NASA first started sending jellyfish to space aboard the Columbia space shuttle during the early '90s to test how space flight would affect their development. Under the fantastic headline "Space-Born Jellyfish Hate Life On Earth" Popular Science notes that jellyfish babies, born in microgravity environments, "have to deal with massive vertigo on Earth after spending their first few days in space". There's a possibility for future generations of space-born human children, who might never be acclimatised to a terrestrial environment, and in fact could be incapacitated by gravity forces approaching "normal". Jellyfish tell up from down through calcium sulfate crystals that ring the bottom edge of their mushroom-like bodies. Humans sense gravity and acceleration through calcium crystals in the inner ear — similar to jellyfish — moving sensitive hair cells that signal our brains on direction of gravitation."
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