As our technology develops and we are able to explore more of the solar system, our top scientific minds have begun to ask the question- could humans survive on a different planet? This is an important question, as our planet will not be able to support human life indefinitely.
You might have seen the 2015 science fiction movie, ‘The Martian’, starring Matt Damon, which depicts him as an astronaut trying to survive on Mars and grow plants. But could this actually happen? Can humans really live on Mars?
Can We Breathe On Mars?
The most important thing that humans would need in order to live on Mars is oxygen. We get our oxygen from breathing in the air from Earth’s atmosphere, but could we breathe on Mars?
The air on Mars is 100 times thinner than the air on Earth, so humans would not be able to breathe it in even if it had a similar composition to Earth’s atmosphere.
The atmosphere on Mars is made up of mostly carbon dioxide, whereas our atmosphere contains 21 percent oxygen, 78 percent nitrogen, 0.9 percent argon and only trace amounts of carbon dioxide and other gases.
If astronauts were able to travel to Mars, they would have to take oxygen to breathe which would add a significant amount of weight to their rocket, which would then increase the amount of fuel they would need to power the rocket.
A recent NASA experiment called MOXIE - The Mars Oxygen In-Situ Resource Utilization Experiment - has been able to suck up the carbon dioxide from Mars’ atmosphere and heat it to 1472 degrees fahrenheit. This separates the oxygen molecules from the carbon monoxide molecules, creating an oxygen source.
MOXIE can produce about 10 grams of oxygen per hour, which is the equivalent of 10 minutes of breathing. Whilst this is a great solution for filling oxygen tanks, we still would not be able to breathe in the atmosphere on Mars without a spacesuit.
Can We Plant Trees On Mars?
If there is not enough oxygen on Mars, can we plant trees in order to produce more oxygen? Trees and plants take in carbon dioxide and convert it to oxygen through a process called photosynthesis. This releases a lot of oxygen into Earth’s atmosphere. So are we able to ‘terraform’ Mars?
There are several factors that would prevent trees from growing on Mars. The first issue is the temperature- whilst it reaches up to 78.8 degrees fahrenheit in the summer, it drops to minus 231.8 degrees during the polar winters.
Some species of trees can survive very cold temperatures if they can handle being gradually dehydrated, as their water content will freeze and will no longer be able to benefit the cells. But they would not cope with the varying temperatures on Mars.
The lowest temperature ever recorded on Earth is minus 126 degrees fahrenheit, but this was in Antarctica where there are no trees, only one type of grass and one type of flower, which grow on the southern part of the island.
The other barrier to growing trees on Mars is the thin atmosphere mentioned above. A thin atmosphere means that the pressure is so low that liquid water would not be stable on the surface of Mars.
Trees need water to survive, but there is no water on the surface of Mars and we would not be able to introduce it due to the thin atmosphere.
The more we learn about geo-engineering our own climate on Earth, the more possible it seems that we could potentially adjust the atmosphere on Mars.
If we introduce greenhouse gases to the atmosphere on Mars then we may be able to increase the temperature of the planet as well as the atmospheric density. This will create an environment with liquid water on the surface of Mars. We already know that Martian soil already contains the necessary nutrients for trees and plants to grow.
If the first few plants we introduce to the surface of Mars are hardy and well adapted to low oxygen levels, drought, and frost, they will speed up the transformation of the atmosphere by releasing oxygen and increasing the temperature, and eventually other species will be able to be planted.
Can We Grow Food On Mars?
If humans are to survive on Mars, we would need to be able to grow food.
As we have already discussed, we could potentially change the atmosphere to allow for liquid water on the surface of mars and get some species of trees to grow on Mars, but growing vegetables and edible plants is a different matter. They require more particular conditions to flourish, and more nutrients from the soil.
Even if we can gradually make the atmosphere on Mars warmer and more dense, it would be a significant amount of time before we could successfully grow vegetables in it.
It is likely that we would need to grow them in some kind of atmosphere-controlled greenhouse, or even in an underground facility, to protect the vegetables from the harsh conditions on the surface.
This would also create an opportunity to control the temperature and humidity, as different types of vegetables require different conditions and climates to grow.
We know that the soil on Mars should contain enough nutrients to support the growth of trees, but can it support the growth of vegetables?
A group of researchers in the Netherlands tested this out back in 2016 with some positive results. They were not able to use Martian soil, but NASA provided them with soil from a Hawaiin volcano which is thought to be the closest equivalent.
The researchers grew the vegetables in greenhouses and underground rooms, as they would expect vegetables to be grown on Mars. The vegetables grew successfully, but there was one big problem- the soil contained traces of mercury and arsenic which made the vegetables poisonous to eat.
If these substances are present in the soil on Mars then we would have to come up with a way to stop the vegetables absorbing them, or process the soil first to remove the harmful substances.
Can Animals Survive On Mars?
It is clear from the information above that domestic animals and farm animals would not be able to survive on Mars as they would not be able to breathe in the atmosphere, would not have enough oxygen, and would not have water.
If we are able to terraform Mars and adjust the atmosphere, this could change in the future, assuming we are able to grow food to feed them and ourselves!
However, there are some microorganisms which might be able to survive on Mars. Some researchers believe that Methanogens, one of the simplest and oldest organisms on Earth- could survive in the planet’s atmosphere.
On Earth, they are found in swamps and marshes, as well as in the guts of cattle and in decaying matter. They get their energy from hydrogen and their carbon from carbon dioxide. Their metabolic process produces methane, and they are anaerobic which means they don’t require oxygen.
They also don’t require organic and are non-photosynthetic, all indicating that they could successfully survive on Mars.
So the answer is no, humans can’t live on Mars at the moment. But it is possible that Mars could support life one day, whether this is microorganisms, plants, or humans. It won’t be in our lifetime, or even the next generation’s lifetime, but perhaps humans will one day live on Mars.