PoS(GOLDEN2019)059 https://pos.sissa.it/ ∗† [email protected] We address some of the major astrophysicalin challenges facing the present local day life, universe. includingdevelopment humans, punctuated A by truly mass successful extinctions.relatively species short This must habitability must lifetime be break accomplished oftinctions. free before its of It the planet the is end and not cycle of withinvulnerability inevitable the of a to that evolutionary window life extinction. between will major Individuals produceand mass must an develop ex- apex build technology species a - capable civilization requiringto of - extraordinary understand understanding mechanical requiring the its skills. hyper-social natural skills, worldvariety They and of must the catastrophes. have universe the Ultimately, well desire anaturally. enough space to Getting faring anticipate, species that and is farextraterrestrials even required; alike, requires prevent, a will a a quality require great not a sophisticatedaccomplishment deal selected of understanding for of tremendous of luck. feats the of physical engineering. universe GettingIn and beyond particular, the that, a successful for species humanshost must and star. learn Eventually to in leave fact, the its Galaxy homeMilky itself Way planet will collision become with to the inhospitable avoid Andromeda to the galaxy. complex demise Long lifederstanding before during that of that the their its they home must planet find requires away protectionvolcanoes, to from the and external un- supernova threats, explosions; like as asteroids, well super- for as example from the internal Covid-19 threats (corona like virus) plague‘evil pandemic, and empires’. as pestilence, well Most importantly, as we destruction argue by forscience rogue the elements and need and to reason. avoid foreseeable Natural catastrophe selectionatrocity. aided has by Mass produced delusion people is capable a ofexisted cultural all throughout the phenomenon. manner pre-scientific of world History and altruism shows persists or fectiveness today. that of This mass science is in despite delusion, improving the as people’s extraordinary lives. a ef- and Finally, rule, when humans we will encounter face extraterrestrial ethical life. challenges, Consider if of that much society of today the technological has advancement beenexpect the the result same of the from quest anylearn for technological to competitive exospecies. self-govern military within A advantage. the major We frame-workat challenge should of understanding for and evidenced humans protecting based the today research. environment is within Research to which that we is have aimed all evolved to survive. Copyright owned by the author(s) under the terms of the Creative Commons c Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). The Golden Age of Cataclysmic Variables2-7 and September Related 2019 Objects V (GOLDEN2019) Palermo, Italy Peter L. Biermann Max Planck Institute for Radio Astronomy,Karlsruhe Bonn, Inst. Germany für Tech. Karlsruhe, Germany Univ. of Alabama, Tuscaloosa, AL, USA Fachb. für Phys. & Astron., Univ. Bonn, Germany Challenges for Life in the Local Universe Paul A. Mason New Mexico State University, Las Cruces,Picture NM, Rocks USA Observatory and Astrobiology ResearchE-mail: Center, Las Cruces, NM, USA PoS(GOLDEN2019)059 Paul A. Mason ]. For just one 1 1 ] as well as anecdotal insight into how the development of life is 2 What kind of life will a particular habitable planet support? ], being not long after the crust cooled enough for surface water. It took far longer for 3 Speaker. This work supported by PRO-ARC Before life can emerge on a planet, the ingredients for life must be synthesized and concen- The transition from simple to complex life on Earth took a great deal of time. In fact, it took Here we examine some of the challenges faced by life in the present day local universe. It is When considering the emergence of life in the universe, it is useful to place qualifications on † ∗ multicellular species to develop, and billions ofit more to years arise. for The the frequency full of bloomingin global of catastrophe life setting as played the we a time know significant for rolethe in the evolution clock emergence on on of Earth. the the First race increasinglyneed to more to evolve protect complex to life life from a forms the space anddevelopment. astrophysical faring then environment species begins to long before set before the the next present-day mass stage of extinction. But the trated to form planets in thetion first of place. clusters Inhomogeneity of in galaxies. theformation. early Galaxies universe The provide resulted the presence in necessary of the conditionsthesis dark forma- for and the matter the formation probably subsequent of acted stars. chemicalsystem as enrichment, Stellar nucleosyn- into transforms a a a catalyst galaxy habitable for from one. galaxy elements. an The uninhabitable key stellar factor is the concentration of the so-calledmost CHNOPS of set Earth’s of history.evidence First shows consider that life that arose simpleformed at life [ most appeared only early a few in hundred Earth’s million history. years after Fossil Earth became fully playing out on Earth. major example: oxygen was deadlyenergy to consuming early animals. lifeforms, yet Somewithout it making planets is the may crucial leap produce now to for complex singlelife life. today’s forms celled voracious That may life, is be possibly to possible say manyconditions only that under times, are multicellular stricter and possible (Earth-like especially on or conscious better)transition a habitability to much conditions. a smaller nitrogen Those subset plusbut of oxygen only rich worlds. after atmosphere billions allowed Time for of playshabitable. high years. a A energy In more consuming critical other important animals, role. question, words, and it Earth’s a is more not difficult sufficient one to to answer say is: this planet or that one is based largely on the vastsummarized literature in from several our generations review of [ investigators in a variety of fields the nature of that life.life-forms For are example, significantly less conditions strict that than allow thoselife. for allowing The the the latter development emergence of is complex of capable multicellular simple ofmore exponentially unicellular complex more life complex behavior. if Simple the lifeof conditions undoubtably a are begets distinctively right. different set However, complex of life environmental likely conditions requires than the does presence simple life [ Challenges for Life 1. Introduction 1.1 The emergence of complex life PoS(GOLDEN2019)059 ]. 2 ]. 