Astronomy Picture of the Day
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2014 August 4
Shadows and Plumes Across Enceladus
Image Credit:
Cassini Imaging Team,
SSI,
JPL,
ESA,
NASA
Explanation:
Why does
Enceladus have ice plumes?
The discovery of jets spewing water vapor and ice was
detected by the Saturn-orbiting
Cassini spacecraft in 2005.
The origin of the water feeding the jets, however, remained a
topic of research.
A leading hypothesis held that the source might originate
from a deep underground sea,
but another hypothesis indicated that it might just be ice melted off walls of deep rifts by the moon's
tidal flexing and heating.
Pictured above,
the textured surface of Enceladus is visible in the foreground,
while rows of plumes rise from ice fractures in the distance.
These jets are made more visible by the
Sun angle and the encroaching shadow of night.
Recent study of over a hundred images like this -- of geysers crossing
Enceladus' South Pole, together with regional heat maps,
indicate that
these plumes likely originate from a hidden sea,
incresaing the chance that this frosty globe might be
harboring life.
Astrophysicists:
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Authors & editors:
Robert Nemiroff
(
MTU) &
Jerry Bonnell (
UMCP)
NASA Official: Phillip Newman
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