An article just published in the journal “Monthly Notices of the Royal Astronomical Society” describes a research on the history and future of the formation of Earth-like planets. A team led by Peter Behroozi of the Space Telescope Science Institute (STScI) used data collected by the Hubble and Kepler space telescopes to evaluate the rate of formation of the Earth-like planets. The conclusion is that only 8% of potentially habitable planets existed at the birth of our solar system.
This conclusion also means that the vast majority of potentially habitable planets will form in the future, even trillions of years away. In essence, according to this study the Earth was born early and it will take a time much longer than its life for this kind of planet to become common in the universe.
The Hubble Space Telescope allowed to analyze the history of star formation during the growth of galaxies. Data show that the universe created stars at a high speed 10 billion years ago but this process was using only a small fraction of the hydrogen and helium available. Today the birth of stars takes place at a much slower pace but there’s still so much gas available that stars and planets will still keep on forming for a very long period.
The Kepler space telescope allowed to understand that planets the size of Earth in the habitable zone of their stars are common in the Milky Way. Based on this investigation, the scientists predict that at this time there should be a billion Earth-sized planets in the Milky Way. This estimate grows enormously considering the 100 billion galaxies in the observable universe.
Putting together the various observations, the authors of this study conclude that stars could keep on shining for more than 100 trillion years. In the meantime, they’ll keep on forming and a part of them will have potentially habitable planets. According to the researchers, the odds of forming are higher within giant galaxy clusters and dwarf galaxies, where there’s a greater amount of gas still usable.
If the conclusions of this study is accurate, it remains to see what percentage of Earth-like planets can host life forms and how many of them can develop sentient species. We’re just beginning to have enough data to understand where life forms can be born and we’re talking about the type of life we know. Other types of life forms have been theorized but we still know too little. In the coming years there may be extraordinary new discoveries that will allow us to understand much more.