4 Paul A. Mason ]. For much of the 2 depends on properties of the host galaxy [ 2 complex life as we know it The elements used by life on Earth were not available until long after the Big-Bang. Nu- Darwinian natural selection and mutations allow for the rise and fall of species, however mass Hominins arose only 5 -7 million years ago, well after the most recent major mass extinction, We suggest that technological civilizations have only relatively recent emerged in the local uni- cleosynthesis during the Big-Bang resultedof only other in light the elements, production see of the helium discussion and in Mason small and amounts Biermann (2018) [ In particular its merger and star formationlogical histories. civilizations Further, are we far suggest from that over. challengesefforts. for Some For techno- of example, these any challenges technological mayotherwise society be inevitable will asteroid overcome need impacts. by to Some engineering harmful quickly astrophysical(GRBs), defend factors, maybe its like Gamma-Ray unavoidable civilization Bursts for against some planets.the habitable Unquestionably, for lifetime any of society their to homemust succeed world, be a beyond achieved. high degree of technology aided by considerable1.2 luck Ingredients of life extinctions transmute life on Earth atbeen the alternately kingdom dominated and by phylum fungi, level.life. plants, The During and surface a animals; vast of expanse each the of contributing time, Earthphysical to creatures has of a environment. the complex biosphere Diversity web-of- existed completely developed, atextinction, usually the mercy and intermittently of then as the re-opened niches to closed,in others precipitating life after forms mass of extinctionemphasize all events. the types, This point, whose diversity note has lineagesevery resulted that have mass extinction all every in living already Earth’s history creature survived since many on the last mass Earth universal extinctions. today common ancestor has65 (LUCA) To million ancestors [ years ago. that Ancestors survived ofhad present to day learn humans to had deal to with overcome eachacross natural other, the predators and planet. and members then They of have related taken species,tion many to during steps immigrate towards out the building of last a Africa 70,000 protective and technological years.to civiliza- survive They in had a competitive to world. develop Ultimately,lization agriculture, science we tools, allowed enjoy and for today. the social To illustrate rise skills this ofwith in point, the note order Newton technological that civi- in the the great age 17th ofthrough century modern bacteria science amid carried originated by the fleas Great livingleast Plague on one common of thousand black London. years. rats. Achievement It The during ravagedspeare, bubonic plague Europe, outbreaks whose plague off was and writing spreads not on, was limited for famously to at during science. influenced outbreaks. by Shake- His his play personal company state evenand cancelled of 1613 performances due mind, much to wrote of legal many the restrictionsis time works during between epidemics. in 1603 Today, retreat the disease throughout is theSimple eradicated world in knowledge despite Europe of and the the fact causeyears that the led there germ to is theory effective no for diseases prevention knownthe has world’s in cure emerging identified or this cities many across proven case. species history. vaccine. responsible Thisto for In resulted become epidemics in a the plaguing a space-faring last human planet-protecting population one-hundred species,to explosion. large develop In first. populations order in This necessitates crowded the spaces development are of likely societies, as well as scienceverse to due maintain to them. the enormous timehabitability likely of needed a to planet for evolve them amidst an unforgiving universe. The Challenges for Life PoS(GOLDEN2019)059 of baryonic Paul A. Mason

, a periodic table 1 3 ]. There are also other options, since we do not know 5 ]. 6 The periodic table of the origin of the elements. The elements originate from a variety of sources, Concentrations of silicates, iron, carbon, water and so on, in molecular clouds will make their way into protoplanetary disks andfuse eventually hydrogen into and helium planets. into carbon, Itto nitrogen, took have and significant the oxygen, concentrations to first of build iron generations life. and of silicates, It stars to took build quite to planets. a In bit Figure longer listing the origin of each element is shown. We see that the elements needed to make rocky planets, Figure 1: see legend, and theCredit: time-scale Jennifer Johnson for (2019) their [ production varies significantly depending of the type of source. what dark matter is. Thematter formed collapse the of first smaller stars. concentrations,the The less periodic production than table, of about is metals, the 100 elements result M beyond of hydrogen the and interplay between helium dark on and visible matter. Challenges for Life history of the universe, thecisely ingredients elements for were life were likely present notunderstood, only however sufficiently what in concentrated seems small to to quantities be facilitatean or clear life. ancient more is pre- lumpiness that Dark of galaxies, matter dark andsupermassive is life matter black itself, poorly in holes, exist the today some universe. because ofafter of When which the we are Big-Bang; look seen we at freneticallyhabitable are quasars, galaxy growing seeing we or less the see it than may beginning accreting a not.at effects nexus billion The of points richest years a of clusters messy dark of matter galaxies processcenters filaments are of that stretching lit the may across up first result the by galaxies might active universe. inclouds galaxies have The devoid a been and first of produced lie black the by holes heavier the atbe nuclei collapse the the required of agglomeration hydrogen for of and potentially massive helium life-bearing stars, gas directly planets. forming a a It million super-massive could star, solar which also mass is just unstable, black and hole makes [ PoS(GOLDEN2019)059 Paul A. Mason ]. While this simple ]. 2 9 , 8 , 7 ] 11 , 10 4 In order to allow Earth-like living conditions, generations of stars produced the necessary The star formation rate in the Milky Way is now considerably less than it was during its early The details for how the ingredients for life facilitated the origin of life remains one of the picture is largely correct,starburst; star formation during in such most periodsgalaxy of galaxies apparently time, occasionally never has life had huge especially a significantBut spikes, complex starburst surface called it period, life a almost at is certainly least notbetween not will Milky viable. in have Way the and such So last the 4.5 a Andromeda our Galaxy! billion period years. [ in about 4 - 5 billion years during the collision elements allowing for a sustained planetarydance habitability of environment. a The variety concentration of and elements abun- aredisks needed allow for for the the development concentration of of complex the life.Si CHNOPS Not elements and only for Fe, do life galactic and they the also planethalf-life building radioactive concentrate elements elements radioactive Th elements and like U Al, on Earth Th, have U. allowed The for presence a prolonged of period very of long geologic history. Star formation beganThe near bulge and the bar center formedthe of stars so the relatively called Galaxy quickly thick while and disk.collapsed the stars into Galactic soon Over what disk time, populated is slowly the the now formedthe gas the halo. stars vast and thin majority in of the disk, stars dust further formedto concentrating (expelled in allow the from the the elements dying halo, development the for stars) of bulge, life. in wet and the even rocky We the disk suggest planets thick with disk their are habitable too metal zones poor [ most important questions inthe science molecules today. to ultraviolet Duringbuilding radiation blocks the provides of for process life. a of Organictime rich star molecules is chemistry must formation, a that overcome key exposure results significant ingredient.variety of hurdles in to of This the become enrichment paths molecular life may from and experience occur molecular directly at cloud influences various points to their along, potential planetarylife potentially, to itself. surface. a participate The wide in surfaces The of prehistoricingredients planets environment chemistry for (or those and life moons) molecules hence in as the in wegalaxies, oceans stars, know and and it. planetary on systems