Figure 1
Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from
beyond the orbit of Neptune has Earth been imaged in color from the outer
solar system. Now, Cassini casts powerful eyes on our home planet, and
captures Earth, a pale blue orb -- and a faint suggestion of our moon --
among the glories of the Saturn system.
Earth is captured here in a natural color portrait made possible by the
passing of Saturn directly in front of the sun from Cassini's point of
view. At the distance of Saturn's orbit, Earth is too narrowly separated
from the sun for the spacecraft to safely point its cameras and other
instruments toward its birthplace without protection from the sun's glare.
The Earth-and-moon system is visible as a bright blue point on the right
side of the image above center. Here, Cassini is looking down on the
Atlantic Ocean and the western coast of north Africa. The phase angle of
Earth, seen from Cassini is about 30 degrees.
A magnified view of the image (see figure 1) taken through the clear
filter (monochrome) shows the moon as a dim protrusion to the upper left
of Earth. Seen from the outer solar system through Cassini's cameras, the
entire expanse of direct human experience, so far, is nothing more than a
few pixels across.
Earth no longer holds the distinction of being our solar system's only
"water world," as several other bodies suggest the possibility that they
too harbor liquid water beneath their surfaces. The Saturnian moon,
Enceladus, is among them, and is also captured on the left in this image,
with its plume of water ice particles and swathed in the blue E ring which
it creates. Delicate fingers of material extend from the active moon into
the E ring. See PIA08321, for a more detailed view of
these newly-revealed features.
The narrow tenuous G ring and the main rings are seen at the right.
The view looks down from about 15 degrees above the un-illuminated side of
the rings.
Images taken using red, green and blue spectral filters were combined to
create this view. The image was taken by the Cassini spacecraft wide-angle
camera on Sept. 15, 2006, at a distance of approximately 2.1 million
kilometers (1.3 million miles) from Saturn and at a sun-Saturn-spacecraft
angle of almost 179 degrees. Image scale is approximately 250 kilometers
(155 miles) per pixel.
At this time, Cassini was nearly 1.5 billion kilometers (930 million
miles) from Earth.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages
the mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter and its two onboard cameras were designed, developed and
assembled at JPL. The imaging operations center is based at the Space
Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/home/index.cfm. The Cassini imaging team
homepage is at http://ciclops.org.
