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Space Science

Is This Moon Three? 317

tetrad writes "The BBC reports that a new object has been discovered orbiting Earth. It's possible that it's just a piece of space junk, but more likely it is a rock that has been recently (in the last year) captured by our planet's gravitational field. If the object is confirmed to be natural, this would be Earth's third moon. (Did you know there were two already?)" Here's our earlier mention of Earth's alleged second moon. Update: 09/12 04:52 GMT by T : Reader cscx adds a link to an article running on which says this newfound object may be some trash from the Apollo missions.
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Is This Moon Three?

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  • size matters? (Score:4, Interesting)

    by Anonymous Coward on Wednesday September 11, 2002 @01:45PM (#4239278)
    Doesnt an orbiting object need to be of some specific minimum size? or does Saturn have billions of moons that just end up looking like rings?
  • just arrived? nah, nah, nah... it's a camouflaged spy device from an alien civilization.
  • What's in a moon? (Score:4, Interesting)

    by (H)olyGeekboy ( 595250 ) on Wednesday September 11, 2002 @01:46PM (#4239284)
    Just out of curiosity, what is the scientific criterion for a moon?

    The "trojan asteroid" described in the previous story is only 3 miles wide and take 770 years to orbit the earth. That is not what elementary schoolteachers say is a moon, a la Jupiter's many moons... giants like Europa and IO.

    I also heard a while back that Charon might not be a real moon either, because of size or rotation or something? Huh?

    I'm not versed in astronomy enough to know, so does anyone have an answer for laypeople, so I can talk with people at work about this? :)
    • by Xunker ( 6905 ) on Wednesday September 11, 2002 @01:49PM (#4239310) Homepage Journal
      Scientifically speaking, a "moon" is any planetary body that orbits a larger body and causes American students to turn to werewolves whilst visiting France.
    • Here, let me bend over and show you.
    • Re:What's in a moon? (Score:4, Informative)

      by NetFu ( 155538 ) on Wednesday September 11, 2002 @02:13PM (#4239522) Homepage Journal
      New Page 1

      Well, here's what Merriam-Webster's Collegiate Dictionary [] says:

      -- 1a : a natural satellite of a planet

      -- 2a : a celestial body orbiting another of larger size

      I think based on these common definitions that these objects, assuming they are found be natural and that they can be proved to orbit Earth, should be called moons. Maybe they don't fit our cultural, unwritten definition of a Moon, but that doesn't change the facts. So, maybe we need to change what most people think of as the Moon...

    • From the Dictionary:

      Moon -- a natural satellite of a planet

      Additionally there is a moon of Jupiter that has these properties:

      S/1999 J 1 (a provisional name)
      The seventeenth and outermost moon; S/1999 J 1 is the smallest-known moon orbiting a major planet. This moon is 3 miles (5 km) in diameter and has an irregular orbit roughly 15 million miles (24 million km) from Jupiter. It orbits Jupiter in 774 (Earth) days and is in a retrograde orbit (orbiting opposite to the direction of Jupiter). It was discovered by Robert S. McMillan et al (at the Spacewatch program at the University of Arizona ) in 2000.
    • Re:What's in a moon? (Score:5, Interesting)

      by Bonker ( 243350 ) on Wednesday September 11, 2002 @02:31PM (#4239658)
      IANAA, but a professor once told me that a body that orbits another non-stellar body is a moon while a body that orbits a star is a planet or an astroid (astro- from star) depending on its size and regularity of its orbit.

      Thus, the Pluto-Charon system is probably much more accurately labeled as either a pair of asteroids due to size considerations, or a dual-planetary system because their orbits are highly regular, albeit at a significant pitch compared to the other 8 planetary systems.

      I've also heard that the Earth/Luna system should be considered a dual-planetary system because Luna has a much higher percentage of it's parent planet's mass than other moons... This jives with the 'Planetary Collision' theory of moon formataion, in which the moon is actualy a significant chunk of Earth, torn off early during our planet's formation.