land, Clearly, undoubtably provide form thisrationally the and investigating elemental develop concentrated the across concentration impact the is universe. of universal However, surfaceGeocentric in radiation bias nature on resulting planets as from requires current overcomingsome placid the conditions circumbinary natural on planets Earth. may Forstellar posses example, XUV it ‘better and is particle than possible flux Earth’ that in the habitability, habitable based zones on of some a binaries reduction [ of Challenges for Life Fe, Ni, Si, Mg, and sothe on, many, longer are lived, formed low-mass mainly stars bymolecules. supply short C, The lived N, abundance high-mass O of stars. and all The P, oflifetime which more these of are massive elements the a of relative constituents to galaxy. of hydrogenquite organic The steadily well increases chemical over understood enrichment the generally, of due theLAMOST especially Milky spectroscopic to Way surveys surveys over to like time mapaddition, the is the Sloan quickly the present Digital becoming Gaia day Sky chemical space Surveybrightest architecture and observatory stars of is visible the from determining Galaxy. Earthmeasurements the In and are distance, being proper using made motions that of parallax,composition when the of to combined closest as will the of many reveal billion these. stars thedata 3-D in will As motions the be of highly and Milky valuable this the Way to as chemical writing, Galactic there habitability are studies. seconds in a human lifetime. These PoS(GOLDEN2019)059 Paul A. Mason ` kilonova that be- ] postulated an ‘aperiodic are produced in neutron star 16 1 ], since there should be plenty of high energy remain to be worked out, it is clear that binary 13 1 5 ]. Models for element production during neutron star merg- 12 ], the lightest of the r-process elements that are fused in the presence 15 ] and observations of the the optical/infrared transient, called a 14 ], among other factors. 2 It has long been predicted that in order for the rare elements beyond iron to be formed, high Too much energy is destructive to life forms. Particle fluxes from radioactive surface rocks Life as we know it exists due to local energy disequilibrium. All organisms must make a living fluxes of neutrons must be involved [ and cosmic rays are destructive atpresent extreme day levels. Earth Cosmic levels rays are atOn likely fluxes the that harmful are to other much surface hand higher lifehave than radiation and beneficial levels may effects. that have Cosmic caused are ray massproducts interaction only are extinctions. with somewhat a DNA source higher molecules of along than genetic withrange mutations. present radioactive for General decay day principles radiation Earth thus allowing suggest might forThe that there sufficient radiation is mutation an level optimal without on compromisinglevels Earth due too has to many the gradually organisms. decrease decreasedEarth in [ from the very star-formation rate high within levels the to Milky present Way over day the low history of the mergers. The factrather that non-uniformly these distributed. events are Oneble rare for or means much two of that local the their neutrongeological Th activity nucleosynthesis star and lifetime; products mergers U while content are may too oferuptions, probably be much like Earth. responsi- radioactivity the likely Having one results too that in little caused96% more of radioactivity the frequent all results End species volcanic Permian in on extinction, a Earth onlywith briefer were 250 too lost million high due years a to ago, a radioactive where for prolonged content complex period may life. of take hyperactive too volcanism. long Planets to settle into a life sustaining environment came visible days after the mergerproduction confirmed of the connection Strontium between [ neutron starof mergers lots and of the neutrons. While some details of Figure crystal’ containing heritable genetic informationa before living the organism discovery as of one DNA.more that He than maintains also compensated low describes entropy. byenvironment. the The entropy entropy decrease The increase inside second outside anoperate law the organism on is organism, is Earth, (Gibbs) by obeyed, free heat and energy isand expelled life needed into energy and maintains in the disequilibrium a our case provide highlymolecular it a is ordered and provided means state, by organism the for level. In Sun.exists energy order Chemical Liquid a to extraction temperature water range and is based entropy on required the reduction in liquid order water at phase, for the within all which life life must to remain. operate, so there by the extraction of energy from their environments. Schrödinger [ ers suggest that they are aneutron-ion probable interactions. r-process site [ The discoverywave detectors of [ the neutron-star merger GW170817 by gravitational neutron star mergers play an importantuniverse. role in constraining the habitability for complex life in the 2. Energy for life Challenges for Life activity. This is becausetemperatures. radioactive Radioactive elements isotopes have of helped certain maintain elements, high see Figure Earth core and mantle PoS(GOLDEN2019)059 Paul A. Mason 6 allows for high energy consuming species. Without 2 , which is the probability that simple life will result in intelligent life. i f 1) the host star(s) 2) local geophysical or geochemical processes 3) external planetary system and astrophysical environmental impact. For example, consider that Earth is near the inner edge of the current habitable zone of the It is often taken for granted that our existence was an inevitable consequence of what was Once produced, the energy content of O sufficient energy, life is notof capable complex of life environmental on transformation, Earth. criticalthe to Sun, On the then the development no other matternow. hand, how if rapidly We speculate the complex life that Earth would the werepossible have extremely even on developed, just high the it a oxygen surface would few consumption of have percent of planet ended closer by with the to a human-like high brain energy is consuming only biosphere near the inner edge of On Earth, we are potentially biasedpresence in and considering the primarily the subsequent influencestudy evolution of of of i) the life exoplanet host on habitability. star Earth.sufficient on So evidence the here, That to we suggest bias take that isagainst the the planetary naturally development catastrophe, position transferred is of that a to an significant the exospecies challenge. the in world capable This the idea around Drake of was equation us self expressed factor, as preservation, provides one of the terms Sun. If theaccording Earth to were the inverse farther square from law, forexperiment, the the that entirety Sun, life of might then Earth’s begin past. it atof Even the would assuming, the same in have habitable time this received zone. thought on less thisthan imaginary That the solar Earth hypothetical real insolation, currently Earth, planet in because would theluminosity the remain middle on habitable its in zone way the to will becoming habitable gradually50% a zone move red less outward giant. a energy as However, bit that integrated the imaginary longer over Sunamong Earth its other increases would receive things, lifetime. about it Significantly wouldto have less occur, taken energy whereby correspondingly on from longer Earth, the for photosynthetic bacteria theanimals. Sun changed Great means, the A Oxygenation atmosphere that biosphere Event and can paved the onlyenergy. way change for the atmosphere if it is consuming an enormousbefore. amount It of has taken a