Best ever view of asteroid Ceres

The best image ever acquired of the largest
asteroid in the Solar System is now in the hands
of science.
The 950km-wide object, known as Ceres, has
been pictured at a resolution that exceeds
anything seen previously by telescopes, even
Hubble.
Nasa's Dawn spacecraft can see details on the
icy rock's surface down to a scale of 22km per
pixel.
And that view will only get better as the probe
heads towards its historic rendezvous with Ceres
on 6 March.
The new picture was taken on Monday from a
distance of 237,000km.
By 12 February, with the gap narrowed still
further, the resolution will be four times better
than Hubble; and by 20 February it will be eight
times better.
Of particular interest is the "white spot" in the
Northern Hemisphere. Hubble could discern this
feature, too, but exactly what it is remains to be
determined.
It is very probably an impact crater. For the first
time, Dawn can see a dark area next to the spot
which could be the shadow cast by the crater's
rim.
Models of the asteroid suggest its interior is
dominated by a rocky core topped by ice that is
then insulated by rocky lag deposits at the
surface. Some researchers suspect there may
even be an ocean of liquid water at depth.
Such a construction would make Ceres' surface
quite responsive, meaning craters would not hold
a defined shape for long before relaxing and
losing some of their structure. For the white
spot to stand so proud may indicate therefore
that its formation was relatively recent.
Ceres is the dominant member of the band of
rocky debris that circles the Sun between the
orbits of Mars and Jupiter. Its great size means
gravity has pulled it into a roughly spherical
shape.
As well as being an asteroid, it is classed as a
"dwarf planet" and has the honour of being the
first such body to be visited by a spacecraft.
The second dwarf to get a visit will be Pluto. It
will receive a flyby from Nasa's New Horizons
probe in July.