      The 'second moon', Cruithne, fits in with a large category of non-moon, non-planetary, non-asteroid bodies in the solar system. If you ever study the 'Trojans', you know that there are huge bodies of apparent moonlets that sit on a sixty-degree angle from Jupiter's, directly along Jupiter's orbit from the sun. (They are apparently held in such a strange place by the gravity of Jupiter vs. the gravity of Sol.) Rather than calling Cruithne a moon, we're probably better off adding a new 'common' cetegory to our solar classification to include it and the Trojans. AFAIC, there's no reason not to call these all Trojans and be done with it.
      • by devphil ( 51341 ) on Wednesday September 11, 2002 @03:25PM (#4240030) Homepage
        If you ever study the 'Trojans', you know that there are huge bodies of apparent moonlets that sit on a sixty-degree angle from Jupiter's, directly along Jupiter's orbit from the sun. (They are apparently held in such a strange place by the gravity of Jupiter vs. the gravity of Sol.)

        Anytime you have something (Foo) orbiting something else (Bar), i.e., once the requirements of "orbit" are met, there are five points of gravitational equilibrium set up amongst the two bodies. They're called LaGrange points. The last two, L4 and L5, are on Foo's orbit around Bar, sixty degrees ahead of Foo (L4) and sixty degrees behind (L5).

        L4 and L5 by themselves, ignoring L1-L3, are often called Trojan points, named for this particular group of satellites.

        As for the defintion of moon versus just another satellite in general, I believe it has to do with respective mass ratios, and where the fulcrum point of rotation is between the two bodies. Right now our own moon isn't in a true rotation around us, we're in a sort of dumbbell tumble, and the center of the dumbbell is a bit below the ground.

        (Actual astronomers please correct me, I'm on a number of narcotic-containing painkillers right now and could have gotten some words tumbled.)

        • (* Right now our own moon isn't in a true rotation around us, we're in a sort of dumbbell tumble, and the center of the dumbbell is a bit below the ground. *)

          That might make a good definition: if the center of gravity between the two bodies is below the surface of one of the bodies, then the other one is a "moon" as long as it is not artificially created (in which case call it a "man-made satellite"). Is this what you mean?

          If the center of g is above the surface, then you have a "double planet". (Or double asteroid, assuming those definitions can be settled.)

          As far as the ones with "funny" orbits (lagrange), I don't know about those. Call them something different, like "Lamoons" or something.
          • Another Criteria (Score:3, Interesting)

            by Royster ( 16042 )
            If the path of an object is concave with respect to the sun, the object is a planet.

            In the case of the Earth/Moon system, it is called a double planet because the path of the moon from the point of view of the sun in strictly concave -- that is it dosn't loop back on itself as do other moons.
      • If you ever study the 'Trojans', you know that there are huge bodies of apparent moonlets that sit on a sixty-degree angle from Jupiter's, directly along Jupiter's orbit from the sun. (They are apparently held in such a strange place by the gravity of Jupiter vs. the gravity of Sol.)

        THis is actually really interesting because it indicates that these are on the L4 and L5 points relative to Jupiter and the Sun. For those that don't know the Lagrange points are the points where the gravity from the orbiting and orbited bodies are equal, and of the five points, only 2 are stable (L4 and L5). This is why, after the Moon, why the L4 and L5 points will be very important politically, economically, and militarily, assuming we want to have commercial relations with Mars...

        But this new object is on a 50 day orbit around earth, so it is not on L4 or L5.
        • But this new object is on a 50 day orbit around earth, so it is not on L4 or L5.

          This means that the object will either crash into the planet, or get flung off into space, eventually, right? Or will it eventually settle in to a stable orbit?

          • It sounds like it may have already settled into a stable orbit. There's no reason I can think of why the earth can't have a 50-day satellite.
          • This means that the object will either crash into the planet, or get flung off into space, eventually, right? Or will it eventually settle in to a stable orbit?