significant fractioncapable of of the habitable self lifetime preservation, of the meaning Earthbillion capable for humans years of to avoiding become ago extinction. and Lifebillion the originated years. Earth roughly That will 3.5 means no(almost) that longer capable life of be on self-preservation. in If Earth this the tookof time-scale 70% habitable is available typical, of zone energy then Earth’s for it of habitability is life the sensible life-timeis would that Sun likely to a lengthen even become reduction in the a about time energy 1.5 capable needed threshold of to below global which life protection. life to is meet incapable this of challenge. global influence There and much less Challenges for Life Life also needs energy that may be supplied by: We suggest further, that the development of amay technological be civilization capable quite of small. self-preservation Equation. A planet’s However, position it is in important thethe in habitable potential limiting zone total the is bio-production habitable of hidden planetary a in lifetime planet. this and term in of determining the Drake PoS(GOLDEN2019)059 Paul A. Mason 7 Certainly, for life to progress beyond the limitations of even it own planetary system envi- High energy radiation, both electromagnetic; ultraviolet (UV), X-Rays, and gamma-rays as An Earth-mass planet may form dry in the habitable zone of a solar-type star, but could receive Stars and their putative planets in globular clusters are formed in the presence of many other ronment, life (maybe ourprotection decedents) from, must or meet at least somenearby a supernovae major resilience (SNe) challenges. against, and extrinsic GRBsor Life catastrophes as pestilence such well has like as as the to asteroid intrinsic 1918 develop collisions, catastrophes fluments a or such speculate the as about current nuclear herd coronavirus destruction, pandemic, immunitypopulation. considering implying that the Despite some death govern- these of setbacks, aderway; the significant consider percentage process that of of the the establishingextinctions. lineage entire sustainability Before of going for every on life to living is discussdangers creature potential well faced future on by un- challenges, Earth life. we has review some survived of countless the external mass 3. The universe is generally dangerous to life well as cosmic raysenvironment (meaning experienced particles) by contribute the molecular to buildingample, the blocks the of environment composition life, experienced of at planets by various and life. stagesthe even entire is condensation planetary key. The of systems For depends ex- grains on in detailsUV concerning the light from protoplanetary the disk newly and formingtoplanetary star on disk removes the and ice impact from thus grains of producesexist. located subsequent the in Additional radiation. so the radiation, called inner that part snow-line, is ofhave beyond radiation the which from a pro- sources icy significant other planetesimals adverse than may nearby that impact O-type from on stars the formed the parent within star, planetary the may ation same formation of cluster a process or dozen worse, itself. or a so close hotnormal encounter UV UV solar-type with intense star, radiation stars an might during OB from not the associ- allow timehad of for planet the experienced formation, formation much around of an higher wet otherwise radiation rockyline planets. levels, far If it out the in would nascent the have Earth protoplanetary haddisk. disk the This or has effect it obvious of could implications have pushing fordisk. even the the completely subsequent A snow- removed habitability planet all for might water a be from planetconsider the the formed the right from classical distance such concept a from of its a host liquid star, water but habitable be zone bone in dry.water this case. It later. makes no Earth sense may to formation. have If received the much snow-line of is itscosmic moved ray water further bombardment, from out during the in comet epoch a impacts offormed planetary planetary as well system formation, a after due then rule giant its to in planets desiccated an initial wouldSolar regions intense not System of period be is the of protoplanetary in disk. the The asteroidplanets. fact belt Ice that allowed the formation ice snow-line appears to of to formcase the be beyond at an into least. cores important which part became of the planetary giant formation in the Solarstars forming System during and around the epoch ofets. protoplanetary The disk intense formation interstellar and radiation evolution and into particle plan- inhibit environment within water which delivery these to planets form habitable may zone planets because giant planets cannot form, as ice, a giant Challenges for Life the habitable zone, just like Earth. PoS(GOLDEN2019)059 ]. 17 Paul A. Mason ]. It is a Galactic magnetized 2 8 . Elemental enrichment of the ISM is the first step. The 2 ], see our review for an in depth discussion [ 18 Here we emphasize a key role for SN in the protection of life on planets in the thin disks of So what kinds of threats might life as we know it (or otherwise) face? These may be broadly Supernovae (SNe) of all types play a central role for life in the Milky Way. A multi-wavelength wind that acts physically very muchacts like the to stellar deflect magnetized incoming wind.disk The galactic magnetized wind cosmic stellar deflects rays wind incoming with extragalacticRays energies cosmic (UHECRs). below rays, about except Without 300 for the thean MeV. protection The Ultra of increased galactic High our flux Energy Galactic of Cosmic disk very wind, high Earth energy radiation would be from subjected a to relatively nearby extragalactic source, for spiral galaxies, especially the Milkydisk Way. and are The the remnants sight ofrays, of SNe meaning particle currently particle acceleration, populate flux SNe thethese from are Galactic high the Galactic velocity source sources. of particles mostwind combined From is of with the established the the perpendicular [ galactic differential (to cosmic rotation the of disk) the flux disk, of a Galactic disk first generation of planets formed inif too a many cluster SNe might occur be too sterilizedby near by the SNe the new is planet. removal a of The benefit, its deliveryGRB balanced of atmosphere is by fresh a radioactive atmospheric significant material impact. provided threat to A surface nearby life. SN and/or being in the beam of a grouped into three classes. Firstly exploding starsGRBs (supernovae) are including the extremely sometimes important. associated black Supernovae holes, are especially central supermassive to galactic allthirdly, center aspects merging black of holes, galaxies life. place and Secondly strongregions the accreting of limits merging otherwise on habitable life. of space. theirsidered And The to supermassive astrophysical be black threats sources particularly described holes to incomplex complex may this ocean life sterilize section on life surfaces are is vast of con- expected Earth-like toSome planets. be of Microbial more the life resilient or astrophysical to threats exposurethis to to section. life high as levels We focus of we surface on knowthe radiation. some it universe of on took the the a challenges long surfaces time facing ofsuggests and life. planets that is are planetary The probably discussed habitability relatively development for recent in of complex in complexthat life the life much is universe. the in fragile. Mounting present evidence, Using day nearby universe in examples, inhospitable we for suggest life. 4.1 Supernovae are central to life view of the Crab Nebula is shown in Figure Earth-like (wet) planets may not be nearly as common as Sun-like stars. 