I'm particularly intrigued by the perspective of hypothetical intelligent life in this era. They'd presumably be able to discover the laws of physics and the evolution of the universe as we have. They'd see that the universe was millions of years old, and presumably that would be considered a really long time. They'd know that the universe was expanding and cooling.
They'd extrapolate out to our era. Would they consider this era to be cold and dead? I imagine their view of this era would be similar to our view of the dark era roughly 100 trillion years hence after all stars burn out and no new ones are being created. Incidentally, the distance is at a similar order of magnitude: we're about 1000 times farther removed from that 15 million year mark, and that "dark era" is about 10000 times farther out from today.
-complex life as we know it has taken 3.7 billion years to form. That doesn't mean it has to, conceivably it could have taken much less if it had of avoided some troughs and pitfalls along the way of its random walk; this also says nothing of life forms that come In conceptions we can't get our heads around.
I prefer to use this information to envisage a universe where protolife arose. And, since the universe was quite a bit smaller then, it was concievably possible for whatever arose (even simple chemical reactions that we would consider quasi-biological today) to spread throughout the universe.
Then, when proper galaxies formed and planets etc they were ready to be seeded by the cosmic leftovers of life's primal beginnings.
I feel this is more likely than the possibility of complex intelligent life because the universe at 15 million years would still have been deeply inhospitable: giant stars going supernova left right and centre laying down the foundations of US and everything we see, and not to forget average temperature when taken to universe-scale extremes still means areas hot as buggery and cold as empty void.
Still, it is fascinating to think that the precursors to all of us (you can probably tell that I was a fan of panspermia even before this news) was laid down so close to the beginning of time
Some one that got such a massive head start could have evolved by now to survive these times. Even more so, they would have technologies to achieve singularity and probably didn't need their biological bodies to survive any more.
Life originating only after some 15 million years after the big bang, would by any means be extremely super intelligent by now. So much that I guess their very nature of existence would be unimaginable to us. If not, what happened to them? Did they just got unlucky, got hit by asteroid every time and finally had no one to start over? Did they self destruct? Did they achieve singularity and those machines have managed to hide themselves since then? Or the universe is just plain unimaginable large that even for some one somebody like them just couldn't travel that long distances to meet others?
>>Would they consider this era to be cold and dead?
There is this thought that the science of universe we discover is based on observation. Ever expanding universe would leave it in a state that some time in the future people on a planet will just see darkness around them. No stars at all!!! They will likely assume universe is just them, and empty space all around. They would no nothing about Big Bang at all. So just like them, are we missing critical pieces of evidence already?
Plus Stephen Hawking has suggested if we manage to survive technology adolescence and survive to move out to space. We will eventually figure out a way to survive the cold dead era too.
The heavy elements (carbon, oxygen, iron, etc) we and our planet are made of were manufactured through fusion in the heart of stars. As as far as I understand it, even 15 million years after the big bang the universe was almost entirely made of hydrogen and traces of helium. Any heavier elements that did exist would still be locked up inside the first generation of stars that were making them. Perhaps the paper mentioned addressed that?
Still, it's an interesting notion. At some point there may have been a sweet spot between the background temperature and the availability of materials, and that point may have been billions of years in the past.
Much of the paper is devoted to calculations regarding the formation of heavier elements and rocky planets. Surprisingly, the lifetime of the largest stars is only 3 million years:
For massive stars that are dominated by radiation pressure and shine near their Eddington luminosity LE = 1.3 × 1040 erg s−1(M⋆/100M⊙), the lifetime is independent of stellar mass M⋆ and set by the 0.7% nuclear efficiency for converting rest mass to radiation, ∼ (0.007M⋆c2)/LE = 3 Myr (El Eid et al., 1983; Bromm et al., 2001).
Then it's a matter of figuring out how long it takes for matter to clump together and form stars/planets. After some math and citations in section 2:
The above calculation implies that rocky planets could have formed within our Hubble volume by (1+z) ∼ 78 but not by (1+z) ∼ 110 if the initial density perturbations were perfectly Gaussian. However, the host halos of the first planets are extremely rare, representing just ∼ 2 × 10−17 of the cos- mic matter inventory. Since they lie ∼ 8.5 standard deviations (σ) away on the exponential tail of the Gaussian probability distribution of initial density perturbations, P(δ), their abundance could have been significantly enhanced by primordial non-Gaussianity (LoVerde and Smith, 2011; Maio et al., 2012; Musso and Sheth, 2013) if the decline of P(δ) at high values of δ/σ is shal- lower than exponential. The needed level of deviation from Gaussianity is not ruled out by existing data sets (Ade et al., 2013b). Non-Gaussianity below the current limits is expected in generic models of cosmic inflation (Maldacena, 2003) that are commonly used to explain the initial density perturbations in the Universe.
