Facts about jellyfish

The term “jellyfish” is commonly used to describe a marine animal, distinguished by its umbrella-shaped bells and tentacles, but it is in fact a predatory, sexual stage of medusozoan cnidarians.

They occupy both surface waters and the deep sea.

They do not possess a vertebral column.

The name derives from Greek mythology and refers to snake-haired Gorgon Medusa.

Although their fossils are a rarity, since they do not have bones, the oldest shell-like fossils date back to Neoproterozoic Era (1000—550 mya).

Jellyfish washed ashore will evaporate in several hours.

It is estimated, however, that there might be over 300,000 species. To establish the current number of species, scientists use a method similar to the Drake equation–an equation used to estimate the number of extraterrestrial civilizations in the Milky Way.

They have a rudimentary nervous system, developed to detect vibrations, chemicals, and light, but also to navigate.

Fully grown, it can reach up to 2 meters in diameter.

They typically measure up to 0,5 millimeters in diameter.

While in a polyp stage, jellyfish can multiply themselves.

Some live for several days, some can live up to a year.

The Turritopsis dohrnii possess an extraordinary skill of reversing their current stage of life. Basically, they can revert to a polyp stage by undergoing the process of transdifferentiation, which can happen infinitely.

A jellyfish sting is painful and mostly not invasive, although it can be lethal.

They mostly occur in northern Australia, and in the Indo-Pacific region. The most venomous is the Australian box jellyfish, whose sting can lead to paralysis, cardiac arrest, or death.

They are widely consumed in Japan, Taiwan, Vietnam, China, and Korea. Usually, people consume it dehydrated and pickled, with soy sauce and vinegar. Jellyfish salad is a popular side dish in wedding banquets, especially in Japan.

It is also a great source of collagen.

Combining it with their rapid reproduction, their numbers grow at a very high rate.

In 1991, in the Space Shuttle Columbia, NASA sent thousands of jellyfish into orbit in order to study their behavior in microgravity. They reproduced well but had massive problems functioning back on Earth.

A sad, but the important conclusion from this experiment may suggest people born in space might also experience functionality problems in Earth gravity.