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    Spectacular Saturn Views - Waves From Daphnis And Spokes At Sunrise (And More)
    By News Staff | April 21st 2009 11:44 PM | 2 comments | Print | E-mail | Track Comments
    Waves from Daphnis

    Undulations mark both sides of the path of Saturn's moon Daphnis through the A ring. 

    Daphnis may be small at only 8 kilometers (5 miles) across, but the moon's gravity is great enough, and the Keeler gap in which it resides is narrow enough, so that the perturbed particles create the wavelike patterns seen here. 

    This view looks toward the unilluminated side of the rings from about 47 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 21, 2009. The view was acquired at a distance of approximately 1.1 million kilometers (684,000 miles) from Daphnis and at a Sun-Daphnis-spacecraft, or phase, angle of 50 degrees. Image scale is 7 kilometers (4 miles) per pixel. 

    Saturn Waves from Daphnis
    Credit: NASA/JPL/Space Science Institute

    Spokes at Sunrise

    Bright spokes emerge from behind the shadow of the planet and into sunlight in this view from the Cassini spacecraft.   Saturn's long shadow covers the left side of the image. This view looks toward the sunlit side of the rings from about 22 degrees below the ringplane. 

    The image was taken in visible light with the Cassini spacecraft wide-angle camera on Feb. 26, 2009. The view was acquired at a distance of approximately 821,000 kilometers (510,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 150 degrees. Image scale is 46 kilometers (29 miles) per pixel.   


    Credit: NASA/JPL/Space Science Institute

    Saturn's Tortured Ring

    The fragile F ring bears the signs of a moon's bruising passage. 

    The A ring and its Keeler Gap sit idly by on the right of this image, but on the left dark lines cut across the F ring and mark where the moon Prometheus has gored the ring and gravitationally drawn streamer-channels of material from the ring . To the left and right of the bright core, the F ring also displays the ghostly stands of its spiral arm which winds around the planet like a compressed spring. 

    This view looks toward the sunlit side of the rings from about 11 degrees below the ringplane. The image was taken in green light with the Cassini spacecraft narrow-angle camera on March 2, 2009. The view was acquired at a distance of approximately 1.2 million kilometers (746,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 33 degrees. Image scale is 7 kilometers (4 miles) per pixel. 


    Credit: NASA/JPL/Space Science Institute

    Hazy Ring of Titan's Sky

    From the dark side of Titan, the Cassini spacecraft profiles the moon's atmosphere as sunlight filters through its upper hazes.   An airless satellite would appear in this viewing geometry only as a lit crescent. But Titan's thick atmosphere scatters light around all edges of the planet to create a ring of light. 

    Images taken using red, green and blue spectral filters were combined to create this full color view of Titan at high phase. The color in the image on the right has been computer enhanced to bring out the outer haze layer, and the contrast in both images has been enhanced.   This view looks toward the Saturn-facing side of Titan. North on Titan is up and rotated 45 degrees to the left. The images were acquired at a distance of approximately 1.8 million kilometers (1.1 million miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 157 degrees. Image scale is 11 kilometers (7 miles) per pixel. 


    Credit: NASA/JPL/Space Science Institute

    Tethys Crater Chasm Combo

    The terminator between shadow and light cuts across a large crater in the high southern latitudes of the moon Tethys.   Also visible near the terminator on the left of the image is a portion of the Ithaca Chasma, a chasm that runs north-south for more than 1,000 kilometers (620 miles). This view looks toward the south pole of Tethys, and the pole lies on the terminator between the crater and the chasm. 

    Lit terrain seen here is mostly on the trailing hemisphere of Tethys (1,062 kilometers, 660 miles across). The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 16, 2009. The view was acquired at a distance of approximately 873,000 kilometers (542,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 96 degrees. Image scale is 5 kilometers (3 miles) per pixel. 


    Tethys Crater Chasm Combo
    Credit: NASA/JPL/Space Science Institute

    Janus' Pole Crater

    A large crater on Saturn's tiny moon Janus is distinctly visible in this Cassini spacecraft image.   Lit terrain seen here is on the leading hemisphere of Janus (179 kilometers, or 111 miles across). North on Janus is up and rotated 7 degrees to the left. 

    The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 5, 2009. The view was acquired at a distance of approximately 1.1 million kilometers (684,000 miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 53 degrees. Resolution in the original image was 6 kilometers (4 miles) per pixel. The image has been magnified by a factor of two to aid visibility. 



    Credit: NASA/JPL/Space Science Institute

    Comments

    HedgehogFive
    The bit about "the wavelike patterns seen here" reminds me of the following:
    on Equilibrium in the Economy

    "Our planned economy is at once in equilibrium and disequilibrium.  Equilibrium is temporary and conditional.... We Marxists hold that disequilibrium, contradiction, struggle and development are absolute, while equilibrium and rest are relative.  Relative means temporary, conditional.  Viewed in this light, is our economy advancing or retreating? We should tell the masses and the cadres that it is both advancing and retreating, but mainly advancing, but not in a straight line but in a wave-like manner."
     
    (Mao Zedong, to the Central Committee, November 1968)

    Very topical, don't you think?
    rholley
    Janus reminds me that a couple of our students, a few years ago, did a project on the orbit-swapping of two of Saturn's moons, though whether it was Janus and Epimetheus or another pair I don't remember.

    One thing, though, was that they used simple Newtonian mechanics, not even Lagrangians or Hamiltonians.  So to all those who think that physics from before Einstein is obsolete, I will take my cue from Sha-Na-Na and say:

    Let me tell all you Relativity freaks ..... Classical Mechanics is Here to Stay!!!

     
    Janus and Epimetheus after swapping orbits.  They're not actually that close, simply line-of-sight at almost opposite points of their orbits.  Image link

    And as my father used to say of one of our leading politicians:

    Don't call him Janus - Janus only had two faces.

    Robert H. Olley / Quondam Physics Department / University of Reading / England