Life in the Early Universe: Origins and Evolution

[GoodUniverse]

Hello Folks,

I have an interesting question (I think)... how far back in the history of universe would you have to go before any form of life existed?

Thanks.
CJ

 

[GoodUniverse]

... sorry, answered my own question. It was 12.7 billion years ago. After the first supernova's seeded space with the elements required for life.

Interestingly, the oldest object we've seen is 13 billion years old... something older than the possibility for life itself... wonder what implications that has for quantum enthusiasts that wonder if there is truly a physical universe in the absence of a biological observer. I guess there must have been.

 

[sigma143]

I guess the physical universe Now could be more so described as a translation of the biological observer, from how it subjectively perceives the effects on it's senses microscopically as contrasted with how the senses are objectively manifested macroscopically. Technically the energy of the 10^-44 universe is still conserved and conversed in how we perceive our reality.

 

[JeffKoch]

... sorry, answered my own question. It was 12.7 billion years ago. After the first supernova's seeded space with the elements required for life.

If you presume, with no evidence or theoretical foundation, that supernova explosions are prerequisites for life. Which by the way also requires a definition of life, and there is no consensus on what that definition is - and even if we had one we could all agree on, it would necessarily only encompass all life as we know it. So you see the problems inherent in your question.

 

[Chronos]

The first supernova/hypernova probably did not originate until the universe was about 500 million years old. Given life as we can imagine it demands an abundance of metallicity, it appears unlikely it could have originated less than ~ 5 billion years after the big bang - or between 8 - 9 billion years ago.

 

[phinds]

Hello Folks,

I have an interesting question (I think)... how far back in the history of universe would you have to go before any form of life existed?

Thanks.
CJ

When you say you answered your own question, I disagree completely. Your question was about "EXISTANCE" not "might have existed" and as Chronos properly pointed out, "EXISTS" is likely to be WAY different that "might have"

 

[GADAMBA]

How do I create a thread here

 

[Ryan_m_b]

How do I create a thread here

Simply go to the relevant forum and you should see in the top left (above the list) a button marked "new topic". Welcome to PF

Hello Folks,

I have an interesting question (I think)... how far back in the history of universe would you have to go before any form of life existed?

Thanks.
CJ

This is largely an unanswerable question as we do not know what conditions are necessary to give rise to life. We have some idea about life on Earth but this is all. Therefore the only meaningful question is "how early could Earth-like life have come into existence?" to which I would suggest the answer would be closely linked to "when did the first Earth-like planets form?"

 

[GADAMBA]

Thanks

 

[Orion1]

how far back in the history of universe would you have to go before any form of life existed?

According to my basic equation, the amount of universal evolutionary time required to generate self-replicating RNA:
t_{RNA} = dt_1 + dt_2 + dt_3 + dt_4 = (t_u - t_s) + (t_{\odot} - t_E) + (t_E - t_z) + (t_z - t_l)
\boxed{t_{RNA} = 1.22 \cdot 10^{9} \; \text{y}}
The first self-replicating RNA life could have been generated 1.22 billion years after the Big Bang on the inner planets around second generation and third generation stars, which formed together at the same time.

key:
dt_1 - minimum time required for second generation stars to form.
dt_2 - minimum time required for inner planets to form.
dt_3 - minimum time required for liquid water to form.
dt_4 - minimum time required for RNA life to form.

t_u = 13.85 \cdot 10^{9} \; \text{y}
t_s = 13.2 \cdot 10^{9} \; \text{y}
t_{\odot} = 4.57 \cdot 10^{9} \; \text{y}
t_E = 4.54 \cdot 10^{9} \; \text{y}
t_z = 4.4 \cdot 10^{9} \; \text{y}
t_l = 4.0 \cdot 10^{9} \; \text{y}
t_u - Universe age
t_s - oldest second generation star age in Milky Way galaxy
t_O - solar age
t_E - Earth age
t_z - oldest Zircon age
t_l - oldest fossilized RNA life age
[/Color]
Reference:
http://en.wikipedia.org/wiki/Universe"
http://en.wikipedia.org/wiki/HE_1523-0901"
http://en.wikipedia.org/wiki/Sun"
http://en.wikipedia.org/wiki/Earth"
http://en.wikipedia.org/wiki/Cryptic_era"
http://en.wikipedia.org/wiki/Basin_Groups"

 

[lone77star]

Orion1, nice formula. Of course, we only have a sample of 1 with Earth, so your dt_2 and dt_3 can only be taken as rough approximations.

