On 3/6/2020 3:31 PM, Lawrence Crowell wrote:
On Friday, March 6, 2020 at 5:28:31 PM UTC-6, Lawrence Crowell wrote:
On Friday, March 6, 2020 at 9:03:21 AM UTC-6, John Clark wrote:
Galactic clusters are the largest structures in the universe
held together by gravity and the Ophiuchus Supercluster
contains 4021 known galaxies, it's likely none of them contain
life, much less intelligent life. Telescopes have seen
evidence that the largest galaxy in the center of the cluster
underwent a gargantuan explosion at least 240 million years
earlier, it's 390 million light years away so the explosion
happened at least 630 million years ago. It's thought that 270
million solar masses of gas and dust was sucked into the black
hole at the center of the galaxy producing something
equivalent to a supernova going off every month for a 100
million years. Something like that would probably sterilize
not only the galaxy but the entire cluster. And Ophiuchus is
relatively nearby so it's almost certain there are more
distant clusters that suffered even larger explosions. It
looks like the Milky Way has just been lucky.
DISCOVERY OF A GIANT RADIO FOSSIL IN THE OPHIUCHUS GALAXY
CLUSTER
<https://www.icrar.org/wp-content/uploads/2020/02/2002.01291.pdf>
John K Clark
Even if life is terribly improbable, such as how nucleotides
emerged or even worse ribosomes, it did so in this galaxy. It is
possible that biology has been spread around this galaxy with
asteroid impacts. Ejecta from such impacts on a bio-active planet
could send microbes on a long journey to another planet. It is
then plausible that biology is fairly common in this galaxy, but
not others.
LC
https://www.u-tokyo.ac.jp/focus/en/press/z0508_00094.html
<https://www.u-tokyo.ac.jp/focus/en/press/z0508_00094.html>
Is life a game of chance? Study reveals life in the universe could
be common, but not in our neighborhood Research news
To help answer one of the great existential questions - how did life
begin? - a new study combines biological and cosmological models.
Professor Tomonori Totani from the Department of Astronomy looked at
how life’s building blocks could spontaneously form in the universe -
a process known as abiogenesis.
If there’s one thing in the universe that is certain, it’s that life
exists. It must have begun at some point in time, somewhere. But
despite all we know from biology and physics, the exact details about
how and when life began, and also whether it began elsewhere, are
largely speculative. This enticing omission from our collective
knowledge has set many curious scientists on a journey to uncover
some new detail which might shed light on existence itself.
RNA shares chemical components with DNA and is an essential precursor
to the existence of life.
As the only life we know of is based on Earth, studies on life’s
origins are limited to the specific conditions we find here.
Therefore, most research in this area looks at the most basic
components common to all known living things: ribonucleic acid, or
RNA. This is a far simpler and more essential molecule than the more
famous deoxyribonucleic acid, or DNA, that defines how we are put
together. But RNA is still orders of magnitude more complex than the
kinds of chemicals one tends to find floating around in space or
stuck to the face of a lifeless planet.
RNA is a polymer, meaning it is made of chemical chains, in this case
known as nucleotides. Researchers in this field have reason to
believe that RNA no less than 40 to 100 nucleotides long is necessary
for the self-replicating behavior required for life to exist. Given
sufficient time, nucleotides can spontaneously connect to form RNA
given the right chemical conditions. But current estimates suggest
that magic number of 40 to 100 nucleotides should not have been
possible in the volume of space we consider the observable universe.
Such estimates generally just assume pure random trials. And they
overlook the build up and availability of short chains if they're in a
confined volume. Here's an actual experiment showing you don't need 40
nucleotides to get replication:
/Letters to Nature//
//Nature 382, 525 - 528 (08 August 1996); doi:10.1038/382525a0//
//David H. Lee, Juan R. Granja, Jose A. Martinez, Kay Severin & M. Reza
Ghadiri//
//Departments of Chemistry and Molecular Biology and the Skaggs
Institute for Chemical Biology, The Scripps Research Institute, La
Jolla, California 92037, USA//
//THE production of amino acids and their condensation to polypeptides
under plausibly prebiotic conditions have long been known1,2. But
despite the central importance of molecular self-replication in the
origin of life, the feasibility of peptide self-replication has not been
established experimentally3–6. Here we report an example of a
self-replicating peptide. We show that a 32-residue α-helical peptide
based on the leucine-zipper domain of the yeast transcription factor
GCN4 can act autocatalytically in templating its own synthesis by
accelerating the thioester-promoted amide-bond condensation of 15- and
17-residue fragments in neutral, dilute aqueous solutions. The
self-replication process displays pa//rabolic growth pattern with the
initial rates of product formation correlating with the square-root of
initial template concentration. //
/When Ventura County Freethinkers were challenged to debate evolution
with a team from a local creationist Church I estimated the time to
produce a self-replicating RNA based on complete mixing in an ocean
containing 1g of organic molecules per metric ton and a complete mixing
time of 10 million years for the ocean. I got 300 million years./
//
/There are also abiogenesis theories based on the concentration of
organic molecules near alkaline ocean vents (white smokers) where lipid
membranes could contain and concentrate biomolecules and provide energy
from ion gradients. There's a good lecture on this by Nick Lane to the
Royal Academy online. The fact that bacterial or archean life appeared
on Earth almost as soon as it was cool enough for survival suggests that
estimates yielding low probability are way off.
Brent
A diagram to show the inflationary history of the universe. Image by
NASA CC-0
“However, there is more to the universe than the observable,” said
Totani. “In contemporary cosmology, it is agreed the universe
underwent a period of rapid inflation producing a vast region of
expansion beyond the horizon of what we can directly observe.
Factoring this greater volume into models of abiogenesis hugely
increases the chances of life occuring.”
Indeed, the observable universe contains about 10 sextillion (10^22 )
stars. Statistically speaking, the matter in such a volume should
only be able to produce RNA of about 20 nucleotides. But it’s
calculated that, thanks to rapid inflation, the universe may contain
more than 1 googol (10^100 ) stars, and if this is the case then more
complex, life-sustaining RNA structures are more than just probable,
they’re practically inevitable.
“Like many in this field of research, I am driven by curiosity and by
big questions,” said Totani. “Combining my recent investigation into
RNA chemistry with my long history of cosmology leads me to realize
there is a plausible way the universe must have gone from an abiotic
(lifeless) state to a biotic one. It’s an exciting thought and I hope
research can build on this to uncover the origins of life.”
----------------
paper is open access:
https://www.nature.com/articles/s41598-020-58060-0
<https://www.nature.com/articles/s41598-020-58060-0>
--
You received this message because you are subscribed to the Google
Groups "Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to [email protected]
<mailto:[email protected]>.
To view this discussion on the web visit
https://groups.google.com/d/msgid/everything-list/25923455-0d2d-456d-bfb0-0ef36e1f1573%40googlegroups.com
<https://groups.google.com/d/msgid/everything-list/25923455-0d2d-456d-bfb0-0ef36e1f1573%40googlegroups.com?utm_medium=email&utm_source=footer>.
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/everything-list/b7341bfe-eacf-b44e-2656-c049be5f34e2%40verizon.net.
