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NASA envisions that within a generation, we'll uncover life beyond our planet, and possibly even in other solar systems. But where will it be found, and what kind of life forms will we encounter? And is it safe to initiate contact with extraterrestrials? Though the journey hasn't been simple, these questions may soon be more than just theoretical. Here are 10 ways the hunt for alien life is becoming a reality.
10. NASA Anticipates the Discovery of Alien Life Within 20 Years
As Matt Mountain, director at the Space Telescope Science Institute in Baltimore, eloquently puts it: 'Imagine the moment when the world wakes up, and the human race realizes that its long loneliness in time and space may be over... It’s within our grasp to pull off a discovery that will change the world forever.'
Utilizing both ground-based and space technologies, NASA experts predict that alien life will be discovered in the Milky Way galaxy within the next two decades. Since its 2009 launch, the Kepler Space Telescope (shown in the image) has been instrumental in finding thousands of exoplanets (planets outside our solar system). Kepler identifies a planet when it passes in front of a star, which causes a brief dip in the star's brightness.
According to data from Kepler, NASA scientists believe that up to 100 million planets within our galaxy could support alien life. However, the soon-to-be-launched James Webb Space Telescope (set for a 2018 debut) will offer the first opportunity to detect life on distant planets indirectly. Webb will focus on identifying gases in a planet's atmosphere that might be signs of life. The ultimate goal is to locate Earth 2.0, a planet strikingly similar to ours.
9. The Alien Life We Encounter May Not Be Intelligent
The Webb Telescope and its successors will search for biosignatures in the atmospheres of exoplanets, such as molecular water, oxygen, and carbon dioxide. However, even if such biosignatures are detected, they won't reveal whether the life on that exoplanet is intelligent. The alien life we discover may be simple, single-celled organisms like amoebas, rather than complex beings capable of communication with us.
Our search for extraterrestrial life is hindered by our own biases and lack of imagination. We tend to assume that life must be carbon-based like ours and use ourselves as the benchmark for intelligence. Carolyn Porco from the Space Science Institute highlights this lack of creativity, stating, "Scientists don't entertain completely wild and far-fetched ideas unless they have some evidence to back them up."
Other experts, such as Peter Ward, coauthor of Rare Earth: Why Complex Life Is Uncommon in the Universe, argue that intelligent alien life would likely have a brief existence. Ward suggests that extraterrestrial civilizations would face challenges like global warming, overpopulation, resource shortages, and eventual societal collapse. He predicts the same fate for humanity.
8. Mars Might Have Hosted Life in the Past—and Could Again
Mars may be too cold to support liquid water and life today, but NASA’s Opportunity Rover, an all-terrain vehicle designed to explore and analyze Martian rocks, has revealed that about four billion years ago, the planet had fresh water and mud that could have sustained life.
Another potential source of water and life in Mars' past is found on the slopes of the planet's third-tallest volcano, Arsia Mons. About 210 million years ago, an eruption beneath a massive glacier caused the ice to melt, creating lakes that may have been like liquid bubbles in a partially frozen ice cube. These lakes might have existed long enough for microbial life to develop there.
Some simple organisms from Earth might be able to survive on Mars even today. For instance, methanogens use hydrogen and carbon dioxide to produce methane, requiring neither oxygen, organic nutrients, nor light. These organisms can endure extreme temperatures, like those experienced during Martian freeze-thaw cycles. So when methane was detected in Mars' atmosphere in 2004, scientists began to wonder if methanogens could already be living beneath the surface of the planet.
As we venture to Mars, scientists are concerned about the risk of contaminating the planet's environment with microorganisms from Earth. This contamination could make it difficult to determine if any life found on Mars is native or if it originated from Earth.
7. NASA Aims to Search for Life on Jupiter’s Moon
NASA is planning a mission to Europa, one of Jupiter’s moons, in the 2020s. One of the mission’s primary objectives is to assess whether the moon’s surface could support life and identify potential landing sites for future spacecraft.
Additionally, NASA is investigating the possibility of life, possibly intelligent, beneath Europa’s thick, icy surface. In an interview with The Guardian, NASA’s chief scientist Dr. Ellen Stofan stated, “We know there is an ocean under that icy crust. There are plumes of water emerging from cracks in the southern polar region. And there’s this orange substance on the surface—what exactly is that?”
The spacecraft sent to Europa may either orbit the moon or perform multiple flybys, possibly flying through the plumes of water in the southern region. This would allow us to collect samples of Europa’s inner layers without the risks and costs associated with landing. However, any mission must ensure the protection of the spacecraft and its instruments from the harsh radiation environment. NASA is also determined to prevent contamination of Europa with Earth’s organisms.
6. Exomoons Could Be Detected by Their Radio Emissions
Until recently, the search for life beyond our solar system has been constrained to exoplanets. However, physicists from the University of Texas believe they have discovered a method to detect exomoons—moons orbiting exoplanets—through radio emissions, potentially expanding the number of habitable bodies where alien life may exist.
Drawing from their understanding of radio emissions created by the interaction between Jupiter’s magnetic field and its moon Io, these scientists have developed formulas to detect radio emissions from exomoons. They also suggest that Alfven waves—plasma ripples formed by the interaction between a planet’s magnetic field and its moon—could assist in identifying exomoons in a similar manner.
In our solar system, moons like Europa and Saturn’s Enceladus hold potential for supporting life due to their position relative to the Sun, their atmospheres, and the possible presence of water. As radio telescopes grow more powerful, scientists aim to study more distant objects in greater detail.
