
Life on Earth may have begun 300M years earlier than previously thought - wrongc0ntinent
http://www.theguardian.com/science/2015/oct/19/life-on-earth-began-300m-years-earlier-than-previously-thought
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6502nerdface
> If confirmed, the discovery means life emerged a remarkably short time after
> the Earth was formed...

So at what point does the lag time between accretion and first evidence of
life become too short for "native" abiogenesis to be plausible, pointing
toward a transfer scenario instead?

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hawkice
Honestly, that might be a different order of magnitude when it comes to speed
-- maybe if we have evidence of life within the first ~10,000 years instead of
hundreds of millions. We've only been trying to replicate the origin of life
for couple hundred years, tops, at an extremely small percentage of locations
on earth where we'd notice if it happened. It might be extremely likely to
happen when you try everywhere on earth for hundreds of thousands of years,
and that's a rounding error compared to dates we are looking at.

A much better source for what you are talking about would be e.g. finding
tardigrades or similar in the asteroid belt. That would show that life was
part of the mix that went into the forming of the planets.

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sunstone
On the other hand, if life creating was so relatively easy it would be much
more likely to find evidence for multiple independent instances of life
starting on earth. My understanding is that, so far, all life on earth is part
'one web' not multiple webs.

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hawkice
tl;dr It's very likely that first-life creates a lock-out, quickly soaking up
all resources that could be used for independent abiogenesis.

Let's say the probability of new life is roughly constant (and a relatively
low probability). It should roughly follow a Poisson distribution -- in other
words, using current knowledge, and assuming (1) life would be created
noticeably differently given similar circumstances and (2) it didn't (molecule
chirality indicates both of these, for instance) AND (3) the events are
independent, which you need for the distribution -- then it'd be pretty weird
for something following a Poisson distribution where:

Earth Exists: Time 0. We have physical things from the time period: Time 2
Event in the distribution: Life: Time 4 Then absolutely no new instances until
time 45 (unit here is 100MM years)

This is all by means of formalizing your argument, which is largely correct.
But it's important to note that it assumes that the events are independent,
which I strongly, strongly suspect they are not. Life takes resources and uses
them up, and will expand until it meets carrying capacity. So first-past-the-
post-wins seems like a much better guess as to the relationship between
origins-of-life.

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amelius
It really makes me wonder if life started multiple times independently.

I guess certain molecules essential to life are right or left-handed, and if
life started several times independently, we should (statistically) see both
types of handedness. So then the question is: why didn't life start multiple
times independently?

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warfangle
I guess if certain particles essential to matter as we know it are either
particles or anti-particles, and if matter coalesced several times
independently, we should see both types of matter ;)

The main difference between particles/antiparticles and chirality, though, is
life tends to extinguish other life in its competition for replication.
Antiparticles just tend to annihilate 1:1.