            I think you misunderstand me. L4 and L5 are important points because they are stable orbits which remain fixed in positions related to the other two bodies. Other orbits are stable, but for example, the relative position of Mercury relative to the Sun and Venus varies, but if you had a planetoid on L4 relative to Venus, its position would be fixed relative to the positions of the Sun and Venus.
      • I think that this whole argument is laughably trivial.

        Why does it matter? Should we call the Moon a moon, a co-planet... It's just a word!

        I've seen a few times on here "When should planet/moon be considered double-planet?". This question illustrates the futility of talking so much about the first question. If you set some exact criteria, there will be a point in which we have a planet/moon system, and by adding a single atom's worth of mass to the moon, it would be a double planet system.

        Obviously there are times that it is clearly Planet/Moon (Neptune/Triton for example), and if two bodies have mass within 10%, it is clearly a double planet. I just don't think that the argument of whether Pluto/Charon and Earth/Moon are double planets or planet/moon systems, just because it is a gradual change.

        When are two galaxies said to be colliding, and when does it stop? At what instant is a person dead? Within .1 picoliters how much alcohol do you have to drink before you are considered drunk?

        You see?
      • IANAA, but a professor once told me that a body that orbits another non-stellar body is a moon

        So that would make the sun a moon. As well as all the stars in the sky.

    • Re:What's in a moon? (Score:5, Interesting)

      by kzinti ( 9651 ) on Wednesday September 11, 2002 @02:51PM (#4239814) Homepage Journal
      Just out of curiosity, what is the scientific criterion for a moon?

      Isaac Asimov, in one of his popular-science articles, once presented a well-reasoned argument that the Earth and Moon should not be considered a planet and satellite, but a double planet. He formed his argument by comparing the masses of all the other moons in the Solar system to the masses of their primaries, and showed that the Moon:Earth mass ratio was far greater than that of any other planet/satellite pair. He suggested that we could account for this "outlier" by considering the Earth and Moon to be a double planet.

      Whether this argument would stand up to real scientific scrutiny, I don't know. It sounded pretty good to me, but I was just 10 at the time. Maybe it was just gee-whiz stuff made up to impress 10-year-olds, but that doesn't really seem like Isaac's style.

      Does anybody else remember this essay?

      • Re:What's in a moon? (Score:5, Informative)

        by Autonomous Crowhard ( 205058 ) on Wednesday September 11, 2002 @04:09PM (#4240375)
        The best explanation I've ever heard of if a two body system is a planet-moon or two-planet combination is this:

        If the center of gravity of two bodies lies inside one of the bodies then that is the planet and the other is the moon. If the center of gravity is between the two objects then it is a two planet system.

      • The "moon" was called "moon" (or something equivalent) long before we even knew that other planets had other things orbiting them. So, if earth and the moon form a double planet, it seems to me "moon" should then be generalized to refer only to the smaller of a pair of double planets. We should find some other term for those in-between things orbiting other planets.
    • Is there a more correct name for what I think of as "The Moon?"

      Not a "moon" like Jupiter has but "The Moon."

      You know the one.

      The one that has drastically affected this planet since before people -- the one the wolves call "Whoooooooooo!"
      • Luna is the term I've heard tossed around but they may be due to reading too much sci-fi.
        • I'm quite sure that Luna is the techincal name for the first moon that humans noticed orbiting Earth. Why do I think this? It fits the pattern of the true name of the sun, the other major body that is readibly visible to us earthlings.

          "the sun" actually = "sol" (latin in origin, i believe)

          "the moon" actually = "luna" (latin in origin, i believe).

          It makes sense to me, but then again, I dunno what validity that holds. :)
    • If it revolves around something, regardless of size, it's a satellite of whatever it revolves around. The planets are satellites of the sun; the moon is a satellite of the Earth. Use of the word "moon" to refer to a "satellite" of a body other than Earth is common usage.

