• ArtsandLectures twitter avatar
    RT @brainpicker: So looking forward to my conversation with the wonderful @PicoIyer at the University of Santa Barbara @ArtsandLectures ser…
    12 hours 41 min ago
  • UCSBgauchos twitter avatar
    Andrew Martinez (3-5, 4 RBI), Ben Brecht (5 IP, 1 H, 0 K), and Armani Smith (3-5, 3 RBI) team up to take down Sac S… https://t.co/uaCjUxpsEc
    14 hours 15 min ago
  • ucsantabarbara twitter avatar
    Current #UCSB physicist Gary Horowitz got to experience Stephen Hawking’s brilliance firsthand, and recalls Hawking… https://t.co/c19uuFTXbK
    15 hours 18 min ago
  • ucsantabarbara twitter avatar
    The 19th Annual UC LEADS Research and Leadership Symposium brought together undergraduates from across the… https://t.co/1gfuDbw8xd
    23 hours 17 min ago
  • UCSBgauchos twitter avatar
    UCSB MVB became just the second team this year to take a lead on No. 1 and undefeated Long Beach State, but the Gau… https://t.co/faB34xJskD
    1 day 10 hours ago
  • UCSBgauchos twitter avatar
    Women's Tennis: Harvard at UC Santa Barb. (3/16/2018 2:00 PM EDT) Rain Day Leads to Cancellation of UCSB vs Harvard https://t.co/K0rSjkMka2
    1 day 11 hours ago
  • UCSBgauchos twitter avatar
    .@UCSB_Baseball opener vs. Sac St suspended due to rain. Gauchos and Hornets to play two tomorrow. https://t.co/JpJxFxXmbV
    1 day 15 hours ago
  • ucsantabarbara twitter avatar
    Here’s the problem: the bigger the parts in a satellite, the more expensive it is to build, launch, and operate. Lu… https://t.co/KLmIBg84Rb
    1 day 15 hours ago
  • ArtsandLectures twitter avatar
    Considered the world's greatest mezzo-soprano, @JoyceDiDonato entrances audiences across the globe with “a warmth i… https://t.co/L3YuZv7m88
    1 day 16 hours ago
  • brenucsb twitter avatar
    Protecting marine mammals, turtles, and birds by rebuilding global fisheries: #BrenUCSB and @sfgucsb post-docs rele… https://t.co/0HTXyi7Mjg
    1 day 17 hours ago
  • UCSBgauchos twitter avatar
    Logan Hotchkiss and Billy Mullis will represent @UCSBSwimming at the 2018 NCAA Division I Men's Swimming Championsh… https://t.co/e92apKJm4f
    1 day 20 hours ago
  • UCSBLibrary twitter avatar
    #deadweek means you'll have to wait just a bit longer to celebrate #worldsleepday. You're almost there, Gauchos!
    1 day 20 hours ago

The Universe in the Heel of a Sock

Physicist at UCSB explains how the same math used in sewing and knitting also helps describe cosmic curvature
Wednesday, February 3, 2016 - 10:15
Santa Barbara, CA

Little-known fact about socks: The mathematics that determines the heel curvature of hosiery has its origins in Einstein’s theory of relativity, which describes curved space-time. So the math and science you learned in high school actually do have real-life applications after all.

Physicist Sabetta Matsumoto, a visiting scholar at UC Santa Barbara’s Kavli Institute for Theoretical Physics (KITP), unpacked the math of curvature in easily understandable terms in her presentation “Purls of Wisdom.” Her talk, part of the ongoing science series Café KITP, addressed the geometry and topology used in sewing garments and knitting clothes.

“The human form — particularly the female body — has innate curvature,” said Matsumoto, currently a postdoctoral scholar in the Applied Mathematics Group at Harvard University. “Fabric is two-dimensional, yet seamstresses, couturiers and dressmakers all know how to make it fit a three-dimensional body by adding darts and pleats, which physicists like to call topological defects. Darts in clothing are an example of positive curvature, where area is removed.”

Matsumoto comes by her penchant for fiber arts genetically. Her mother is a fiber artist who taught her to sew and knit. Matsumoto used her own designer wedding dress as part of her slideshow, comparing its ruffles to human intestines.

“You might think that these two things have absolutely nothing in common, but surprisingly, it is actually the same physical mechanism that gives both their shape —negative curvature,” Matsumoto said. In negative curvature, the surface curves away in two different directions in the same way a saddle or a Pringles potato chip does.

Matsumoto’s ruffled wedding dress was created by stretching tulle — adding extra area — and stitching it to stiff boning. When the tension on the fabric was relaxed, a ruffled structure appeared. “It turns out that the same thing is going on in this fabric treatment and in your intestines,” Matsumoto explained. “A small membrane that connects the intestines to the spine created tension when your intestines grew and ruffled them.”

Matsumoto also used knitting to discuss two categories of topological defects: dislocation and disclination. “Dislocations are where we add in new columns of material — for instance, on the bustline of a sweater," she said. “But you also see dislocations when you knit in new rows of material —this is called adding in short rows — and this is exactly what’s going on in the heel of a sock.”

Both dislocation and disclination can also be seen in the stripe pattern of a zebra. The dislocations are areas where the girth of the animal changes and a new stripe is added. The disclinations are areas where curvature changes to accommodate the animal’s limbs.

At the core of Matsumoto’s presentation was her handmade fabric rendition of the hyperbolic plane geometry known as Klein’s Quartic Curve. Her creation consists of 24 heptagons (seven-sided flat pieces) coordinated in groups of three. “I took all this space and I wrapped it in on itself to come up with a compact object containing three holes,” Matsumoto said.

Matsumoto also walked the audience through the math of Euler’s formula in order to demonstrate the deep relationship between the geometry (the counting of edges) and the topology of the object (the number of holes).

“You may have remembered your geometry classroom as something dry, but I hope I’ve convinced you that if you keep your eyes open, you can find interesting geometry all around you in your daily life,” Matsumoto concluded. 

Contact Info: 

Julie Cohen
(805) 893-7220