Introduction
While growing up, our family camping trips were often without tents, lying under the open sky. Those nights, gazing at the stars, sparked my curiosity about the cosmos and the possibility of extra-terrestrial life. This sense of wonder has persisted into my adulthood, deepening as I’ve learned more about the vastness of outer space, and the ongoing search for extra-terrestrial life. Are we alone in the universe? This question has fascinated humanity for centuries, driving both ancient myths and modern scientific inquiry.
The potential for life beyond Earth challenges our understanding of biology, the cosmos, and our place within it. It’s a topic that ignites the imagination, inspiring countless works of fiction, from H.G. Wells’ War of the Worlds to Star Trek. Beyond the realms of fiction, the scientific pursuit of extra-terrestrial life is very real and based on systematic research.
This exploration also addresses philosophical questions. Discovering extra-terrestrial life would have significant implications, transforming our understanding of biology, evolution, and our place in the universe. It would provoke deep questions about the uniqueness of human life.
In this blog post, we will examine the historical context of humanity’s fascination with extra-terrestrial life. We will discuss the complexities of defining what life is. We will look at potential habitats within our solar system where life might exist. Additionally, consider life on exoplanets, planets outside our solar system. Our focus will be on those located in the “Goldilocks Zone” where conditions might be just right for life. Moreover, we will discuss ongoing efforts to detect intelligent life beyond Earth. This includes the work of the Search for Extra-Terrestrial Intelligence (SETI).
The Historical Context
Ancient Beliefs and Myths
Ancient civilizations were fascinated by the possibility of extra-terrestrial life, a curiosity that continues today. Many cultures imagined the heavens populated by gods, spirits, and otherworldly beings. The ancient Greeks, for instance, believed in a cosmos filled with deities and mythological creatures inhabiting the stars and planets. Plato and Aristotle speculated about the existence of other worlds, though they differed on the details. Similarly, Hindu scriptures speak of numerous worlds (lokas) inhabited by various beings, suggesting a universe teeming with life.
In ancient Egypt, the sky was seen as a realm of gods, with each star representing a deity. Native American cultures often depicted star beings in their folklore, attributing certain constellations to mythological figures and stories. These early beliefs and myths illustrate a deep curiosity about the cosmos and the potential for life beyond our planet.
Early Scientific Speculation
The Renaissance period marked a significant shift from mythological to scientific inquiry regarding extra-terrestrial life. Key figures in this transformative era began to view the universe through the lens of observation and reason, laying the groundwork for modern science.
Giordano Bruno, an Italian philosopher, proposed radical ideas for his time. In the late 16th century, Bruno suggested that the stars were distant suns surrounded by their own planets, some of which could harbor life. His assertion challenged the geocentric model that placed Earth at the center of the universe and led to his execution for heresy.
Galileo Galilei, often hailed as the father of modern astronomy, made significant contributions to the heliocentric model. Using his improved telescope, Galileo observed moons orbiting Jupiter and phases of Venus. This provided compelling evidence that not all celestial bodies revolved around the Earth. Although Galileo did not directly speculate about extra-terrestrial life, his discoveries expanded the scope of the known universe. His work opened the door to considering other planets as potential habitats for life.
Johannes Kepler, a contemporary of Galileo, also speculated about life on other planets. Kepler’s laws of planetary motion described the orbits of planets around the sun with unprecedented accuracy. He imagined intelligent beings on the moon and other planets, driven by the belief that the vast universe must hold diverse forms of life.
These early scientific speculations laid the foundation for modern astrobiology and the ongoing search for extra-terrestrial life. They shifted the discussion from mythological realms to observable, testable phenomena, paving the way for the systematic exploration of our cosmos. Reading about these early scientific speculations, I can’t help but feel a connection to these great thinkers. Their willingness to challenge established beliefs and explore new ideas resonates with my own curiosity about the universe.
What is Life?