      Charon is a satellite of Pluto. Perhaps you're thinking of recent evidence that both Pluto and Charon were not formed by the proceses that formed the other planets, but are, instead, Kuiper Belt [] objects. The Kuiper Belt is a region of the Solar System beyond the orbit of Pluto that is believed to be the source many comets and other objects.
  • by ishmalius ( 153450 ) on Wednesday September 11, 2002 @01:46PM (#4239285)
    Here is a link I saw just before your posting: []

  • God really is trying to moon us. Maybe we should practice asteroid demolition on these things so we are less likely to screw up if there's one coming straight at us.
  • to the debate about what constitutes a moon....

    Even if this does turn out to be a natural object, it is probable too small to be of any significance. One of these days we'll have to distinguish between a large boulder in space and a moon. Otherwise we might have to start counting particles of space dust.
  • Asteroids (Score:2, Funny)

    by evilviper ( 135110 )
    Maybe this is just fate's way of teasing us. Quite a bit of talk lately that we are overdue for a deadly asteroid collision. Maybe we are going to be gaining more and more objects locked in our gravitational field, just to make us nervous. Similar to vultures circling overhead.

    Excuse me. How many objects are obiting the earth now? Twenty!? I'll be moving to Mars tommorow.

    • No no no. This is actually Mr. Burns' long term plan to destroy the sun, again. The plan is to bring in so many rocks to orbit the earth, that the entire space surrounding us will be filled with such objects, preventing the dreaded sun from reaching us.

      It may take another few hundred thousand years, but eventually, we will all fall under the sway of Burns Nuclear Power yet again.
  • yes what is the criteria for a moon. and if its not a piece of alien stuff, maybe its that truck from star trek voyager. or, if you remember that bbspot article about the Fly Feature of win XP!
  • by lateralus_1024 ( 583730 ) <mattbaha&gmail,com> on Wednesday September 11, 2002 @01:52PM (#4239334)

    Nasa and I had our hopes of a 4th moon dashed when that NSync kid couldn't cough up the money on time. He hadn't even read the fine print regarding a conditional return.
  • I thought it was the responsibility of NORAD to track space junk. Their job is to insure that there isn't an incoming ICBM amongst the junk. What do they have to say?
  • by amorsen ( 7485 ) <> on Wednesday September 11, 2002 @01:52PM (#4239345)
    ...has decided to deploy an advanced warning system, due to the number of missiles coming from Earth that have been hitting or narrowly missing Mars in recent years. While planetary defenses have had a decent intercept rate, some of the missiles are still getting through. Hopefully the new early warning system will enable the Martian Space Defense to improve intercept rates considerably.
    • According to the inner teachings of Scientology* this is the 4th Invader Fleet. (The 5th Invader Fleet had to make do with Venus, but don't call them Venusians!)

      * Sort of inner. Scientology is like a Mystic Onion. You peel it off layer by expensive layer until you reach the center of the onion. (Where you have nothing -- except tears.)

      Stop laughing, this is science damn it!

  • by zulux ( 112259 ) on Wednesday September 11, 2002 @01:53PM (#4239348) Homepage Journal

    We all have grown up with the notion that there are three earth-orbiting natural satlites, but did you know that there is no mention of the third satelite in any media before 2002!

    It's true!

    See, it's all a plot of the Libertarians - they have been secretly construcing this "third moon" in order to live there and to not pay any of their taxes - taxes that you and I need in order to buy delicious governemnt cheese!

    Being cheap bastards, this new moon is nesesairly small - but if you look at it with a high-power "telescope", then you'll realise that this "moon" has been meticulously constructed to look like Montanna!

    Complete with Moon-Sheep!

    I urge you, the right minded American, to rise up and take a stand! No third moon, unless taxes are to be paid on it.

  • Just how big does a piece of spave junk have to be before it becomes a moon? I mean, surely my collection of neat quartz crystals wouldn't count because they are all about the size of a quarter.
  • This kinda reminds me of the move "Signs"... This thing appeared in our skys, we don't know what it is... Wait till three lights appear in Mexico City...
  • It would be cool to do some scientific experiements on this thing. Maybe even put a "moon 3 cam" or whatever on it.

