Jim Simons’ Life, Legacy and 5 Guiding Principles

Over the past decade, two very different ways of calculating the rate at which the universe is expanding have come to be at odds, a disagreement dubbed the Hubble tension, after 20th-century astronomer Edwin Hubble. Experts have speculated that this dispute might be temporary, stemming from subtle shortcomings in observations or analyses that will eventually be corrected rather than from some flawed understanding of the physics of the cosmos. Now, however, a new study that relies on an independent measure of the properties of galaxies has strengthened the case for the tension. Quite possibly, it’s here to stay.

Modern science wouldn’t exist without the online research repository known as arXiv. Three decades in, its creator still can’t let it go.

The oceans teem with photosynthesizing bacteria, tiny-tailed dinoflagellates gobbling other plankton, algae surrounded by intricate glass skeletons. In the 1960s, the ecologist G. Evelyn Hutchinson pointed out something confusing: why do so many kinds of plankton exist?

Penn physicist Randall Kamien, visiting scholar Lauren Niu, and collaborator Geneviève Dion of Drexel bring unprecedented levels of predictability to the ancient practice of knitting by developing a mathematical model that could be used to create a new class of lightweight, ultra-strong materials.