The Difficulty of Defining Life
When pondering the mysteries of the universe my mind immediatly goes to Douglas Adams. In his book The Hitchhiker’s Guide to the Galaxy, the answer to the ultimate question of life, the universe, and everything is a simple yet cryptic “42.” However, the catch is that no one actually knows the question. This enigmatic answer leaves us pondering: could the question be as fundamental as “What is life?”
As we venture into the realm of defining life, we find ourselves grappling with concepts that stretch the boundaries of our understanding. I find it exciting to think about how diverse and unexpected extraterrestrial life forms might be. However, this potential makes defining life a complex task with significant implications for astrobiology. By adopting a flexible and inclusive definition, we enhance our chances of discovering and understanding life beyond our planet.
Traditional definitions for life emphasize characteristics like metabolism, homeostasis, growth, reproduction and response to stimuli. These criteria can help guide our search by identifying key characteristics that living systems on Earth exhibit.The difficulty with these criteria, however, is that they leave room for ambiguity. For instance, viruses are obviously biological entities, made of genes and proteins. However, they lack a cellular structure, independent metabolism, and although they can reproduce, this function requires the host cell. These caveats make their status as living organisms debatable. The point is, if we only search for entities that meet the above criterion, certain prospective forms of life that fail to do so may be overlooked.
Aware of these limitations, NASA proposed working definition of life life as “a self-sustaining chemical system capable of Darwinian evolution.” highlighting the dynamic and adaptive nature of living systems. This broader definition allows for a more inclusive approach, increasing the likelihood of recognizing life in its many potential forms. But would viruses and other parasites be included in this definition? They certainly evolve, but they rely on their hosts to sustain themselves, so perhaps not.
A Novel Approach: Life is Complicated
Scientists Leroy Cronin of the University of Glasgow, and Sara Imari Walker at Arizona State University have proposed a new way to define extraterrestrial life: by measuring molecular complexity. This method is based on assembly theory, which posits that the complexity of a molecule can be quantified by considering the number of steps required to assemble it from basic building blocks.
Assembly theory suggests that living systems are characterized by a higher degree of molecular complexity compared to non-living matter due to the elaborate processes involved in their formation. This innovative approach provides a new way of defining life by focusing on the inherent complexity of molecular structures. It moves beyond traditional methods that often rely on specific biochemical markers, which may not be universal to all forms of life. Instead, it offers a more generalized and potentially more accurate means of detecting life by assessing the assembly pathways of molecules.
By leveraging this theory, the goal is to identify molecules with high assembly numbers. This indicates a high level of complexity associated with biological origin. This advancement holds promise for future astrobiological missions, enhancing our ability to recognize life in various forms and environments across the universe. However, I’m still not sure how the number 42 fits in. Just saying : )
Biosignatures as Signs of Life
In addition to molecular complexity per se, Biosignatures are specific indicators suggestive of life. These include chemical compounds, elements, or structures that are typically associated with biological processes. For example, the presence of oxygen, methane, or phosphine in an exoplanet’s atmosphere may indicate biological activity, as these gases are often produced by living organisms. Researchers are developing advanced instruments to detect these biosignatures on other planets and moons. The discovery of such signs would be a significant step forward in confirming the possibility of extra-terrestrial life.
Possible Places for Life in Our Solar System
As we extend our search for extra-terrestrial life beyond Earth, our solar system offers several intriguing locations where life might exist. From planets to moons, these celestial bodies present unique environments that could harbor alien forms that are relatively accessible. This possibility has helped to drive numerous scientific missions. Here, we will explore five key locations that have captured the attention of scientists and continue to inspire the quest for discovering life beyond Earth.
Mars
Mars has long fascinated scientists as a potential site for extraterrestrial life. The planet’s surface is etched with dried-up riverbeds, deltas, and ancient lake basins, which clearly indicate that water once flowed abundantly across this now barren world. Since water is a critical component for life as we understand it, this evidence has fueled speculation about Mars’ potential to have once harbored life. However, about 3.5 billion years ago, Mars underwent a drastic climate shift that removed much of its surface water, leaving the planet dry and inhospitable.
