The Martian: Why Would Mark Watney’s Body Not Decompose on Mars?

In the movie The Martian, the character Mark Watney is initially believed to be dead on Mars, but his body is later discovered to have not decomposed. This phenomenon can be attributed to the harsh and unique environmental conditions on Mars. Let's explore the reasons why decomposition would be significantly slowed or even halted on Mars.

Key Factors Influencing Decomposition on Mars

The lack of oxygen, extreme cold, low pressure, and high radiation are the primary reasons why decomposition would be much slower on Mars than on Earth. These factors work together to create a preservation environment for Mark Watney's body.

Lack of Oxygen

Decomposition primarily occurs due to the activity of bacteria and other microorganisms. These organisms thrive in environments where oxygen is present. On Mars, the atmosphere is very thin and primarily composed of carbon dioxide with only trace amounts of oxygen. This makes the environment inhospitable for most decomposers, significantly slowing down the decomposition process.

Extreme Cold

Mars experiences frigid temperatures, averaging around -80°F (-60°C), which are considerably colder than the average temperature inside a freezer (-18°C). These extreme cold conditions slow down biological processes, including the metabolic activities of bacteria and other decomposers. This further inhibits decomposition, contributing to the preservation of the body.

Low Pressure

The atmospheric pressure on Mars is much lower than on Earth, being only about 1% of Earth's atmospheric pressure. This low pressure can affect the ability of certain microorganisms to survive and carry out decomposition processes. The thin atmosphere also means that there are fewer pollutants, which might prevent the growth of certain decomposers.

Radiation

Mars lacks a protective magnetic field and has a thin atmosphere, resulting in higher levels of cosmic radiation. This radiation can be harmful to living organisms, potentially leading to their death or mutation. High levels of radiation would likely reduce the rate of decomposition by killing any surviving bacteria or microorganisms.

Temperature and Environments on Mars

The average temperature on Mars is -60°C (-81°F), which is colder than the standard temperature inside a freezer. In the movie, the events take place on Acidalia Planitia, at Mars' 49th parallel, which is far from the equator. This region is typically colder than average. Additionally, the space suit's batteries would provide warmth for a short time (a few hours), but eventually, the body would freeze due to the cold conditions.

Even if Mark Watney had been in a climate-controlled area, the environmental controls would not have worked for long. If the suit's batteries kept his body warm for a few hours, the subsequent cold night temperatures would have quickly frozen his body. The reflective nature of a space suit would further reduce the warmth he could receive from direct sunlight, making it unlikely for the body to thaw.

The cold ground would act as a heat sink, drawing heat away from the body, thus keeping it cold. Even if there was some microbial activity early on, generating its own heat, the cold environment would eventually overcome this effect, leading to the body becoming as frozen as a popsicle.

In conclusion, the combination of low oxygen levels, extreme cold, low atmospheric pressure, and high radiation on Mars creates a unique environment where Mark Watney's body would not decompose in the same way it would on Earth. The cold temperatures, especially, play a significant role in preserving the body.