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Comment by hinkley | Hacker News Reader

We have people like string theorists thinking about higher dimensions in space.

It occurred to me the other day when the dark matter article hit the front page that our equation for gravity works with three dimensions but those dimensions are uniform. I can turn an object with very little effort (literally without doing work) and it’s the same size from our perspective.

How would it work if matter has more dimensions that aren’t proportional, or if space is curved in higher dimensions and the differences are in the noise floor here on earth and in orbit?

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> I can turn an object with very little effort (literally without doing work) and it’s the same size from our perspective.

I can't reproduce your experiment... I tried turning a piece of paper. At first it looked, say, about as large as a cantaloupe, but when I turned it got smaller and smaller until it practically disappeared, and it becomes very tiny... basically nothing more than a thin line in space. At certain angles I can barely see it at all. What is going on?

Some objects have axes of symmetry, right? Think of a disk or a cylinder or a sphere. You can rotate these on some axes without a change in shape. This concept extends to higher dimensions. Not that I agree with the first poster's point necessarily.

The distance between any two ink dots remained constant as you rotated the paper, which is what you would expect when the metric is x^2+y^2+z^2. If the "dimensions were not uniform," then the same transformation may alter the distances. Perhaps the parent is on their way to discovering relativity.

PBS Space Time did a recent episode on higher spacial dimensions and gravity.

https://www.youtube.com/watch?v=3HYw6vPR9qU

The delivery on this program is extremely annoying and slow paced (and rushed on points that ought be slow).

I think the delivery is good and paced just right.

Keep watching. It's a series that covers a lot of great spacetime and quantum physics topics from a rare perspective.

Also, go through the older videos. A lot of what's covered today builds on the previously released shows.

It's designed to be watched at 1.5x speed

then it sounds like normal speech.

Yea that's a part of the string theoretic calculation, that some of these higher dimensions are different than the three we're accustomed to. They're curved and swirled and weird. It's pretty unclear that they're real, but it's an interesting idea

Indeed. The usual layman example is that a string has two dimensions when you're close enough to it that it resembles a cylinder, but only one when you zoom out far enough that it becomes a line.

It took me second to realize that you're talking about actual real-life strings, not the strings from string theory which are precisely 1-dimensional. :)

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