This Cassini narrow-angle camera image — one of those acquired in the survey conducted by the Cassini imaging science team of the geyser basin at the south pole of Enceladus — was taken as Cassini was looking across the moon’s south pole. At the time, the spacecraft was essentially in the moon’s equatorial plane. The image scale is 1280 feet (390 meters) per pixel and the sun-Enceladus-spacecraft, or phase, angle is 162.5 degrees.
The image was taken through the clear filter of the narrow angle camera on Nov. 30, 2010, 1.4 years after southern autumnal equinox. The shadow of the body of Enceladus on the lower portions of the jets is clearly seen.
In an annotated version of the image, the colored lines represent the projection of Enceladus’ shadow on a plane normal to the branch of the Cairo fracture (yellow line), normal to the Baghdad fracture (blue line) and normal to the Damascus fracture (pink line).
Post-equinox images like this, clearly showing the different projected locations of the intersection between the shadow and the curtain of jets from each fracture, were useful for scientists in checking the triangulated positions of the geysers, as described in a paper by Porco, DiNino, and Nimmo, and published in the online version of the Astronomical Journal in July 2014
Image Credit: NASA/JPL-Caltech.
Holograms Might Help Search for Alien Life
If a space probe detected microbial life on another planet, would scientists know it when they saw it?
Identifying bacteria by sight is challenging enough on Earth, even for experts. To the naked eye, bacteria look like featureless blobs — not unlike the mineral grains that might surround them in a sample.
A form of holographic imaging could help. A new paper in the journal Astrobiology highlights a detection method called digital holographic microscopy, which uses laser light to capture 3-D images. Whereas standard microscopes can only view a thin slice of a drop of water, this method adds more depth.
The paper was co-authored by Chris Lindensmith of NASA’s Jet Propulsion Laboratory, Pasadena, California; Jay Nadeau of Caltech; and Manuel Bedrossian, a Caltech graduate student.
source: NASA – Jet Propulsion Laboratory – California Institute of Technology