Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Due to inconsistencies between General Relativity and the Standard Model, tests of gravity remain at the forefront of experimental physics. At Humboldt State University, undergraduates and faculty are designing an experiment sensitive enough to detect gravitational interactions below the 50 micron scale. The experiment measures the twist of a torsion pendulum as an attractor mass is oscillated nearby in a parallel plate configuration, providing time varying gravitational torque on the pendulum. The size and distance dependence of the torque variation will provide a means to determine any deviation from current models of gravity on untested scales.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Theories attempting to unify the Standard Model and General Relativity often include features that violate the Weak Equivalence Principle and gravitational Inverse-Square Law. Motivated by these considerations, undergraduates and faculty at Humboldt State University are operating an experiment to probe gravitational interactions below the 50-micron length scale. The experiment employs a torsion pendulum whose twist is measured as an attractor mass is oscillated nearby. The size and distance dependence of the torque variation provides a means to determine the existence of deviations from expected behavior at untested scales.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

Gravity has been tested rigorously at distance scales from 1cm up to astronomical distances. The experiment being run in Humboldt State Universities Gravity Lab seeks to test gravity at previously untested distances below the centimeter level. To do this, a pendulum is suspended by a torsion fiber and oscillates in front of a movable mass. By moving the mass back and forth, one can measure a gravitational force on the pendulum by looking at the twist in the fiber. The data from the pendulum are then compared with well established theories of gravity to see if the accuracy of the theories at large distances translates to smaller scales.

Novel Tests of Gravity Below Fifty Microns

College of Natural Resources & Sciences

The Gravity Lab at Humboldt State is concerned with measuring the force of gravity at unprecedented distance scales. Theories new and old make predictions about how gravity should behave, but accurate measurements of gravitational forces between objects close together have remained challenging. The crux of the experiment lies in sufficiently silencing the non-gravitational forces acting at the measuring site, and accomplishing this requires applying at least a little knowledge from most undergraduate physics classes. The implications of progress in this lab make it exciting to a general audience while remaining beneficial from an undergraduate learning perspective.

Novel Tests of Gravity Under 50 Microns

Abby Keltz, Physics & Astronomy Undergraduate Student

College of Natural Resources & Sciences

Attempts to unify the Standard Model and General Relativity often include features that violate the Weak Equivalence Principle (WEP) and/or the gravitational Inverse-Square Law (ISL). A violation would question our understanding of gravity. To further understand this, undergraduate researchers and faculty at Humboldt are experimenting to measure gravitational interactions below 50 microns. The experiment uses a composition dipole torsion pendulum next to an oscillating mass. This creates torque on the pendulum, the magnitude of which may provide evidence for deviations in the WEP or ISL.

Novice Cyclists Using Shorter Crank Lengths Produced Greater Power at Same V̇O2

College of Professional Studies

Compared to trained runners, novice runners employ lower stride frequencies and shorter stride lengths as they run at lower speeds vs trained runners. Novice cyclists may benefit from a similar paradigm, utilizing shorter crank lengths as an analog to the lower stride frequencies and shorter stride lengths used by novice runners. The purpose was to determine the impact of short crank arms on novice cyclist’s performance and comfort during a bout of moderate intensity cycling. Data analysis and conclusion will be included on poster.

Nowhere 2 Go Humboldt

Jasmine Guerra, Social Work Graduate Student

College of Professional Studies

Nowhere 2 Go Humboldt is a multi-media storytelling project which interviews and photographs people who are criminalized and displaced in Humboldt County.

Observer Bias of Giant Kangaroo Rat Precinct Indexing

College of Natural Resources & Sciences

This was a side-project of the Carrizo Ecosystem Project where two observers independently surveyed precincts of the Federally Endangered Giant kangaroo rat (Dipodomys ingens) on 10 plots in the Carrizo Plain National Monument, San Luis Obispo County, California. The goals were to note the bias between observers, to determine if the number of active precincts correlate with the current population density estimates, and to determine if indexing Giant kangaroo rat (GKR) precincts is a reliable method for determining the current GKR population status.

Ocean Acidification and Surfgrass Buffering on Calcifying Intertidal Organisms

College of Natural Resources & Sciences

Our project addresses the question of whether Phyllospadix spp., a surfgrass, can effectively buffer calcium carbonate uptake by calcifying intertidal organisms. This question has significant ramifications for the Humboldt County coastline, which is considered an ocean acidification “hot spot” due to its exposure to acidic water during periods of upwelling. Our group will observe Phyllospadix spp. and it's influence on calcium carbonate deposition on cockle clams and articulated coralline algae . The results will vary due to the abundance of Phyllospadix spp. and invertebrates in each aquarium, and will determine if the calcification rate will be higher in the presence of Phyllospadix spp.

Offshore Wind Resource Assessment

College of Natural Resources & Sciences

Offshore wind energy has enormous potential to help meet California’s 100% clean electricity target. The Schatz Energy Research Center at Humboldt State University is studying the feasibility of offshore wind farms in Northern California. One project, funded by the Bureau of Ocean Energy Management (BOEM), models the power generation from different size offshore wind farms including 50, 150 and 1,800 MW, each located 20-30 miles offshore. The results show that the wind speeds in this region are some of the highest on the West Coast, producing up to 7,540 GWh/year for the largest MW wind farms. This represents 900% of Humboldt County’s electrical needs and 3.8% of California’s demand.