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Only 8% of the Universe's Habitable Worlds Have Formed So Far (sciencemag.org)
sciencehabit writes: According to a new study, 92% of Earth-like planets haven't been born yet. Science reports: "Using data from the Hubble Space Telescope, researchers estimated the rates of past star and planet formation in the universe, which is now about 13.8 billion years old. They then combined that information with data from previous surveys that estimated the amounts of hydrogen and helium left over from the big bang that still haven't collapsed to form stars. At the time our solar system formed about 4.6 billion years ago, only about 39% of the hydrogen and helium in our galaxy had collapsed into clouds that then evolved into stars, they say. That means that the remaining 61% is available to form future solar systems that may include Earth-like planets in their habitable zones, the researchers report online today in Monthly Notices of the Royal Astronomical Society. In the universe as a whole, the researchers suggest, only 8% of its original starmaking gases was locked up in stars by Earth's first birthday. The rest will, over the remaining trillions of years of the universe's lifetime, coalesce into stars whose solar systems will contain a myriad of Earth-like planets."
This makes me wonder how many planets (as a percentage or otherwise) were around when the background temperature of the universe was in the 40-100 degrees Fahrenheit range where water would be most amenable to life. You could make an argument that period of time would contain the best conditions for life. However, if there aren't many planets (let alone with an appropriate size, temperature, and atmosphere), it makes life kinda hard.
This could help explain the Fermi Paradox: we are simply early-birds. However, this then creates a Copernican Paradox: it's unlikely that we are the earliest or latest: the chance of being on the edges of the bell curve is low (or even a roughly rectangular curve). We are more likely to be approximately in the middle.
This could mean if there were a lot of intelligent species, they'd probably conquer each other. Thus, a middle-age universe would be a hostile place. A curve of universal intelligent population would thus be an initial spike and then a drop-off as aggressive species or machines spread and kill.
This would make our existence at this time less "special": we are merely part of the early population boom (spike) before nasty happens and reduces the population of the universe. Doesn't bode well for the future, though.
If the future were about humans spreading and populating the universe, we'd more likely be one of those mass spreaders (as a randomly selected intelligent being in space and time). We are not. (Hell, we may not even survive ourselves, let alone aliens.)
Better hope Copernicus is wrong and we are in a lucky or special place or time.
Table-ized A.I.
Species could never conquer each other. The distances between planets are too vast. By the time you arrived at the planet, the civilization would have ceased to exist. Space is big. Really big. You might think it is a long way to the chemist, but that is just peanuts to space.
Not necessarily. Say you undertook a planetary-scale effort and built a spacecraft capable of moving 1/100th of c, it would take 1200+ years to make the journey to, for example, a very close (12 light years) habitable planet. That's a very long time by our local political standards, but if we ever actually achieve a stable government then it's not all that long. If good AI enables us to build a stable civilization for a few hundred thousand years, there might be some meaningful interstellar travel.
That being said, the best bet for expanding our sandbox is still terraforming a planet (or other environment, like the ocean or arctic or sky) that is already nearby.
This is an astonishingly arrogant "deduction" considering that:
- as recently as 1988 identifications of exoplanets were considered dubious (many were later confirmed by subsequent observation). In fact, even the concept that there were other planets out there was still in some debate in the 1990s
- our detection technologies, while highly advanced from where they were, are still astonishingly rudimentary, largely only by deduction (not direct observation) and likely only finding a *tiny* subset of the bell-curve of planetary bodies out there; in fact, it's unlikely that ANY planets in our solar system would be detectable by observers located at the very closest stars using our current tech.
All we can say for sure is that:
- our system took about 5 billion years to get where it is today, developmentally.
- our system developed from a nebula, perhaps either the remnant of, or subject to the shockwave of, a nova/supernova. Given that such structures had to develop (but age much faster than our star), we can add another 1 billion years to that process to come to a total age of our system of 6 bn yrs for the full process, incl "pre-solar" development
- our universe is about 13.8 billion years old, with stellar formation around 1 billion years ...call it 2 billion, just to be conservative.
- If stars were forming at 2 bn yrs, and our system is about 6bn yrs, that means there could have been planetary formation and systems like ours developing for 5 BILLION years before today.
- Since our system is an entirely average sun, in an entirely average stellar neighborhood, it's probable that our experience is entirely typical.
To deduce then that only 8% of potential planets have formed is nonsense.
-Styopa