Extraterrestrial Life- Living Creatures Beyond Our Earth

Extraterrestrial life refers to any living matter found beyond Earth’s atmosphere. This can include everything from single-celled organisms on an asteroid to advanced civilizations on other planets. Study of extraterrestrial life has grown over the last several decades, and this field of research is known as astrobiology. Astrobiologists combine elements of astronomy, biology, and geology in their search for life beyond our world.

Centuries of humans have wondered whether extraterrestrial life exists somewhere in outer space. In fact, the earliest theories regarding otherworldly life were proposed by the ancient Greeks. The Greeks postulated that if the universe was infinite, then there could be an infinite number of worlds possessing life. Some early religious texts, such as those from Judaism and Hinduism, also suggest the existence of extraterrestrial organisms. The first modern theorists to suggest extraterrestrial life published works in the 16th and 17th centuries. Many of these scholars faced criticism and persecution from the Catholic Church. However, as astronomical knowledge increased, the theory that extraterrestrial life existed became more credible.

To find extraterrestrial life, one must first establish a definition of what it means to be alive. At its most basic level, a living creature is capable of unassisted reproduction. However, for most scientists, a more thorough set of criteria is required. Since Earth’s organisms provide the only known examples of life, these have become the model for theories regarding extraterrestrial creatures. On Earth, all living beings are formed from the following elements: carbon, hydrogen, oxygen, and nitrogen. Subsequently, these are the elements believed necessary for life. Water is also considered a vital component since all life on Earth requires this basic substance.

Some scientists have recognized the possibility that life on other worlds may not resemble earthly organisms in any way. They propose alternatives to the notion of carbon-based life forms. For example, one popular theory is that extraterrestrial life could be silicon-based. Such organisms would life in high-temperature settings and possess a crystalline form. Another possibility is that life could utilize ammonia as a substitute to water. Finally, some theorize that life could exist inside the plasma of stars.

Some researchers have specifically researched on how extraterrestrial life might look and act. These scholars focus on those characteristics most common in earthly life, such as vision and limbs. The more species on Earth with a certain feature, the more that feature may be found in extraterrestrial life. However, the exact manifestation of these traits would depend on a life form’s natural environment. Gravity, temperature, atmosphere, light, and other variable would impact the form an organism takes. For example, life surviving in a high-gravity setting may have a stronger skeletal structure for support.

Most scientists researching possible extraterrestrial life have had to rely on earth-based data. Thus, they utilize long-range telescope readings and computer projections for most of their data. However, a few extraterrestrial missions have focused on the search for life. These include several recent missions to Mars, like NASA’s Viking rovers and Beagle 2 probe. Scientists believe Mars may once have possessed planetary conditions conducive to supporting life. For example, evidence of water has been round on this planet. Thus, missions to Mars have included soil sampling to test for organic matter. Other probes have investigated several moons in our solar system, including Jupiter’s ice-covered Europa and Saturn’s giant Titan.

Currently, there exists no definitive proof of extraterrestrial life. The only tangible evidence that life might exist beyond Earth comes from microfossil of organisms lodged in meteorites found in Antarctica. However, this data is not conclusive. Thus, scientists continue using a variety of data to speculate on where life might exist and what form it might take.