# Dual Earth **URL:** \ **Category:** Factual Questions\ **Created:** [June 3, 2001, 1:25am UTC](https://boards.straightdope.com/t/dual-earth/67377 "2001-06-03T01:25:46Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![ramanon](https://avatars.discourse-cdn.com/v4/letter/r/65b543/32.png) [@ramanon](https://boards.straightdope.com/u/ramanon)\ **Post date:** [June 3, 2001, 1:25am UTC](https://boards.straightdope.com/t/dual-earth/67377/1 "2001-06-03T01:25:46Z")
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. ---
**Author:** ![ramanon](https://avatars.discourse-cdn.com/v4/letter/r/65b543/32.png) [@ramanon](https://boards.straightdope.com/u/ramanon)\ **Post date:** [June 3, 2001, 1:31am UTC](https://boards.straightdope.com/t/dual-earth/67377/2 "2001-06-03T01:31:58Z")
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. ---
**Author:** ![MEBuckner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mebuckner/32/2896_2.png) [@MEBuckner](https://boards.straightdope.com/u/MEBuckner)\ **Post date:** [June 3, 2001, 1:39am UTC](https://boards.straightdope.com/t/dual-earth/67377/3 "2001-06-03T01:39:37Z")
[This thread](http://boards.straightdope.com/sdmb/showthread.php?threadid=61764) addressed the idea a few months ago. Basically: 1. We’d have spotted the gravitational effects of “Counter Earth” on other planets of the Solar System (Venus and Mars and so on). 2. We’ve launched several space probes that should have spotted such a planet. 3. As [this NASA page](http://image.gsfc.nasa.gov/poetry//ask/a10412.html) linked to in the other thread notes: > [@](#): > > There is no way that a CounterEarth would remain exactly behind the Sun while being constantly perturbed by the other planets. Eventually it would end up on a slightly different orbit by a few miles, and the synchrony would vanish. It would slowly slide out from behind the Sun and would have been observed over the millenia as a new planet. ---
**Author:** ![PerfectDark](https://avatars.discourse-cdn.com/v4/letter/p/ebca7d/32.png) [@PerfectDark](https://boards.straightdope.com/u/PerfectDark)\ **Post date:** [June 3, 2001, 1:41am UTC](https://boards.straightdope.com/t/dual-earth/67377/4 "2001-06-03T01:41:23Z")
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 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 couldn’t have said it better myself, well actually I did by adding the bold text around ‘stupid movie’ and ‘corny Science Fiction’. > [@](#): > > I got to thinking this could be real. As this other earth would distort all measurements and such. These two sentences contradict each other… if this ‘other earth’ were to exist than wouldn’t we notice the distorted measurements? PerfectDark ---
**Author:** ![ramanon](https://avatars.discourse-cdn.com/v4/letter/r/65b543/32.png) [@ramanon](https://boards.straightdope.com/u/ramanon)\ **Post date:** [June 3, 2001, 3:21am UTC](https://boards.straightdope.com/t/dual-earth/67377/5 "2001-06-03T03:21:10Z")
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. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [June 3, 2001, 5:37am UTC](https://boards.straightdope.com/t/dual-earth/67377/6 "2001-06-03T05:37:31Z")
Of course there is a opposite earth. We can’t detect it 'cause it’s in an _opposite dimension_. ---
**Author:** ![Chas.E](https://avatars.discourse-cdn.com/v4/letter/c/e99b99/32.png) [@Chas.E](https://boards.straightdope.com/u/Chas.E)\ **Post date:** [June 3, 2001, 6:17am UTC](https://boards.straightdope.com/t/dual-earth/67377/7 "2001-06-03T06:17:21Z")
oh no, the counter-earth is inside the hollow earth, you get to it through the big hole at the north pole. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [June 3, 2001, 6:37am UTC](https://boards.straightdope.com/t/dual-earth/67377/8 "2001-06-03T06:37:06Z")
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 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 3, 2001, 8:23pm UTC](https://boards.straightdope.com/t/dual-earth/67377/9 "2001-06-03T20:23:32Z")
> [@](#): > > 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. Wow, I didn’t know that they were making corny B movies in the 1600s! ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [June 3, 2001, 9:08pm UTC](https://boards.straightdope.com/t/dual-earth/67377/10 "2001-06-03T21:08:05Z")
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 ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [June 3, 2001, 9:59pm UTC](https://boards.straightdope.com/t/dual-earth/67377/11 "2001-06-03T21:59:49Z")
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 ?? ---
**Author:** ![Montfort](https://avatars.discourse-cdn.com/v4/letter/m/d6d6ee/32.png) [@Montfort](https://boards.straightdope.com/u/Montfort)\ **Post date:** [June 3, 2001, 10:37pm UTC](https://boards.straightdope.com/t/dual-earth/67377/12 "2001-06-03T22:37:21Z")
> [@](#): > > \*Originally posted by mangeorge \* > \*\*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. \*\* 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. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [June 4, 2001, 1:03am UTC](https://boards.straightdope.com/t/dual-earth/67377/13 "2001-06-04T01:03:41Z")
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 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 4, 2001, 1:30am UTC](https://boards.straightdope.com/t/dual-earth/67377/14 "2001-06-04T01:30:56Z")
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.