We live at the beginning of the time when life is possible

[robertjford80]

Because it take about 3 generations of stars to build enough carbon to the point where life is possible, roughly 9 billion years, our Earth therefore was among one of the first planets that housed enough carbon to make life possible. Stars will continue to exist for hundreds of billions of years. But according to Paul Davies in his book the Cosmological Jackpot:

It will be hundreds of billions of years before stars become a rarity. Even then, there will still be black holes — the dead remnants of stars — which store a colossal amount of potentially usable energy. There is no fundamental reason why life and mind could not endure for
trillions upon trillions of years

And Alex Vilenkin in his book Many Worlds in one puts the limit on the life span of matter at

In less than a trillion years all stars will exhaust their nuclear fuel. Galaxies will turn into swarms of cold stellar remnants—white dwarfs, neutron stars, and black holes. The universe will be completely dark, with ghostly galaxies flying apart into the expanding void. This state of affairs endures for at least 10 to the 31 years, but eventually nucleons that make up the stellar remnants decay, turning into lighter particles— positrons, electrons, and neutrinos. Electrons and positrons annihilate into photons, and the dead stars begin slowly to dissolve. Even black holes do not last forever. Hawking’s famous insight, that a black hole leaks out quanta of radiation, implies mat it gradually loses all its mass, or, as physicists say, “evaporates

In other words, life might be possible from 9 * 10⁹ to 10³¹ and we live practically at the beginning of that span. I find this fishy. Does anyone else? I'm not sure what this fact means, but I'm interested to hear what other people have to say.

 

[phinds]

Doesn't seem odd or fishy to me. It seems to be based on what we know about the universe right now, and that's a fair amount, even with some big gaps. What is it about it that bothers you?

 

[robertjford80]

If you choose a number between 1 and 10^20 you should choose something in the middle, not something right near the beginning.

 

[phinds]

If you choose a number between 1 and 10^20 you should choose something in the middle, not something right near the beginning.

Yes, but that's math. This is reality. It is inevitable that early life in the universe will wonder WHY it is the early life in the universe, so if we ARE early life then ...

 

[robertjford80]

Yes, but that's math. This is reality. It is inevitable that early life in the universe will wonder WHY it is the early life in the universe, so if we ARE early life then ...

Yes, it is inevitable that we will wonder why, but that is not an answer as to why we live at the beginning of the age of the habitable zone.

 

[robertjford80]

I don't know how to calculate standard deviations, maybe I'll look it up, but I would seriously like to know how many stadev we are away from the likely habitable zone.

 

[phinds]

Yes, it is inevitable that we will wonder why, but that is not an answer as to why we live at the beginning of the age of the habitable zone.

Well, hey ... SOMEBODY has to. Why not us?

 

[robertjford80]

Well, hey ... SOMEBODY has to. Why not us?

That answer doesn't make the fishiness go away.

 

[Naty1]

Because it take about 3 generations of stars to build enough carbon to the point where life is possible, roughly 9 billion years, our Earth therefore was among one of the first planets that housed enough carbon to make life possible.

My first thought is that carbon based 'life' appears very opportunistic, perhaps emerging far more simply than we so far imagine. That could be a subject for another forum. There was a meteor or some other object recently tested and one of the AGTC building blocks was found in it! I still wonder where that object might have originated.

It seems you think Earth may be unique in some way? It seems more likely to me there are billions upon billions of carbon life form habitable objects, planets included. One thing for sure, life during a period when there were not the necessary elements for it is unlikely. So I'm not surprised it popped up when it could; Quantum theory almost demands it should do so.

Would you find our situation less 'fishy' if other non carbon perhaps more ancient life forms are discovered?

The most distant light is we receive is from 'only' about 45 billion light years away; but a likely ‘minimum distance’ for the 'most distant matter' is about 360 billion light years or thereabouts. Maybe it’s infinity. So there is a lot more than we can see even if not infinitely more. Could lots of that be 'older than us??

 

[Chronos]

9 billion years puts the earliest likely time for life arise in the universe [according to Vilenkin] at least a billion years before life on earth. That does not seem particularly odd. Like corn in a popper, the action can get pretty furious in a hurry after the first few pops.

 

[DaveC426913]

In other words, life might be possible from 9 * 10⁹ to 10³¹ and we live practically at the beginning of that span. I find this fishy. Does anyone else?

You are looking at it wrong.

What you're saying is tantamount to this:

March is when the snow thaws and rain falls regularly, raising the water table. November is when rainfall drops off to near nil.

Why is it that the there's so much growth in March/April? This seems fishy. Why shouldn't it strike a balance - somewhere in the middle - in July?

