Ever since Galileo discovered that Earth was just one of many planets revolving around the Sun, humanity has been wondering whether Earth is the only inhabitable planet in the Universe or not. In the 21st century, this question is not idle curiosity. Humanity has a vast interest in finding and studying extraterrestrial lifeforms. Seager’s equations state that there are significant changes in finding alien lifeforms in relatively close proximity to Earth (Maccone 278).
We will write a custom Essay on Discovering Live on Other Planets Before 2050 specifically for you
301 certified writers online
At least 20% of known exoplanets are located within the “comfort zone” of their stars and have a rock-based structure, meaning they could potentially serve as homeworlds for extraterrestrial species (Han 828). However, planets and moons located in less hospitable environments be that increasingly high temperature or permafrost, are still capable of carrying life. Some of the Earth-based organisms, called extremophiles, are incredibly resilient, capable of surviving harsh environments and even radiation. The purpose of this paper is to analyze Titan’s potential as a life carrier and make suggestions and estimations regarding the upcoming mission to the moon’s surface.
The Most Likely Place Life will be Found on is Titan
Titan is the largest moon of Saturn. It was discovered by a Dutch astronomer Christiaan Huygens in 1655 (McKay 1). The distance between Earth and Titan is 1.4 billion kilometers, which is why it took approximately 3-4 years for Voyager 1 and Voyager 2 to reach the moon. Due to a series of planetary features unique to Titan, it is considered to be one of the most likely locations to contain life.
Titan’s diameter is approximately 1.48 times larger than that of Earth’s moon and more than two times larger in terms of surface area. It possesses a dense nitrogen-rich atmosphere, thus being the only stellar body aside from Earth to possess a layer of gasses above the surface of the moon. According to recent observations, the chemical composition of Titan’s atmosphere consists of nitrogen (97-98%), hydrogen (2%+- 0.1%), and hydrogen (0.1%-0.2%) (McKay 3).
Trace amounts of various other gaseous elements have also been detected. The upper layers of Titan’s atmosphere are filled with the results of methane breakdown under the influence of ultraviolet, the resulting clouds helping shield the planet from radiation and solar wind. It is likely for the planet to have a large source of methane either on or under its surface in order to replenish the element in the atmosphere.
Due to its thick atmosphere in combination with large distances from the Sun and close proximity to Saturn, the surface of the planet is very cold. Average temperatures vary between 170-180 degrees Celsius because 90% of the Sun’s energy is mirrored back into space by thick smog found in the upper atmosphere (McKay 4). At the same time, the atmosphere causes a greenhouse gas effect, which helps retain some of the warmth that manages to get through to the surface of the moon. Without it, Titan would have been much colder. These extreme temperatures rule out the existence of Earth-based life on Titan.
The moon’s surface has clear processes of natural erosion and stable bodies of liquid methane and ethane, which is something no other moon or planet in the Solar System has. It is covered with crystallized water taking the shape of dust, small stones, and pebbles. This water was likely thrust towards the surface as a result of cryovolcano eruptions caused by Saturn’s gravity. There is evidence of large underground oceans located underneath the moon, where water can exist in liquid form.
There are several reasons why Titan is to be considered the most perspective world to explore for new lifeforms. The first reason is the number of organic chemicals present in the atmosphere. Ethane, methane, carbon monoxide, nitrogen, hydrogen, and many others make up the building blocks, out of which new lifeforms could be born into existence (Dohm and Maruyama 99). The presence of an atmosphere, in general, is a very important feature – without it, the planet’s surface would be irradiated and incapable of containing any meaningful sources of gases or surface liquids. Although low temperatures would present a threat to any lifeforms that use water as a solvent to facilitate metabolism processes, it would not be a detriment for organisms reliant on liquid methane or ethane.
Another argument to be made for Titan in comparison to other planets in the Solar system lies in the presence of water. There is enough evidence to support the existence of large sources of water underneath the surface of the planet. Water is being released from various cryovolcanoes on the surface of the planet, in liquid form (Dohm and Maruyama 96). It indicates that the core of the moon and the distance from permafrost above keep water in liquid form, which makes the existence of water-based life similar to that on Earth possible. One of the largest obstacles to that theory is the saline nature of underwater oceans due to proximity with various minerals found in its soil as well as the lack of sunlight to initiate certain kinds of metabolism.
