Could dark energy change over time? Scientists find an unusual idea hiding in a well-known theory of gravity - EurekAlert!

SN 2018zd matched six predicted signatures of an electron-capture supernova in a 2021 study, making it a leading candidate. Electron capture can remove pressure supporting a stellar core, triggering collapse in a narrow range of stellar masses. Competing interpretations and later Webb observations leave both SN 2018zd’s mechanism and the Crab Nebula’s origin unresolved. An unusual supernova reveals a possible third way stars explodeA fading star in a nearby galaxy offered astronomers an unusually complete set of clues about a long-predicted stellar death. Its surroundings, changing brightness and chemical signatures pointed toward an electron-capture supernova, an explosion triggered when a stellar core loses part of its internal support. The finding also raised hopes of explaining the explosion that created the Crab Nebula in 1054. However, subsequent research has complicated that connection. Both objects remain valuable tests of stellar physics, rather than settled examples of one explosion mechanism. The host galaxy and post- and pre-explosion images of SN 2018zd.

Gravity is something that we’re all innately familiar with. It keeps our feet on the ground, fights against a rocket trying to leave Earth and governs the movement of the planets and stars. And yet, gravity is something that most of us do not fully understand. General relativity, the best theory of gravity that we have, is complicated and doesn’t operate effectively at all scales.