 

[marcus]

Robert, I'm trying to understand what's fishy. It seems to apply to EARTH history as well as cosmic, anytime you can define a long historical era and we happen to be living at or near the beginning.

what's logically different for example if I make the reasonable prediction that humans or more evolved Earth species will continue to be able to put things in orbit for, say, 5 billion years?
Define that kind of Earth life to be space-life "S-life" and remember I'm just looking at Earth history, not cosmic.
Isn't it fishy?! S-life is likely to exist for 5 billion years and we are living nearly at the start! S-life has only existed for around 60 years!

I would not call it fishy, I would call it interesting. Something interesting to learn about and reflect on. Part of seeing ourselves in historical context.
========================

Maybe there is some logical difference you can explain to me. Life is hard to define, one doesn't know what's possible life-wise. You seem to have chosen to imagine CARBON chemistry life arising on planets in orbit around functioning stars. Call it PC-life for "planet&carbon". Sort of recognizably like the life we know. that then defines an era. The era during which PC-life exists.

We can conjecture that this will be a long historical era and that we happen to be near the beginning of it. I don't know how near the beginning of PC-life we actually are but it doesn't matter so much. Suppose we are near the beginning of the PC-life era. That's nice, it is something to think about, reflect on. See ourselves as pioneers. But I don't immediately see it as fishy.

Maybe you can explain.

 

[Haelfix]

There is actually a tangential story to say about this having to do with exponential expansion.

Take the population of the earth. It is a fact that because population seems to move on an exponential growth curve, a person born at any time t will note something rather odd. That is that the number of people living in his or her era, is roughly the same order of magnitude as the number of people in history that are dead. Very Copernican, but also quite odd upon further reflection.

Namely, assume that the observer wasn't that smart and didn't know that population growth was on an exponential. Any such observer would wonder why they seem to be in such a special place in time, when at any other time (given an infinite duration) naively the amount of dead people should be much much bigger. Of course, this isn't quite well defined, b/c there is no countably additive uniform probability measure over the integers.

Mathematically this is a simplified version of this coincidence problem in cosmology under the influence of exponential mechanisms like Cosmic inflation. Asking whether such and such a coincidence is really odd or not boils down to how you regulate the probability measures. Alas, there is no canonical choice.

 

[robertjford80]

You are looking at it wrong.

What you're saying is tantamount to this:

March is when the snow thaws and rain falls regularly, raising the water table. November is when rainfall drops off to near nil.

Why is it that the there's so much growth in March/April? This seems fishy. Why shouldn't it strike a balance - somewhere in the middle - in July?

That's a false analogy. Snow thaws in March due to a confluence of physical laws, namely position of the Earth at that time in the year, among other things. There is no physical law that obligates intelligent beings to exist in the beginning of the habitable age.

 

[rbj]

If you choose a number between 1 and 10^20 you should choose something in the middle, not something right near the beginning.

any life that gets intelligent enough to ask where they are in the timeline from beginning to end, soon that life will destroy itself. how long do you think the human race and our "world order" will last?

not long.

 

[robertjford80]

Robert, I'm trying to understand what's fishy. It seems to apply to EARTH history as well as cosmic, anytime you can define a long historical era and we happen to be living at or near the beginning.

what's logically different for example if I make the reasonable prediction that humans or more evolved Earth species will continue to be able to put things in orbit for, say, 5 billion years?
Define that kind of Earth life to be space-life "S-life" and remember I'm just looking at Earth history, not cosmic.
Isn't it fishy?! S-life is likely to exist for 5 billion years and we are living nearly at the start! S-life has only existed for around 60 years!

I would not call it fishy, I would call it interesting. Something interesting to learn about and reflect on. Part of seeing ourselves in historical context.
========================

Maybe there is some logical difference you can explain to me. Life is hard to define, one doesn't know what's possible life-wise. You seem to have chosen to imagine CARBON chemistry life arising on planets in orbit around functioning stars. Call it PC-life for "planet&carbon". Sort of recognizably like the life we know. that then defines an era. The era during which PC-life exists.

We can conjecture that this will be a long historical era and that we happen to be near the beginning of it. I don't know how near the beginning of PC-life we actually are but it doesn't matter so much. Suppose we are near the beginning of the PC-life era. That's nice, it is something to think about, reflect on. See ourselves as pioneers. But I don't immediately see it as fishy.

Maybe you can explain.

Sorry, Marcus but I really don't understand your point. I understand bit and pieces but not the whole of your meaning.

 

[robertjford80]

any life that gets intelligent enough to ask where they are in the timeline from beginning to end, soon that life will destroy itself. how long do you think the human race and our "world order" will last?

not long.

You're arguing from ignorance when you conjecture that intelligent life will not last long. You have no knowledge of the life spans of other intelligent species, say, any species with radio technology, so you have nothing to draw your conclusion on.

