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NASA Science

Hubble Discovers 5th Moon of Pluto 137

Posted by Soulskill from the more-traffic-for-some-new-horizons-frogger dept.
Stirling Newberry writes "This image shows 'P5,' the placeholder name for a fifth natural moon of Pluto, a tiny sliver that orbits ~29,000 miles from its primary in a circular orbit. Other than Charon, Hubble has been the means by which astronomers have found all of the known moons of Pluto. 'The new detection will help scientists navigate NASA’s New Horizons spacecraft through the Pluto system in 2015, when it makes an historic and long-awaited high-speed flyby of the distant world. The team is using Hubble’s powerful vision to scour the Pluto system to uncover potential hazards to the New Horizons spacecraft. Moving past the dwarf planet at a speed of 30,000 miles per hour, New Horizons could be destroyed in a collision with even a BB-shot-size piece of orbital debris.'"
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Hubble Discovers 5th Moon of Pluto More

Hubble Discovers 5th Moon of Pluto

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  • So it has five moons, but they still do not classify it as a planet?

    • Re:Not a planet (Score:4, Informative)

      by Anonymous Coward on Wednesday July 11, 2012 @03:07PM (#40618305)

      http://en.wikipedia.org/wiki/Minor-planet_moon [wikipedia.org]

      Lots of asteroids have moons.

      • Yeah but those all have names that start with random numbers while Pluto is just Pluto. Having a cool name should count for something.

    • One'd expect thing that don't clear their orbit to have more moons...

      • Neptune didn't clear out its orbit either (Since Pluto is in it), and it has 5 (currently known) moons too.

        • Re: (Score:2)

          by Meumeu ( 848638 )

          Neptune didn't clear out its orbit either (Since Pluto is in it), and it has 5 (currently known) moons too.

          Next to Neptune, Pluto is a speck of dust, so yes Neptune cleared its orbit. You can't say the same for Pluto.

          • Re: (Score:1)

            by Anonymous Coward

            Neptune didn't clear out its orbit either (Since Pluto is in it), and it has 5 (currently known) moons too.

            Next to Neptune, Pluto is a speck of dust, so yes Neptune cleared its orbit. You can't say the same for Pluto.

            Not to mention, Pluto is not even in Neptune's orbit, so yeah. (Sorry oodaloop, but because of how the orbit of Pluto is inclined, when it "crosses" Neptune's orbit, it's so far out of the orbital plane of the 8 planets that it doesn't matter.)

    • Its not a moon.

    • Actually Pluto & Co. only has 4 moons, Charon is not a moon, it is co-dwarf planet, in that Pluto orbits around Charon just as much as Charon orbits Pluto.

      • To be accurate, both Pluto and Charon orbit their common center of gravity. Just like the Earth and Moon orbit their common center of gravity, or like any two other orbiting objects.

        • To be accurate, both Pluto and Charon orbit their common center of gravity. Just like the Earth and Moon orbit their common center of gravity, or like any two other orbiting objects.

          Yeah, but the common center of gravity of the Earth and the Moon, is _inside_ the Earth, which means the Moon orbits a point inside Earth (just not the center), which is what makes it a satellite or moon of Earth.

          In the case of Pluto and Charon the common center of gravity is between them and not inside either of them, w

          • Re: (Score:2)

            by arth1 ( 260657 )

            Yeah, but the common center of gravity of the Earth and the Moon, is _inside_ the Earth, which means the Moon orbits a point inside Earth (just not the center), which is what makes it a satellite or moon of Earth.

            In the case of Pluto and Charon the common center of gravity is between them and not inside either of them, which means none of them is a moon to the the other, but they share a common co-orbit.

            By that measure, Jupiter isn't a planet either, because the barycenter between Jupiter and the sun lies above the surface of the sun.

            Also consider this: The moon is slowly expanding its orbit and decreasing its speed accordingly. Which means that the barycenter of the Earth/Luna system slowly creeps towards the Earth's surface, and one day it will be above it. Will that elevate Luna from moon status to co-planet?

            • Will that elevate Luna from moon status to co-planet?

              It would if it was actually possible. The moon will leave Earths orbit when it gets far enough away, at that point it becomes a huge motherfucking asteroid.

              • Re: (Score:2)

                by arth1 ( 260657 )

                It would if it was actually possible. The moon will leave Earths orbit when it gets far enough away, at that point it becomes a huge motherfucking asteroid.