While the surface of Mars today is harsh—dry, cold, and seemingly lifeless—recent research offers new perspective. Data from NASA’s InSight lander suggests that a massive underground reservoir of water might still exist. This reservoir, trapped within fractured igneous rock miles beneath the surface, could potentially cover the entire planet in a mile of water if it were accessible. Although reaching this water with current technology is not yet possible, it presents a promising target for future searches for life.
Adding to the intrigue, methane plumes detected in Mars’ atmosphere hint at the possibility of life. On Earth, methane is often produced by microorganisms, suggesting that similar processes might be occurring on Mars. However, it’s important to note that non-biological processes could also explain these findings, which means the search for definitive evidence of life continues.
In another exciting development, NASA’s Perseverance Rover recently discovered a rock, named “Cheyava Falls,” that could hold clues to ancient life on Mars. This rock, with its large white veins and reddish bands, shows signs of past water activity. What’s particularly intriguing are the off-white spots surrounded by black material found within the rock. On Earth, similar patterns are often linked to microbial activity. While more research is necessary to confirm this, Cheyava Falls adds another piece to the puzzle in the ongoing quest to determine whether Mars once supported life.
Europa
Europa, one of Jupiter’s largest moons, is another promising candidate for the possibility of extra-terrestrial life. Beneath its icy crust lies a vast subsurface ocean, kept liquid by the moon’s internal heat. Scientists believe that hydrothermal vents on Europa’s ocean floor could provide the necessary energy and nutrients to support life, similar to those found in Earth’s deep oceans. The upcoming Europa Clipper mission aims to further investigate these possibilities, focusing on the moon’s ice shell and subsurface ocean. Detecting biosignatures such as water vapor plumes containing organic molecules could be key indicators of life.
Enceladus
Saturn’s moon Enceladus has captured the attention of the scientific community with its dramatic geysers that eject water vapor and organic molecules into space. These geysers suggest the presence of a subsurface ocean, which could be a potential habitat for life. The Cassini spacecraft’s flybys through these plumes have detected complex organic compounds, further supporting the idea that Enceladus might host microbial life. The search for biosignatures like amino acids or other organic molecules in the plumes continues to excite scientists about the possibility of extra-terrestrial life in such an unexpected place.
Titan
Saturn’s largest moon, Titan, offers a unique environment that could support alternative forms of life. Titan has a thick atmosphere rich in nitrogen and methane, and its surface features lakes and rivers of liquid methane and ethane. These conditions suggest that life, if it exists on Titan, might be based on biochemistry different from that of Earth. The Dragonfly mission, scheduled to launch in the mid-2020s, will explore Titan’s surface to study its chemistry and search for signs of life. Detecting biosignatures such as complex organic molecules in Titan’s atmosphere and surface could provide evidence of life with a completely different biochemical makeup.
Venus
Despite its harsh surface conditions, Venus has recently emerged as a possible location for extra-terrestrial life. In 2020, scientists announced the detection of phosphine gas in the upper atmosphere of Venus, a compound that on Earth is associated with biological processes. This finding has sparked renewed interest in the possibility of microbial life existing in the temperate cloud layers of Venus, where temperatures and pressures are more hospitable. The detection of biosignatures like phosphine challenges our understanding and expands the scope of our search for life.
Exploring these diverse environments within our solar system underscores the vast potential for discovering extra-terrestrial life. Each of these celestial bodies presents unique conditions that could support life, reminding us of the incredible variety of possibilities that exist beyond our planet.
The Search for Habitable Planets Outside our Solar System
Looking for Exoplanets
We have extended the search for extra-terrestrial life to the vast expanse of the Milky Way galaxy, where countless exoplanets (planets outside our solar system) orbit distant stars. Discovering these exoplanets and determining their potential to support life is a major focus of modern astronomy.
Two primary methods have been instrumental in these discoveries: the transit method and radial velocity. The transit method detects exoplanets by measuring the slight dimming of a star’s light as a planet passes in front of it. By observing these transits, scientists can determine the planet’s size, orbit, and sometimes even its atmospheric composition. The transit method has been particularly successful, leading to the discovery of thousands of exoplanets.