 

[robertjford80]

Here is another fishy coincidence. This is from Lawrence Krauss' A Universe from Nothing

The catalyst for this new gestalt originates from the argument I gave in the last chapter: dark energy is measurable today because “now” is the only time in the history of the universe when the energy in empty space is comparable to the energy density in matter.
Why should we be living at such a “special” time in the history of the universe? Indeed, this flies in the face of everything that has characterized science since Copernicus. We have learned that the Earth is not the center of the solar system and that the Sun is a star on the lonely outer edges of a galaxy that is merely one out of 400 billion galaxies in the observable universe. We have come to accept the “Copernican principle” that there is nothing special about our place and time in the universe.
But with the energy of empty space being what it is, we do appear to live at a special time

He doesn't reflect on why this has happened, he just states it.

 

[robertjford80]

Take the population of the earth. It is a fact that because population seems to move on an exponential growth curve, a person born at any time t will note something rather odd. That is that the number of people living in his or her era, is roughly the same order of magnitude as the number of people in history that are dead.

This is a separate issue, namely, why there are so many patterns in our number system. All of that I find much more problematic and much more spooky than the fact that we live in the beginning of the habitable age.

 

[Haelfix]

It is not really a separate issue. The crux of the problem is in determining whether you are 'typical' or 'atypical' in the statistical sense of the word. Defining what that means precisely is thorny, as I tried to illustrate. Certain assumptions need to be put into the system before you can make a mathematically rigorous statement (its like wondering what the probability is to pull a small O(1) integer out of the set of all positive integers)

For instance, if you lived in a universe where there was an exponentially growing distribution of life giving planets, then it doesn't matter when you were born. The value 't' is irrelevant, b/c no matter what value 't' takes (young, old, very old), you will always be in an era where there were about as many observers before as there are in the present. However if you don't realize that you are in an exponentially growing phase, and instead simply try to put a uniform probability measure on the space, you end up making all sorts of wrong conclusions.

 

[robertjford80]

Certain assumptions need to be put into the system before you can make a mathematically rigorous statement (its like wondering what the probability is to pull a small O(1) integer out of the set of all positive integers)

The odds of picking a small O(1) integer out of the set of all integers is infinitely small. The odds of picking an integer near zero from integers 1 to 10^20 is finite. So your analogy breaks down there.

For instance, if you lived in a universe where there was an exponentially growing distribution of life giving planets, then it doesn't matter when you were born. The value 't' is irrelevant, b/c no matter what value 't' takes (young, old, very old), you will always be in an era where there were about as many observers before as there are in the present. However if you don't realize that you are in an exponentially growing phase, and instead simply try to put a uniform probability measure on the space, you end up making all sorts of wrong conclusions.

This is a law of mathematics. It's like asking what are the odds of the circumference being 3.14 times greater than the diameter. It's always going to be 3.14. These two issues are not related. To demonstrate that they are not related let me try to sum up succinctly the two different issues:

1. the abundance of patterns in the set of all real numbers
2. the fact that we live right at the beginning of the habitable zone

Those two subjects are not related.

 

[Haelfix]

Except that the universe, galaxy formation and so forth is not necessarily bounded in time or in space. That would be an extra assumption that you would need to justify.

Worse, as in any physical system described by unitary physics there is a Poincare recurrence time, and indeed there might be all sorts of processes that produce galaxies and observers at very late times quite independant of that.

 

[robertjford80]

Except that the universe, galaxy formation and so forth is not necessarily bounded in time or in space. That would be an extra assumption that you would need to justify.

Quite simple, the BB occurred 13.7 billion years ago, so time and space are bounded by the present and the BB.

Worse, as in any physical system described by unitary physics there is a Poincare recurrence time, and indeed there might be all sorts of processes that produce galaxies and observers at very late times quite independant of that.

Might does not imply is. You have an argument from ignorance here. Whenever you see the word could or might in an argument, then you know it's an argument from ignorance. The fact of the matter is, anything could happen. Seriously, could the universe end tomorrow? Sure. Could the gravitational constant change? Sure. So when you posit that x can happen you're not making a positive assertion, you're just stating a tautology, we already know that anything can happen.

 

[Haelfix]

Obviously we are talking about boundedness into the future and not the past!

The Friedman-Robertson-Walker and eventual DeSitter solution that is under discussion here only has a boundary at timelike infinity, and its eventual fate is unclear.

http://en.wikipedia.org/wiki/Future_of_an_expanding_universe

The reason I use the word 'might' is b/c the exact physics at very late times (see the Wiki for what that means) is complicated and in fact significantly more complicated than what that page shows. I'd rather not get into the exact details as it very much depends on parts of physics that are not entirely understood.

One thing that we do know, is that if the laws of physics satisfy the conditions necessary for Liouvilles theorem and its quantum analogue to hold, then there absolutely will be a recurrence time, and you won't have any sort of finite probability measure available to use.

