No matter who we are or who we come from, everyone at some point in their lives thinks about whether there is life beyond Earth. For the first time in human history, we have the information and technology needed to detect life in other worlds. To do this, we must first identify the markers of life. That is, what should we look for when determining whether life exists in another world without actually traveling to other worlds?
The often cited chemical marker for living organisms is methane, an organic compound that is commonly associated with living things on Earth. However, methane can also be produced through processes that do not involve life. If we do detect methane in another world, should it be seen as evidence of extraterrestrial life?
Methane is an organic compound made up of one carbon atom and four hydrogen atoms. Although methane is not common in the Earth's atmosphere, it plays a vital role in the Earth's atmosphere. Like carbon dioxide, methane is a greenhouse gas that helps maintain a stable temperature on the Earth's surface. On Earth, the vast majority of methane is produced by living organisms. Bacteria often produce methane in wetlands, and larger organisms often produce methane as a byproduct of digestion as well. When organisms die, they also release methane when they decompose.
Most of the methane on Earth is produced through these biological processes, but not all methane on Earth is produced by life. Volcanic eruptions release small amounts of methane, a process that may be common in countless worlds. The presence of methane alone does not prove the existence of life, but the amount of methane and its presence with other chemicals can prove that life exists.
Methane is a fairly unstable compound. Sunlight usually breaks it down quickly, so if methane is not replenished over time, it will slowly disappear from the planet's atmosphere. Without biological processes, methane would be almost non-existent in the Earth's atmosphere. Although volcanoes do release small amounts of methane, over time, these methanes are not enough to replenish them. If a planet has a steady amount of methane and can replenish quickly, it could mean that organisms on the surface are producing methane. In addition, other chemicals other than methane can also provide evidence of extraterrestrial life.
On Earth, biological processes produce a variety of chemicals as well as methane, most notably oxygen and carbon dioxide. If a planet is rich in methane and large amounts of oxygen and carbon dioxide, it may indicate that biological processes are taking place on its surface. If methane is present with other chemicals, especially carbon monoxide, it means that volcanic eruptions or other geological processes produce methane. Volcanic eruptions release large amounts of carbon monoxide, however, on Earth, most of the carbon monoxide is absorbed by organisms such as plants.
If a planet's atmosphere contains large amounts of both methane and carbon monoxide, it indicates that the presence of extraterrestrial life has nothing to do with the presence of methane. However, suppose a planet has an atmosphere rich in methane but lacks a large amount of carbon monoxide. In this case, it indicates not only the presence of organisms that produce methane, but also the presence of organisms that absorb carbon monoxide. Observations like this would be a strong indicator of the existence of extraterrestrial life.
On Earth, methane is the main indicator of the existence of life, but the presence of methane itself is not necessarily evidence of the existence of life. The amount of methane, the frequency of replenishment, and its presence with other chemicals will provide strong evidence for the existence of extraterrestrial life on another world. For the first time in human history, technology has advanced enough that scientists can now begin to observe other planets and determine their atmospheres. Opus. It may only be a matter of time before scientists discover a world with compositions that mimic Earth's atmosphere. The answer to one of humanity's most important questions may depend on whether we detect methane or not.
List of high-quality authors