Radial Velocity is a technique that measures the wobbling motion of a star caused by the gravitational pull of an orbiting planet. As the planet orbits, it causes the star to move slightly, which can be detected through shifts in the star’s spectral lines. This method helps determine the planet’s mass and orbit, providing crucial information about its potential habitability.
I find it astonishing that we are able to detect these extremely subtle properties of stars, allowing us to identify planets light-years away.
The Goldilocks Zone
The “Goldilocks Zone,” or habitable zone, refers to the region around a star where conditions are just right for liquid water to exist on a planet’s surface. This zone is crucial in the search for extra-terrestrial life because water is considered essential for life as we know it. Planets within this zone are neither too hot nor too cold, making them prime candidates for further study.
The concept of the habitable zone emphasizes the importance of a planet’s distance from its star. For instance, Earth resides comfortably in the Sun’s habitable zone, allowing for stable bodies of liquid water. Identifying exoplanets in similar zones around other stars increases the chances of finding life-supporting conditions.
Kepler and TESS Missions
The Kepler and TESS missions have been groundbreaking in the hunt for exoplanets, particularly those in the habitable zone. Kepler was a space telescope launched in 2009, designed to find Earth-sized planets in the habitable zones of their stars. Kepler used the transit method to monitor over 150,000 stars in a single field of view.
By detecting the periodic dimming of these stars, Kepler identified more than 2,600 confirmed exoplanets. Many of these are located in their star’s habitable zone, significantly boosting our understanding of the universe’s potential to support life. The mission’s success was due to its highly sensitive onboard telescope, which could detect minuscule changes in star brightness caused by transiting planets.
The Transiting Exoplanet Survey Satellite (TESS), launched in 2018, continues Kepler’s legacy with a focus on bright, nearby stars. Unlike Kepler, which observed a fixed field of stars, TESS surveys nearly the entire sky in search of transiting exoplanets. TESS’s wide-field cameras enable it to monitor large sections of the sky, allowing it to discover smaller planets around the nearest stars.
By observing the transit of planets across their host stars, TESS has identified numerous exoplanet candidates, some of which lie in the habitable zones of their stars. TESS’s onboard telescopes are optimized to detect these transits, providing a treasure trove of data for follow-up observations.
The contributions of Kepler and TESS missions provide a wealth of data helping scientists identify and study potentially habitable exoplanets. The possibility of extra-terrestrial life becomes more tangible with each new discovery, fueling our quest to find life beyond Earth.
The Contribution of the Webb Telescope
Launched in December 2021, the JWST is designed to peer deeper into space and provide unprecedented clarity in its observations. One of its primary missions is to study the atmospheres of exoplanets in the habitable zone.
The JWST’s ability to analyze atmospheric composition with precision is a significant advancement over previous telescopes. It provides critical data that could confirm the habitability of these distant worlds. Equipped with advanced instruments like the Near Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI), the JWST can detect faint molecular signatures. These capabilities allow scientists to identify key biosignatures, such as water vapor, methane, and oxygen. These could indicate the presence of life.
The JWST can also help us understand the formation and evolution of planetary systems. By studying young star systems and their protoplanetary disks, the JWST provides insights into the processes that lead to planet formation. This information will help us identify the characteristics that make a planet habitable.
Promising Exoplanets for the Possibility of Life
In the vast expanse of the Milky Way, numerous exoplanets have been discovered that exhibit promising possibilities for supporting life. These planets, located within their star’s habitable zone, have conditions that could allow for the presence of liquid water—a crucial ingredient for life as we know it.
Proxima Centauri b
One of the most exciting discoveries is Proxima Centauri b, an exoplanet orbiting the star Proxima Centauri. This star is part of the Alpha Centauri system. Located about 4.37 light-years away, it is the closest star system to Earth. Proxima Centauri b resides in the habitable zone of its star, meaning it could have liquid water on its surface. It orbits very closely, resulting in a shorter orbital period than Earth. However, its habitable zone position makes it a prime candidate for study. Scientists are particularly interested in its atmosphere and surface conditions to determine its potential for supporting life.