 

[robertjford80]

Obviously we are talking about boundedness into the future and not the past!

We're talking about a point in time in the future when matter will not be able to hold together. Some people put that at 10^31, others much higher, the point is though there is a boundary. Even if there is not, it is still fishy that we live at the beginning of the habitable age.

 

[Haelfix]

Sorry, there is no consensus at all on whether the universe is or is not compact spatially, or what boundary conditions one imposes.. In fact, it is not even clear whether there is a boundary in the past, as it is quite easy to write models that go beyond the standard big bang.

As I have said, assuming that indeed we are dealing with some sort of infinite set, then it is no more or less fishy that we happen to pull the number 3 out of a hat as opposed to a number like a googol. This is one of the difficulties with doing cosmology in a universe that might admit astronomically large distance scales and/or time scales and is very much a contemporary problem in modern cosmology.

 

[robertjford80]

Sorry, there is no consensus at all on whether the universe is or is not compact spatially, or what boundary conditions one imposes..

We certainly have much more evidence that the universe will continue to expand forever and that matter one day will not hold together than any other model. Even if matter continues to exist forever that merely makes things even more fishy.

In fact, it is not even clear whether there is a boundary in the past, as it is quite easy to write models that go beyond the standard big bang.

The evidence overwhelmingly suggests the BB began 13.7 bya. Even if there is some odd pieces of evidence that conflict with that thesis the BB is certainly the best explanation given the evidence. To advocate anything other than the best explanation is tantamount to irrationality.

As I have said, assuming that indeed we are dealing with some sort of infinite set, then it is no more or less fishy that we happen to pull the number 3 out of a hat as opposed to a number like a googol.

Not every integer is special. What's fishy is when you pick a special number from an infinite set such as pi or e. Numbers at the beginning are special. The number one for instance is much more special than 1,254,785,854

 

[Haelfix]

We certainly have much more evidence that the universe will continue to expand forever and that matter one day will not hold together than any other model.

As I said, it is significantly more involved than you might imagine. For one, quantum mechanics becomes involved when we start talking about astronomically big time scales. Further the eventual heat death of the universe does not mean that galaxies will no longer form. The picture to have in mind is of two liquid canisters mixing. Eventually they reach an equilibrium mixed state, and seem to stay that way, but over very large timescales eventually they go back to their starting configuration (or arbitrarily closely)

The evidence overwhelmingly suggests the BB began 13.7 bya. Even if there is some odd pieces of evidence that conflict with that thesis the BB is certainly the best explanation given the evidence. To advocate anything other than the best explanation is tantamount to irrationality.

Yes, although I don't think this means what you think it does. In particular the evidence for the BB says nothing about whether there is a singularity in the past.

Not every integer is special. What's fishy is when you pick a special number from an infinite set such as pi or e. Numbers at the beginning are special. The number one for instance is much more special than 1,254,785,854

This is the incorrect albeit very common notion that I have been trying to unsuccessfully dispel since the beginning. This is very wrong mathematically!

 

[robertjford80]

As I said, it is significantly more involved than you might imagine. For one, quantum mechanics becomes involved when we start talking about astronomically big time scales. Further the eventual heat death of the universe does not mean that galaxies will no longer form. The picture to have in mind is of two liquid canisters mixing. Eventually they reach an equilibrium mixed state, and seem to stay that way, but over very large timescales eventually they go back to their starting configuration (or arbitrarily closely)

I don't see what you're driving at. Either way, if there is or is not a boundary in the future for life existing that doesn't dispel the fact that there is something fishy about finding ourselves at the beginning of the habitable age.

Yes, although I don't think this means what you think it does. In particular the evidence for the BB says nothing about whether there is a singularity in the past.

We have no evidence that life existed before the CMB, hence there is no reason to believe it.

This is the incorrect albeit very common notion that I have been trying to unsuccessfully dispel since the beginning. This is very wrong mathematically!

Look, it's quite obvious that there are some numbers that are special and some that aren't. Since you can't understand that, there is no point in dialoguing.

 

[robertjford80]

Moreover, the thesis that no numbers are special is an extreme minority view. If you're going to prove that it should be a majority view then you're going to have to do better than a mere assertion.

 

[Haelfix]

Look, it's quite obvious that there are some numbers that are special and some that aren't. Since you can't understand that, there is no point in dialoguing.

Don't take my word for it. Try to prove this to yourself mathematically! Define what you mean by 'special', and then show that the irrational number PI satisfies your definition over say the real numbers.

 

[robertjford80]

You're just begging the question that things must be proven mathematically. Not everything must be proven using mathematics. Take beauty, beauty certainly isn't proven with mathematics. Only a conscious agent can determine what is special and they do it without recourse to mathematics.

 

[Astronuc]

Closed pending moderation.