Can moons have their own moons?

[vogon13]

Poynting/Robertson effects can decay orbits of dust particles too.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[qso1]

Technically, if dust particles are in orbit around the moon, they could be considered as perhaps microsats IMO. However, it would be impractical to say the least to track all the possible dust particles that orbit the moon, earth etc. Earth orbit contains micrometeoroids which may or may not have been captured in earth orbit. We become concerned about them because of their threat potential to manned spacecraft.<br /><br />I wouldn't be surprised a bit to find that there are micrometeoroid fragments no larger than sand grains orbiting the moon which in effect makes them moons orbiting the moon. As MeteorWayne pointed out though, what would the particles be classified as? I'll leave that one up to the IAU. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[derekmcd]

I would think after so many billions of years, that our earth/moon system would have cleared up a huge majority of the meandoring, random dust floating around. No doubt there is some, but it would be insignificant. I could be (and usually am) wrong... <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[qso1]

Like you said, "after so many billions of years, that our earth/moon system would have cleared up a huge majority of the meandoring, random dust floating around". majority implies something is still left behind and even if it were just a few particles per millions of miles, those few particles if orbiting earth or moon would be natural satellites simply by definition. Because of this, technically, it is possible for the moon to have moons orbiting it depending on the definition of satellites by the IAU. I don't think there is a size limit for defining what is meant by satellite.<br /><br />What is not known with certainty by way of observation, is whether there actually is something that would in a general sense, be considered a moon orbiting a moon around a planet. I know of none in our system and exoplanet research is still in its infancy.<br /><br />And BTW, you've been a pretty good debator so I wouldn't say your usually wrong. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[derekmcd]

Haha!! The original question of "Can moons have their own moons?" has turned into discussion of considering dust particles as 'moons'. You guys are awesomely space nerds. I say that as a compliment <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[willpittenger]

Sorry. But if Pluto, far larger than a "submillimeter meteoroid," is no longer a planet, those dust particles can't be either. At best, they would be asteroids. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

Your welcome. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[qso1]

derekmcd:<br />Haha!! The original question of "Can moons have their own moons?" has turned into discussion of considering dust particles as 'moons'.<br /><br />Me:<br />Gotta love it. I'm definetely a space nerd and fine with it, thanks for the compliment. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

willpittenger:<br />Sorry. But if Pluto, far larger than a "submillimeter meteoroid," is no longer a planet, those dust particles can't be either. At best, they would be asteroids.<br /><br />Me:<br />The proper definition of an object orbiting another object is satellite. AFAIK, there is no size limit on what constitutes a satellite as evidenced by the thousands of artificial ones that orbit earth. Of course, even if I turn out to be wrong. We would still be left with the possibility of discovering say, a baseball sized rock in a nearly circular orbit around the moon. I'll leave the semantics up to the IAU as to what it should be called at that point. In fact, this issue has probably never really been seriously looked at by the IAU because they have no known objects of this sort to categorize.<br /><br />That ought to make for a fun IAU debate. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[alokmohan]

Dust particles may be moon in principal..

 

[qso1]

Thats the way I see it. I just don't know if its ever been addressed by anyone before this thread surfaced. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[vogon13]

Post deleted by vogon13 <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[qso1]

Keep in mind, orbital periods have not been specified here. A dust particle might orbit a bodie such as the moon for 3 days but as you mention, their orbit is decayed. However, during that 3 days, they could be considered a moon or satellite.<br /><br />For practical purposes however, I'm sure dust particles normally do not merit consideration in astronomical circles and in that sense, they would be moot points. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>