4. Astrophysical threats to life Challenges for Life planet formation catalyst, and thus giant planetsdelivery are at not early available to times, scatter or, cometsing, in to or fact, provide absorbing water to asteroids protect and life cometsexists on at that a later giant habitable (more planet critical) zone times formation planetlow in is by metallicity bio-development. deflecting, strongly is Evidence captur- inhibited also in a47 regions Tuc contributing of was and observed high confounding using radiation HST factor.upper although in limit very an For on attempt the example, to frequency the observe of transits such globular planets involving cluster giant was planets; obtained as a not strong a single planet was detected [ PoS(GOLDEN2019)059 Paul A. Mason ], due to angular 20 9 ] and its recent discussion in Biermann et al. (2018) [ 19 The Crab Nebula supernova remnant. A composite image from five observatories. For a short When two black holes merge, their respective jets swing through a huge solid angle, see Figure Figure 2: example an accreting black holeprotection in of a a neighboring galactic galaxy. diskbiological It wind lifetime. is to very maintain likely livable that surface a conditions planet at needs some the point4.2 during its Accreting black holes and merging black holes are dangerous 1 in Kronberg et al. [ time after this supernova occurredlife. in They July fuse of together 1054, the itthe elements, was especially new visible carbon during elements that the life into day.connected is the to based Supernovae complex on, interstellar are life and central in medium. then several to possiblyacceleration supernovae surprising distribute of Besides ways. Galactic the Supernovae cosmic remnants fusion rays. areexplosions the This of main aided particle site essential flux by for elements is the differential responsible supernovaethe rotation for are of galactic mutations. the disk. In addition, disk, supernova the This produce heliosphere magnetized a with galactic wind particles wind issupernovae that flowing akin remnants, stop perpendicular from to galactic from impacting the cosmic life solar(infrared) on rays magnetized in Earth. with yellow; wind. Credits: E Hubble < VLAChandra The Space (radio) X-ray 300 Telescope solar Observatory in MeV (visible) (X-ray) wind red; in largely in supplies Spitzer purple. originating green; Space from XMM-Newton Telescope (ultraviolet) in blue; and Challenges for Life PoS(GOLDEN2019)059 more distant. Paul A. Mason ] suggest that 3 20 ] estimates that events 20 ] gives the various time scales. 21 more mass at a distance 10 6 ]. Biermann et al. (2018) [ 21 10 . One can estimate the total swing time scale to be of order 5 . 2 − ] there is a discussion of the time scales in Cen A. Of course that all 22 , so of order 10 2 − π 10 showing the Virgo Supercluster and its central galaxies. The most recent supermassive ]. They discuss the source 41.9+58 in M82 and argue that it is a binary black hole merger, 3 20 Whether merging stellar mass black holes contribute to any measurable effects on the Earth Merging black holes, both stellar and supermassive, are likely to be the main source of UHE- In Gopal-Krishna et al. [ black hole merger inwould M87 be corresponded in to the a detrimentalperiod, mass range, as much seems if evident higher we in M82. assume than Table the that 2 Eddington in in Gergely limit et Cen in al. A, all (2009) [ so cases for again the it spin-flip through their spin/jet-flips is an open question. However, Biermann et al. [ CRs, high-energy gamma rays, and neutrinos.Galaxy The is effect of equivalent to a a black hole black merger/GRB hole model merger in of our order 10 100 years, so ina other powerful words, jet every for planet adense within version few that of months. perhaps swing the solid Orion As cluster.clusters, angle all The would as nearby of galaxy experience do M82 this such shows many has manypowerful other such to jets young of starburst happen stellar super-massive galaxies. black in hole anyears, mergers, One young when and can the so stellar swing the make cluster, time jet a scale like exposure could time corresponding a be would argument millions be of thousands for of the years. as seen in M82 happen everysum couple of of the thousand conical of regions years affectedwhich in could is such reach about a all the starburst. parts same of That time the as impliesregion, the that inner that starburst region galaxy the lasts. will in be So, a as hit fewas soon by million as two well years, we effects, as have the a by massive starburst star the inwould SNe, some spin-flipping follow. their small radiation If of and the the cosmic Earth jets. rays, a gets third hit We pass more can coming than consider faster once than whatwould at the seem temporal all, second unlikely, pattern it since pass, the would such and conal be a a patternto an possible gets model the accelerating fourth narrower as pattern, merger pass well. with yet of A faster. a massin Many binary extinction passes mass on supermassive Earth black extinction due hole data. inextent of a The the nearby effects effects external depend on galaxy mainlysurvivors habitability may on bias be may the might detectable lead mass extend us of across to theand the underestimate SMBH. therefore the On overestimate host severity the the cluster of likelihood other this of and hand, kind complex we the of life. caution astrophysical that catastrophe 4.3 Merging galaxies and their supermassive black holes are threats So there should be concernstarburst for galaxy distances M82 up as to well upFigure as to Cen about A, 7 but Mpc, not clearly quite encompassing to both M87 the at the heart of the Virgo cluster, see with a large spin-flip angle. Thatthe implies that jet every planet briefly. in that The precessionalvery jet cone roughly will is solid experience angle divided by the swing solid angle, for this observed example, Challenges for Life momentum conservation. Consider thatgreatly orbital exceed angular the momentum angular momentum of of the thedirected individual black along black the hole holes. black binary In hole addition, may spin relativisticthe axis. jets merger are So there compared is to oftenrelativistic after a calculations completely the different of merger. jet Gergely direction and This before the Biermann is energies for [ called the a observed clean-out blacklimit imply [ hole that the spin-flip. jets have See to run the at general their respective Eddington PoS(GOLDEN2019)059 Paul A. Mason ]. It may be too speculative, but the 23 [ 4 11 , suggests a spin-flip angle of nearly 180 degrees, which is 4 ]. That would have been maximally violent, if true. 21 shows the high energy gamma-ray emission associated with particles trapped in 5 Map of the Virgo Supercluster of galaxies. The Local Group, in the center of the plot, containing To summarize, our existence is owed to the fact that we do not reside in, or even near, an the Fermi bubbles, which are located above and below the Galactic center. Dense galaxy clusters only possible if the two blackGergely holes & merging are Biermann of [ very similar mass, as shown by the equationsactive in galaxy. The Milkymajor Way mergers. has remained This habitable, isexample, not in Figure to this say sense, that due the to Milky a Way shows low no frequency evidence of of central activity. For was a while ago, but closeold enough radio in structures, time at that 90 in cm, both in cases M87 (Cen as A shown and in M87) Figure you can still see the Figure 3: the Milky and Andromeda galaxies, isZ. in Colvin. the low density suburbs of the Virgo Supercluster. Credit: Andrew overall image here of M87 in Figure Challenges for Life PoS(GOLDEN2019)059 , where 7 Paul A. Mason Spectacular jets are seen projected ] (SGHZ), see Figure 2 Top: 12 A radio image of M87 at 90-cm, shows a very extended Bottom: The enormous galaxy M87 has undergone many mergers. ]. 