Thursday, January 29, 2015


The Dawn spacecraft observed Ceres for an hour on Jan. 13, 2015,
 from a distance of 238,000 miles (383,000 kilometers).
 A little more than half of its surface was
observed at a resolution of 27 pixels.

This BLOG entry is a bit lengthily so bare with me . That's why it took me so long to write this. I have  put a bit of  more lore into it.

2015 A SPACE ODYSSEY. This year is going to be a pivotal year for astro-science. Right now there could be major discoveries . On MARS , on a COMET , CERES and PLUTO. Between January and July the news is going to be filled with amazing discoveries regarding the nature of two bodies dubbed " dwarf  planets" . In March, a NASA spacecraft will arrive there to begin the first close-up examination of a dwarf planet.It is not Pluto.
It is instead Ceres, 600 miles wide, the largest of the asteroids between Mars and Jupiter. “We’re going to reveal the fascinating details of a giant world of rock and ice,” said Marc Rayman, the chief engineer for NASA’s Dawn spacecraft.  It will also examine Ceres’ composition. Over the next several weeks, Dawn will deliver increasingly better and better images of the dwarf planet, leading up to the spacecraft's capture into orbit around Ceres on March 6. The images will continue to improve as the spacecraft spirals closer to the surface during its 16-month study of the dwarf planet.The best images of Ceres so far were taken by NASA's Hubble Space Telescope in 2003 and 2004. This most recent images from Dawn, taken January 13, 2015, at about 80 percent of Hubble resolution, are not quite as sharp. But Dawn's images will surpass Hubble's resolution at the next imaging opportunity, which will be at the end of January.Ceres is the largest body in the main asteroid belt, which lies between Mars and Jupiter. It has an average diameter of 590 miles (950 kilometers), and is thought to contain a large amount of ice. Some scientists think it's
Ceres as seen via Hubble
Space Telescope .
possible that the surface conceals an ocean. 
Dawn's arrival at Ceres will mark the first time a spacecraft has ever visited a dwarf planet.Astronomers have discovered direct evidence of water on the dwarf planet Ceres in the form of vapor plumes erupting into space, possibly from volcano-like ice geysers on its surface.Using European Space Agency's Herschel Space Observatory, scientists detected water vapor escaping from two regions on Ceres, a dwarf planet that is also the largest asteroid in the solar system. The water is likely erupting from icy volcanoes or sublimation of ice into clouds of vapor. At almost 1000 kms in diameter, icy Ceres is thought to be still warm enough inside to provide clement conditions for at least some sort of bacterial life.Models suggest that the dwarf planet coalesced within 5 million years of our solar system’s first formative salvos. And the Hubble Space Telescope (HST) has determined that Ceres is likely to be differentiated. That is, with the help of radioactive nuclides, water ice melted into an icy mantle while rocky silicates sank to form its putative inner core. Another space craft is heading out to PLUTO some 4 billion miles a way, for the most part Pluto is as strange as Ceres . You might call these bodies the ultimo Thule of space science exploration . When get to Pluto we are
Pluto seen by
Hubble Space Telescope .
also heading into bizarre territory of a mini world surrounded by a dozen or so small moons , and one large moon that is almost nearly the same size of Pluto . 
The encounter phase of the New Horizons mission officially began Thursday, 180 days before the spacecraft’s closest approach July 14. New Horizons, launched in 2006 on a three-billion-mile trip to Pluto, came out of hibernation in December and is still 135 million miles away, closing in at a speed of more than 30,000 miles per hour. It will start photographing Pluto on Sunday, and by May, those photographs will be sharper than the sharpest taken by the Hubble Space Telescope. Pluto’s demotion from planethood in 2006 left fuzzy notions of what a planet is and is not. The International Astronomical Union, the organization in charge of astronomy nomenclature and names, invented a new category, dwarf planets, to place Pluto and Eris, an object discovered a decade ago that is a virtual twin of Pluto in size.Up until now, the best images of Pluto have been a few pixels shot by the Hubble Space Telescope. The images, released in 2010, took four years and 20 computers operating continuously and simultaneously to produce, according to Marc Buie of the Southwest Research Institute in Boulder, Colorado.New Horizons is aiming its Long-Range Reconnaissance Imager (LORRI) telescope at Pluto to help navigate the final 135 million miles (220 kilometers) of its 3 billion mile journey. Besides LORRI, the space probe is packed with cameras and other instruments. By mid-May, we should get "better than Hubble" photos. We'll also see Pluto's five moons: Charon, Nix, Hydra, Kerberos and Styx. New Horizons will also carry the ashes of Pluto's discoverer . It's been  85 years,  really isn’t that long, when you think about it. That’s how long it took Clyde Tombaugh to go from the discovery of the now-dwarf-planet Pluto to an eventual visit. Though people could barely believe in the existence of such a world in 1930, by Tombaugh’s death in 1997 NASA has already decided to go there. The astronomer had a simple request: to have his ashes transported to the distant orb he discovered. Now, after almost a decade en-route, the New Horizons probe has entered Pluto’s vicinity, and in so doing allowed Tombaugh to complete his relocation. It is now beginning the Pluto approach phase of its mission, culminating in a much-anticipated close flyby this July.