TRAPPIST-1 System
The TRAPPIST-1 system, located about 39 light-years away, has garnered significant attention due to its seven Earth-sized planets. Four of these planets—TRAPPIST-1d, TRAPPIST-1e (the featured image of this post), TRAPPIST-1f, and TRAPPIST-1g—may be located within the habitable zone. These planets have densities similar to Earth’s, suggesting that they could have rocky surfaces and potentially hold water. The TRAPPIST-1 system provides a unique opportunity to study multiple potentially habitable worlds within a single star system, increasing the chances of finding conditions suitable for life.
Kepler-452b
Kepler-452b, often referred to as Earth’s “cousin,” is another fascinating exoplanet. Located about 1,400 light-years away, Kepler-452b orbits within the habitable zone of a star very similar to our Sun. It is about 60% larger than Earth, making it a super-Earth. Its orbit around its star is also similar to Earth’s, taking 385 days to complete. The similarity of Kepler-452b’s star to our Sun and its location in the habitable zone make it one of the most promising candidates for hosting life.
LHS 1140 b
LHS 1140 b, located about 40 light-years away, is a super-Earth exoplanet that lies in the habitable zone of its red dwarf star. What makes LHS 1140 b particularly intriguing is its density, which suggests it has a large, rocky composition. Moreover, its host star emits lower levels of radiation compared to other red dwarfs, potentially creating a more stable environment for life. The combination of its size, composition, and stellar environment makes LHS 1140 b a compelling target for further investigation.
These exoplanets, with their diverse characteristics and promising conditions, are at the forefront of our search for extra-terrestrial life. Each discovery deepens our appreciation for the complexity and diversity of planetary systems. As technology advances and exploration continues, finding life on these distant worlds remains an exciting prospect in modern science.
Future Missions and Probes
Scientists have entertained the possibility of sending space probes to promising exoplanets we identify. Such missions would be monumental undertakings, requiring advancements in technology and propulsion. These probes would need to travel at a significant fraction of the speed of light to reach their destinations within a reasonable timeframe. Concepts like Breakthrough Starshot aims for a 20-year travel time to Alpha Centauri. This would be done by sending small, lightweight probes propelled to high speeds using powerful lasers.
Once these probes reach their targets, they would collect data on the exoplanet’s atmosphere, surface conditions, and potential biosignatures. They would send this information back to Earth. The data gathered could provide invaluable insights into the habitability of these distant worlds. This would bring us closer to confirming the existence of extra-terrestrial life.
SETI (Search for Extra-Terrestrial Intelligence)
The Search for Extra-Terrestrial Intelligence (SETI) may be the most captivating aspects of the quest for extra-terrestrial life. Organizations and scientists worldwide are dedicated to detecting signals from intelligent civilizations, using a variety of innovative methods and technologies.
SETI is an exploratory science that seeks evidence of life beyond Earth by looking for some signature of its technology. Founded in the 1980s, SETI aims to detect radio signals from distant civilizations. These efforts are based on the assumption that other intelligent beings might use radio waves to communicate, similar to how humans do.
My personal experience with SETI consisted of having the SETI@home program installed on the computers of my grad school lab. This program allowed individuals to donate their computer’s idle processing power to analyze radio telescope data. This distributed computing project, launched in 1999, significantly expanded SETI’s data analysis capabilities. Although SETI@home stopped distributing new work in 2020, its legacy continues to inspire citizen science initiatives.
Radio signals
Radio telescopes are the primary tools used by SETI researchers to listen for signals from space. These telescopes, such as the Arecibo Observatory (before its collapse in 2020) and the Green Bank Telescope, detect and amplify radio waves from distant sources. By scanning the sky, these telescopes collect vast amounts of data. This data is then analyzed for patterns that might indicate intelligent communication.
