Shouldn’t another life have existed before us?
If the solar system is only 4.6 billion years old but the universe has been around for 13.8 billion years, isn’t it likely that other forms of life existed long before us in the universe?
With estimates suggesting that there are more than 10 billion terrestrial planets in the Milky Way and several hundred billion galaxies in the observable universe, it seems statistically unlikely that lightning only struck once. when she comes to life. Because we currently know of only one planet capable of sustaining life, scientists are basing their research on Earth, looking for small rocky worlds in the habitable zone – where surface liquid may exist – around stars. with a few common key elements necessary for life: carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
Even limiting ourselves to these conditions, as you point out, the universe is significantly older than the Sun, which means that an intelligent civilization should have existed long before humanity. So where are all the aliens? Why haven’t we received any message? Scientists call this disparity between the apparent likelihood of life being abundant and our complete lack of evidence the Fermi Paradox.
We don’t yet know why the cosmos seems so deafening, but many people have offered hypotheses. One, known as the Great Filter, claims that although intelligent life can evolve frequently, certain factors prevent it from lasting long enough for us to observe it. This may be the case even for microbial life. Take Mars, for example, which proves that it could have hosted such life a long time ago. Or perhaps intelligent life inevitably develops technology faster than it can develop the ability to use it responsibly, forcing advanced civilizations to eradicate themselves. Or chance can wipe out life – if a nearby supernova, gamma-ray burst or giant asteroid were to hit Earth, there was nothing we could do to stop it.
But astronomers are still searching for life due to other arguments like the Drake equation, which estimates the number of extraterrestrial civilizations active at any given time with the ability to communicate. Although the Drake equation can never be calculated precisely, a 2016 paper published in Astrobiology found that as long as the odds of a civilization developing on a habitable planet are greater than approximately 1 in 10 trillion, humanity is not alone in the universe.