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.
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.
What is survival without a biological body? If you transfer a brain to a computer, is it still surviving, is it still "living"? or is part of the magic of life in it's uniqueness? Once we can instantly replicate any part of ourselves, what will that mean, are we still living at that point? or just useless machines?
People whose limbs have been amputated, generally report of phantom limbs. They even experience sweating, itch etc on the phantom limb. Now how come the brain detects all that on a limb that isn't even present? It seems sense originates in the brain and the body parts are just acting mere like sensors and output peripherals.
If that is true you should not worry much about this biological body thing at all. After all we have organ transplants already. Like the argument about Ship of Theseus, you have to ask if a person who underwent organ transplants for more than one organ is actually the original person. If you were to wake that person post surgery, how much less of his original self he is since a good deal of body parts are replaced I am sure to bet he will say nothing changed at all.
Transferring brain to a computer is just brain transplant. If you accept organ transplant you should hardly have any problem with this at all.
I disagree, because the brain itself is the source of sentience and the only thing that really matters. The other organs all have a support role for the brain. Replacing those organs will of course not feel like there's any difference (unless they don't work correctly) because the source of a person's sentience is in the brain itself, not in those organs.
On the other hand, if there was a way to "digitalize" a brain and let it run in a simulation, it could still be conscious and have the same possibilities as the brain of a normal person with a normal body, but it would still be a duplicate of it. I don't think it's ever going to be possible to "transfer" yourself to a copy without dying. Sentience is far too intertwined with the physical aspect of the brain for it to be possible to transfer yourself into a copy without dying.
I share your viewpoint but I think there is a potential solution to this problem (not that I advocate doing it, treat it as a thought experiment): implant the blank slate hardware for the digital copy years before it takes over everyday operation and let it observe your brain to learn. Give the digital copy all the same inputs as the biological brain and make sure the (at first unused) continuous output of the digital copy matches true brain behavior to a desired level of error. Slowly assign control of the biological body to the digital copy over years of time -- somewhere in there "you" may have died but nobody will notice, including yourself. Then when the biological body dies, the digital copy will have already been "you" for quite some time and you're ready to be dropped directly into a mechanical body or a virtual world -- though those would also likely be gradual processes.
(I also think the underlying problem of thinking the digital copy isn't you may even be an illusory one in that our consciousness experiences a discontinuity every night when we go to sleep.)
Transferring brain to a computer is just brain transplant.
If you accept organ transplant you should hardly have any
problem with this at all.
Your "uploaded" brain probably won't have any problem with this, but your original physical instance brain probably won't be too happy to have the lights turned off.
John Weldon's "To Be" (https://www.youtube.com/watch?v=pdxucpPq6Lc) kind of touches on this. It focuses on teleportation, but I think a brain upload is pretty much the same idea at heart.
If you're a materialist, yes, as far as I can tell simulating a brain or running any sort of equivalent software must cause consciousness to arise. Speed is not really part of the question. It's the shape of the computation that determines consciousness.
Life may have started in warmish carbon-water chemistry and humans may currently run on meat brains, but there's no reason to assume we have to stay limited to that sphere.
So far as I'm concerned, anything which computes accurately "what I would think" is a copy of me. And anything which computes a mind and is temporally descended from me is me, even if we wouldn't recognize each other.
That's the kind of wanna be phylosophical question that is based on disagreements about the meaning of words.
If it quacks like a duck, walks like a duck, eats like a duck and reproduces like a duck, does it matter that's solid state instead of packs of water inside membranes?
One idea I've had about past civilisations is to do with quantum immortality. Suppose you did a Schroedinger's cat type experiment, but you were the cat. If the multiple universe hypothesis is true, then when the box is opened, two universes form, one in which you're alive and one in which you're dead. Since you're not in the universe where you're dead, subjectively, you would simply always survive the experiment. Now, imagine if you linked the trigger for death to a measurement of energy. You create a box that kills you unless some observed material randomly spikes in energy. It's a bit like a quantum suicide version of Maxwell's demon. Subjectively, you get free energy. More than that, this quantum killer Maxwell demon would be a fairy Godmother in disguise. You could make anything happen as long as it is directly observable and has non-zero probability. However, if you do it enough, anyone who isn't in the box with you, will very likely see you die.