                I think you missed the part where it slows down. It gets further away, but also loses speed, which means it doesn't get to break away until long after the barycenter is outside earth itself, and pulls from other solar system masses can pull it away.
                At the present speed, it will take around 6 thousand million years for the moon to recede enough that the barycenter is outside the earth's surface, while the moon is unlikely to run away for more than 40 thousand million years.

                (Granted, something else will like

                • No, it won't slow down. Moons in orbits further out moves more slowly not by some magical force, but because they wouldn't have that orbit if they didn't have the exact necessary speed for it. A moon or satellite moving to an outer orbit will not slow down to a matching slower speed, it will be flung away. Similarly any moon or satellite moving to an inner orbit will not magically accelerate to a new stationary orbit, it will instead crash into the planet.

                  Our moon is not a stable orbit, we are just lucky e

                  • Re: (Score:2)

                    by arth1 ( 260657 )

                    No, it won't slow down. Moons in orbits further out moves more slowly not by some magical force, but because they wouldn't have that orbit if they didn't have the exact necessary speed for it. A moon or satellite moving to an outer orbit will not slow down to a matching slower speed, it will be flung away. Similarly any moon or satellite moving to an inner orbit will not magically accelerate to a new stationary orbit, it will instead crash into the planet.

                    You're wrong. [wikipedia.org]

                    Just as a figure skater slows her spin when extending her arms, the moon slows down as its orbit increases.

                    For the moon/earth system, this is explained in Another wikipedia article [wikipedia.org]:

                    "The gravitational torque between the Moon and the tidal bulge of the Earth causes the Moon to be promoted in its orbit, and the Earth to be decelerated in its rotation. As in any physical process within an isolated system, total energy and angular momentum are conserved. Effectively, energy and angular momentum are

            • Best nerd fight in recent memory. I had nearly given up on slashdot, but I keep finding gold like this.

              Disagreeing informatively is by far the most enlightening discussion for my taste.

              As you were, sorry for the interruption.

          • Re:Not a planet (Score:4, Interesting)

            by Will.Woodhull ( 1038600 ) <wwoodhull@gmail.com> on Wednesday July 11, 2012 @11:38PM (#40624391) Homepage Journal

            Which is a pretty damn hokey and arbitrary distinction. The Earth's orbit is significantly affected by the Moon's gravitation: its path around the Sun is sinusoidal, quite far from a true elipse, far enough that the locations of perihelion and aphelion shift from year to year depending on the Moon's phase in early January and early July, and these points cannot be predicted without accounting for the Moon's influence.

            The points of perihelion and aphelion of the barycenter of the Earth - Moon pair can be predicted using the same simple formula that works for all the other visible planets, plus Uranus and Neptune. But the Earth itself is sometimes faster, sometimes slower, sometimes closer to the Sun, sometimes further away than the barycenter, all due to its partner's influence. That is the mark of a double planet, not a planet that has a Moon.

            That the most unique feature of the Earth, the presence of our kind of life, could not have come about without the Moon's action as a constant stirring rod is an entirely separate and equally valid argument for regarding the Earth and Moon as parts of a binary planet system.

    • Re: (Score:1)

      by mrmeval ( 662166 )

      It's not a planet by scientific consensus so it can't have moons. Nasa is wrong, that's just debris.

  • ORLY? (Score:5, Funny)

    by yt8znu35 ( 1202731 ) on Wednesday July 11, 2012 @03:06PM (#40618297)
    That's no moon.

  • So let me get this straight (Score:5, Funny)

    by kiriath ( 2670145 ) on Wednesday July 11, 2012 @03:10PM (#40618349)

    NASA is going to drive a 650 million dollar spacecraft through a system @40AU away at 30,000 miles per hour - and that spacecraft could be destroyed by a BB.

    The phrase "That thing could put your eye out" brings on a whole new meaning...

    • Re: (Score:3)

      by Jhon ( 241832 )

      New Horizons should be named the "Ralphie Probe"?

    • Re: (Score:1)

      by Anonymous Coward

      Dude, after the cornering and hairpins of the Cassini mission [nytimes.com], 30,000 mph through a debris field 40 AU's away is a walk in the park for these guys.

    • Re: (Score:3)

      by Hadlock ( 143607 )

      The typically positioned the space shuttle so that debris would impact the tiles rather than the windshield after a micrometeorite left a pinprick in the 1"+ thick windshield and embedded itself in the pilot's headrest durring a mission. Shit happens. Stuff is flying everywhere at absolutely insane speeds. Luckily, once you get beyond the asteroid belt, you're generally good to go. We've had a couple of probes die randomly in transit, about half of them are chalked up to human error, the other are suspected

      • Re: (Score:2)

        by cusco ( 717999 )
        Still jumping up and down to get that one way ticket to mars?

