One can rate far-off planets by their cosiness—especially the extremes, good or bad, of coziness—as homes or potential homes to tardigrades. That’s what this study tries to do:
“Tardigrade Indexing Approach on Exoplanets,” Madhu Kashyap Jagadeesh, Milena Roszkowska, and Łukasz Kaczmarek, Life Science in Space Research, epub 2018. The authors, at Jyoti Nivas College, India, and Adam Mickiewicz University, Poland, explain:
“Finding life on other worlds is a fascinating area of astrobiology and planetary sciences. Presently, over 3800 exoplanets, representing a very wide range of physical and chemical environments, are known. Scientists are not only looking for traces of life outside Earth, but they are also trying to find out which of Earth’s known organisms (ex: tardigrades (water bears)) would be able to survive on other planets. In our study, we have established a metric tool for distinguishing the potential survivability of active and cryptobiotic tardigrades on rocky-water and water-gas planets in our solar system and exoplanets.”