String Dimensions Must Be Less Than 44 Micrometers

String Emitting Gravitational Waves

Yesterday in statistics I was sitting next to a math major who was trying to convince me to ditch physics and go to into math since I have a talent for pure mathematics. I told him I want to do more than just prove theorems all my life. I like using math to construct models. I like pure math since I feel it is beautiful and has lots of potential as physical theories become more advanced. But I want to use math to describe things, not just prove theorems.

My friend then told me physicists are like functions trying to map every aspect of reality to some sector of math. I'll think about that for a while. In the meantime I am pleased to report that we have another experiment putting constraints on fundamental theories. According to a research group from the University of Washington, if higher dimensions exist, they must be less than 44 micrometers. They came to this conclusion measuring gravity. If there were extra dimensions, they would affect gravity on distances similar to length of the extra dimension. In fact their wiggles might even produce gravitational waves! They found no gravitational change at all to a small enough scale to rule out dimensions larger than 44 micrometers. These results are printed in this week's Physical Review Letters.