        Hell yes, in fact I'd settle for one-way to Luna. Not many places on Earth where one can still be a true pioneer any more, and all of those are completely explored anyway.

      • a micrometeorite left a pinprick in the 1"+ thick windshield and embedded itself in the pilot's headrest durring a mission.

        [citation needed]

        • Before my father retired, he was doing research into hypervelocity impacts. It's really intense and pretty scary. He showed me the results of a glass bead the size of a grain of rice that had been shot out of a magnetic rail gun at 17,000 kph (around the orbital velocity of the shuttle, etc.). The glass bead was shot into a steel plate 1 inch thick and ~1 sq foot in size. The entry hole was the size of a quarter, and the exit hole (yes it went all the way through) was the size of a baseball with frozen meta

          • Thanks - although to clarify, I wasn't questioning that tiny things can do huge damage at high speed. I was looking for some more info on the "micro meteorite puts hole in shuttle windshield and ends up in headrest" story. I just would have naively thought that, y'know, all the air'd blow out and stuff.

    • Re: (Score:3, Insightful)

      by Cuddlah ( 2677847 )
      You hit ANYTHING with a BB at 30,000 miles an hour, it's a catastrophic collision.

  • Four (Score:4, Funny)

    by bazald ( 886779 ) <bazald@NoSPAM.zenipex.com> on Wednesday July 11, 2012 @03:13PM (#40618397) Homepage

    There... are... four... moons!

  • Nevermind the 19,000 man-made objects larger than 10 centimetres in LEO. I wonder how anyone navigates past this stuff. http://en.wikipedia.org/wiki/File:Space_Debris_Low_Earth_Orbit.png [wikipedia.org]

    • Re: (Score:1)

      by Anonymous Coward

      *debris not to scale :)

    • Re:BB sized debris (Score:4, Informative)

      by jnaujok ( 804613 ) on Wednesday July 11, 2012 @04:00PM (#40619193) Homepage Journal
      Because space is big...

      Imagine there were only 19,000 people on Earth, roughly evenly distributed. What's the chance you'd ever run into another person? Now, instead of just the land area, make sure that 3/4ths of those people are on the ocean. What are the odds of running into one of them now?

      Now, imagine that, instead of just the surface of the Earth, you stack up about 500 layers, each one of them the surface of a sphere wrapping the entire Earth, each one a mile higher than the last and starting about 160 miles up. Now instead of just the surface of the Earth, spread those 19,000 people across those 500 spheres evenly and evenly spread them around the surface of the sphere they're on. And all of those spheres have more area than the surface of the Earth.

      Now, would you consider that area "dangerously heavily populated?" On top of that, you need to shrink the people down for most of the debris.

      Now, to be fair, the real test is that many of these "people" are moving really, really fast, although most of them are moving in roughly the same direction. But a few of them are going in different directions. And some of those are jumping between spheres. But it's still areas larger than the whole surface of the Earth. There have been only a tiny number of collisions between these objects. (I think the number is actually -- one.)

      Like I said, space is big. Really big. Bigger than the biggest thing you can imagine. You may think it's a long way down to the pharmacy, but that's peanuts compared to space. (With apologies to Douglas Adams)

      • Imagine there were only 19,000 people on Earth, roughly evenly distributed. What's the chance you'd ever run into another person? Now, instead of just the land area, make sure that 3/4ths of those people are on the ocean. What are the odds of running into one of them now?

        A quick back of the envelope calculation shows that the odds of running into one are, to three significant digits, 29.2/70.8 of the chance of swimming into one. I hope this helps.

  • I am surprised the count is that low.

    Pluto does not wear any clothes and I don't think it is just the fifth time they found it walking away from the camera. Surely it has done it many more times and it is not Pluto's fifth moon.

    Sorry I called you Shirley.

  • "The Pluto team is intrigued that such a small planet can have such a complex collection of satellites."

    They call it a planet. Is this a case of NASA getting confused again, ala English/Metric, or is this a subtle acknowledgement that calling it a planet makes more sense than not calling it one?

    • Re: (Score:1)

      by Anonymous Coward

      The official classification is "dwarf planet" which would likely be shortened to "planet" when there is no need to be precise (on account of "dwarf" being even more ambiguous.)