Radio telescopes work by capturing radio waves and converting them into electrical signals. These signals are then processed to filter out noise and identify potential patterns of interest. The search involves looking for narrow-bandwidth radio signals, which are not known to occur naturally, making them prime candidates for signs of intelligent life.
Optical SETI
In addition to radio waves, scientists also explore the use of optical signals in the search for extra-terrestrial intelligence. Optical SETI involves using lasers and optical telescopes to detect light signals that could be sent by advanced civilizations. Lasers can produce very focused and powerful beams of light, which might be used by intelligent beings to communicate across vast distances.
Optical SETI projects, such as those conducted by the SETI Institute and Harvard University’s Oak Ridge Observatory, look for brief flashes of light (pulses) that stand out from the background noise of stars and galaxies. These pulses could indicate the presence of an advanced technology capable of generating such signals.
The Voyager Probes
The Voyager probes, launched in 1977, carry messages intended for any intelligent beings they might encounter. Each Voyager probe includes a Golden Record, which contains sounds and images from Earth, as well as greetings in multiple languages.
The Golden Records are designed to communicate the diversity of life and culture on Earth. These probes continue to travel through space, currently beyond our solar system, symbolizing humanity’s desire to reach out and connect with other civilizations.
Theoretical Speculation About the Presence of Intelligent Extraterrestrial Life
Fermi Paradox
Despite decades of dedicated searching, SETI has yet to detect any definitive signals from intelligent civilizations. The Fermi Paradox, named after physicist Enrico Fermi, encapsulates the contradiction between the high probability of the existence of intelligent life in the universe and the lack of evidence for, or contact with, such civilizations. Simply put, if there are so many stars and potentially habitable planets, then where is everybody?
Several hypotheses have been proposed to resolve the Fermi Paradox:
- Rare Earth Hypothesis: This suggests that the conditions necessary for life, particularly intelligent life, are extremely rare and that Earth might be one of the few places where life has developed.
- Great Filter: This concept posits that there is a stage in the development of life that is extremely unlikely or difficult to surpass. This filter could be behind us (suggesting life rarely develops beyond a certain stage) or ahead of us (implying that advanced civilizations tend to self-destruct before spreading widely in the galaxy).
The Drake Equation
The Drake Equation, formulated by Dr. Frank Drake in 1961, provides a framework for estimating the number of active, communicative extra-terrestrial civilizations in the Milky Way galaxy. The equation considers several factors, including the rate of star formation, the fraction of those stars with planetary systems, and the number of planets that could potentially support life.
A critical variable in the Drake Equation is the average length of time that intelligent civilizations can communicate. If civilizations tend to self-annihilate through wars, environmental destruction, or other means, their fleeting existence might explain why we haven’t detected them. This key variable highlights the fragility and potential brevity of technological civilizations.
The Dark Forest Hypothesis
Another compelling explanation for the Fermi Paradox is the Dark Forest Hypothesis. This idea, popularized by science fiction author Liu Cixin, suggests that intelligent civilizations are intentionally keeping silent to avoid detection by potentially hostile extraterrestrial beings. In a universe where resources are finite and the intentions of others are unknown, the safest strategy is to remain hidden, much like hunters in a dark forest.
The Dark Forest Hypothesis rests on three assumptions:
- Survival is the primary goal of any civilization: To ensure their survival, civilizations may choose to remain undetectable.
- Lack of trust: Civilizations cannot trust that other civilizations will be friendly. Therefore, broadcasting one’s location could lead to being targeted by others.
- Resource competition: With finite resources available, civilizations may see others as competitors, making secrecy a strategic necessity.
History provides a sobering context for this hypothesis. Throughout human history, encounters between civilizations have often resulted in conflict and exploitation. From the colonization of the Americas to the imperial conquests in Africa and Asia, more technologically advanced societies have frequently subjugated or eradicated those they deemed weaker or less advanced. This historical precedent suggests that extra-terrestrial civilizations might similarly view new contacts with suspicion or hostility, reinforcing the need to stay hidden.