I think Chronos made a good point about requiring an abundance of metallicity. The first string of second generation stars might not have had sufficient "abundance." Of course, this plays with probabilities. For anything more accurate, one might need to model dispersal of early universe "metals," and the likelihood that those metals would remain in sufficient concentrations upon nebular collapse to yield metal-rich planetary bodies.

Could some of the so-called first string, second generation stars have modified metallicities from nebula passage doping? That could certainly skew any models. Such a star might look fairly metal-rich, but did it start out that way? If not, then it is quite likely that any planets it possesses would not have snared a comparable load of "metals" from the process (smaller cross section and smaller gravity potential). Such planets, then, would likely only be hydrogen-helium gas giants with a little "flavoring."

 

[Orion1]

Orion1, nice formula. Of course, we only have a sample of 1 with Earth, so your dt_2 and dt_3 can only be taken as rough approximations.

I think Chronos made a good point about requiring an abundance of metallicity. The first string of second generation stars might not have had sufficient "abundance."

All the solar inner planets probably formed from a stellar accretion disc at the same time, regardless of their mass and distance from their primary star, some 4.54 billion years ago.

I have attached a plot based upon the model in post #10 with the stellar generation number on the x-axis and the Iron to Hydrogen (Fe/H) ratio on the y-axis.

Even though second and third generation stars formed at the same time, the inner planets for second generation stars are probably dwarf planets composed primarily of Period I-III elements (Carbon, Silicon) and inner planets around third generation stars are probably composed primarily of Period III-IV elements (Silicon, Iron).
[/Color]
Reference:
http://en.wikipedia.org/wiki/Metallicity"

 

[tvscientist]

Early Life

The chemical necessities seem to exist at a very early stage. In fact, I am fond of saying the universe is old enough that anything that could happen has already happened. I base this on the fact our own sun is, I believe, third generation and thus our solar system includes all the elements of the Periodic Table.

However, we have absolutely no evidence life exists anyplace else in the Universe. In fact, over the last half century all, or almost all, of the accumulated data on the subject has REDUCED the statistical probability of other civilizations by many orders of magnitude. My friends simply tell me the mathematics are not in my favor: Billions of solar systems in billions of galaxies.

I have been keeping a log book on The Drake Equation. The original Wild *** Guess, I believe, was nineteen technologically advance civilizations within our own Galaxy. During the last several decades, however, actual data accumulation has reduced this SWAG by many orders of magnitude.

Here are a few of the data sets:

1) Not only is there a Goldie Locks zone in our solar system, there is a Goldie Locks zone in our own Galaxy. The last time I heard an estimate was that many millions of suns are in our Galactic Goldie Locks Zone. So forget about billions and billions of potentially habitable planets in the Milky Way. But I am happy with millions.

2) But it gets worse. It always gets worse. We have actually sampled several hundred planetary systems. and not one single one of them seems even remotely conducive to complex life. For instance, the norm seems to be that Gas Giants normally occupy orbits within their respective inner solar systems.

3) However, the most discouraging SETI statistic has to be the fact that our own gloriously human friendly cosmological situation is a statistical rounding error of about .000,001. In five billion years, we have managed to accumulate one single mathematically capable species descended from nothing more then a few hundred breading pairs.

I really really want to talk with ET. So let's keep listening. But lest not hold our breath.

 

[Ryan_m_b]

1) Not only is there a Goldie Locks zone in our solar system, there is a Goldie Locks zone in our own Galaxy. The last time I heard an estimate was that many millions of suns are in our Galactic Goldie Locks Zone. So forget about billions and billions of potentially habitable planets in the Milky Way. But I am happy with millions.

This is of course only (potentially) true for the specific kind of biochemistry of life we are familiar with and not a statement about life in general.

2) But it gets worse. It always gets worse. We have actually sampled several hundred planetary systems. and not one single one of them seems even remotely conducive to complex life. For instance, the norm seems to be that Gas Giants normally occupy orbits within their respective inner solar systems.

I'd be aware of the statistics of this observation. Firstly hundreds of systems is not significant and secondly we are using limited instruments that have a far easier time picking out large mass objects.

In addendum my first point still stands; for all you know everyone of those gas giants is teeming with life.

3) However, the most discouraging SETI statistic has to be the fact that our own gloriously human friendly cosmological situation is a statistical rounding error of about .000,001. In five billion years, we have managed to accumulate one single mathematically capable species descended from nothing more then a few hundred breading pairs.

I really really want to talk with ET. So let's keep listening. But lest not hold our breath.