Using current best knowledge about the early universe, it looks like planets did form, but were extremely rare. With some plausible tweaks to how "clumpy" the initial universe was, one ends up with lots more planets.
I suspect there were just enough heavy elements to kick-start life at the microscopic level but I doubt there was enough for a sentient species to develop at that time.
Then again all life could have originated at that time and just now got the chance to evolve into a sentient species.
That would explain why a lot of comets and meteorites have the necessary building blocks of life in them.
I have to admit it would be poetic and typical of scientific progress in general that while the religious texts have marked the creation of mankind as the beginning of the great cosmic opera, with our story as the center, if in fact it turned out we're not only nothing special, but worse: an epilogue, a post-credits reel, an afterthought appearing in a flicker as the lights go out well after the real saga has ended.
While an interesting idea, I have the same objection to that idea that I have to the idea that life in general is abundant today, which is that we should see the evidence of it. Any truly long-lived society is going to have to engage in some cosmological engineering to survive, and we don't see it.
Furthermore, while any given species might not have survived from so long ago, life itself should never have died out, if intelligent life was common and abundant. The challenges of surviving that era are such that even we can plausibly imagine being able to meet the challenges in a century, or less if we were concentrating.
It's a poetic idea, but the universe does not look like one in which we are some last dying ember living in the carcass of past giants; it looks like one in which there's little-to-no intelligent life in our past light cone.
Anybody considered that life was then not restricted to planets? That's a 'modern' conceit. IF the entire soup of the much-denser smaller universe was room-temperature, then life could have existed in any dust-cloud or water-rich soupy place. It may have been life from a real primordial soup that settled onto planets as they formed.
Eh? What about the lack of heavier elements at this stage of the universe? Or the fact that it wasn't this warm for the next 3-4 billion years (about the time it took to form complex life here)?
Also:
>By demonstrating that life could have formed so early, Loeb may even have delivered a blow to so-called anthropic arguments about life in the universe.
I'm more intrigued by the possibility (however minute) that we are alone. That's the scariest thing in the world to me: that it's up to us to preserve ourselves, what may be the most precious jewel in the universe. And we're failing.
whenever watching movies about aliens attacking our planet to consume our resources, i've always had the thought that we're actually making movies about ourselves when we do eventually find sentient beings somewhere out there. which corporation is going to shell out enough money to hire an army to go get that unobtainium?
That's nonsense. I studied Physics in the early 90s and the various possibilities for early habitability used to crop up in conversation - in the common room if nothing else.
This is addressed in the paper. In the second paragraph of the third section, labeled Discussion:
Thermal gradients are needed for life. These can be supplied by geological variations on the surface of rocky planets. Examples for sources of free energy are geothermal energy powered by the planet’s gravitational binding energy at formation and radioactive energy from unstable elements produced by the earliest supernova. These internal heat sources (in addition to possible heating by a nearby star), may have kept planets warm even without the CMB, extending the habitable epoch from z ∼ 100 to later times.
So where are those life forms today? Have most of them gone extinct? Have some evolved to the point where we wouldn't recognize them as "life forms" today?
Imagine their despair as the temperature dropped (how quickly?) on their planet far, far from any star. They must have thought the universe is cruel, and God is a jerk.
What would the wavelengths of the background radiation be at this time? Wouldn't there be an awful lot of high energy particles bouncing around?
I ask because I wonder what limits there would be to complex molecules forming under those circumstances: how much insulation would they need to protect them and whether that amount of insulation would limit the development of life.
As we peer back with our telescopes toward the beginning of time, and measure the age of the universe, we are beginning to find that the universe is closer to ten billion years old than to fifty; that the oldest of the stars we see around us are, in fact, as old as any star can be; as old as the universe itself. Looking outward, we are finding that the gravity of the universe is not enough to pull it back together in some future cataclysmic big-crunch. The universe will expand forever.
Ten billion years. A mere eyeblink in cosmic time. We stand at the beginning of time, looking outward into the void of infinite time.
Ctrl-f metal.. nope. Metallicity. I would've thought at that time when the first stars were forming there weren't enough heavy elements to produce rocky planets yet. Some time after the first few supernovas, which should've taken just a few million years more, it should've been possible.
