecta from these geysers. According to principal investigator Hunter Waite of the Southwest Research Institute and his co-investigators, the source almost certainly has to be hydrothermal vents at Enceladus’ sea floor. This means there’s plenty of geological activity, increasing the chances for life.
Indeed, researchers published a paper last year suggesting that hydrothermal vents were the source of life on Earth, where chemical reactions fed these early microbes. If that’s the case on Enceladus, the ocean may have microbial life at the very least.
"The hydrogen could be a potential source of chemical energy for any microbes living in Enceladus' ocean," Spilker says.
Of course, it may be years or even decades until we know for sure — in September, NASA will intentionally crash Cassini into Saturn to make sure it doesn’t crash land into Titan or Enceladus and accidentally contaminate either potentially habitable moon with Earth bacteria.