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 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. 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 (1022) 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 (10100) 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 -- 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/25923455-0d2d-456d-bfb0-0ef36e1f1573%40googlegroups.com.
