I know this sounds like corny Science Fiction, but how do we know that another Earth is not in an exact orbit from us?
I saw this stupid movie awhile back where this other earth was in an exact 180 degree orbit from us. I got to thinking this could be real. As this other earth would distort all measurements and such.
I tried to edit my post.
What I meant was, an earth in exact orbit on the other side of the sun from our earth.
This thread addressed the idea a few months ago. Basically:
We’d have spotted the gravitational effects of “Counter Earth” on other planets of the Solar System (Venus and Mars and so on).
We’ve launched several space probes that should have spotted such a planet.
As this NASA page linked to in the other thread notes:
ahahahahahahaa!! I am sorry… I just can’t stop laughing.
No seriously. That is a good joke to bring up in a party when your drunk.
I couldn’t have said it better myself, well actually I did by adding the bold text around ‘stupid movie’ and ‘corny Science Fiction’.
These two sentences contradict each other… if this ‘other earth’ were to exist than wouldn’t we notice the distorted measurements?
PerfectDark
Sorry to bring up an old topic, I lurk quite a bit here and should have seen it. I knew it wasn’t an earth shattering topic but it really got my interest.
Thanks for your input.
P.S.: I would delete this thread is I could to save other people from reading it.
Of course there is a opposite earth. We can’t detect it 'cause it’s in an opposite dimension.
oh no, the counter-earth is inside the hollow earth, you get to it through the big hole at the north pole.
Welcome to posting on the SDMD, ramanon.
Don’t let the “mister smarty pants” types here discourage you.
I saw that movie too, and at the time it was made not so many of us would’ve been so cocksure of the answer.
Peace,
mangeorge
Wow, I didn’t know that they were making corny B movies in the 1600s!
No, Chronos, they didn’t. And they didn’t have the NASA site linked above by MEBuckner either. In '69. when the movie was made, most people didn’t have this kind of information at their fingertips.
Just a few short years ago most “great minds” were cocksure that there were only nine planets in the entire universe. A few of these folks still believe so.
Can I take a peek through your inter-dimensional telescope? 
Peace,
mangeorge
in the SF story, didn’t the exploratory ship that was sent to investigate crash into either:
-A big mirror
-Another (identical) ship sent from the other earth
??
I would daresay that any filmmaker making a sci-fi film would seek the advice of an astronomer, to get even the basic facts correct. I’m sure the astronomer laughed at the basic premise of a dual Earth, but I find it rather incredulous that a film was made without any professional advice.
And, while they might not be at the fingertips, libraries did exist in '69. Or so my parents told me.
Why, Montfort, should the film maker seek the advice of an expert? I’m sure that the author knew there was no “doppelganger”. The movie was a work of fantasy, not a documentary. It’s purpose was to entertain, not inform. And it did a pretty fair job.
Had the producers sought and followed the advice of astronomers, the movie would not have been made.
I agree that if one’s aim is to educate, they should seek the very best information available. But in a work of fiction, imagination rules.
Ask your parents if they ran to the library to check the facts in every movie they watched. I didn’t. Nor did I, or anyone I knew, believe there was actually an opposite earth on the other side of the sun. But most of us enjoyed the movie anyway.
Well, I’ve got to go. I’m going to go see Angel Eyes, and fantasize about Jennifer Lopez.
Peace,
mangeorge
To clarify what I said earlier: It’s been known since the time of Newton that a system of two bodies orbiting on opposite sides of a central body would be unstable. True, it was mostly just physicists who knew this. That’s still the case today, though: Most people nowadays wouldn’t know that there couldn’t be an anti-Earth. Even Heinlein, perhaps the greatest of SF writers, posited an anti-Earth in a few of his stories (just an asteroid, admittedly, but the dynamics are the same). Of course, Heinlein, great though he was, was neither an astronomer nor a physicist.
Of course filmmakers should consult with experts, but you’d be amazed how often they don’t.