The Voyage to a Comet. 
Four image mosaic comprising images taken on
21 January 2015 by Rosetta's Navigation Camera (NAVCAM).
Last year was an extraordinary year for Comet lovers . It began when Rosetta arrived at comet 67P/Churyumov-Gerasimenko last  August, then surveyed candidate landing sites for the mission’s piggyback Philae landing craft. Philae dropped to the comet’s nucleus Nov. 12 and bounced to rest near the face of a cliff made of rock and ice, beaming back unprecedented measurements from the surface of a comet for two days.Imagery from Rosetta’s main camera has seen 70 percent of the comet’s surface, revealing it to be rugged and diverse, ranging from jagged knife-like rock outcrops to dust dunes up to several meters deep that appear to be blown by wind on the airless body.Scientists believe gases flowing from jets on the nucleus could drive dust particles across the surface, creating features similar to sand dunes on Earth.The origin of the comet’s irregular shape — a subject fascinating to scientists and the public alike — remains a mystery, scientists said in an ESA press release.Comet 67P has two distinct lobes separated by a narrow neck, resembling the head and body of a duck. t is noticeable how similar this formation is to many others on 67P, in particular the larger "basin" of Hatmehit seen in the Jan 18th image. I can imagine, given what we know so far, a possible scenario for the erosion of a circular scarp to give the current appearance of these formations, but how these cliffs or mountain ridges are formed still evades me. Their scale makes it difficult to imagine sublimation is involved, and impacts making that size of dent in the comet, given its porosity, would surely have smashed it to pieces.One plausible suggestion might be large scale voids beneath the surface and their collapse. This just moves the
This odd ball comet
poised a landing problem.
problem on to the mechanisms for the development of such voids in the past.
Another mechanism may be due to internal mass loss and the subsequent contraction in volume of the comet. This could lead to fracturing and buckling of the sintered ice sub-surface crust, which gives the appearance of being relatively hard and solid, but brittle. Certainly the large scarps and mountain ridges in the Ash area near Cheops look to be formed in this way and the OSIRIS team suggest there is evidence for such tectonic forces. Again, how do you loose such large amounts of mass from well below the surface and sub-surface of the comet? scientists at theEuropean Space Agency (ESA) are deliberating to send Rosetta spacecraft, which is still orbiting the comet, to swoop down just six kilometres over the patch where the lander is thought to be.Since its batteries ran out just days after a bumpy landing on the comet named 67P/Churyumov-Gerasimenko (C-G) in November last year, Philae has been silent and its exact location remains a mystery, scientific journal Nature reported.But Rosetta has only limited fuel and any attempt to look for Philae would mean scrapping another flyby, sacrificing a chance to image the comet in a shadow-free shot that should reveal unprecedented detail.Of the regions of the comet imaged so far, scientists have found 19 distinct areas and named them after Egyptian deities, which is a naming theme for all features identified on the comet. These
A rather nice place for vacation
gray ice and dust.
regions are grouped by the terrain that dominates each sector.
The five basic regions are dust-covered (regions Ma'at, Ash and Babi), pits and circular structures underlain with brittle materials (Seth), those with big depressions (Hatmehit, Nut and Aten), those with smoother features (Hapi, Imhotep and Anubis) and those with rocklike surfaces, which encompass all of the remaining regions.Based on observations so far, scientists think the comet is about 70 to 80 percent porous, assuming that the comet is made up mostly of ice and water. "The interior structure [is] likely comprising weakly bonded ice-dust clumps with small void spaces between them," ESA officials said.

MORE TO COME...............................................

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