We evolved to the level we are now over the past few million years. There is little reason why throughout most of post-Cambrian history a species could not evolve with our level of intelligence. The reason is that selective pressure happened to show itself when it did and evolution managed to follow this path. It is nonsensical to say "this even happened once in X therefore the chance is 1 in X" because you have no idea of the variables involved.

 

[Cosmo Novice]

In addendum my first point still stands; for all you know everyone of those gas giants is teeming with life.

Yes we do place a lot of empahsis on our single sample of life. It may actually be that life on rocky planets is a rarity and gaseous planets are abundant - until we have a decent sample, once we have warp drive, then we will know

 

[Pythagorean]

[...]
Firstly hundreds of systems is not significant and secondly we are using limited instruments that have a far easier time picking out large mass objects[...]

and thirdly, we are only looking in a small temporal window; if life is pervasive in the universe, many systems would have bypassed (or have yet to pass through) a habitable stage. Whole arrays of species could have evolved and went extinct long ago, or won't evolve until long after humans are extinct and the Earth is cold.

We may very well always be alone locally, even if we're not alone in the whole spatiotemporal frame of the universe.

 

[qraal]

According to the work of Carl Gibson, and colleagues, the first Biocompatible planets appeared about 3 million years after the Big Bang...

http://arxiv.org/abs/1109.1262

 

[Flustered]

Taking the goldy zone theory into theory, do you believe that there is more intelligent life out there sometime in the past or present. Or do you guys believe that all this space is needed for us to survive?

 

[Ryan_m_b]

Taking the goldy zone theory into theory, do you believe that there is more intelligent life out there sometime in the past or present. Or do you guys believe that all this space is needed for us to survive?

Patently we don't need all this space to survive insofar as the universe was necessary for Earth and thus us to come about.

As to whether or not there has been or is tool-using, sentient life in the universe I have no idea. Whilst stars with planets seem to be common in the galaxy we have no way of knowing how likely or common it is for life to form and no idea how common it is for sentient, tool-using life to evolve on these planets, until we get meaningful data for that and plug it into the Drake equation (or something similar) we can't really talk about probability. An if we assume for a moment that tool-using, sentient life has evolved at some point in the galaxy's/universe's past the Fermi paradox rears it's ugly head.

 

[H2Bro]

I have a request for a more mathematically able PFer, and it relates to the SETI question.

I'd like to have a way (i.e. mathematical method) of thinking about how likely it is for any technical-species bearing planet to encounter radio transmissions sent by another technical species.

Lets say that once a species develops that is capable of producing technological societies it takes 100,000 years to reach the level of sending / receiving radio waves. Also let's say there is a time window of 1000 years where radio technology is frequently utilized, call it the receiving/broadcasting window.

My intuition is that I would model this using a differential equation that describes an expanding sphere of radio waves 1000ly thick, then find out the probability that this sphere intersects another technical planet during that planets radio-window. However, I'm afraid I haven't yet acquired the right calculus methods to describe that, and also I'm not sure how the statistical mechanics plays in here determining the probability of interception based on likelihood/distribution of technical civilizations.

What makes me bring this up is the question on whether there are intelligent species past our present. I suppose this is how we would go about estimating the likelihood of hearing from them.

 

[Drakkith]

H2Bro, did you know that if a radio signal was sent from Alpha Centauri, the nearest star system, with a signal strength equal to our most powerful transmitters, we wouldn't be able to receive it with our largest dishes? It would be so weak as to be undetectable.

 

[chill_factor]

Also optical signalling methods would not work, even UV lasers, because the star's glare would totally wipe it out and the angular divergence would be unresolvable.

The only way to do it is a totally automated system that launches a smaller film package back that'll automatically brake as it nears the solar system.

It would be an EXTREMELY high risk project.

 

[Chronos]

That paper may be the finest example of anthropomorphic creationism I've seen in years

 

[H2Bro]

H2Bro, did you know that if a radio signal was sent from Alpha Centauri, the nearest star system, with a signal strength equal to our most powerful transmitters, we wouldn't be able to receive it with our largest dishes? It would be so weak as to be undetectable.

This is something I did not know. What should I make of the SETI project then? totally hopeless?

Also, do you think Carl Sagan was unaware of this when he wrote 'Contact'? the plot premise is that a machine in orbit around Vega receives pretty much the earliest radio broadcast powerful enough to escape the ionosphere.

He had another idea on how to say 'I'm here' - to seed a star with a huge amount of rare metals to give it a totally unnature absorption spectrum. Probably even more impossible, though.

 

[Drakkith]

This is something I did not know. What should I make of the SETI project then? totally hopeless?

If they are broadcasting a sufficiently large signal, then not at all.