Currently, two exoplanets are considered prime candidates for hosting life-bearing exomoons: Gliese 876b, about 15 light-years away, and Epsilon Eridani b, around 11 light-years distant. Both are gas giants, as are most exoplanets discovered so far, but many reside in their stars' habitable zones. Exomoons orbiting these planets may hold the potential to support life.
5. The Detection of Advanced Alien Life Through Pollution
Until now, the search for alien life has focused on finding exoplanets with gases like oxygen, carbon dioxide, and methane. However, with the Webb Telescope's capability to detect ozone-depleting chlorofluorocarbons, some researchers suggest that looking for industrial pollution could be a new way to identify advanced alien civilizations.
While scientists are eager to detect a thriving alien civilization, it's also possible that we might encounter evidence of a vanished culture that caused its own demise. Researchers propose that the most effective way to determine whether a civilization is still active is to search for both long-lasting pollutants (those that remain in the atmosphere for tens of thousands of years) and short-lived pollutants (which persist only for about a decade). If the Webb Telescope detects only the long-lasting pollutants, it could indicate that the civilization is no longer present.
However, this method has its limitations. The Webb Telescope is currently capable of detecting pollutants only on exoplanets orbiting white dwarfs (the remnants of stars that have died, similar in size to our Sun). Since dead stars are typically associated with extinct civilizations, the search for life actively producing pollutants may have to wait until our technology advances further.
4. Oceans Could Make Exoplanets More Suitable for Life
In the search for planets that might support intelligent life, scientists typically concentrate on analyzing the atmospheres of planets located within a star’s habitable zone. However, new research indicates that our models should also consider the influence of vast, liquid oceans.
Taking a look at our own solar system, Earth provides a stable environment that nurtures life, whereas Mars—located on the outer edge of the habitable zone—remains frozen with temperatures that can swing by more than 100 degrees Celsius (212 °F). Venus, situated on the inner edge of the habitable zone, experiences extreme heat. Neither planet seems to be a prime candidate for supporting intelligent life, although they may harbor microorganisms that can endure harsh conditions.
In contrast to Earth, neither Mars nor Venus possesses a liquid ocean. According to David Stevens of the University of East Anglia, “Oceans have an immense capacity to control climate. They are beneficial because they cause the surface temperature to respond very slowly to seasonal changes in solar heating. And they help ensure that temperature swings across a planet are kept to tolerable levels.” For this reason, Stevens argues that the presence of oceans should be a key factor in our models when seeking extraterrestrial life.
3. Experts Debate Whether We Are Truly Ready to Make Contact With Alien Life
NASA is taking an aggressive stance in the quest to discover alien life across the universe. The Search for Extraterrestrial Intelligence (SETI) project has expanded its mission, seeking to go beyond just monitoring and analyzing extraterrestrial signals. SETI aims to actively send messages into space to signal our location to other civilizations.
However, reaching out to intelligent alien life could pose a risk we are not yet equipped to handle. Stephen Hawking has cautioned that an advanced civilization might use its superior power to subjugate humanity. There are also concerns that NASA and SETI may be crossing ethical lines. Neuropsychologist Gabriel G. de la Torre raises important questions, asking, “Can such a decision be made on behalf of the entire planet? What would happen if our signal was received by ‘someone’? Are we truly prepared for this kind of encounter?”
Drawing from a survey of college students, de la Torre believes that the general public currently lacks the understanding and preparedness necessary to respond to intelligent alien contact. Many people’s opinions on the matter are also shaped by their religious beliefs.
2. Unusual Exoplanets Could Be Home to Extraordinary Life Forms
Astronomers typically focus their search for life on exoplanets located within their star’s habitable zone. However, some ‘eccentric’ exoplanets only pass through the habitable zone intermittently. When these planets are outside the zone, they may face scorching heat or extreme cold.
Nevertheless, these planets may still harbor life. Scientists point to Earth’s resilient microscopic organisms, such as bacteria, lichen, and spores, which survive in extreme environments—both on Earth and in outer space. This implies that a star’s habitable zone could extend further than previously thought. To discover alien life, we need to broaden our perspective to include planets that seem inhospitable to life as we know it but may actually be ideal for life forms that thrive in, or can endure, harsh conditions.
1. ‘Tilt-A-Worlds’ Could Broaden the Reach of Habitable Zones
Exoplanets with shifting tilts in their orbits could harbor life in regions where planets with fixed spins, like Earth, cannot. These ‘tilt-a-worlds’ interact with their neighboring planets in a way that creates unique conditions for life.
While Earth and its neighboring planets orbit the Sun along a similar plane, tilt-a-worlds and their neighbors follow orbital paths at varying angles. This interaction causes occasional tilts of the poles of a tilt-a-world toward its host star, creating a wobble similar to that of a spinning top slowing down.
Tilt-a-worlds are more likely than planets with fixed spins to have liquid surface water. The heat from their host star is distributed more evenly, especially when the planet’s poles are facing the star. This causes rapid melting of ice caps, leading to the formation of surface water, which increases the likelihood of supporting life. This ability may extend the habitable zone of a star by 10 to 20 percent beyond where planets with fixed spins would be frozen.
The Search For Alien Life Isn’t As Simple As We Thought
Our technology for searching for alien life has advanced tremendously, but the task remains far more complex than initially thought. For example, biosignatures, which are commonly interpreted as signs of life, can now be found on lifeless planets and moons as well. This discovery implies that our current methods for identifying life on exoplanets might lead to numerous false positives.
Additionally, the chances of life existing on other planets may be much slimmer than we once assumed. Red dwarf stars, which are smaller and cooler than our Sun, are the most abundant stars in the universe. However, new findings suggest that exoplanets in a red dwarf’s habitable zone may suffer from extreme weather conditions that can strip away their atmospheres, making life highly improbable.