So there's the problem. You have a source of free energy or entropy or free anything, but using it will make you appear dead to everyone you care about. The solution would be to get everyone you care about together in the same box.
From our point of view, when we explore the galaxy in the future and we will keep on finding long dead previously civilised planets which had advanced aliens who one day suddenly bundled everyone on onto a massive spaceship and then blew themselves up. Then one day, we'll start bundling ourselves up and do the same.
In practical terms "bundling everyone together" might mean merging into one consciousness (for convenience). Which would make the whole process a lot like "The Last Question" by Asimov.
Wow this is sort of like Greg Egan's Permutation City but actually seems slightly less far fetched and it solves the "where are all the aliens?" problem. In order to hack entropy we erase ourselves from all possible universes where entropy is increasing.
The Schrödinger's cat is a deliberately absurd argument anyway, and it's widely misunderstood as a serious argument.
The quantum effects will collapse when there are any macroscopic effects: there has to be a detector that will trigger the hammer that breaks the poison.
You speak of singularity as if it is something that can be achieved, while in fact it is just a hypothesis, or a sci-fi thought experiment, that imagines one possible outcome of developing smarter-than-human AI. In particular, singularity proposes that such a discovery would cause a complete qualitative phase-shift in technology and human existence in general, but for this outcome the hypothesis relies on many speculations. As many have pointed out, smarter-than-human AI might not bring about singularity (or is even unlikely to do so).
At our current technological era, speaking of singularity is no different from speaking of other science-fiction ideas like warp drive or even time travel.
Would you say that a very old civilization would have surely developed warp-drive or time travel by now? Same with singularity. We don't know it's possible. We don't even know it exists. We're not even sure what it is.
I'm not sure. What you could say about warp-drives or time travel could have been said about Airplanes, organ transplant too.
Yet they are possible now.
Its very much like some in Newton or Gauss's era talking about a small piece of device made from silicon being able to do some million of arithmetic calculations in one second. You would be considered insane for even having such thoughts.
I think any entity that has to somehow be attracted to any kind of "food", and be repelled from any kind of "pain", ie, I think, any kind of life, has due to the above, ingrained the concept of "happy".
-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
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.
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.
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.
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.
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.
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.
I guess my point is that it wouldn't surprise me, given the way science tends to downgrade humans from being at the center of the universe, if we were in fact not alone but instead are one of many intelligent species throughout the galaxy and universe today (while on the lower end of the intelligence scale as our relative lack of time in existence would suggest.)
What would be rather surprising but yet poetic to me is if we find out that ultimately humans are special: we are special in our solitude, entering the cosmos in a period of declining intelligent life due to the expansion. It would be a strange twist: we get some satisfaction in knowing we are unique in being an unremarkable, irrelevant, isolated civilization.
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.
If you consider the "infinite" of space and, especially, time, I believe that the probability of the existence of (at least) one "inteligent" species capable of reaching any given place of the universe is 100%.
The Prime Directive only works if you assume that these hypothetical species are much more altruistic than we ourselves are. I find it highly unrealistic that any species, however highly evolved, would be 100% altruistic, with no rebels/thieves/slavers/prospectors that would desire to interfere with or destroy us humans.
And that's not to mention that realistically it would be almost impossible for a civilization to completely hide its presence. For example as humans our radio footprint from TV and radio and satellite broadcasts is spreading out of our solar system. That's going to keep on traveling and I don't see any way that we'd be able to just "erase" that so that no one else would notice it.
Time is not infinite, and our past light cone is not infinite. It grows as less than the cube of the space we can observe (the universe is very not universally distributed), while the independent probabilities of whatever is required for life multiply exponentially. The idea that the odds of life are 100% is just a naive "Big Numbers" fallacy.
The Prime Directive was created to preserve the desired structure of drama on a TV show. It is ludicrous from any other perspective.
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.
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.
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.
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?
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.
That gave me pause too, and this is the best explanation I could think of for why the author brought it up: The anthropic principle can explain why we find ourselves in a universe exactly this old, because billions of years earlier the conditions weren't yet suitable for life. If you mistakenly think the anthropic principle is making a fixed prediction about the point at which suitability began, then you might think that discovery of an earlier period of suitability would invalidate the principle, but of course it does not.
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.
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.
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.