23 exist beyond the limits of the Super-Galactic Habitable Zone [ Figure 4: outward across the galaxy.M87 These is jets the site of of relativistic the cannibalizationHubble particles of Heritage are roughly Team 100 bad (STScI/AURA). Milky news Way typeold for galaxies. jet life Credits: in caught NASA, a ESA in and different theira the direction black beams. than hole the spin-flip inner during (red) theworsened active merger by of jet. the supermassive sweeping This black out holes. directionalet of change The al. large impact is [ volumes on strong as complex evidence the habitability for jets is precess in advance of the merger. Credit: Owen Challenges for Life PoS(GOLDEN2019)059 the 4 . 3 t = Paul A. Mason = 2,500 years 4 . ], as mentioned. 3 t 19 . The binary black hole 6 ] would be the fate of any 20 , with 2,500 years 1 − yr 3 − Gpc 1 4 . − 3 1, first via the UHECR flux observed by the t ' 4 . 13 . The time scale of repetition of 3 1 t ] of 40 − yr 20 3 − ], and second via the GRB and relativistic SN rate derived 26 Gpc 27 44 − + ] as 56 25 ], and they both agree. So the prediction is consistent. Using this argument , 27 24 years; the less informed, short term, warning might be of order 100 years. Fermi bubbles of trapped particles are shown as the orange/yellow lobes of high energy gamma- 7 Closer to home, the prospects for complex life in the nearby LMC and SMC are not optimistic. We use as an example the nearby starburst galaxy M82, see Figure to 10 6 can be checked in twoTelescope independent Array ways, Collaboration i.e. (TA) [ These galaxies are metal poor and apparently have had a long history of mutual interaction. They merger rate derived byestimated Biermann time-scale et between al. such mergersby [ in LIGO+VIRGO a [ starburst galaxy such as M82, is now confirmed galaxy undergoing a major merger, and sofor every probably roughly 3,000 3 years million (for years, athe galaxy so consequences similar roughly to of M82), 1,000 powerful jets timesSo clearing (i.e. a our fate a a such as stellar large experienced cone, mass byend detected black M82 civilizations, (currently in or hole taking M82 force merger, place [ them with in tomight the help, repatriate local allowing universe) to for would somewhere a probably else, long term indeed.10 warning Astrophysical time that knowledge would be the length of the starburst, of order in this way implies the assumptionindependent that (so most different) such spin-directions black will holeas result mergers opposed in involved to two a a black wider stationary holes detrimental of jet. impact What to is habitability currently happening in M82 [ complex life is highly improbable. 4.4 Starburst galaxies are detrimental to complex life ray emission above and belowparticles the giving rise Galactic to center. theet Galactic Along al. disk the wind Galactic is disk also plane, seen. emission Credits: from NASA/DOE/Fermi LAT trapped D. Finkbinder by Soderberg et al. [ Figure 5: Challenges for Life PoS(GOLDEN2019)059 Paul A. Mason ]. Despite be- 4 ], confirm earlier 28 14 The nearby starburst galaxy M82, The high star formation rate in the central region of M82 Astrobiology, as a science discipline, suffers from having but a single example of life to in- vestigate. In fact, DNA,is from thought an to albeit originate geocentric from view, a is single life Last on Universal Earth. Common All Ancestor life (LUCA) [ on Earth today predictions that theses three will collideand resulting protection in for cosmic fireworks, life disrupting along themerging with Galactic with it, disk spin-flips, and as of nowGRBs in course is M82, the not right prospect optimistic along of for with life. many everything stellar else, mass like black a holes spike in SNe5. and Challenges for the Far Future 5.1 Successful escape comes to DNA selected for intelligence ing our only example, lifeEarth on today, Earth in provides all its some forms, important adapts,tinuously clues. through undergoes survival The and change. RNA/DNA-based subsequent life selection, on This toextinctions, a includes pandemics, planet as relatively that well con- frequent as and constant environmental sometimes variation. catastrophic Life mass has adapted wonderfully are predicted to merge in aboutWay 2.5 will billion years. be Later, compromised. ingalaxies about in The 4.5 the billion Andromeda Local years, Group Galaxy life of and in galaxiesMilky will the Way, the collide. Andromeda, Milky Milky Three-dimensional and space the Way, motion third the of largest stars two spiral in most the in the massive Local Group, M33 [ produces the galactic wind shown. Theopment environmental of conditions complex within life. this Credit: galaxy HST, likely The inhibit Hubble the Heritage devel- Team. Figure 6: Challenges for Life PoS(GOLDEN2019)059 Paul A. Mason 15 There are several important points concerning mass extinctions. First, on Earth there does not Consider that dinosaurs evolved on Earth for hundreds of millions of years, but they could not Recently, the Earth entered the Anthropocene - the proposed current geological epoch during seem to have ever have beenthat, a total then extinction, we at might least never sinceand know LUCA. has the If never difference. completely it disappeared. had Life happened Thisof as earlier is we complex that probably of know life critical it on importance began forlast Earth. early the 3.5 in development billion Life’s Earth’s history experiment years (on agodone so Earth) or in so. has spite mass not However, extinctionof needed threats as others. and to has because restart been they Life, in have noted, benefitedsignificant especially at the from setbacks its least the due survivors to mass development on the the extinctions of Earth frequencyuntil complex and today an severity forms, have intelligence of is mass it developed extinction, seems, that by isto asteroids must capable heavy for or of remain example, frequent averting limited such bombardment catastrophes. may to same stagnate A is evolutionarily biosphere until true subject that for frequency any decreases. causewhen The of one mass group extinction. (species), Ultimately, the withother extinction sufficient species, cycle from intelligence, may extinction. rises terminate If only upwe that to can can say protect be that itself, achieved, an here as advanced on level well of Earth as sustainability or many has elsewhere been by reached. protect others, themselves then from their ignorancethere of planetary is science. no Without reason destructionexist to by as think an colossal asteroid, that feats things ofthemselves. would engineering They be will should be much attempt required differenthope to for today. that prolong members humans the manage Even of to inevitable an greater succeed. enddistance apex challenges by If of species adding humans their angular to are momentum planet’s able protect to habitability. to itsinexorable increase orbit, increase We the we in may size avoid the of global luminosity the heatingextinct Earth’s of due due orbital to the to the sun. slow a but It failurerun, to is avoid in also some possible order sort to to of imaginesociety survive catastrophe, across humans the the like becoming universe nearly pestilence must master or endless medicine, asteroids. astrophysics,space battle planetary colonization. protection, In between and the ultimately life With long and optimism,engineering