Also, do you think Carl Sagan was unaware of this when he wrote 'Contact'? the plot premise is that a machine in orbit around Vega receives pretty much the earliest radio broadcast powerful enough to escape the ionosphere.

The possibility exists that futuristic alien technology has the ability to detect extremely faint radio waves. I'd say it is exceedingly remote, but I have never seen alien technology either.

He had another idea on how to say 'I'm here' - to seed a star with a huge amount of rare metals to give it a totally unnature absorption spectrum. Probably even more impossible, though.

It would take a LOT of material. Much more than we could currently could do.

 

[chill_factor]

This is something I did not know. What should I make of the SETI project then? totally hopeless?

Also, do you think Carl Sagan was unaware of this when he wrote 'Contact'? the plot premise is that a machine in orbit around Vega receives pretty much the earliest radio broadcast powerful enough to escape the ionosphere.

He had another idea on how to say 'I'm here' - to seed a star with a huge amount of rare metals to give it a totally unnature absorption spectrum. Probably even more impossible, though.

impossible to filter it from the interstellar hydrogen noise.

 

[H2Bro]

impossible to filter it from the interstellar hydrogen noise.

This is what I thought too earlier today while on the train. If our radio signals are actually that weak, they would be drowned out by any random nearby cloud of gas that's a lot closer.

Or were you referring to the spectral absorption line characteristic?

 

[chill_factor]

This is what I thought too earlier today while on the train. If our radio signals are actually that weak, they would be drowned out by any random nearby cloud of gas that's a lot closer.

Or were you referring to the spectral absorption line characteristic?

yep i meant to say that artificial radio signals will be easily drowned out by interstellar noise.

 

[Vanadium 50]

H2Bro, did you know that if a radio signal was sent from Alpha Centauri, the nearest star system, with a signal strength equal to our most powerful transmitters, we wouldn't be able to receive it with our largest dishes? It would be so weak as to be undetectable.

Can you point me to a reference for that? Using Aricebo's radar dish, I get a signal of 20 mJy at alpha centauri. That's well within our ability to detect.

 

[Drakkith]

Can you point me to a reference for that? Using Aricebo's radar dish, I get a signal of 20 mJy at alpha centauri. That's well within our ability to detect.

I'd have to find it. I just remember reading it a while back. It's possible I am mistaken.
I tried doing the math before I posted, but couldn't figure out how to calculate it.

 

[mfb]

H2Bro, did you know that if a radio signal was sent from Alpha Centauri, the nearest star system, with a signal strength equal to our most powerful transmitters, we wouldn't be able to receive it with our largest dishes? It would be so weak as to be undetectable.

The VLT looked for signals from some exoplanet recently. I checked the numbers, we would have been able to detect signals similar to some of our transmissions in the past.

Also optical signalling methods would not work, even UV lasers, because the star's glare would totally wipe it out and the angular divergence would be unresolvable.

Humans can outshine sun with a very narrow frequency band (like 1 Hz) and high-power lasers (or multiple lasers) - it is expensive, but possible with current technology. However, you have to know the specific frequency and the radial velocity between sender and receiver to see the signal.



An old post:

3) However, the most discouraging SETI statistic has to be the fact that our own gloriously human friendly cosmological situation is a statistical rounding error of about .000,001. In five billion years, we have managed to accumulate one single mathematically capable species descended from nothing more then a few hundred breading pairs.

If (on average) 1 out of 1 billion species develops intelligence on a human level and an average planet with life sees 1 billion species during the lifetime of the star, where is the point?

 

[Drakkith]

The VLT looked for signals from some exoplanet recently. I checked the numbers, we would have been able to detect signals similar to some of our transmissions in the past.

I guess I must be remembering what I read incorrectly then.

 

[H2Bro]

If (on average) 1 out of 1 billion species develops intelligence on a human level and an average planet with life sees 1 billion species during the lifetime of the star, where is the point?

Our planet will likely experience a lot more species yet, as we are only 60 - 70% of the way through our planet's habitability. However the rate of mass extinctions is decreasing as solar system debris is swept up, which stymies the rate of new species production.

I would like to point out that the Earth is likely an extreme example of life. Microbial life is almost stupidly abundant, hardy, and quick to form (based on geological records) - its animal life that's the hail mary. Maybe saying 'every planet that sustains complex animal life' instead of just 'any planet with life' is a more accurate estimate.

 

[H2Bro]

The first supernova/hypernova probably did not originate until the universe was about 500 million years old. Given life as we can imagine it demands an abundance of metallicity, it appears unlikely it could have originated less than ~ 5 billion years after the big bang - or between 8 - 9 billion years ago.