Another reason why Titan is the best place to find proof of life is that there are chances for it to still exist and even thrive either on the surface or underneath it. Candidates like Venus and Mars have conditions far more hostile than those of Titan, as Mars is irradiated and Venus’s close proximity to the Sun means the surface is extremely hot, with average temperatures varying between 450-500 degrees Celsius (McKay 9).
Even if life existed on these planets at some point, the chances of finding any evidence of it are slim, as the planets are exposed to hostile elements, radiation, and meteor showers from outer space. Titan, on the other hand, is relatively safe from these influences due to close proximity to Saturn, which acts as a shield from the Sun, whose light would have otherwise caused methane to transform into complex organic elements and negatively influence the moon’s atmosphere. Saturn’s gravity field also attracts the asteroids that could have otherwise hit Titan.
The last argument for choosing Titan as a possible location for space exploration is connected to economic profitability. Even if the mission does not find any signs of life on Titan, it still represents a vault of valuable natural resources, such as oil and gas. Current estimations state that the amount of hydrocarbons on Titan exceeds Earth’s total supply by at least ten times (Badescu and Zacny 34). Although it is possible that by the time any commercial extraction of resources from Titan would be possible, humanity would transcend to renewable and more efficient sources of energy, oil and gas can be used for the production of other materials, such as plastics, which are widely used in production.
Therefore, it would be easier to find supporters and investors for NASA’s expedition, as the exploration of Titan would not only bring about the enrichment of existing knowledge of extraterrestrial life, but also long-term profit and sustenance for humanity. As it stands, automated missions can reach Titan in only 3-4 years (Badescu and Zacny 71). It is likely for human technology to improve by the year 2050 and enable much faster and more reliable flights. These trends would make missions to Saturn’s largest moon more viable. Discovering new lifeforms would significantly boost our understanding of the mechanisms behind the evolution of life, likely leading to a greater understanding of astronomy, biology, and medicine.
The Most Likely Life Form We Would Find on Titan are Extremophiles and Methane-Based Organisms
Although Titan does offer the best bet of finding life in our Solar system, it is far from being a perfect place. Extremely low temperatures at the surface and high levels of salinity of its underwater oceans suggest that whatever life could exist in these conditions would have to be extremely resilient to these conditions. Observations of Earth-based extremophiles and theoretical knowledge of life form creation suggests only two possible variants for life on Titan to exist: either as extremophiles underneath the surface of the moon, living in complete darkness in its hypersaline oceans, or as surface-based lifeforms.
Get your first paper with 15% OFF
One potential way for life to exist on the surface of Titan involves a methane-based life, which would use methane either as a solvent or as a material for biogenic membranes of cells and microorganisms (Lai et al. 7025). These creatures should be capable of living under the conditions of permafrost without suffering from extremely low temperatures. Another obstacle in the path of life existing on Titan includes limited resources available for growth and sustenance. Energy sources on Titan are very scarce due to a lack of warmth and sunlight as well as organic ways of supply, meaning that whatever organisms may inhabit it would have to be extremely efficient in spending their energy and extracting it through alternative biochemical processes.
Extremophiles present on Earth are viewed by many researchers in the fields of astronomy and biology as potential blueprints for lifeforms on other planets. Despite Earth being relatively benign in terms of climate when compared to Titan or Venus, there are still places where temperatures are significantly higher or lower than the median norm.
For example, the highest temperature on Earth (58 degrees Celsius) was observed in the Libyan Desert, whereas the lowest peak (-88 degrees Celsius) was found in Antarctica, recorded by the Vostok Station (Fendrihan 147). Some lifeforms are capable of existing in these extremities. One such creature is the Tardigrades, which can survive temperatures of up to -272 degrees Celsius, hot temperatures of up to 300 degrees Celsius, high pressures, lack of sustenance, and ionizing radiation (Fendrihan 147).
