APOD: 2026 July 2 - Sibling Supernova Remnants - NASA Science (.gov)

Orbital observations suggest that a deeply eroded region near Mars’ equator contains the remains of a giant volcanic complex. Landforms and sulfate deposits point to past interactions between volcanic material and ice, but surviving buried glacier ice remains unconfirmed. Follow-up research and a proposed helicopter mission highlight the region’s scientific appeal without establishing present volcanic activity or a usable water reserve. A maze of fractured plateaus and canyons near Mars’ equator may preserve the remains of an enormous volcano. Within that landscape, scientists have also identified clues that glacier ice could survive beneath volcanic debris. Together, the observations make eastern Noctis Labyrinthus a compelling target for investigating the planet’s changing environment. The proposal concerns terrain already photographed by generations of spacecraft. Its significance lies in recognizing a possible geological structure within that familiar landscape, rather than discovering an unseen mountain. The volcano’s history and the present condition of any buried ice remain open questions.

Pa 30, linked to a supernova seen in 1181, reveals chains of tiny gas knots in a new image from the Gemini North telescope in Hawaii.

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.

NASA’s Hubble Space Telescope completed its 200,000th orbit around Earth on Sept. 19, marking another new milestone for an observatory that continues to transform our understanding of the universe. Hubble has traveled more than 5 billion miles around Earth over its 36-year lifetime, exceeding 1.7 million total observations. An observation completed on the day of the 200,000th orbit pertains to one of Hubble’s defining scientific legacies: measuring the expansion rate of the universe, or the Hubble Constant. The image takes advantage of the telescope’s ability to return to the same regions of the sky over time to monitor for the reappearance of a supernova, or explosion of a star, called Athena.