2019-07-01_neScholar

planetary formation in the asteroid belt

between Mars and Jupiter.

Structure

Ceres is more similar to the terrestrial

planets (Mercury, Venus, Earth and

Mars) than its asteroid neighbors,

but it is much less dense. One of the

similarities is a layered interior, but

Ceres’ layers aren’t as clearly defined.

Ceres probably has a solid core and a

mantle made of water ice. In fact, Ceres

could be composed of as much as 25

percent water. If that is correct, Ceres

has more water than Earth does. Ceres’

crust is rocky and dusty with large salt

deposits. The salts on Ceres aren’t like

table salt (sodium chloride), but instead

are made of different minerals like

magnesium sulfate.

Surface

Ceres is covered in countless small,

young craters, but none are larger than

175 miles (280 kilometers) in diameter.

This is surprising, given that the dwarf

planet must have been hit by numerous

large asteroids during its 4.5 billion-year

lifetime.

The lack of craters might be due to

layers of ice just below the surface.

The surface features could smooth

out over time if ice or another lower-

density material, such as salt, is just

below the surface. It’s also possible that

past hydrothermal activity, such as ice

volcanoes, erased some large craters.

Within some of Ceres’ craters, there are

regions that are always in shadow. It’s

possible that without direct sunlight,

these “cold traps” could have water ice

in them for long periods of time.

Atmosphere

Ceres has a very thin atmosphere, and

there is evidence it contains water

vapor. The vapor may be produced by

ice volcanoes or by ice near the surface

sublimating (transforming from solid to

gas).

Potential for Life

Ceres is one of the few places in our

solar system where scientists would like

to search for possible signs of life. Ceres

has something a lot of other planets

don’t: water. Here on Earth, water is

essential for life, so it’s possible that

with this ingredient and a few other

conditions met, life could maybe exist

there. Living things on Ceres, if they are

there at all, would likely be very small

microbes similar to bacteria. And while

Ceres might not have living things

Researchers from NASA's Dawn mission have composed the first comprehensive views of the north (left) and south pole regions (right) of

dwarf planet Ceres, using images obtained by the Dawn spacecraft. The images were taken between Aug. 17 and Oct. 23, 2015, from an

altitude of 915 miles (1,470 kilometers).

The region around the south pole appears black in this view because this area has been in shade ever since Dawn's arrival on March 6,

2015, and is therefore not visible. At the north polar region, craters Jarovit, Ghanan and Asari are visible, as well as the mountain Ysolo

Mons. Near the south pole, craters Attis and Zadeni can be seen.

Detailed maps of the polar regions allow researchers to study the craters in this area and compare them to those covering other parts of

Ceres. Variations in shape and complexity can point to different surface compositions. In addition, the bottoms of some craters located close

to the poles receive no sunlight throughout Ceres' orbit around the sun. Scientists want to investigate whether surface ice can be found

there.

Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

12 neScholar^0 vol 4^0 issue 4