The phrase "transient phenomena" refers to things that happen for a short duration or occur temporarily. It describes events or occurrences that are not lasting or permanent. Full definition
The repeat observations will help astronomers detect changes in stars and galaxies in an unprecedented way, probe dark matter and dark energy, and discover transient phenomena such as stellar explosions. (sciencemag.org)
The Caltech Center for Advanced Computing Research's VOEventNet project, which created a virtual observatory by linking a number of telescopes, introduced a software program this week that works with Sky, allowing users to post and view images and video of transient phenomena such as exploding and colliding stars, gamma - ray bursts, and supernovae within minutes of their detection. (scientificamerican.com)
Both sides on these points — moreover — lack a theoretical context that places transient phenomenon in the context of globally coupled fluid flows in the spatio / temporal chaotic Earth system. (watertechbyrie.com)