    By the way, I've always wondered- why don't we have a moon cam (maybe we do?)? Or some telescoping equipment on the moon to peer even further into our universe? How hard would it be to put a camera on the moon and have it beam pictures to a nearby satellite or whatever?
    • How hard would it be to put a camera on the moon?

      harder than putting one in orbit (since you have to land it), and half the sky would be blocked by the moon.
    • Hubble space telescope does a lot of this, though its limited in size. Because it doens't have atmospeheric distortions, it's mlearer even with it's relatively small size lens.
  • Read this [] and this [] and have a good laugh. Go Buzz, go !!!
  • If you take into account Sun Myung Moon and Keith Moon...
  • I'm missing something. I thought a moon was an object that orbited a planet. Cruithne's orbit is profoundly perturbed by the Earth's gravity, but it stil orbits the sun [].
    • Cruithne isn't really a moon - it's a coorbital companion. And if you look at the Cruithne FAQ [] fm6 linked to, you'll see that it's not the only one. So if these coorbital companions counted as moons, this new object (if it isn't just a spent rocket booster) really would be the fifth moon.

      Does the Earth have any other companions or moons?

      Yes, the Moon. But apart from that, there are no natural objects known to be in close dynamical relationships with the Earth. NEW! Asteroid 1998 UP1 and 2000 PH5 have been found to be in similar relationships with our planet. We are currently (18 Sept 2001) working on publishing these results. Look for more info here soon.

  • ... the rocket guy []?
  • Hey, see that moon? No that one there. I think that moon is a bit of a spy. Yes I do. There was a moon like that on the summer of my sixteenth year. Some say I was sixteen but [sigh] I don't know. And there was a girl, too; her name was Marie. At night together we would walk down by the sea and oh my god if you could see the body on this woman. The way at night her long legs would stick into the moist night sand like gods own barge poles, you know. And I longed to tell her the feeling I had in my heart for her but the words would not come, they would not come through my spotty adolescent face, they would not come through my angry hair or my sweaty feet or any other part on this body that I know call a man. So the words je t'aime were never passed between us but the moon, yes, that moon spied on us.
  • Why do we only see news of this on the BBC page? I've not once seen mention of second or third moons on MSNBC, CNN, or any of the other online news places. I'm starting to consider the BBC as the National Enquirer of online news.
    • I think you're looking at it the wrong way. More accurate is to consider MSNBC, CNN, et al. as the buck-toothed stepchildren of the BBC.
    • Re:Suspicious (Score:3, Insightful)

      by cmallinson ( 538852 )
      I've not once seen mention of second or third moons on MSNBC, CNN, or any of the other online news places. I'm starting to consider the BBC as the National Enquirer of online news.

      That's really backward. The main reason there is nothing about this story on the main page of CNN or MSNBC is that the american news media has barely reported anything non related to 9/11 this week. Comparing these news sources to the BBC is laughable, and an insult to those who provide proper and disinterested news reporting.

      If you look at the BBC World Service [] news site, there are also many more very [] important [] news stories that will never make it to the mainstream US media outlets. It doesn't mean those stories are not important, they just don't help sell advertising.

    • There is something fishy about this story. How come Bill Yeung, the guy who the BBC credit [] as discovering this third moon doesn't mention the discovery on his web-page?
  • by xlation ( 228159 ) on Wednesday September 11, 2002 @02:29PM (#4239636)
    The JPL has an ephemeris generator [] that now calculates the position of the object.
    To see the data:
    1. Click the "Target Body" Button
    2. Choose "Spacecraft" from the "Select Major Body" dropdown.
    3. Select "J002E3 Spacecraft (UNCONFIRMED)"
  • by cyclist1200 ( 513080 ) on Wednesday September 11, 2002 @02:43PM (#4239751) Homepage
    I hear there's some really good calamari on Cruithne. Some weird blue loop that seems to lead to other universes too, but mainly, good calamari.
  • If you google for "Cruithne," the name of the second "moon," you'll find that researchers think there are two other objects in strange orbits like Cruithne's. That would make this new discovery the fifth.

