# Negative Dimensions: attn Mathematicians! **URL:** \ **Category:** Factual Questions\ **Created:** [March 13, 2002, 11:47pm UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147 "2002-03-13T23:47:35Z")\ **Posts on this page:** 6\ **Page:** 2
**Author:** ![John\_Kentzel-Griffin](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@John\_Kentzel-Griffin](https://boards.straightdope.com/u/John_Kentzel-Griffin)\ **Post date:** [March 15, 2002, 7:19pm UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147/21 "2002-03-15T19:19:22Z")
> [@](#): > > \*Originally posted by \*\*\*Enola Straight \*\* > I figured, if you use the rules to derive gravity from four positive > dimensions, maybe you could get anti-gravity from four negative > dimensions. Except that the number of dimensions is a global property of the entire space. You can’t have four dimensions here and another number of dimensions somewhere else. The dimensionality is a count of the number of coordinates necessary to locate a point. It does not matter whether the coordinates are positive, negative, or zero. Let’s take the 2d plane. It takes two coordinates to locate a point. The coordinates themselves can be positive, negative, or zero. The space has two dimensions because it takes two coordinates to locate a point. > [@](#): > > \*Originally posted by \*\*\*Stinky \*\* > Could the 6 or 7 tightly curled up (Plank sized) dimensions called for in String Theory and M Theory be called negative dimensions[?] No. The extra coordinates are more like coordinates on a sphere, like latitude and longitude lines on the surface of the earth. If you measure the number of degrees from a particular longitude line and the number of degrees above the equator, you get two coordinates. These coordinates differ from coordinates in a plane in that they are cyclical. x + 360[sup]o[/sup] is the same coordinate as x. The dimensionality is the count of the coordinates. The nature of the coordinates does not matter. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [July 10, 2002, 2:52am UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147/22 "2002-07-10T02:52:52Z")
Bingo. [http://geocities.com/autotheist/Physics/sr.htm](http://geocities.com/autotheist/Physics/sr.htm) ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [July 10, 2002, 3:03am UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147/23 "2002-07-10T03:03:18Z")
A relevant quote would be nice. Also, no offense, but I don’t think that geocities is the best source for cutting-edge physics research. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [July 10, 2002, 4:01am UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147/24 "2002-07-10T04:01:20Z")
Its in there, about half-way down. Google search “time negative dimension” and cache the highlighted words. I didn’t know how to do all that while simultaneously providing a link. ---
**Author:** ![g8rguy](https://avatars.discourse-cdn.com/v4/letter/g/7cd45c/32.png) [@g8rguy](https://boards.straightdope.com/u/g8rguy)\ **Post date:** [July 10, 2002, 5:10am UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147/25 "2002-07-10T05:10:45Z")
Hmm… I think that’s just an unfortunate turn of a phrase by the author. What he means is (warning: technobabble) the sign in front of the time part in the invariant length is the opposite of the sign in front of the space part. He doesn’t actually mean that time is a negative dimension in the sense you’re suggesting. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [July 10, 2002, 5:16am UTC](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147/26 "2002-07-10T05:16:30Z")
Yeah, that’s the impression I got. Of course, there’s nothing on that page to indicate that’s what he means–I was just guessing based on what little I know about SR. [Previous page](https://boards.straightdope.com/t/negative-dimensions-attn-mathematicians/98147.md?page=1)