This makes me wonder if we are just children of some of the earlier species. If not, did life spontaneously come to existence here, on our lump of rock in space?
In any way, as someone already had said, we're a bit late for the show now.
My mind is utterly blown. So it's possible that there were life forms (roll of the dice) before when the temperature of the universe was best. They did not figure out how to survive or did they? If they had wouldn't they have already made contact and transferred some of their survival know hows?
The idea that universe gets colder and colder resulting in less and less life is reflection of our current state. We haven't found a civilization beyond this planet and I fear we never will.
[+] [-] mikeash|12 years ago|reply
I'm particularly intrigued by the perspective of hypothetical intelligent life in this era. They'd presumably be able to discover the laws of physics and the evolution of the universe as we have. They'd see that the universe was millions of years old, and presumably that would be considered a really long time. They'd know that the universe was expanding and cooling.
They'd extrapolate out to our era. Would they consider this era to be cold and dead? I imagine their view of this era would be similar to our view of the dark era roughly 100 trillion years hence after all stars burn out and no new ones are being created. Incidentally, the distance is at a similar order of magnitude: we're about 1000 times farther removed from that 15 million year mark, and that "dark era" is about 10000 times farther out from today.
[+] [-] robbiep|12 years ago|reply
A counterpoint for consideration:
-complex life as we know it has taken 3.7 billion years to form. That doesn't mean it has to, conceivably it could have taken much less if it had of avoided some troughs and pitfalls along the way of its random walk; this also says nothing of life forms that come In conceptions we can't get our heads around.
I prefer to use this information to envisage a universe where protolife arose. And, since the universe was quite a bit smaller then, it was concievably possible for whatever arose (even simple chemical reactions that we would consider quasi-biological today) to spread throughout the universe.
Then, when proper galaxies formed and planets etc they were ready to be seeded by the cosmic leftovers of life's primal beginnings.
I feel this is more likely than the possibility of complex intelligent life because the universe at 15 million years would still have been deeply inhospitable: giant stars going supernova left right and centre laying down the foundations of US and everything we see, and not to forget average temperature when taken to universe-scale extremes still means areas hot as buggery and cold as empty void.
Still, it is fascinating to think that the precursors to all of us (you can probably tell that I was a fan of panspermia even before this news) was laid down so close to the beginning of time
[+] [-] kamaal|12 years ago|reply
Life originating only after some 15 million years after the big bang, would by any means be extremely super intelligent by now. So much that I guess their very nature of existence would be unimaginable to us. If not, what happened to them? Did they just got unlucky, got hit by asteroid every time and finally had no one to start over? Did they self destruct? Did they achieve singularity and those machines have managed to hide themselves since then? Or the universe is just plain unimaginable large that even for some one somebody like them just couldn't travel that long distances to meet others?
>>Would they consider this era to be cold and dead?
There is this thought that the science of universe we discover is based on observation. Ever expanding universe would leave it in a state that some time in the future people on a planet will just see darkness around them. No stars at all!!! They will likely assume universe is just them, and empty space all around. They would no nothing about Big Bang at all. So just like them, are we missing critical pieces of evidence already?
Plus Stephen Hawking has suggested if we manage to survive technology adolescence and survive to move out to space. We will eventually figure out a way to survive the cold dead era too.
So its like they are still alive.
[+] [-] simonh|12 years ago|reply
Still, it's an interesting notion. At some point there may have been a sweet spot between the background temperature and the availability of materials, and that point may have been billions of years in the past.
[+] [-] ggreer|12 years ago|reply
For massive stars that are dominated by radiation pressure and shine near their Eddington luminosity LE = 1.3 × 1040 erg s−1(M⋆/100M⊙), the lifetime is independent of stellar mass M⋆ and set by the 0.7% nuclear efficiency for converting rest mass to radiation, ∼ (0.007M⋆c2)/LE = 3 Myr (El Eid et al., 1983; Bromm et al., 2001).
Then it's a matter of figuring out how long it takes for matter to clump together and form stars/planets. After some math and citations in section 2:
The above calculation implies that rocky planets could have formed within our Hubble volume by (1+z) ∼ 78 but not by (1+z) ∼ 110 if the initial density perturbations were perfectly Gaussian. However, the host halos of the first planets are extremely rare, representing just ∼ 2 × 10−17 of the cos- mic matter inventory. Since they lie ∼ 8.5 standard deviations (σ) away on the exponential tail of the Gaussian probability distribution of initial density perturbations, P(δ), their abundance could have been significantly enhanced by primordial non-Gaussianity (LoVerde and Smith, 2011; Maio et al., 2012; Musso and Sheth, 2013) if the decline of P(δ) at high values of δ/σ is shal- lower than exponential. The needed level of deviation from Gaussianity is not ruled out by existing data sets (Ade et al., 2013b). Non-Gaussianity below the current limits is expected in generic models of cosmic inflation (Maldacena, 2003) that are commonly used to explain the initial density perturbations in the Universe.
