Are we alone in the universe? The answer is almost certainly no. Given the vastness of the universe and the fact that its physical laws allow for the emergence of life in at least one place (on Earth), the existence of life elsewhere is virtually guaranteed. But so far, despite generations of searching, it still hasn’t been found. But in the meantime, we declare that perhaps, while we may not be alone, the interstellar gulf between us and our nearest neighbors effectively puts us in isolation wards. I have learned enough. This doesn’t mean you should stop looking. It just means you need to manage your expectations and prepare for a long and lonely journey through space and time before meeting them virtually or physically.
The possibility of extraterrestrial life has been debated since ancient times. But rigorous exploration has only taken place in the century since physicists Giuseppe Cocconi and Philip Morrison first proposed the approach in 1959, demonstrating the feasibility of interstellar communication using radio telescopes. It hasn’t passed. A year later, astronomer Frank Drake led the first Exploration for Extraterrestrial Intelligence (SETI) effort, called Project Ozma, using facilities at the National Radio Astronomy Observatory in Green Bank, West Virginia. We looked for such signals from putative alien civilizations. As part of his preparations for the project’s follow-up meetings, he developed the now famous “Drake equation,” a probabilistic mathematical formula for estimating the number of communicable civilizations. NC, It may exist in the Milky Way.
We are the product of progressive stages of evolution. With this in mind, the Drake equation can be cast as:
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NC = Astrophysical evolution × Biological evolution × Cultural evolution × Technological evolution × Lifespan of technological civilization
In that equation, each subsequent evolutionary step arises from the previous step. For us, this progress would take almost the entire lifetime of the Earth, about 4.5 billion years.
Attempts to “solve” the Drake equation are hampered by insufficient knowledge about the likelihood of completing each evolutionary step. However, advances in modern observational technology have primarily enabled us to find and study what are generally considered “Earth-like” exoplanets in our galaxy, i.e., other small rocky worlds in surrounding temperate orbits. It is now possible to make much more reliable estimates of astrophysical evolution. their stars. Astronomers’ catalog currently includes more than 5,700 confirmed exoplanets, some of which reside in the habitable zone of their stars, where the star’s light deposits liquid water on the surface. It can warm the planet enough for it to exist. Applying these results to the estimated number of Earth-like planets in the Milky Way galaxy as a whole, we get NEon the order of 3 billion. know this experiential As a result, the Drake equation no longer needs to include an estimate of the lifespan of a technological civilization and can now be simplified to:
Nc ≈ αNE
Here, the variable is α (Alpha) is a portion of an Earth-like planet that has reached its evolutionary limit as it relates to life, intelligence, and technology. Until extraterrestrial life is discovered outside Earth (or perhaps created in a laboratory). α It will still be very speculative, and speculation about otherworldly perceptions and technology will be even more unrestricted. However, for the sake of argument, let’s assume that the probability that each of these evolutionary thresholds is met is 1 in 100. In that case:
α = 0.01 × 0.01 × 0.01 = 0.000001
So in this (perhaps optimistic) scenario, the chances that the evolution of an Earth-like planet will lead to a civilization capable of interstellar radio communication are literally 1 in a million. If so, the number of communicating civilizations currently existing in the Milky Way galaxy would be approximately 3,000. If their home worlds are evenly scattered among the hundreds of billions of stars in our galaxy, the average distance between them is rs, It would be on the order of 3,000 light years. Therefore, contact via direct interstellar travel seems highly unlikely. Even under ideal conditions, two-way communication via radio waves (or other forms of light) takes about 6,000 years on average. This can prove difficult, to say the least, from a cultural longevity perspective.
Therefore, as has been suggested many times recently, interstellar communication between civilizations will necessarily be unidirectional, similar to traditional radio and television broadcasts. The best homegrown example of ours happened just over 50 years ago. At this time, Frank Drake directed a powerful radio beam from Arecibo Observatory’s 1,000-foot-wide reflector to send a message to the globular cluster M13, about 25,000 light-years away. In Puerto Rico. Although it was essentially a symbolic effort and only a three-minute technology demonstration, it nevertheless marked a new evolutionary milestone for humanity.
Since then, the chances of another planet emerging from the ravages of evolution are small. So this means that of all the possible communicating civilizations in our galaxy, We may perhaps be the youngest and least advanced. Since it is technically easier to receive radio waves than to transmit them, it makes sense for us to play the role of listeners rather than broadcasters. It is possible to search for less intentionally directed “technosignatures” from more advanced civilizations. But a preliminary survey of more than 100,000 galaxies for signs of waste heat from rampant alien technology yielded fewer than 100 targets with an attractive excess of infrared light (all of which It may be possible to explain this without relying on a pangalactic supercivilization). This somewhat perplexing conclusion, and the still-ineffective results resulting from decades of wireless SETI efforts, do not preclude the possibility that such efforts will ultimately succeed, but we It reinforces the idea that it exists alone.
For now, it’s our best chance to find life elsewhere and limit its value. α Researchers will search for biosignatures in the atmospheres of a statistically significant number of exoplanets, and more directly, the exhaustive search for life elsewhere in the solar system. Such research does not take thousands of years. In fact, using existing technology, they can be perfected within a human lifetime. We are already launching a fleet of robotic probes to search for life on various moons of the giant planet, including Mars and oceans. They are also planning advanced space telescopes like NASA’s Habitable World Observatory (which could launch in the late 2030s or 2040s), which will explore dozens of potentially Earth-like worlds. Explore spectrally for signs of life.
Given such seemingly long odds, some may wonder why you should even bother looking. Cocconi and Morrison had the answer to this all along, writing in their 1959 paper: But if you don’t search, your chances of success are zero. ” Consider this: one Some of these searches yielded positive results suggesting that the universe is indeed teeming with life. If all the results are negative, it means we are the winners of the cosmic lottery, living in an oasis of a priceless planet in a vast galactic desert, the best ever. This will be the empirical evidence. If scientists can prove that we can win such huge prizes, we can be more careful about our world and each other so that we don’t waste it. Is that so? I like to think so.
This is an opinion and analysis article and the views expressed by the author are not necessarily those of the author. scientific american.
