Are we alone in the universe? Until recently, many people thought so—the Earth is unique, they believed, and we are created in the image of a god who favors us, and life itself likely does not exist elsewhere. We can see millions of stars in the night sky, but there probably aren’t more planets like Earth.
Others disagreed, particularly those who believe in UFOs, or those, like me who have never thought that Earth was unique. The universe is too vast for our planet to be the only extraordinary place where life arose. My assumption gained credibility in 1992 when Michel Mayor and Didier Queloz discovered a planet orbiting 51 Pegasi, a star similar to our sun.
Exoplanets are planets existing outside our solar system. Since the discovery of 51 Pegasi, astronomers have confirmed 5,240 more exoplanets in our galaxy. Scientists now have another list of 9,185 more exoplanet candidates that have been found but have yet to be confirmed by additional evidence. From the limited exoplanet exploration done since 1992, scientists estimate that the Milky Way Galaxy could host at least 100 billion planets, and others believe the number could be closer to 200-300 billion.
Most of those planets would not be habitable. They would be too close or too far from their stars to have temperatures that could sustain life, they would not have rocky surfaces or liquid water, or they would have toxic atmospheres or other conditions that would not be conducive to the formation of life, much less life’s evolution to more intelligent life forms. Most exoplanets discovered so far are gas giants like Neptune or hot Jupiters that orbit too close to their sun. Still, of the 4.1 billion sun-like stars in our galaxy, scientists conservatively predict that at least 300 million of them have an Earth-like rocky planet in their orbit. Less-conservative estimates put that number as high as 3.6 billion Earth-like planets.
So where is everybody? We should have daily visits from one alien civilization or another (and some people believe that’s happening). The short answer is that they are just too far away. The galaxy is more than one hundred thousand light years across. That’s 600 quadrillion miles. If you could fly at 100,000 miles per hour, traversing the galaxy would take you 685 billion years. That’s why we don’t see spaceships from far away parked on the White House lawn. Advanced alien civilizations are out there—but they are very far away.
To give you more perspective on the potential for life elsewhere in the universe, consider that the Milky Way is only one of the hundreds of billions of galaxies in the observable universe. If every galaxy is about the same size as ours, then there could be . . . (drum roll) . . . as many as 7,200,000,000,000,000,000 Earth-like planets in the part of the universe we can observe. That’s seven sextillion, two hundred quintillion. And there are countless more such planets in the part of the universe we can’t see.
Still think Earth is unique? We may never know if life exists elsewhere simply because we can’t detect it, but with each passing day, more exoplanets are observed. Astronomers now have a new tool to search for exoplanets and extraterrestrial life—artificial intelligence.
The A.I. Revolution
Recent advancements in artificial intelligence (A.I.) have been significant. In the last two years, A.I. has progressed in various areas, including natural language processing, image and video generation, decision-making, and machine learning. A.I. played a critical role in combating the COVID-19 pandemic by aiding vaccine development and providing real-time data to healthcare professionals. Additionally, A.I. has been used for autonomous driving and automated medical diagnoses, movie recommendations, and voice assistants, among other things. Now, with ChatGPT and software like it, the A.I. revolution is reaching everyone and everywhere all at once. Here are the four hottest areas of A.I. development:
Natural Language Processing (NLP): A.I. has made significant strides in NLP, enabling machines to understand and interpret human language. This has led to the development of chatbots, virtual assistants, and language translation tools, among other things. In 2020, OpenAI released GPT-3, a language model that can generate high-quality text with human-like coherence and language structure. This development has significant implications for content creation and marketing. Some alarms have been raised about ChatGPT, namely that students are using it to cheat at school, and this is a legitimate concern that the A.I. community must address.
Image and Video Generation: A.I. algorithms have become increasingly adept at generating realistic images and videos. For example, Nvidia’s StyleGAN2, released in 2020, can generate high-resolution images that are difficult to distinguish from actual photographs. This technology has applications in video game design, fashion, and film production. It has become possible to create motion pictures entirely through A.I. If you saw the most recent Avatar movie, you witnessed some of these advances in computer-generated videos.
