Another Cassini flyby of Titan

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We await the data! Yesterday Cassini did its 118th flyby of Titan, getting close enough for two of its instruments to directly measure the planet’s upper atmosphere.

More here.


  • Wodun

    So we lost Pluto but gained Titan in the planet count? Whose behind this, the textbook publishers?

  • D K Rögnvald Williams

    Good catch, Wodun.

  • The definition of a planet will be determined by the way people use the words. To me, and to almost every planetary scientist I’ve ever interviewed, moons like Titan are planets, big, active, and complex. So, when I discuss them, I use that word, because the word “moon” only refers to the object’s location. It does not describe it very well otherwise.

  • Wodun

    Fair enough, I am still upset Pluto isn’t considered a planet.

  • Steve Earle

    Call me a retro-grouch if you will, but I am teaching my son that there are Nine Planets and that Pluto is not only a planet but has always been one.

    He is already trying to correct his Kindergarten teachers when they talk about 8 planets…. LOL

    We all watched the reports of the New Horizons mission with interest since in our house it was the last planet to be visited by a spaceprobe.

    History in the making :-)

  • Wayne

    Steve & Wodun:
    Call me a retro-grouch as well. (I only play a rocket-scientist on the Internet.)
    I totally trend toward your camp on all this– “Planets” orbit the Sun, “Moons” orbit Planets. (And Pluto was the last Planet to be visited by a space probe.) It might not be as precise & exact as it could be, and/but, as Mr. Z notes the words do get defined by the way in which they are used, but I think the planetary scientists do themselves a disservice in the eyes of the general-public when they change things drastically.

    Tangentially– What are the “official” name(s) of our Sun and our Moon?

  • One correction, Steve. Pluto is not the last planet to be visited by a space probe. There will be many more, in the future, hopefully when you son is still alive. Not only do we have exoplanets, but the Kuiper Belt has planets in it as large as Pluto.

  • Steve Earle

    Thanks for the correction Bob, I should have said the last planet of the original nine that I was taught, and I do tell him often that we have just begun to see whats out there. I hope he will remain interested enough as he grows up to follow a career somewhere in the sciences and/or exploration.

    I would much rather keep Pluto as a full-member of the “Planets of the Sol System” and then add more as necessary instead of demoting it to dwarf status. I get very irritated with the newer school books that speak of eight planets only and have no mention whatsoever of any other bodies dwarf or otherwise….. as though Pluto never even existed!

    Wayne: I was always under the impression that our sun was “Sol” as in the above “Sol System” and that the moon was called “Luna”. I rely on the very smart people here to let me know if that’s correct.

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