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| Photo : NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI |
Excerpt from sciencetimes.com
Originally discovered in 1801 by an astronomer in Sicily, Ceres has
had quite an interesting history to date. Originally believed to be a
shining star in the sky, when it was first observed to move, it was
redesignated as a comet.
“I have announced this star as a comet” astronomer who discovered
Ceres, Giuseppe Piazzi de Palermo said. “But since it is not accompanied
by any nebulosity and further, since its movement is so slow and rather
uniform, it has occurred to me several times that it might be something
better than a comet.”
Piazzi fell ill and passed away before he could ever find Ceres
again, but thanks to his preliminary research, astronomers today have
verified that the beaming light in the sky is something better than a
comet-it’s a dwarf planet. And though it is largely composed of ice and
rock, lying in-between Mars and Jupiter, Ceres continues to fascinate
astronomers with its strange and unanswerable features.
To better answer Piazzi’s original questions, and some new ones that
have arisen in the more than two centuries since it was first
discovered, researchers with NASA developed the Dawn Spacecraft mission
which was originally launched in 2007. After a successful 14-month-orbit
around Vesta in the asteroid belt, Dawn is now moving onto the next
dwarf planet and will arrive to Ceres within the next week. And the
first question that the Dawn mission would like to answer is a glaring
one, visible on the surface.
When astronomers first peering into the telescope to view Ceres, a
glaring spot of light seemed to illuminate through the rocky surface.
Data has been collected, and though researchers have made educated
guesses as to what it may be, they have not met an answer that could
quite fit the bill. Today this question is even further complicated as
with Dawn’s close approach NASA has captured an even closer glimpse of
the surface of Ceres, and now it appears that two shining spots are
visible on the surface-not just one.
Captured on last Thursday, Feb. 19, the two bright spots appeared
when Dawn was only 29,000 miles away from Ceres. But while NASA
researchers are still pondering the question of two spots, the team is
expecting even a few more surprises as Dawn will orbit the dwarf planet a
mere 233 miles from its surface, detailing it entirely to develop a
detailed 3D image of Ceres.
“We knew from Hubble observations that there was variation in the
colouration and reflectivity of the surface” lead scientist with the Dawn mission, Chris Russell says. “But when we got [near] Ceres we saw bright spots, and they are really, really bright.”
So what could the spots be?
While researchers are just speculating, until they can gain a better
view of the surface, NASA astronomers say that the two spots may be
patches of ice reflecting sunlight, who became exposed when objects from
the nearby asteroid belt collided. Another posited theory is that shiny
minerals or ice could be pushed to the surface by subterranean volcanic
activity. But they’re still not ruling out that the lights may be
evidence of Ceres hiding liquid water. And if it is, that means that
life on the distant dwarf planet may exist.
Source Article from http://feedproxy.google.com/~r/AscensionEarth2012/~3/-bSgjdniEug/as-dawn-spacecraft-approaches-second.html
As Dawn Spacecraft Approaches, A Second Mysterious Light Emerges on Planet Ceres
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