Get ready! NASA spacecraft soon to rendezvous with dwarf planet Ceres

Excerpt from latimes.com


After voyaging 2.4 billion miles through space, NASA’s Dawn

spacecraft is finally in the home stretch of its journey to Ceres, the

largest member of the asteroid belt and one of five dwarf planets in the

solar system.

Dawn

was launched in 2007 to study two very different asteroids and learn

more about the building blocks of our solar system. Ceres is Dawn’s

second stop; its first was Vesta, which the spacecraft circled from July

2011 to September 2012.

Now,

after leaving Vesta and traveling through space for more than two

years, the spacecraft is roughly 400,000 miles away from Ceres and

speeding toward it at about 450 mph, with a rendezvous set for March 6.

Ceres

is a dwarf planet, along with Haumea, Makemake, Pluto and Eris (whose

discovery led to Pluto’s infamous planetary demotion). At 590 miles

across and holding roughly a third of the mass of the asteroid belt,

Ceres is large enough that its own gravity pulls it into a spherical

shape – which is part of why it was once considered to be very planet-like.

In fact, Ceres was listed as a planet for decades after its discovery

in 1801, and was briefly reconsidered during the 2006 debate surrounding

Pluto’s planetary status.

Ceres

is the only dwarf planet in the inner solar system. Although it’s much

larger than Vesta, it’s more of a mystery. Scientists have meteorites that they believe are from Vesta,

which they can study and compare to Dawn’s observations of the

asteroid; but no such fragments found on Earth have been linked to

Ceres. Until now, fuzzy images taken by NASA’s Hubble Space Telescope

have provided our best view of the icy dwarf planet. But that should

change by the end of January, as Dawn approaches its target.

Why

are these two “protoplanets” so different? Scientists think Vesta

formed earlier, when radioactive material was more abundant and produced

more heat, leaving the asteroid very dry. Ceres may have formed later.

Some researchers also think that Ceres may have originated much farther

out in the solar system, before being yanked into its current position

during a dramatic upheaval earlier in the solar system’s development.

As

building blocks of our solar system that never became full planets,

these protoplanets’ divergent life stories could shed light on the early

solar system’s history.

Source Article from http://feedproxy.google.com/~r/AscensionEarth2012/~3/8F5ItEObdk4/get-ready-nasa-spacecraft-soon-to.html

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Get ready! NASA spacecraft soon to rendezvous with dwarf planet Ceres