towing another planet size object to earth?

[patriotagent]

Hello, I am new to this board and wanted to ask a question. What would the possibility be for mankind to 'tow' a planet size body to the earth and get it to take on the same orbit as earth? Allowing another planet to be terra formed into a livable place? Would it be possible for one and would it cause great havoc here on earth? I look forward to the answer.

 

[vogon13]

Probably wouldn't be a problem if you had the technology to move planets around, but an earth size object sharing earth's orbit would not be gravitationally stable. Trojan type relationship (60 degrees leading or lagging) is only stable if additional object is much less massive than the primary.<br /><br />Having the new object set up in a double planet arrangement with earth while attractive from the aspect of generating more solar eclipses (cool!), would also cause tidal problems. And another problem of what to do with the earth's existing moon.<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>

 

[tony873004]

The primary in this case is the Sun. I believe that an Earth-mass planet could share Earth's orbit if it were in the L4 or L5 points.

 

[vogon13]

IIRC, mass of tertiary object should be 'negligble' compared to secondary. There is also a minimum mass ratio between primary and secondary, (IIRC) but I don't recall the value.<br /><br />All known trojan relationships in our solar system meet the requirements of this. Dione B, Hektor (IIRC), and others.<br /><br />Binary earths' would probably have a possible trojan spot for an object the size of current moon, but tidal interactions between the binaries pretty extreme. For 250,000 mile spacing, tides 81 times bigger (if I did that right in my head just now). No homes at Malibu anymore..... <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>

 

[tony873004]

Hi,<br /><br />The secondary needs to be less than ~4% of the primary for the L4 & L5 points to work.<br /><br />But there is no limiting ratio between two secondary objects as long as their combined mass is < 4% of the primary.<br /><br />I did a simulation to confirm this. Placing an Earth-mass planet in Earth's orbit, 60 degrees from Earth, I let the simulation run for nearly 3 million years. The 2 Earths were still seperated by 60 degrees. <br /><br />Also, here's a link to the Celestia forum where this topic was discussed in detail.<br />http://www.shatters.net/forum/viewtopic.php?t=4735&postdays=0&postorder=asc&start=0

 

[cyrostir]

superman could do it

 

[alokmohan]

Easily just as shepherds keep on pulling the sheep with rope.