Decision-Making: A.I. systems have improved their ability to make data-based decisions. This has led to the development of predictive analytics tools that can identify trends and patterns in large data sets. For example, A.I.-powered fraud detection systems can identify patterns of fraudulent activity in financial transactions.
Machine Learning: A.I. has progressed in machine learning, which involves training machines to learn from data. This has resulted in the development of more accurate predictive models and improved data analysis tools. In 2020, Google released TensorFlow 2.0, an open-source machine learning framework that simplifies developing A.I. models.
Overall, A.I. is becoming increasingly prevalent in many industries, and its potential impact is significant. While there are concerns about the ethical implications of A.I., continued research and development can lead to improvements in healthcare, transportation, and education.
A.I. in Exoplanet Exploration
Researchers at NASA’s Frontier Development Lab recently developed a deep-learning algorithm called ExoGAN that can simulate the atmospheric conditions of exoplanets and predict the spectral signatures of different gases that may indicate the presence of life, such as oxygen, methane, and carbon dioxide. By training the algorithm on known exoplanets and their properties, ExoGAN can generate synthetic spectra for hypothetical planets and estimate the likelihood of detecting certain gases with future telescopes.
In robotic exploration, NASA’s Mars rovers, Spirit and Opportunity, used a technique called “autonomous exploration” to navigate and analyze the Martian terrain without direct human control. The rovers could detect obstacles, plan safe paths, and prioritize interesting targets based on their scientific value. Given the approximately eight-minute time it takes for signals from Earth to reach Mars, robotic vehicles must be able to operate autonomously. A.I. techniques such as reinforcement learning, where the robot learns from experience and feedback, could further enhance the autonomy and adaptability of future robotic missions.
A.I. can facilitate the communication and collaboration between humans and machines in the search for extraterrestrial life. With astrobiology’s growing complexity and interdisciplinary nature, it is becoming more important to integrate expertise and insights from multiple fields, such as astronomy, biology, chemistry, and computer science. A.I. systems can help bridge the gaps between these fields by processing and integrating diverse data sources, providing interactive interfaces for exploration and visualization, and facilitating human-machine dialogue and decision-making. In effect, A.I. acts as a tool for collaboration among scientists of different disciplines who might otherwise be on different wavelengths.
NASA’s SETI program, founded in 1984, is the space agency’s office searching for extraterrestrial intelligence. The SETI Institute searches for intelligent signals from other civilizations using A.I. to analyze vast amounts of radio telescope data and detect unusual patterns indicative of extraterrestrial technology. SETI’s A.I. system, called Breakthrough Listen, can simultaneously scan millions of radio channels and identify candidate signals for further investigation. Moreover, Breakthrough Listen uses machine learning algorithms to classify the signals based on their characteristics and compare them with known radio interference and natural phenomena.
The future of exoplanet research is bright. Many new missions were launched in the past few years, including NASA’s Transiting Exoplanet Survey Satellite (TESS) and the European Space Agency’s Characterising Exoplanets Satellite (CHEOPS). These missions are helping us discover even more new worlds and provide better data about them.
Exciting techniques and technologies are also being developed that could lead to breakthroughs in our understanding of exoplanets. For example, scientists are working on using gravitational microlensing—where light from distant stars bends around a planet as it passes between Earth and those stars—to detect planets around other stars without actually seeing them directly.
This would allow us to study planets much farther away than we can currently see them without having any idea if they exist or not. So far this technique has only been used successfully once, but if successful again, it could revolutionize our knowledge about alien worlds. Because of the sheer number of planets that we have discovered so far, it isn’t surprising that there are many more waiting to be found. This trend will continue as technology improves, allowing us to find more and more exoplanets with each passing year.
For an excellent overview of the rapid development of artificial intelligence, see https://www.g2.com/categories/artificial-intelligence.
Photo credits: Andromeda Galaxy: Photo 37448809 © Boris Stromar | Dreamstime.com; all other images were created with DALL-E2.