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.
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[ 3.3 ms ] story [ 105 ms ] threadI'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.
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.
People whose limbs have been amputated, generally report of phantom limbs. They even experience sweating, itch etc on the phantom limb. Now how come the brain detects all that on a limb that isn't even present? It seems sense originates in the brain and the body parts are just acting mere like sensors and output peripherals.
If that is true you should not worry much about this biological body thing at all. After all we have organ transplants already. Like the argument about Ship of Theseus, you have to ask if a person who underwent organ transplants for more than one organ is actually the original person. If you were to wake that person post surgery, how much less of his original self he is since a good deal of body parts are replaced I am sure to bet he will say nothing changed at all.
Transferring brain to a computer is just brain transplant. If you accept organ transplant you should hardly have any problem with this at all.
On the other hand, if there was a way to "digitalize" a brain and let it run in a simulation, it could still be conscious and have the same possibilities as the brain of a normal person with a normal body, but it would still be a duplicate of it. I don't think it's ever going to be possible to "transfer" yourself to a copy without dying. Sentience is far too intertwined with the physical aspect of the brain for it to be possible to transfer yourself into a copy without dying.
(I also think the underlying problem of thinking the digital copy isn't you may even be an illusory one in that our consciousness experiences a discontinuity every night when we go to sleep.)
John Weldon's "To Be" (https://www.youtube.com/watch?v=pdxucpPq6Lc) kind of touches on this. It focuses on teleportation, but I think a brain upload is pretty much the same idea at heart.
If someone built a gigantic abacus and used to slowly simulate a brain, would that cause a consciousness to emerge?
So far as I'm concerned, anything which computes accurately "what I would think" is a copy of me. And anything which computes a mind and is temporally descended from me is me, even if we wouldn't recognize each other.
If it quacks like a duck, walks like a duck, eats like a duck and reproduces like a duck, does it matter that's solid state instead of packs of water inside membranes?
So there's the problem. You have a source of free energy or entropy or free anything, but using it will make you appear dead to everyone you care about. The solution would be to get everyone you care about together in the same box.
From our point of view, when we explore the galaxy in the future and we will keep on finding long dead previously civilised planets which had advanced aliens who one day suddenly bundled everyone on onto a massive spaceship and then blew themselves up. Then one day, we'll start bundling ourselves up and do the same.
In practical terms "bundling everyone together" might mean merging into one consciousness (for convenience). Which would make the whole process a lot like "The Last Question" by Asimov.
The quantum effects will collapse when there are any macroscopic effects: there has to be a detector that will trigger the hammer that breaks the poison.
At our current technological era, speaking of singularity is no different from speaking of other science-fiction ideas like warp drive or even time travel.
Would you say that a very old civilization would have surely developed warp-drive or time travel by now? Same with singularity. We don't know it's possible. We don't even know it exists. We're not even sure what it is.
Yet they are possible now.
Its very much like some in Newton or Gauss's era talking about a small piece of device made from silicon being able to do some million of arithmetic calculations in one second. You would be considered insane for even having such thoughts.
Who needs (super) intelligence, when one can be happy?
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
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.
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.
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.
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.
Do you have a math relationship between time and CMB temperature?
Interested to know how long this early era of habitability lasted (not mentioned in the article).
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.
"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
What would be rather surprising but yet poetic to me is if we find out that ultimately humans are special: we are special in our solitude, entering the cosmos in a period of declining intelligent life due to the expansion. It would be a strange twist: we get some satisfaction in knowing we are unique in being an unremarkable, irrelevant, isolated civilization.
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.
The question of why they don't contact us is simple: Prime Directive (http://en.wikipedia.org/wiki/Prime_Directive)
Disclaimer: I'm not a particular fan of Star Trek and bumped into this interesting principle, which I believe makes perfect sense.
And that's not to mention that realistically it would be almost impossible for a civilization to completely hide its presence. For example as humans our radio footprint from TV and radio and satellite broadcasts is spreading out of our solar system. That's going to keep on traveling and I don't see any way that we'd be able to just "erase" that so that no one else would notice it.
The Prime Directive was created to preserve the desired structure of drama on a TV show. It is ludicrous from any other perspective.
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.
In any way, as someone already had said, we're a bit late for the show now.
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.
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.
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.