    Beat that, Jupiter!

  • ...why my key policies never get implemented. I hope the newspaper prints a retraction.
  • The music industry is going to ban any mention of multiple moons. For they have thousands of songs that would be obsolete if word got out.

    "Moons River"

    "Blue Moons"

    "Sad Moons Nite"

    Etc. Etc. Etc.

    "We must protect the integrity and consistency of our content", said an anonymous industry spokesperson. "If you have to force legislation by any means available, we will."
  • OK, all together now:

    B.G. DeSylva, 1927, from _Good News_, (modified)

    The moon belongs to everyone,
    The best things in life are three.
    The stars belong to everyone,
    They gleam there for you and me.
    The flowers in spring, the robins that sing,
    The moonbeams that shine, they're yours, they're mine.
    And love can come to everyone,
    The best things in life are three.

    Of course, Trinitarians could say
    "And God belongs to everyone
    The best things in life are Three."

  • You mean that thing that keeps flying around our world without doing anything constructive? It's called a troll.
  • According to NEO [], "J002E3 was not a minor planet (Sept. 6.68 UT)". Does this means that they've already confirmed that it's space junk?

  • Whether or not something is a "moon" is really a function of the language, more than the details of its size, orbital distance, etc. Remember that, at least in English, dictionaries are descriptive, not proscriptive -- that is, they give usages, not definitions. The language changes and evolves on its own; what is considered "correct" is really nothing more than popular opinion. Of course, different ways of communicating can be more or less useful or efficient, so it's not like it doesn't matter whether we use a word to mean one thing or another.

    But there's no "official" definition of what a "moon" is, unless you happen to accept the particular definition of a particular person or group. If it's useful to call this 3-mile chunk of rock a "moon," then people probably will. If it's misleading or confusing, then (hopefully) people won't.
  • As for Cruithne (Score:2, Informative)

    by KewlPC ( 245768 )
    As for our second alleged moon: it is not a moon!

    It orbits the sun in a horseshoe-shaped orbit that goes quite a distance above and below the elliptical plane. The horseshoe orbits overlap, but don't take 770 years. However, because these horseshoe-shaped orbits overlap, Cruithne eventually goes all the way around the sun. It is this that takes 770 years.

    It is affected by Earth's gravity (indeed, that is why its orbit is shaped like a horseshoe), but that doesn't make it a satellite of Earth.

    Therefore, this "third" moon is actually the second. :b
  • It is the end of the world! it is the second coming of Christ! and this time he's coming as a HAxx0r:
    Much uncertainty surrounds the mysterious object, designated J002E2.
    AHH never mind. false alarm. I thought it was JE2002...

  • I sense a great disturbance in the force.

    Sorry, someone had to say it...

  • That's not a moon, that's the mothership! Mama, come and get me! I'm ready!
  • by AndroidCat ( 229562 ) on Thursday September 12, 2002 @08:28AM (#4244074) Homepage
    Scientists suspect object orbiting Earth is space 'junk' []

    Scientists think a newly-found object orbiting the Earth could be a remnant from the Apollo era.

    Experts at Nasa's Jet Propulsion Laboratory believe its brightness and distance shows it's a rocket booster.

    'J002E3' was discovered on September 3 and listed by scientists as a minor planet or asteroid.

    But Nasa's Donald Yeomans believes that designation is erroneous.

    He told "It's most likely a spacecraft. It's not likely to be a natural object, not in that kind of orbit."

    He said minor planets or asteroids tend to be on strange orbits gravitationally-influenced by the Sun. This does not appear to be the case with this object.

    Nasa are currently running computer calculations and expect to be able to identify the object conclusively soon.

    Story filed: 10:39 Thursday 12th September 2002

  • Couldn't they take the *spectrum* of the object? That should be able to determine if it is man-made (Apollo left-overs, for example), or a space rock.

    Perhaps it is too dim to get a spectrum of. But, if they try hard/long enough eventually you can get a "print" I believe.

Real programmers don't comment their code. It was hard to write, it should be hard to understand.