Chronos, I strongly disagree. Since the question is how soon life COULD form, we can make a series of best-case scenario assumptions and remain within the bounds of plausibility considering the number of star clusters in the universe as a sample size.

We do not need to wait for galaxies to form, we can consider any cluster of gas capable of star formation. Star formation could have occurred as soon as 100 million years after the Big Bang (0). Supermassive stars can fuse their supply of nuclear fuel in as little as 1 million years or less (1). We could have a run of several generations of supermassive stars in less than 50 million years years, including time for dispersal and reformation of metallic elements. Within this one cluster there would be a substantially metal-rich material.

Within this cluster, shockwave compression from aformentioned supernovas could produce a spinning protoplanetary disc in as little as 100,000 years (2). For the next 50 million years our star is in the T-Tauri phase, however during this period planetisimals are forming, and recent work suggests most of the amino acids for life formed during this period as well (3). In fact, before the sun has even entered the main sequence, by 10 million years after protoplanetary disc accretion the outer planets have already formed their rocky cores (4).

Therefore we already have the necessary conditions for life by roughly 160 million years after universe initiation. Rocky cores with internal heating by isotope decay, deposition of amino acids, and abundance of water ice which can be melted by geothermal heat. A lower bound estimate for how long is takes life to form in these conditions is a surprising 10 million years (Millar and Lazcano; 5).

Therefore the absolute lower bound estimate for the formation of microbial / RNA life is 170 million years after the Big Bang.

References:
0. http://www.scientificamerican.com/article.cfm?id=the-first-stars-in-the-un
1. http://astronomy.nmsu.edu/tharriso/ast110/class19.html
2. Thierry Montmerle, Jean-Charles Augereau, Marc Chaussidon (2006). "Solar System Formation and Early Evolution: the First 100 Million Years". Earth, Moon, and Planets (Spinger) 98 (1–4): 39–95
3. Moskowitz, Clara (29 March 2012). "Life's Building Blocks May Have Formed in Dust Around Young Sun"
4. Douglas N. C. Lin (May 2008). "The Genesis of Planets" (fee required). Scientific American 298 (5): 50–59.
5. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980209932_1998078963.pdf

 

[mfb]

@Drakkith: Sorry, it was not the the VLT (that would be optical/infrared anyway), I confused it with VLBI - radio waves.

From our results we place an upper limit of 7 MW/Hz on the power output of any isotropic emitter located in the Gliese 581 system, within this frequency range.

Gliese 581 is ~20 light years away.

As comparison, the Arecibo message had 1MW with ~1 Hz bandwidth, but not isotropic. This reduces the required power a lot.

There were two transmissions directed at Gliese 581, but I could not find power values for them.

I would like to point out that the Earth is likely an extreme example of life. Microbial life is almost stupidly abundant, hardy, and quick to form (based on geological records) - its animal life that's the hail mary. Maybe saying 'every planet that sustains complex animal life' instead of just 'any planet with life' is a more accurate estimate.

It does not matter which values you use as comparison. The fact that just one species on Earth developed human-scale intelligence is not an argument against the probability that human-scale intelligence evolves. That probability could be everything from "extremely small" to "something around 1/2" without any evidence to distinguish between those numbers.

 

[Vanadium 50]

The Aricebo message has an effective isotropic radiated power of 20 TW and a bandwidth of 5 MHz (well, that's the narrowest it goes; I don't know what they actually used). That's 4 MW/Hz.

Alpha Centauri is 4.6 times closer, so the signal would be 20x stronger, or about 100 MW/Hz equivalent. No problem to see with a sensitivity of 7.

 

[mfb]

5 MHz bandwidth?

transmitted at a frequency of 2380 MHz and modulated by shifting the frequency by 10 Hz

Source
On November 16, 1974, the Arecibo Observatory transmitted at 2380 MHz at an effective bandwidth of 10 Hz a message directed at the globular cluster M13.

I think there is a good safety margin, if the receiver listens at the whole frequency band or the communication is coordinated.

10 Hz instead of 5 MHz increases the power (per frequency range) by a factor of nearly 10^6, which corresponds to an increased range of a factor of 10^3 (20000 ly instead of 20) - or a factor of 10^6 (?) in bit rate.

 

[Vanadium 50]

Yes, the width is 5 MHz. The modulation rate is 10 MHz.

 

[mfb]

Where does that number come from?
With a width of 5 MHz, I would imagine that it is hard to detect a shift of 10 Hz (not MHz!).