I have no problems with anything you say I was simply trying to second guess the author who first mentioned Earth like,. as for my money the is no place like home er Earth. I effectively was making it up as I went along it has not been a primary interest for me but I recalled that sort of thing.
Still as a personal opinion now that I consider the possibilities it would not surprise me if there were not many "Earth like" planets in the closest of comparision, I see no reason why we should be the only place like this or very similar. I mean look at Star Trek they think so
What i do doubt is that we will ever be able to observe a planet that is truely Earth like a twin. Solar systems may follow a pattern the same as ours, formation may dictate a similar distribution of planets and sizes similar to our system..in fact one would think it more probable that the one pattern will repeat over and over as with other things we see. Its the first time I have given it any thought and all this is off the top of my head not a recollection from something I have read.
All planets if the system is moving will be inclined to the axis of their Sun, that comes about from the speed of gravity really, planets will orbit an "imaginary" Sun that has moved down the road by the time the gravity message is recieved, so a tilt in axis must result. The Suns speed thru space I would think to be similar to others Suns in another galaxy within a similar distance from the gallactic centre that our Sun enjoys. I think solar systems (and spiral gallaxies) must travel as does a "pie in the face" through space and as such this produces an incline and hence the seasons. I dont know really again off the top of my head..thinking aloud to share my idea.
Dam it I have developed an interest now and will look at what they are really doing.
alex