extinction; we and will every bioethical challenges meet conceivable that our our current decedents will challenges. certainly face And will in alsowhich the be human overcome. future, activity the is thedenly, dominant and agent only for after 4.5 change billion toglobal years, the Earth catastrophes. surface now and maintains This a climate species, isIn of humans, this Earth. an capable context optimistic of Sud- it averting mark istaming for interesting flooding. to our note So, civilization, that the not many interplayitself. simply known between great humans for Remove civilizations and our in 20,000 their species. the environment yearsplanetary world is protection of started as than civilization by old a and as bumble bee. civilization (large brained) humans are no more capable of Challenges for Life to predictable environmental change such as seasonalitation. temperature fluctuations One and only seasonal needs precip- to lookin up, to the see summer the migration and offollowing winter, birds the between to seasonal higher rainfall. and see lower Life an latitudes impacts, adapts example; volcanic much hyperactivity, or less the readily to removal to of herdsThese stochastic atmospheric of latter events ozone, such effects mammals due as result on to asteroid in adescendancy the mass for supernova African extinctions entire and which species, savanna so while are on. opening double up edged niches swords for for the survivors. life, cutting off PoS(GOLDEN2019)059 ]. A biased 29 Paul A. Mason 16 Our intelligent decedents, if humans have them, will face new challenges. They will have to To be a successful species into the far future, humans will have learned to deal with all manner How do we make certain that our value judgements will not go awry, given human history? i) We accept the others as equivalent to us and leave them inii) peace, Deal perhaps with open diplomatic them as if they are equivalent toiii) animals Completely ignore and whatever plants, is there. with the most advanced This last option (iii) may be the only one available if we would get sick or die from some con- line of reasoning may bewhereas a the trap, evidence as is the overwhelming temptation thatstart is evolution suddenly to is after a highly consider considerable complex, evolution change with as inwater many a environmental supply conditions branches, linear such and that progression, as the temperature, like. acidity, If Such branches we can were end to just follow,chimpanzees as say, separated suddenly option from following (ii) the cosmic line catastrophes. here, leadingargument this to to is humans make equivalent about to such 5 - make an 7 the arbitrary million split split, years at ago. considering that What that point is life the when on Earth has already lasted more live with themselves among awith growing otherwise population inevitable and pandemics, mass limitedeven delusion, resources. Earth’s climate long change, They term asteroid will orbital and havenosity variations. comet to of impacts, deal Eventually, the they Sun must address asmanage all the it of increase slowly that, in the but merger the inexorably ofing lumi- evolves the the Milky Solar towards Way System becoming with to the a go Andromeda tochallenges, red Galaxy another astro-bioethical may giant galaxy necessitate choices for star. leav- must survival. be In If additiona made. to they choice, In these and technical such all engineering cases, such not choices making have consequences. a choice is inof effect global threats. Including those fromand its planet, Mars its appears star, even inevitable. its galaxy. Colonizationreduce Colonization within of the and the risk Moon beyond of the Solarplanet, human System extinction. or will moon. dramatically Consider thatevent, They like a could a colony recolonize pandemic of or their order nuclearon home the war, 100 planet time on on needed their a for a planet a thousand space ofhumankind species years searches to origin. ship, for rise after The or and a an then stellar new a to planet lifetime extinction question successfully to places is, colonize settle a what exoplanets. on, limit should it When we Earth’s has value to in be the checked resident for life resident we life. find? TheAt critical first one mightdifferentiate be between three tempted cases: to use the analogy of human evolution,relations so and as say to avoid that misunderstandings one when our would two societies meet elsewhere in theperhaps universe. equivalent to non-human primates, and then confine them to zoos and botanical gardens. tact. An important lessonhave comes diseases from that Earth we colonization. are defenselessnity Even against. to if different When friendly, diseases, two extraterrestrials then populationshappened may one meet, many of and times them they carry is in immu- victimized, humanity’shad and more history. people almost than For completely all wiped example, of out. Europe; before about Columbus, This 95% America of them probably were wiped out by diseases [ Challenges for Life 5.2 Colonization poses technological and ethical challenges PoS(GOLDEN2019)059 Paul A. Mason 17 However, we could go down another path, and try to communicate with whoever is there, Life on Earth has managed to meet countless challenges to get to where we are today. Most It is only a matter of luck and apparently only a recent phenomenon that any resident of Earth and leave them aloneunderstand if our they communication, but do not not careservice, to a respond combination respond. at of This expertise all, option ineven requires anthropology, leaving diplomacy, allow a and aside cosmic for astrophysics. diplomatic the the All this possibility possibilityadvanced does that that not than we they ours, might in may encounter termsmight another also of society comprehend space evolution that very travel, is much andthreshold better considerably in that then more the defines likely future, the and minimum think might time aboutbillion find from years, that us planet and there formation on then is to only their a evolve consider time life planets terms.to on that the its are We younger own, policy than say that such a we a few turn threshold. should leads That mark to then seeding all leads such such planetsthere planets with remains as life, friends but ours with our already us. life, beforetry carefully However, to we tended, under do so go such exactly that resettle. a the whatever logic, same. evolves whatever This everybody There and in else whoever is is in no out obvious the there, and universe beingConsidering convincing might careful how answer, not except much to to we act carefully have until learnt explore consequenceswe in are have the well gone last understood. through, 200 such years, as and witha how General hundred many Relativity intellectual years and revolutions Quantum ago, Mechanics and alreadythe more still next than not hundred fully years developed,ethical that it challenges is will it almost will change also certain our be thataccepting incumbent ethical inevitable we to terraforming thinking. will protect on some learn other exoplanet When more planets. life considering in from exploitation, these while complex 6. Conclusions of those challenges were met longsavanna. before our Pre-biological ancestors chemistry climbed and down early fromand organic the evolution DNA, trees of and to replicating explore the the molecules, formationlife like of RNA appeared. the Relatively first recently, cells, plantsflourish. are and important animals Today, we examples. populated humans the Much seem forbiddingand later, naturally land to multicellular inclined wonder, eventually are to to we peer alone?it, into This even the is state