Author: Ioannes Salamanes
Editors: Vincent Chang and Peggy Yang
Artist: Daisy Zheng
Astrobiology, also known as xenobiology or exobiology, is the study of life in the universe. Humans have long wondered what lies beyond planet Earth. The Ancient Greeks argued that Earth was not the only planet capable of providing life, but they also did not have the technology to prove it. Now, with new and improved technology available in the 21st century, humans can better address the fundamental question: “Is there life outside of Earth?”
To search for life beyond Earth, there must be an understanding of life as well as the nature of the environments that support it. There also needs to be an understanding of planetary, planetary systems, and stellar interactions and processes. To help support this understanding, astrobiology combines techniques and knowledge from various fields such as aeronautical engineering, astronomy, atmospheric science, biology, chemistry, geology, and oceanography. Some astrobiologists work alone on specific scientific questions while others work together to answer questions that would be impossible to tackle alone.
Astrobiology is a new field but it already has a promising and secure future. Its research has had a great impact on how agencies such as the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) plan for any current and future space missions. For example, there have been many recent missions focused on exploring worlds in our solar system for signs of past and present life including the Global Surveyor, Pathfinder, and Phoenix on Mars and the Cassini-Huygens on Titan. In addition, recent investments and advances in telescope technology have allowed researchers to begin searching for inhabitable planets outside of our solar system. In the United States, NASA’s Astrobiology Institute is the leading funder and policymaker in astrobiology. Internationally, astrobiology institutes and networks like the Australian Center for Astrobiology, the Centro de Astrobiologia in Spain, and the Nordic Network of Astrobiology Graduate Schools, have been established.
So far, there has not been any solid evidence of extraterrestrial life, however, the possibility of biota throughout the universe has been strengthened by the discovery of extrasolar planets, or planets surrounding other stars, which indicates that there may be multiple habitats for life. This possibility has also been strengthened by the existence of microorganisms called extremophiles that are tolerant of environmental extremes, suggesting that life can arise under a wide range of conditions. In addition, there have been strong suspicions that some of Saturn and Jupiter’s moons might have vast reserves of liquid, which suggests that there may be other worlds in our solar system where life may have evolved. Because planets either too far or too close from their host stars will be at temperatures causing water to either freeze or boil, a “habitable zone” as defined by astrobiologists, is a range of orbital distances within which planets can support liquid water on their surfaces. Earth is the only planet inside the Sun’s habitable zone, however, there have been data and photographs showing that water once flowed on the surface of Mars and that there is still large quantities of water underground. Because of this, there have been international efforts to send robotic probes to examine Mars for evidence of past and present life that could have retreated to subsurface, liquid aquifers.
Discoveries from the space probe Galileo launched in 1989 also suggest that Saturn’s moon Enceladus and Jupiter’s moons Callisto, Europa, and Ganymede might have long-lived liquid oceans under their icy outer skins. These oceans can be kept warm because of the gravitational interactions between the moon and their host planet, even if they are far from the Sun. It is even possible that these oceans might support the type of life found in deep-sea vents on Earth. Another of Saturn’s moons called Titan might also be home to unusual biology on its cold surface. Huygens, a European space probe, landed on this large moon on January 14, 2005, and saw signs of liquid flow on its surface. These are a few of the discoveries that have promoted the emergence of the field of astrobiology by broadening the range of possible extraterrestrial habitats far beyond the conventional notion of a “habitable zone.”
If astrobiology and the idea of life on other planets seem interesting, then becoming an astrobiologist might be a future career to consider, especially those who are flexible, persistent, and an “outside-of-the-box” thinker. Astrobiologists should be open to change, be able to preserve even when facing the hardest challenges, and be able to come up with many innovative ideas. As an astrobiologist, one would study the possibility of life beyond Earth and the origins of these species, and their adaptability to many different environments. This can include studying existing life on Earth or studying different moons and planets to see if their conditions might be able to support life. Some astrobiologists look for places where the simplest forms of life are present, while others search for radio signals from intelligent life in the universe. However, something all astrobiologists have in common is the fact that they are usually experts in both biology and astronomy.
Although astrobiology is a small field, finding a job in the field is not difficult. There are various places astrobiologists can work including universities, government-funded agencies such as NASA or the ESA, and private research institutions such as the Scripps Research Institute. To prepare for their entry into the interdisciplinary field of astrobiology, most astrobiologists have focused their studies on science, technology, engineering, and mathematics. However, there are some astrobiologists with academic backgrounds in social sciences such as history and psychology, as well as humanities. Astrobiologists also spend an extensive amount of time in the lab. They look at fossils of the earliest life forms to try to deduce how they arrived on Earth and they also record and test the life cycle of bacteria that can survive in harsh conditions to find out if life can exist in other worlds.
“Astrobiology.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.,
“What Is Astrobiology?” Uwastrobiology,
“Who Is an Astrobiologist?” Educate & Inspire | Space Awareness, www.space-