  • Future headline: (Score:5, Funny)

    by cvtan ( 752695 ) on Wednesday July 11, 2012 @03:41PM (#40618869)
    "NASA's New Horizons spacecraft was unexpectedly destroyed today when it crashed into a previously unknown 6th moon of Pluto..."

  • ...it's just a bigger shame with each discovery we couldn't field a proper orbiter to Pluto to poke around for months. Yeah, I know all the problems in accomplishing that, but still...

  • I propose to solve the naming conundrum for the satellites of Pluto. Presumably as they are somewhat close to white in hue, just call them Snow White 1, Snow White 2, etc. Since Pluto is merely a dwarf planet, this seems fitting. If one is found to be reddish in hue, it can be called "The Poison Apple".
    • Excellent observation, good sir. In fact, perhaps we could take things one step further and rename Pluto to Grumpy...or Sleepy...or perhaps Dopey?

    • Re: (Score:1)

      by iztaru ( 832035 )

      >> to solve the naming conundrum for the satellites of Pluto.

      Which one? Of all the Roman gods, Pluto is the one not short of lackeys.

      Charon -> Used!
      Nyx -> Used!
      Hydra -> Used!
      Allecto
      Tisiphone
      Megaera -> For the 6th

  • or any other far out solar system object

    i bet we find that most of these objects are more like swarms of loosely coupled rocks

    way out there, there's no sun or gas giant to sweep the area, and nothing grouped together in the earlier part so the solar system: too much distance. so it is accretion in slow motion, and, being mostly solid and cold, bits of junk that never really gelled, just sort of banged together

    these cloudy wobbly grainy agglomerations are going to smash any probe we send to them

  • Flyby nice, but we need a probe in Pluto orbit (Score:4, Insightful)

    by Morgaine ( 4316 ) on Wednesday July 11, 2012 @03:53PM (#40619081)

    A probe in orbit around every planet or dwarf planet in the solar system would seems like a fairly basic NASA objective to me.

    I know that New Horizons will be using its velocity to also attempt flybys of one or more other Kuiper belt objects after it shoots through the Pluto system, and that is very worthwhile indeed, but we also seriously need a probe in orbit around Pluto itself.

    I hope that they're working on such a mission already, so that when New Horizons returns Pluto data in 2015 they just need to tweak a few parameters and be ready to launch an orbital mission. Such new data could even be sent to an orbital mission that's already en route to Pluto.

    • I am intrigued by your ideas and wish to subscribe to your newsletter.

      But seriously, Mankind really needs to take a leap into a deep space network seriously.

      Automated drones (lots of technology, blasted into space) sent on crazy-long orbits through the Solar System (and beyond?) bringing multi-scopic, n-D views of the heavens in every colour of radiation for less than a round of bankers KY errr... Quantitive Easing. Pfft, write it off as Job Creation.

    • Comment removed based on user account deletion
  • These scientists call it a "dwarf planet" yet, it has several moons orbiting around it.... I think it is time to move Pluto, give it back the rank of FULL PLANET....

    • Re: (Score:2)

      by sconeu ( 64226 )

      "Dwarf Planet" is damaging to Pluto's self-esteem. It prefers the term, "Gravitationally Challenged"

  • Pluto is a planet (Score:1, Insightful)

    by Anonymous Coward

    The word planet dates back to antiquity.
    IAU was founded in 1919.

    What gives IAU the authority to muck with definition of something prediating itself by thousands of years?

    Scientists are free to develop their own definitions and language to help convey concepts with necessary precision. I however refuse to accept their self granting of authority to redefine the meaning of popular terms. Languages belongs to everyone not just members of IAU. Internal votes conducted mostly to whore attention don't cut it.

    Pl

    • Re: (Score:2)

      by epine ( 68316 )

      Anyone who feels the need to correct me can go fuck themselves as far as I'm concerned.

      You can't correct a statement like that. You can mock, but not correct.

      Sure, define a long string of dental floss as a "one piece" because it's physically contiguous, if that fills your love glove. Your other topological suggestion I'll not take up.

      One small question though: if the string bikini top and the string bikini bottom are connected together only at brass rings, does it still count as a one piece, or is continu

    • Re: (Score:2)

      by dissy ( 172727 )

      Pluto will always be a planet to me for as long as I exist. Anyone who feels the need to correct me can go fuck themselves as far as I'm concerned.

      So when discussing large bodies in space we might have an interest in sending probes to, how do you single out those eight bodies from the millions upon millions of planets you think our solar system has?