Another form of life likely to survive in the hypersaline underground oceans of Titan is halophilic bacteria. These organisms are capable of astounding feats of resilience, surviving in waters that are approaching the barrier of full salt saturation. They also fit several other criteria that are required for survival on Titan. According to King (4465), extremely halophilic organisms possess some of the following abilities that ensure their survival:
- CO as an energy source. It is a known fact that there are deposits of CO gas underneath the surface of Titan. Some halophilic organisms can use it to facilitate cellular metabolism, thus not requiring oxygen to do so.
- High-temperature resistance. Most halophilic organisms live in hot areas, with high levels of water evaporation. Such location includes various saline lakes in Australia as well as the Dead Sea in the Middle East.
- Resistance to radiation. Various laboratory tests have proven that halophilic organisms can survive exposure to radiation.
Most of these conditions can be applied to projections of the environment underneath Titan’s surface. With close proximity to the planet’s core, it is likely for temperatures to rise up to 60 degrees Celsius. High levels of salinity would ensure that the water is uninhabitable for most other microorganisms, but would make a perfect environment for halophilic bacteria. Lastly, the sources of CO and methane are coming from underneath the planet’s surface. These elements would provide the lifeforms with sources of energy needed for the continuation of existence. Consequently, some of the halophilic microorganisms are also lithotrophic, meaning they could use sulfur and other minerals as energy sources. This further increases the chances of survival of certain kinds of bacteria.
There are also theoretic possibilities of encountering methane-based lifeforms on the surface of the planet. The article by Lai et al. (7026) indicates that it is possible for naturally occurring methane reactions to form biofilm membranes. The biological membranes of Earth organisms are formed by phospholipids. They play an important part in cell adhesion, electron connectivity, and cell signaling. In addition, they protect the organelles of cells from damage and control the passage of elements in and out of the cell. These are some of the core functions found even at the simplest levels of cellular organization.
It is theorized that methane-based membranes could perform similar functions, thus making the existence of life possible even in permafrost. Methane’s boiling point is at -161.5 degrees Celsius, meaning that at Titan’s natural -180 degrees Celsius it is unlikely for methane-based life to vaporize. It is possible for these organisms to exist even in bodies of liquid methane, assembling around sources of nitrogen exiting from underneath the planet’s surface, similar to how methane-consuming microorganisms could be found at the bottom of ocean floors on Earth. However, high atmospheric pressure may have the potential of turning methane into ice.
As is known from chemistry, methane is more sensitive to pressure than to temperature in terms of solidifying itself into ice (Lai et al. 7031). However, considering that methane exists in a liquid state at the surface of the planet, it is unlikely for pressure to cause such adverse reactions. The existence of stable bodies of liquid is one of Titan’s peculiarities, which makes it similar to Earth.
Thus, we have two potential models of life existing on the surface and underneath it. Halophilic bacteria can exist in the saline oceans of Titan, whereas theorized methane-based lifeforms could be found on the surface. The abundance of nitrogen and nitrogen-based compounds could serve as a source of energy to these creatures, in addition to methane and ethane also found on the surface. Neither of these lifeforms would be able to survive in environments not suited for them, as the underground would be too hot for methane-based bacteria, and the upper side would be too cold for halophilic bacteria. Nevertheless, exploring the surface should lend results about both types of creatures, as it would be possible to study the flash-frozen remains of underground bacteria ejected to the surface through cryovolcanoes.
What We Would Need to Explore This World Is Various Unmanned Drones
As it stands, our telescope technology told us all that could be visually known about the surface of Titan from a distance. However, much of what lies underneath the foggy atmosphere is concealed from us. In order to thoroughly explore Titan and its depths, all kinds of robotic equipment may be utilized. Titan offers a variety of environments that would not be suitable for an all-terrain-type vehicle used to explore Mars.
