Jellyfish the first vortex and pushes the animal forward, but the mesoglea is so elastic that the expansion is powered exclusively by relaxing the bell, which releases the energy stored from the contraction. Meanwhile, the second vortex ring starts to spin faster, sucking water into the bell and pushing against the centre of the body, giving a secondary and "free" boost forward. The mechanism, called passive energy recapture, only works in relatively small jellyfish moving at low speeds, allowing the animal to travel 30 percent farther on each swimming cycle. Jellyfish achieved a 48 percent lower cost of transport (the amount
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