On Monday, November 19, 2012 5:30:54 AM UTC+5:30, bob haller wrote:
if one of those loose planets ever visited our solar system it could

cause a disaster, such a large body could alter the earths orbit



Not too likely, unless it came into close proximity of the Earth. Such a

planet would enter at superorbital speed, pass perihelion, and then fly

off into space, never to return.



Theres a asteroid following earth, a visiting large planet could and

probably will change the planetary alinement

Just in 2 or 3 billion years of existence, earth developed infinite variety of life! Were earth and Mars such wandering planets which came from elsewhere with spores of life? The planet now under discussion is definitely an exoplanet that withered!
http://crestvideos.com/exoplanet-withers/