Are There Signs of Alien Life on Other Planets?

Human beings have always wondered if we are alone in the universe. The search for alien life has been the mission of many scientists, astronomers, and explorers for centuries. With advancements in technology and space exploration, the question of whether there are signs of alien life on other planets feels closer to being answered. 

In this article, let’s dive into the evidence, studies, and discoveries that suggest we might not be alone.  

What Are the Signs of Alien Life Scientists Look For?  

In order to detect alien life, signs that suggest biological activity must be identified first. Scientists look for biosignatures, which are chemical or physical markers that suggest the presence of life. 

Scientists Focus on Biosignatures  

Biosignatures are among the most significant indicators of life. They are markers of organic and inorganic substances in an organism. Nature Astronomy in 2020 revealed the detection of phosphine gas in the clouds of Venus. This gas, which on Earth is typically produced by biological organisms, was found by a team led by Professor Jane Greaves from the University of Cardiff. While this discovery doesn’t guarantee life, it sparks scientific debate about the possibility of microbial life on Venus. The study, titled "Phosphine gas in the cloud decks of Venus," has prompted further investigation, as it offers a glimpse into conditions where life might exist.  Through this profound discovery, scientists set their eyes on the biological possibilities on the planet. 

Water Remains a Key Element  

Water is considered as the most essential element to sustain life. Also, it is one of the primary things that scientists and astronauts seek on a planet or moon as it serves as a strong evidence of life development. For instance, Mars has long been a target for study due to evidence of ancient riverbeds, lakes, and signs of seasonal methane releases. In 2015, NASA’s Mars Science Laboratory mission, with its Curiosity rover, published findings on the detection of liquid water in Mars' past, as well as periodic methane emissions that could indicate biological processes. Furthermore, water has been found on Jupiter’s moon Europa and Saturn’s moon Enceladus, both of which have subsurface oceans. These findings, from studies like the NASA Astrobiology Institute's Europa Clipper mission, show that these moons could harbor life beneath their icy surfaces.  

Unusual Atmospheres Offer Important Clues  

Another critical sign scientists look for is unusual atmospheric conditions. Certain gases in a planet’s atmosphere can suggest biological activity. Earth’s atmosphere contains oxygen and methane, gases that coexist due to biological processes. One of the most significant studies in this area is the Kepler Space Telescope’s mission to detect Earth-like exoplanets. The study, published in The Astrophysical Journal in 2013, found that exoplanets with atmospheres similar to Earth’s could potentially support life. If similar atmospheres are detected on other planets, it could signal the presence of life. Scientists are excited by the potential for these discoveries as they help narrow down the search for habitable worlds.  

Which Planets Hold the Best Potential for Alien Life?  

Several planets and moons within our solar system and beyond show promise in the search for alien life. Planets or moons within the "habitable zone" of their stars—where conditions are just right for liquid water—are key targets for exploration.  

Mars Presents Compelling Evidence  

Mars has always been regarded as one of the areas where the search for life beyond our planet could be fruitful. Recently, researchers managed to find further substantiation that liquid water existed on this planet. The Curiosity rover within NASA‘s Mars Science Laboratory mission has reported finding signs of previous lakes and rivers on the planet. The rover had previously reported seasonal methane emissions in 2009, and such emissions may indicate the presence of microbes that are active. The Science Journal, authored and published in 2019, discussed the potential of life as one of the sources of methane found in the Martian atmosphere. Other missions like NASA’s Perseverance Rover are examining further the surface of Mars in search of traces left by ancient or contemporary life forms.

Icy Moons Show Unique Potential  

Europa and Enceladus are among the most remarkable moons that exist in our solar system. Both these moons consist of subsurface oceans, which are heated up by the tidal forces of the parent planets, Jupiter in the case of Europa and Saturn in the case of Enceladus. In the late 1990s, after the discoveries of the Galileo space probe, it was established that the Europan ocean is covered by ice, hence prompting further missions such as NASA Europa Clipper to investigate the theory further. In a similar fashion, plumes of vaporized water were also seen by NASA’s Cassini spacecraft as erupting out of Enceladus, suggesting the presence of a potentially warm ocean under the icy shell. This suggests that life could still thrive in these moons at a microbial level, and further missions are expected to further these prospects.

Exoplanets Offer New Possibilities  

In recent years, the discovery of exoplanets, known as planets orbiting stars outside our solar system, has opened up exciting possibilities in the search for alien life. The Kepler Space Telescope has detected thousands of exoplanets, many of which are located in their star's habitable zone. A particularly promising discovery came in 2016 when scientists identified Proxima Centauri b, an Earth-like exoplanet orbiting the closest star to our Sun. Studies like those published in Nature in 2016 suggest that planets like Proxima Centauri B may have the conditions necessary for life. Additionally, with the recent launch of the James Webb Space Telescope, scientists are now able to study the atmospheres of exoplanets in unprecedented detail, searching for signs of life.  

What Does the Future Hold for Finding Alien Life?  

The future of the search for alien life is full of promise, with new missions and advanced technology offering fresh opportunities for discovery.  

New Telescopes Revolutionize Observations  

The month of December 2021 saw the launch of the James Webb Space Telescope (JWST), which will assist in spotting signs of alien life. The JWST will examine exoplanet atmospheres like never before. One paper published in 2020 in The Astrophysical Journal suggests that the JWST will find biosignatures in the atmospheres of other gas-rich planets, including oxygen, methane, and carbon dioxide. This significantly enhances efforts of identifying possible candidates of life existence on exoplanets.

Space Missions Push Life Detection Further  

Upcoming space missions are focused on exploring Mars, Europa, and other promising targets. NASA's Europa Clipper mission, set to launch in the 2020s, will investigate the potential habitability of Europa's subsurface ocean. Meanwhile, the Mars Sample Return mission, a collaboration between NASA and the European Space Agency, aims to bring Martian soil samples back to Earth, where scientists will analyze them for signs of life.  

Scientists Predict Exciting Discoveries  

While we haven't yet found definitive proof of alien life, scientists remain optimistic. The discovery of microbial life or even intelligent life may be just a matter of time. As technology advances and our understanding of the universe grows, the likelihood of discovering alien life increases. Studies from the SETI Institute suggest that the search for life may soon reach a tipping point, with significant breakthroughs expected in the coming decades.  

Conclusion  

So, are there signs of alien life on other planets? The answer is yes—there are promising signs but no definitive proof yet. Through the detection of biosignatures, the discovery of water on moons and planets, and the study of unusual atmospheric conditions, scientists have found compelling evidence that alien life could exist. With future missions and the advancement of technology, humanity is closer than ever to answering the age-old question of whether we are truly alone in the universe.