Conclusion
The discovery of extra-terrestrial life would be a watershed moment for humanity, fundamentally altering our scientific, philosophical, and societal landscapes. Scientifically, it would revolutionize our understanding of biology and the universe, opening new avenues for research and technological advancement. Philosophically, it would challenge our perceptions of human identity and our place in the cosmos, prompting deep reflections on the nature of life. Societally, the reactions would be complex, ranging from excitement and wonder to fear and uncertainty, necessitating new policies and international cooperation.
As we continue to explore the cosmos, the possibility of finding extra-terrestrial life keeps us motivated and curious. Each discovery, each mission, and each technological advancement brings us closer to answering one of humanity’s most profound questions: Are we alone in the universe? This quest drives scientific progress, and unites us in a shared journey of exploration and discovery. The potential impact of finding extra-terrestrial life is immense. As we stand on the brink of these discoveries, the future holds endless possibilities.
Additional Materials For Further Study
Books/Blogs/Websites
- SETI Institute – Explore current projects and research initiatives focused on the search for intelligent life.
- NASA Astrobiology – Learn about NASA’s efforts to study the origin, evolution, and distribution of life in the universe.
- Breakthrough Initiatives – Discover the latest in the quest to explore the universe, including Breakthrough Listen and Starshot projects.
- NASA’s Kepler and TESS Missions – Find detailed information on these groundbreaking missions and their discoveries of exoplanets.
- Planetary Society – Engage with a global community dedicated to advancing space exploration and finding life beyond Earth.
- The Fermi Paradox – Wait But Why: The Fermi Paradox – An accessible and engaging explanation of the Fermi Paradox and its implications.
- Astrobiology: The Search for Life Elsewhere in the Universe by Andrew May, Icon Books 2019. A comprehensive book covering the science and the search for extra-terrestrial life.
TED Talks
- “The Search for Planets Beyond Our Solar System” by Sara Seager – Astrophysicist Sara Seager discusses the search for exoplanets and the potential for finding life beyond Earth.
- “How Mars Might Hold the Secret to the Origin of Life” by Nathalie Cabrol An exploration of the possibilities of life on Mars and the research being conducted to find it.
- “How We’ll Find Life on Other Planets” by Aomawa Shields – Astronomer Aomawa Shields explains the importance of searching for life on exoplanets.
- “What a Planet Needs to Sustain Life” by Dave Brain – An exploration of the science behind what it takes for a planet to host life — and why humanity may just be in the right place at the right time when it comes to the timeline of life-sustaining planets.
Videos
- “Are We Alone? Galactic Civilization Challenge” by PBS Space Time – A detailed explanation of the Drake Equation and its significance in the search for extra-terrestrial life.
- “The Search for Life on Mars” Space Science Documentary 2019 – A documentary exploring the efforts to find life on Mars.
- Life Beyond I: “Alien Life, Deep Time, and our Place in Cosmic History”. This first episode in the Life Beyond series takes you to alien worlds and distant places in time and space, in search of where alien life might be hiding and what our place is within the history of life.
- Life Beyond II: “The Museum of Alien Life”. What if there was a museum that contained every type of life form in the universe? This episode takes you on a tour through the possible forms it might take.
- Life Beyond III. “In Search of Giants. The Hunt for Intelligent Alien Life”. In this episode, we will see how far we’ve come in the search for intelligent life, how they might be communicating, just how advanced they might be, and what it would mean if we really did make contact.
- Cosmos: A Personal Voyage by Carl Sagan – Watch the classic series that explores the universe and the possibility of life beyond Earth. Produced in 1980, it is still brilliant and relevant. There is also the somewhat inferior but more current (2014) remake Cosmos: A Spacetime Odyssey hosted by Neil Degrasse Tyson.
Your Thoughts?
What do you think about the possibility of finding extra-terrestrial life? How do you believe it would impact our world? I’d love to hear your thoughts and opinions on this fascinating topic. Share your views in the comments below and join the conversation about one of humanity’s most profound questions.