vast the of expanse essential question the ofenormous of the art multidisciplinary astrobiology, universe approaches, effort yet has attempts are shown to subject that answer ever, to many we a factors are contributed pernicious now to confirmation completely our bias. existence.ignorance ignorant is How- of Simply merely the put, a frequency current an of observationalhospitable planets limitation. conditions with Yet, for when life, life combined complex on with or Earth; thepossible that not. extraordinary alternative bias Earth That tends histories. to blind the human mind to the multitudehas of been capable of rational thought.are Indeed, only an marginally argument rational can be beings, made since that present they day are hominins only 10,000 generations with brains distinct Challenges for Life than 3 billion years?protect However, today that in zoos is and the wildably choice parks. within On that the the we last other hundred did hand, years,countries our make were when own exhibited when slavery attitudes as was we have ’savages’ in changed still consider exhibitions. consider- common, Some whom and traces to some of this people survive from in certain politics of today. PoS(GOLDEN2019)059 Paul A. Mason . In the far future, of order 100 7 shows the Virgo Supercluster, of which 7 ]. ]. The elemental abundances slowly enrich the 2 30 18 ], where the dangers in the inner parts of the Milky 31 The SGHZ dramatically evolves with time [ Intelligence is expensive and there is no reason to think that human-like intelligence (defined We introduced the concept of a Super-Galactic Habitable Zone in Mason and Biermann (2018) A note on terminology. We say hominin to mean humans and our ancestors until the last So when we think about 10,000 generations, and count each generation as 25 years, that means ] in order to address the question posed in the introduction. Namely, what kind of life will a 2 particular habitable planet support?are extremely We suggest dependent on that location conditionsthe and for Local time. complex group life of Figure asSuper-Galactic Galaxies we Habitable is know Zone. member. it Overlayingespecially Starburst supermassive this galaxy black map phases, hole is supermassive mergers,than a occur black excluding qualitative frequently hole the illustration in possibility activity, rich of of and clustersfor life the of in the galaxies. regions development dense of Rather withlike complex galaxies, the life we Galactic argue is Habitable that dramatically Zone theWay reduced probability concept outweigh over [ the the benefits local ofthe value. high Galaxy metallicity provide This and for too is theprotection few low a by concentrated metallicity a bit metals. species regions has It in taken is the about significant outskirts 75% in of of this the context habitable thatmedium lifetime of planetary out Earth. of whichof stars magnitude are as formed. theevolution The Galaxy of threats has the habitable to evolved structures from complex within the surface formation SGHZ, life to see decrease its Figure by current orders state. Now consider the here as able toasteroid escape did not the destroy nascent planetary humans,destroyed nest) delaying due the is the rise our of at own rationalism hand all onof or Earth. inevitable. a by If external mass civilization calamity, extinction, is humanity It maybe may even isnext recover. of apex If certainly species, all humans capable primates, are only of part then both luck it superiorescape will cognition that Earth and be before an technology a the invention, challenge that end for willexoplanet of life attempt may Earth’s to to have habitability, at develop about best the a only a billionof few planetary and lucky habitability. a chances to half develop years beings from capable now. of escaping An the end [ common ancestor of chimpanzees.common ancestor (LCA) Great for apes hominin’s lived andHomo sometime sapiens hominins, between 5-7 are together million about are years 300,000(though ago. hominids. years they The old, were oldest close). The but those last TheHowever, specimens there LCA is did date no not is species have baseda which modern on lot anthropologists brain genetics, of have skeletal size arguments designated evidence, about to and whetherwere be hypothesis. certain definitely the very branching LCA early events hominin and with speciesrecently, there gorillas are all are before actually of that, hominins. orangoutangs these before There species that, at gibbons before earlier that, points monkeys, of and250,000 so years. time, on. Stone chimps age most tools areancestor known for from hominins slightly over and 3 chimpanzees million washappened years roughly about ago. about 400,000 The yrs 8 last ago, million common is yearsThen that ago. we we What, got began fire, we to could believe, cook, learnhuman and to that brain allowed live to the together become brain much in to more grow. larger intelligent. numbers, [ an on going process, that allowed the Challenges for Life from other hominids. Probably, dolphins orintelligent whales species have on spent Earth substantially than more humans. time as the most PoS(GOLDEN2019)059 Paul A. Mason 19 Principles of Foreign Policy for the next 100 billion Will humans protect themselves into the unforeseeable future? A possible Super-Galactic Habitable Zone (SGHZ). The highest probability for the existence of Optimistically, we are on the cusp of that ability at present. The key is to change engage our PAM acknowledges travel funding from Picture Rocks Observatory and thanks Franco Gio- vannelli for the after dinnercluding talk those invitation. given by This PLB paper with is the derived from title several presentations in- intellect to overcome our otherwisesince inevitable the demise. KT impact, The absence 65since of million the years a Cambrian ago, planet wide and Explosionimportant catastrophe significantly, 241 role the in million lack Earth’s of years life. a ago,where We snowball have do suggest now Earth we made go period that it from good to here? the fortune Antropocene. has The played key question an 7. is now, Acknowledgements Gyr (note: we areto not be aware only of an a order simulation ofthe Local that magnitude Group estimate), goes will the this slowly mega-Galaxy descend far, consistingwill towards so of the be 100 center the a of Gyr merged newly the remains should Virgo formed of the Supercluster. be region merger The considered of event new or galaxy the if SGHZ. itGyr Complex originated of afterwards. life post-merger However, may calm, as again the they better Virgo thrive, cluster get if approaches, out either after of 100 it the way survived again! Figure 7: complex life is likely in regionsclusters, of intermediate within density, within the the yellow green bubbles. bubbles,density The are (and higher regions low density galaxy of metallicity) frequentCredit: volume galaxy Andrew outside Z. and of Colvin black with all hole adaptation. of mergers. the shapes The is vast low also beyond the limits of the SGHZ. Challenges for Life PoS(GOLDEN2019)059 Paul A. Mason 20 , Copernicus press. Rare Earth , given at Castel Gandolfo, Italy, 5 Sep, 2019, as well the talk given in Mondello (Palermo), Gordon, R., Sharov, A.A. (Eds.), Habitability89-126. of the Universe before Earth. Elsevier B.V, Amsterdam, [1] Ward, P. & Brownlee, D., 2000, [2] Mason, P. A., Biermann, P. L., 2018. Astrophysical and Cosmological Constraints on Life, In: [3] Dodd, M. S., et al., 2017,[4] Nature. 543,Theobald, 60. D.L., 2010, Nature. 465, 219. [5] Biermann, P. L., et al. 2014,[6] MNRAS, 441, 1147. Johnson, J., 2019, Science, 363, 474. [7] Mason, P. 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