Therefore, there are three types of drones necessary for properly exploring the outsides and insides of the moon. The first type is an aerial drone. Since the atmosphere on Titan is thicker than that of Earth, in combination with lower gravity, an aerial drone would be able to perform well, traveling over the surface unhindered (Badescu and Zacny 59). It would enable advanced topography of the moon as well as supervision of naturally-occurring events, such as cryovolcano eruptions, methane river movements, cyclones, and other interesting events. The first mission to Titan must include this drone, as it would enable us to plan out future missions by creating accurate maps and recordings of the moon’s surface from above.
The second type of drone to participate in the expedition would be an all-terrain drone. Being capable of crossing various obstacles is paramount for the long-term maintenance of the expedition (Badescu and Zacny 55). The purpose of this drone would be to collect and analyze samples, take pictures, and search for signs of microscopic life in ground probes. It could also explore the blocks of ice launched from cryovolcanoes, as they could contain remains of life hidden underneath the surface. It is unlikely for human technology to allow for drilling operations on Titan by the end of 2050, so the researchers would have to rely on these emissions as primary sources of knowledge.
The last type of drone to be used in an expedition to Titan would need to be an aquatic drone. Namely, it should be able to explore the bodies of liquid methane found on the surface of the planet (Badescu and Zacny 53). There is a potential for methane-based organisms living in these natural sources of organic gasses. These machines would be capable of taking samples of methane and ground samples from the bottom, analyzing them, and transmitting reports of findings back to Earth. However, this drone would be highly specialized, thus not as important as aerial or all-terrain machines.
There are several demands towards research drones. The first and crucial demand is that they have to be autonomous. Radio commands take too much time to travel, and laser-guidance would be unavailable due to Titan’s thick atmosphere. Therefore, these machines would be required to make decisions on their own and perform their activities without the need for human input. The second demand is resilience and reliability. The machines would need to be able to operate in extremely low temperatures. The first land-based mission to Titan, the Huygens, went dark after only 90 minutes of operational time due to a malfunction. In order to extract any valuable data, it would require months of active operational time.
Titan is the most likely place in the Solar system to contain life. The combination of location, natural resources, and geology make it possible for not one, but two forms of life to potentially existing on and underneath its surface. In addition, exploring Titan would bring economic profit in the long-term perspective and further humanity’s advancements into space. In order to properly explore Titan, telescopic observations would not be enough.
Aerial, all-terrain, and aquatic drones will be used to provide knowledge of the Titan’s surface and depths. This endeavor has the potential to discover extraterrestrial life. Chances of finding it on Titan are higher when compared to Mars, Venus, Uranus, and other planets and moons in the Solar system.
Badescu, Viorel, and Kris Zacny. Inner Solar System: Prospective Energy and Material Resources. Springer, 2015.
Dohm, James, and Shigenori Maruyama. “Habitable Trinity.” Geoscience Frontiers, vol. 6, no. 1, 2015, pp. 95-101.
Fendrihan, Sergiu. “The Extremely Halophilic Microorganisms, a Possible Model for Life on Other Planets.” Current Trends in Natural Sciences, vol. 6, no. 12, 2017, pp. 147-151.
Han, Eunkyu, et al. “Exoplanet Orbit Database. II. Updates to Exoplanets.org.” Publications of the Astronomical Society of the Pacific, vol. 126, no. 943, 2014, pp. 827-837.
King, Gary M. “Carbon Monoxide as a Metabolic Energy Source for Extremely Halophilic Microbes: Implications for Microbial Activity in Mars Regolith.” PNAS, vol. 112, no. 14, 2015, pp. 4465-4470.
Lai, Chun-Yu et al. “Bromate and Nitrate Bioreduction Coupled with Poly-β-hydroxybutyrate Production in a Methane-Based Membrane Biofilm Reactor.” Environmental Science and Technology, vol. 52, no. 12, 2018, 7024-7031.
Maccone, Claudio. “Statistical Drake-Seager Equation for Exoplanet and SETI Searches.” Acta Astronautica, vol. 115, 2015, pp. 277-285.
McKay, Christopher. “Titan as the Abode of Life.” Life, vol. 6, no. 1, 2016, pp. 1-15.