The Challenging Task of Terraforming Mars
Almost every science fiction story revolves around the idea of terraforming Mars, the process of making the planet more habitable. However, due to its extremely cold temperatures, distance from the sun, and abundance of dust, transforming Mars into an Earth-like planet is much more difficult than it appears.
Mars: A Once-Livable World
Billions of years ago, Mars had a thick atmosphere rich in carbon, lakes and oceans of liquid water, and possibly even fluffy white clouds. This was during a time when our sun was smaller and more volatile than it is today. Despite these favorable conditions for life, Mars is now a barren, red planet.
Unfortunately, Mars was doomed from the start. Being smaller than Earth, it cooled off at a much faster rate. Unlike Mars, the core of our planet remains molten, generating a strong magnetic field that shields us from the solar wind, a continuous stream of high-energy particles emitted by the sun.
As Mars cooled, its core solidified, causing its magnetic field to dissipate. Without this protective shield, the Martian atmosphere became susceptible to the solar wind. Over the course of approximately 100 million years, the solar wind stripped away Mars’ atmosphere. As a result, the air pressure dropped to near-vacuum, causing the oceans on the surface to evaporate and the planet to dry up.
The fact that Mars was once similar to Earth makes the idea of restoring it even more tantalizing. Is there any way to bring back its former glory?
The Possibility of Warming Mars’ Polar Caps
Fortunately, humans have unintentionally warmed up Earth through carbon emissions, primarily due to the greenhouse effect. Carbon dioxide, which permits sunlight to enter while preventing thermal radiation from escaping, acts as a massive invisible blanket over Earth. This increased heat prompts moisture to leave the oceans and become vapor in the atmosphere, resulting in a further increase in temperature.
If this mechanism works on Earth, it might also work on Mars. Although we can’t access Mars’ original atmosphere, the planet does possess significant deposits of water ice and frozen carbon dioxide in its polar caps and beneath the surface.
If we could find a way to warm these caps, it might release enough carbon into the atmosphere to initiate a greenhouse warming trend. Then, we would only need to sit back, be patient, and let physics gradually turn Mars into a less inhospitable place.
Unfortunately, this seemingly straightforward idea is unlikely to succeed.
The first hurdle to overcome is developing the technology to warm the polar caps. Proposed solutions range from sprinkling dust across the poles to decrease reflectivity and increase warmth, to constructing a giant space mirror to focus sunlight onto the caps. However, all these ideas require significant advancements in technology and an extensive manufacturing presence in space, well beyond our current capabilities.
Even if we manage to address the technological challenges, there still remains a critical problem. Mars lacks sufficient carbon dioxide to trigger a substantial warming trend. Currently, the planet’s air pressure is less than 1% of that at sea level on Earth. Even if we were to release every molecule of carbon dioxide and water vapor on Mars into the atmosphere, it would only amount to 2% of Earth’s air pressure. To reach a comfortable level that would prevent sweat and skin oils from boiling, we would need twice as much atmosphere. Moreover, a pressure suit would still be necessary for survival.
The scarcity of oxygen on Mars is yet another significant obstacle.
To counter the lack of easily accessible greenhouse gases, radical proposals have been suggested. Some suggest creating factories dedicated to producing chlorofluorocarbons, a potent greenhouse gas. Others propose introducing ammonia-rich comets from the outer solar system. Ammonia acts as an effective greenhouse blanket and eventually breaks down into harmless nitrogen, which constitutes the majority of Earth’s atmosphere.
However, even if we manage to overcome the technological challenges associated with these proposals, there is still one major hurdle: the absence of a magnetic field. Without protection from the solar wind, any molecules we introduce into the Martian atmosphere would be blasted away. Like attempting to construct a pyramid using desert sand, this is an extremely difficult task.
Various creative solutions have been suggested, such as building a gigantic electromagnet in space to deflect the solar wind or encircling Mars with a superconductor to create an artificial magnetosphere. Unfortunately, we currently lack the necessary expertise to realize these solutions. Although it is theoretically possible to terraform Mars and make it more habitable, it is not something we should expect to happen anytime soon.
Transforming Mars into a livable planet is an aspiration shared by many. However, the process of terraforming Mars is fraught with challenges and obstacles that make it far more arduous than it initially appears. While there are potential strategies to warm the planet and create a more hospitable environment, the technological limitations and the lack of crucial resources, such as sufficient greenhouse gases and a magnetic field, hinder our progress. Although it is theoretically possible to make Mars more habitable, achieving this will require significant advancements in technology and an unwavering commitment to exploration and scientific innovation.
To learn more about terraforming Mars and the possibilities it holds, listen to the episode “Could we really terraform Mars?” on the Ask A Spaceman podcast, available on iTunes and on the web at http://www.askaspaceman.com. If you have any questions of your own, you can ask them on Twitter using the hashtag #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter.