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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.
There is only so much gas that will become stars, most of it will forever float in the space between galaxies. The timeline is 100Gyr-1Tyr.
NB: The message above might reflect my opinion right now, but not necessarily tomorrow or next year.
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.
So 61% of all the pain, struggle, and deprivation in the Universe hasn't even happened yet. Depressing.
You may want to reread up on the Heat Death of the Universe. Our Sun won't even be cold in 5 billion years, never mind the rest of universe. Existing red dwarf stars may last a 100 billion years. Most models put the Stelliferous Era (era of stars) as extending 10s of trillions to 100s of trillions of years into the future. True Heat Death is 10E100 or 10E1000 years out depending on the model, but there won't be any stars or planets (protons will have decayed). Although the Big Rip may occur in as little as 20 Billion years
If you're going to be a Grammar Nazi, at least do it right. Myriad technically refers to the quantity 10,000, in which case "a myriad planets" is just as legitimate as "a dozen eggs". It's also used colloquially to mean "a very large amount" or even, yes, "uncountable". In English It was originally only used in the plural form (many myriads of Xs) but was later adopted in the single form (a myriad of Ys), and later still (18th century) without need for prepositions (myriad wonders)
Basically it's a very old word whose usage is historically very poorly defined. You'd be better off focussing your angst on words with more definite "proper" usages.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
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.
Both. Actually it's been happening since day 1 of the Universe. Even now everything is getting further and further away from, well... everything else (on average) (https://en.wikipedia.org/wiki/Hubble%27s_law). Space between galaxies, systems, planets and atoms expands and the Universe is getting cooler (on average, there might be spots when locally it gets hotter but as a whole it gets cooler). So first everything will run out of energy and then it will diffuse into atoms and eventually even atoms will break apart.
Black holes radiate energy too and those will evaporate at some point in time too (it may take trillions of years or more but eventually it will happen). (https://en.wikipedia.org/wiki/Hawking_radiation)
At least that's one of current theories. We really don't know what will happen in billion or trillion years. Universe is strange and it might turn out that our models of physics (I always cringe when someone speaks of "laws of physics") don' capture vast majority of what's happening in it.