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New Moon Found Orbiting Neptune

Posted by Soulskill on from the welcome-to-the-party dept.

Dave Knott writes "A tiny, previously unknown moon circling Neptune has been spotted by astronomers using the Hubble telescope. The moon, which is currently known as S/2004 N1, was found on July 1 by Mark Showalter of the SETI Institute in Mountain View, Calif., NASA announced Monday. It is less than 20 kilometres wide and its orbit is 105,000 kilometres from Neptune, between those of Larissa and Proteus, two of Neptune's other 14 known moons. It circles Neptune once every 23 hours."

8 of 120 comments (clear)

  1. But wait... by ls671 · · Score: 4, Insightful

    Since Pluto is not a planet anymore, we shouldn't be allowed to call a 20 km wide rock a moon. Let's have a big convention to decide how we should call it.

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    Everything I write is lies, read between the lines.
    1. Re:But wait... by JaredOfEuropa · · Score: 5, Funny

      A space station?

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      If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
    2. Re:But wait... by dltaylor · · Score: 5, Informative

      The dividing line between "moons" and "rings" seems to be shared orbits, otherwise every little rock and/or ice ball in the outer planets' rings would have to be a "moon". A 20 km rock (or whatever) has enough gravity to sweep the space through which it passes, either clustering smaller bits into rings, adding them to its mass, or ejecting them from the planetary system.

      Remember, Pluto was only a "planet" because we didn't realize it was an instance of a much larger class of KBOs. Now it appears to be more like a cluster of bits orbiting a mutual center, different from the planets and their moons, which have an orbital center deep inside the respective planets. Even without the companion bits, though, it's still a KBO.

      We had already separated the "asteroids" from the 8 planets.

    3. Re:But wait... by Sockatume · · Score: 5, Informative

      The IAU uses "moon" and "natural satellite" synonymously, which in this context refers to any natural body in a bound orbit of Neptune. I'm not sure why you think a 20km rock would fail to meet that definition.

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      No kidding!!! What do you say at this point?
    4. Re:But wait... by evilviper · · Score: 4, Funny

      Too small to call it a moon, huh? Well... how about a "planet-orbiiting object" or "poo" for short?

      As in, Neptune has a bit of poo right over there... Scientists suspect it came out of the moon.

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    5. Re:But wait... by ibwolf · · Score: 4, Informative

      How about specifying it must have enough gravity to make it round to be called a moon and not just a satellite?

      That would reduce the number of moons in the solar system rather dramatically. Mars, for example, would no longer have any "moons" as neither Phobos nor Deimos meet this definition. In fact both Phobos (11.1 km) and Deimos (6.2 km) are smaller than this newly discovered moon of Neptune (20 km).

  2. Planets and moons are just objects by bytesex · · Score: 4, Interesting

    Thinking of 'planets' and 'moons' is all nineteenth century 'science' - the edge of ascribing to God's plan and capturing everything observable in orderly lists, so that school-children have something to recite in groups: five continents, five senses, five races, seven seas, seven wonders of the ancient world, order species genus family class kingdom, and nine planets.

    In reality, things don't work out that way.

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    Religion is what happens when nature strikes and groupthink goes wrong.
    1. Re:Planets and moons are just objects by JaredOfEuropa · · Score: 5, Insightful

      Capturing everything observable in orderly lists (based on the mechanics of the underlying model) is science. Calling planets and moons "objects" is akin to discovering more and more kinds of atoms and particles and deciding to call everything just "stuff" because it doesn't fit your model anymore. The right answer is to rethink the definitions and perhaps alter the model. The distinction between planets and moons is still a useful one even if we found a few cases where we're not sure how we should classify them.

      --
      If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...