A Light Bridge Captured in a Sunspot A light bridge is seen crossing a sunspot’s umbra from one end of the penumbra to the other. Light bridges are believed to be the signature of the start of a decaying sunspot, which will eventually break apart. Light bridges are very complex, taking different forms and phases. It is unknown how deep these structures form. This image shows one example of a light bridge in remarkable detail. Umbra: Dark, central region of a sunspot where the magnetic field is strongest. Penumbra: The brighter, surrounding region of a sunspot’s umbra characterized by bright filamentary structures.

Umbral Fragments Suggest the “End Phase” of a Sunspot A sunspot is identifiable by its dark, central umbra and surrounding filamentary-structured penumbra. A closer look reveals the presence of nearby umbral fragments - essentially, a sunspot that’s lost its penumbra. These fragments were previously a part of the neighboring sunspot, suggesting that this may be the “end phase” of a sunspot’s evolution. While this image shows the presence of umbral fragments, it is extraordinarily rare to capture the process of a penumbra forming or decaying. Umbra: Dark, central region of a sunspot where the magnetic field is strongest. Penumbra: The brighter, surrounding region of a sunspot’s umbra characterized by bright filamentary structures.