Ο
ωκεανός του Τιτάνα φωτοβολεί καθώς τον χτυπά ο Ήλιος. This near-infrared,
color mosaic from NASA's Cassini spacecraft shows the sun glinting off of
Titan's north polar seas. While Cassini has captured, separately, views of the
polar seas and the sun glinting off of them in the past, this is the first time
both have been seen together in the same view. The sunglint, also called a
specular reflection, is the bright area near the 11 o'clock position at upper
left. This mirror-like reflection, known as the specular point, is in the south
of Titan's largest sea, Kraken Mare, just north of an island archipelago
separating two separate parts of the sea. This particular sunglint was so
bright as to saturate the detector of Cassini's Visual and Infrared Mapping
Spectrometer (VIMS) instrument, which captures the view. It is also the
sunglint seen with the highest observation elevation so far -- the sun was a
full 40 degrees above the horizon as seen from Kraken Mare at this time -- much
higher than the 22 degrees seen in PIA18433. Because it was so bright, this
glint was visible through the haze at much lower wavelengths than before, down
to 1.3 microns. The southern portion of Kraken Mare (the area surrounding the
specular feature toward upper left) displays a "bathtub ring" -- a
bright margin of evaporate deposits -- which indicates that the sea was larger
at some point in the past and has become smaller due to evaporation. The
deposits are material left behind after the methane & ethane liquid
evaporates, somewhat akin to the saline crust on a salt flat. The highest
resolution data from this flyby -- the area seen immediately to the right of
the sunglint -- cover the labyrinth of channels that connect Kraken Mare to
another large sea, Ligeia Mare. Ligeia Mare itself is partially covered in its
northern reaches by a bright, arrow-shaped complex of clouds. The clouds are
made of liquid methane droplets, and could be actively refilling the lakes with
rainfall. The view was acquired during Cassini's August 21, 2014, flyby of
Titan, also referred to as "T104" by the Cassini team. The view
contains real color information, although it is not the natural color the human
eye would see. Here, red in the image corresponds to 5.0 microns, green to 2.0
microns, and blue to 1.3 microns. These wavelengths correspond to atmospheric
windows through which Titan's surface is visible. The unaided human eye would
see nothing but haze. Credit: NASA/JPL-Caltech/University of Arizona/University
of Idaho
Μια
εντυπωσιακή εικόνα έδωσε στη δημοσιότητα η NASA. Πρόκειται για μια σύνθεση από πολλές
εικόνες, ένα φωτογραφικό μωσαϊκό όπως το χαρακτηρίζει η NASA, στο οποίο απεικονίζεται η μεγαλύτερη
θάλασσα του Τιτάνα να λαμπυρίζει στο Διάστημα. Ο μεγαλύτερος δορυφόρος του
Κρόνου βρίσκεται σύμφωνα με τους επιστήμονες σε μια γεωλογική κατάσταση
παρόμοια με εκείνη που βρισκόταν η Γη στη βρεφική της ηλικία για αυτό και
αποτελεί μόνιμο στόχο παρατήρησης.
Sunglint on a
Hydrocarbon Lake: This near-infrared color image shows a specular reflection,
or sunglint, off of a hydrocarbon lake named Kivu Lacus on Saturn's moon Titan.
Kivu Lacus is a relatively small lake for Titan -- about 48.2 miles (77.5 km)
wide -- located very close to the moon's north pole. Image Credit: NASA/JPL-Caltech/University
of Arizona/University of Idaho
Στον
Τιτάνα υπάρχουν μικρότερες και μεγαλύτερες λίμνες και θάλασσες υγρών
υδρογονανθράκων (μεθάνιο, αιθάνιο προπάνιο, βουτάνιο, αιθυλένιο). Η μεγαλύτερη
είναι η Θάλασσα Κράκεν (Kraken
Mare) που βρίσκεται
κοντά στον Νότιο Πόλο του Τιτάνα και στην οποία υπολογίζεται ότι υπάρχουν 45
χιλιάδες χιλιάδες κυβικά χλμ. υγρών υδρογονανθράκων. Σύμφωνα με τους ειδικούς
της NASA το λαμπύρισμα
προκαλείται από την αντανάκλαση του Ήλιου στη Θάλασσα Κράκεν.