      We changed the definition because instead of 9 interesting objects in one group, the old definition means we have millions of planets and no way to distinguish the rare few large ones.
      The new definition separates the eight large bodies we are interested in, from the millions upon millions of rocks out there

      • First, you could, and probably should, have coined some new word to distinguish your eight "interesting" objects from everything you do not find interesting. That is what most scientific confabs do, and it would have been the sensible thing for a bunch of astronomers to do. But instead you chose to do the stupid thing and muck about in a field of study that not a single one of you have any degrees or expertise or even experience in. I am quite confident that there were no astronomers who know anything at al

        • Re: (Score:2)

          by dissy ( 172727 )

          Are you serious? Pretty sure you're just trolling, but wow.

          So yea, they did actually reference linguists. That's why one group of objects is called "Planet" and the other group is called "Dwarf Planet", being a subset and all.

          Also, since when did the Earths moon orbit the Sun alone? It's sorta part of the definition, of both words. The moon is a satellite, not a planet or dwarf planet.

          If you can't even bother to learn the definitions of the new terms, you don't have much right to complain about them.

          • So yea, they did actually reference linguists.

            Meaning, apparently, that "they" (interesting that there has been a change from "we" to "they") used a dictionary or thesaurus or some other tool developed by linguists. Or perhaps "they" (probably means the IAU) even phoned a linguist or maybe emailed one and asked a question or two. In any case, either "they" did not pay the linguist enough to get him to bring his full attention to the matter at hand, or "they" did not get their money's worth. Or perhaps "they" did get good advice, but with their lofty fa

            • Re: (Score:1)

              by dissy ( 172727 )

              The only thing even close to correct is your #3.

              If the Earth was not present, the Moon would continue in its present orbit about the Sun, so it meets the other major criterion for planet status.

              You have some 'tense' mistakes near the end.

              Yes, if the Earth was not present, then yes the Moon would then be a planet.
              But that isn't the case. The Earth is present, so the moon does Not match either definition of planet right now.

              The detail you refuse to accept is that the Earth DOES exist, and the moon is in orb

              • If the Earth was not present, the Moon would continue in its present orbit about the Sun, so it meets the other major criterion for planet status.

                You have some 'tense' mistakes near the end.

                Yes, if the Earth was not present, then yes the Moon would then be a planet.

                But that isn't the case. The Earth is present, so the moon does Not match either definition of planet right now.

                The verb tenses in the sentence of mine that you quoted above are precisely correct. It is the failure of the reader to grasp the concept described that has caused him to regard them as mismatched.

                Either a planet is a planet or it is not. If it is a planet when some external conditions exist, then it cannot miraculously change to not being a planet if those external conditions are not present. Much as the IAU would like that to be the case.

                What the IAU have come up with is an absurd logic where you can m

                • Re: (Score:2)

                  by dissy ( 172727 )

                  I have neither the time nor feel the need to respond to the rest of parent post.

                  Then enjoy rambling to yourself, instead of having a civilized conversation. I'll leave you to it.

    • What gives IAU the authority to muck with definition of something prediating itself by thousands of years?

      This implies you still believe a planet should keep it's original definition of "wandering star", so it follows you must also have an interseting definition of "star" - can you tell the rest of us what it is?

  • Hubble Discovers 5th Moon of Pluto

    That's no moon.... that's a battle station.

  • How is this and the other (the 4th one from last year) still unnamed? One would think they'd just have a sheet of names ready to go at this point, like they do with hurricanes. Nyx is already up there as a moon of Pluto, we can't name her brother Erebus? Why not some of Pluto's assistants: Aeacus, Minos, or Rhadamanthus?

    • The IAU only meets every three years. The 28th meeting was 2009, the 29th will be in August this year. The fourth moon of Pluto was only discovered last year.

      You can suggest Erebus for the 5th moon, to the Committee on Small Body Nomenclature. (Although it may be too late to have it considered for the 29th meeting, presumably they already have a name chosen for the 4th moon.)

      You should also suggest your idea about having a prepared list of names for obvious future discoveries. Such as inevitable future moon

  • But any signs of water?

  • that we spend 100's of Billions of dollars in some stupid ass war we don't need or want, when we could be spending money on something valuable, like learning more about our solar system.

    We spend $20 billion on air condition in Iraq & Afghanistan, and spent just over $18 Billion on Nasa. (http://theweek.com/article/index/216786/the-militarys-20-billion-air-conditioning-bill-by-the-numbers)

    fuck you US Government, fucking corporate fuck toys.

     

  • New Horizons could be destroyed in a collision with even a BB-shot-size piece of orbital debris

    Then perhaps they should raise shields :-P

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