Jellyfish Jellyfish Jellyfish or sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are not mobile, being anchored to the seabed by stalks. The bell can pulsate to provide propulsion and highly efficient locomotion. The tentacles are armed with stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex life cycle; the medusa is normally the sexual phase, the planula larva can
Space jellyfish Space jellyfish A space jellyfish (or "jellyfish UFO"; also "rocket jellyfish") is a rocket launch related phenomenon that frequently is misidentified as an alien UFO. The phenomenon is caused by sunlight reflecting off the high altitude rocket plume gases emitted by the launching rocket, at pre-dawn and post-dusk, the twilight plumes. The observer is shrouded in darkness, while at high altitudes, sunlight is able to reflect off the exhaust that is being lit before dawn reaches lower altitudes or after dusk has already left lower altitudes, due the curvature of the Earth and its rotation causing the day-night cycle. This