As Dawn spacecraft closes in on Ceres, things start to look 'rough'

This

image, taken 147,000 miles from Ceres by NASA’s Dawn spacecraft, is

part of a series of views representing the best look so far at the dwarf

planet. The spacecraft is set to enter orbit March 6. (NASA)

“What

we expect at Ceres is to be surprised, so it’s getting off to a good

start,” said deputy principal investigator Carol Raymond.

The

images, taken 147,000 miles from Ceres on Jan. 25, are 30%

higher-resolution than the images taken by NASA’s Hubble Space Telescope

in 2003 and 2004. They measure 43 pixels wide, a significant

improvement over Dawn’s images from earlier this month, which were 27 pixels across.

The

images show significant brightness and darkness variations over the

surface – particularly a bright spot gleaming in the northern hemisphere

and darker spots in the southern hemisphere. While the scientists were

aware of those major spots, they weren’t expecting to see quite so much

texture on the surface, said Raymond, a geophysicist at the Jet

Propulsion Laboratory.

Ceres is fairly warm by ice-world

standards; temperatures generally range from 180 to 240 Kelvin (or

minus-136 degrees Fahrenheit to minus-28 degrees Fahrenheit), Raymond

said. Theoretically, the ice on Ceres’ surface

should start to flow as it warms up, smoothing out any bumps such as

those from impact craters. But the brightness variations across the

surface make it appear very rough, she said.

“This

is just starting to illuminate the fact that Ceres is one of these

unique bodies that has astrobiological potential … and it’s just

continued to become more intriguing as we’ve been marching inexorably

closer,” she added.

Ceres

was not the first stop in Dawn’s 3-billion-mile journey. The first was

the protoplanet Vesta, which is vastly different from its fellow

mega-asteroid, Ceres. Where Vesta is dry and lumpy, Ceres is icy and

round, massive enough to have been pulled into a planet-like shape.

Scientists want to find out why these two space-fossils from the early

solar system ended up with such different geophysical life stories.
At least with Vesta, there were meteorites linked to the asteroid

that planetary scientists can study, Raymond pointed out. For Ceres,

there are no such space rocks found on Earth – so the researchers have

somewhat less of an idea of what to expect.

“I am excited,”

Raymond said. “Just having had the wild ride at Vesta, I’m also just in

awe of what’s going to happen. It’s going to be amazing.”

Source Article from http://feedproxy.google.com/~r/AscensionEarth2012/~3/sd2ahQlYBIA/as-dawn-spacecraft-closes-in-on-ceres.html

[ Add Comment ]

As Dawn spacecraft closes in on Ceres, things start to look 'rough'