Using current best knowledge about the early universe, it looks like planets did form, but were extremely rare. With some plausible tweaks to how "clumpy" the initial universe was, one ends up with lots more planets.
Side note: much of the paper measures time in z (red shift) instead of years. See http://en.wikipedia.org/wiki/File:Distance_compared_to_z.png to get an idea of the relationship between the two. The red dotted line is time in the past. The black solid line is comoving distance[1]. For comparison, some really old objects are mentioned at http://en.wikipedia.org/wiki/Redshift#Highest_redshifts
1. Distance if you could freeze the universe at the present day and lay out a bunch of yard sticks.
[+] [-] Fuxy|12 years ago|reply
Then again all life could have originated at that time and just now got the chance to evolve into a sentient species.
That would explain why a lot of comets and meteorites have the necessary building blocks of life in them.
[+] [-] gfodor|12 years ago|reply
[+] [-] jerf|12 years ago|reply
Furthermore, while any given species might not have survived from so long ago, life itself should never have died out, if intelligent life was common and abundant. The challenges of surviving that era are such that even we can plausibly imagine being able to meet the challenges in a century, or less if we were concentrating.
It's a poetic idea, but the universe does not look like one in which we are some last dying ember living in the carcass of past giants; it looks like one in which there's little-to-no intelligent life in our past light cone.
[+] [-] arethuza|12 years ago|reply
"the mind seemed to grow giddy by looking so far into the abyss of time."
and
"The result, therefore, of our present enquiry is, that we find no vestige of a beginning,–no prospect of an end."
http://en.wikipedia.org/wiki/Deep_time
[+] [-] JoeAltmaier|12 years ago|reply
[+] [-] Tenoke|12 years ago|reply
Also: >By demonstrating that life could have formed so early, Loeb may even have delivered a blow to so-called anthropic arguments about life in the universe.
What? No.
[+] [-] leobelle|12 years ago|reply
[+] [-] drjesusphd|12 years ago|reply
[+] [-] ultimatedelman|12 years ago|reply
[+] [-] richardjordan|12 years ago|reply
That's nonsense. I studied Physics in the early 90s and the various possibilities for early habitability used to crop up in conversation - in the common room if nothing else.
[+] [-] GotAnyMegadeth|12 years ago|reply
[+] [-] eru|12 years ago|reply
[+] [-] ggreer|12 years ago|reply
Thermal gradients are needed for life. These can be supplied by geological variations on the surface of rocky planets. Examples for sources of free energy are geothermal energy powered by the planet’s gravitational binding energy at formation and radioactive energy from unstable elements produced by the earliest supernova. These internal heat sources (in addition to possible heating by a nearby star), may have kept planets warm even without the CMB, extending the habitable epoch from z ∼ 100 to later times.
[+] [-] higherpurpose|12 years ago|reply
[+] [-] JoeAltmaier|12 years ago|reply
[+] [-] bladedtoys|12 years ago|reply
I ask because I wonder what limits there would be to complex molecules forming under those circumstances: how much insulation would they need to protect them and whether that amount of insulation would limit the development of life.
[+] [-] zem|12 years ago|reply
We live at the very beginning of the Universe.
As we peer back with our telescopes toward the beginning of time, and measure the age of the universe, we are beginning to find that the universe is closer to ten billion years old than to fifty; that the oldest of the stars we see around us are, in fact, as old as any star can be; as old as the universe itself. Looking outward, we are finding that the gravity of the universe is not enough to pull it back together in some future cataclysmic big-crunch. The universe will expand forever.
Ten billion years. A mere eyeblink in cosmic time. We stand at the beginning of time, looking outward into the void of infinite time.
[+] [-] rollo|12 years ago|reply
[+] [-] parandroid|12 years ago|reply
In any way, as someone already had said, we're a bit late for the show now.
[+] [-] MarkTee|12 years ago|reply
[+] [-] idoco|12 years ago|reply
[+] [-] notastartup|12 years ago|reply
The idea that universe gets colder and colder resulting in less and less life is reflection of our current state. We haven't found a civilization beyond this planet and I fear we never will.