Silicon-based life forms are another possible form of alien life. These hypothesized life forms are often depicted in science fiction movies, TV shows and books. Like carbon, silicon can form a lot of complex compounds, but among its many disadvantages is an inherent instability. Silicon is also far less common than carbon in the known universe.
Are plasma crystals alive?
In July 2007, a group of American scientists, in association with the National Research Council, issued a report recommending that scientists search for so-called weird life on other worlds, in space and even on Earth. Weird life is believed to be far different from life forms we're used to seeing. Weird life may be organisms that don't depend on water or that don't have DNA at all. Some people even believe that weird life existed on Earth in the ancient past and that it may still exist on this planet. In reality, scientists don't know what weird life is, but its presence has many reexamining notions of what alien life may be and where it might be found.
Whether or not the plasma crystals are an example of weird life is difficult to determine. Some of the questions regarding these potential organisms come back to the debate about what life is. For example, on Earth, we consider life to be carbon-based and dependent on the presence of water. Life forms also perform certain basic functions, like reproducing, evolving and metabolizing. But even using those functions as a classification can be tricky. David Grier, a physics professor at New York University, told New Scientist that "there is no mathematically rigorous definition of life," which makes it difficult to call these crystals "alive" [source: New Scientist Space].
Gregor Morfill, one of the experiment's participants, said that while the crystals contain a lot of the "hallmarks" of life, they're still "just a special form of plasma crystal" [source: New Scientist Space]. Another of the researchers, V.N. Tsytovich, said that the clusters have "all the necessary properties to qualify them as candidates for inorganic living matter" [source:Science Daily]. The researchers also stated that while they're not ready to confidently state that these structures represent a new form of life, their study should add to the discussion of how scientists define life [source: USA Today].
If the plasma crystals do exist in their simulated form, they live and develop at a pace at least a hundred thousand times slower than Earth's biological organisms. The question is then raised: given their fragility and slow pace of development, can they become intelligent or sentient?
If they are considered life, it may mean that these organisms are the most common life form in the universe, given the prevalence of plasma and massive interstellar dust clouds. There has also been some suggestion that these inorganic life forms somehow spurred development of organic life on Earth.
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