The search for life -- It-tiftix għall-ħajja

Maybe some of you might be curious in the fascinating search for signs of life outside our dear planet earth, the one that has all the (proven) requisites to maintain life, a world that man has been sucking from, polluting and abusing in an alarming and unsustainable fashion.  If at the end of the day life is truly found somewhere else, I sure hope it in no way, shape or form resembles humanity!

 

Today we feel comfortable speaking openly about this and similar subjects, however in the past when the powers-that-be used to maintain the Aristotelian view of the earth at the centre of the universe, you would certainly think twice.  After Aristarchus, the Greek philosopher living 300 B.C. and Copernicus, an Polish astronomer in the sixth century A.D., had proposed the earth, planets and other stars revolve around the sun, the Italian philosopher and monk Giordano Bruno also in the sixteenth century went further and argued there are planets around other stars, and also that they might have life.  Bruno was condemned to death by the Roman Catholic Church, and in fact was burnt alive, naked and upside down, for this apparent heresy.1

 

The thought of life existing outside of our plane is naturally speculation, as so far it's only our world that has been proven to support life.  Nevertheless when thinking of the bilions of galaxies in the universe, and the billions of stars in each, with their planets and moons, it is not that inconceivable that a small proportion might have suitable conditions for life.  This principle can even be extended to the possibility that some of this life might be intelligent, expressed by the Drake Equation which provides an estimate (again speculative) of how many civilisations might exist in the universe.2

 

To take a position whether this all makes sense or otherwise, it would be good to consider certain characteristics of life as found in our own world.

 

Firstly, molecules considered essential for life are based on a few elements, primarily carbon, hydrogen, oxygen and nitrogen, which are abundant not only in our world but in the universe.  These elements in various combinations have the ability to form stable molecules which are called organic when containing carbon.3

 

Many chemicals include organic ones dissolve well in water in its liquid state.  This permits them to meet and undergo chemical reactions that permit life.

 

For these reactions to occur, energy sources are necessary, for example electrical energy from lightning (which catalyses chemical reactions leading to the formation of complex organic molecules)4, sunlight (which permist photosynthesis used by plants and grasses) or chemical energy from vents in the dark deep ocean floor (which permits chemosynthesis by bacteria in cold or boiling water)5.

 

Creatures that don't use these sources or energy directly, use them indirectly when eating the ones that use them directly.  Thus is formed the food chain, where creatures using energy sources directly are at the bottom, and predators on top.

 

The search for life outside our world is carried out via telescopes based on earth, telescopes on satellites circling the earth and satellites sent to other planets, moons or space objects.

 

You could divide the work of scientists into two tracks.   The first is basically to identify planets or moons that have characteristics similar to our own world known to permit life.  Stars are excluded as their conditions are considered to be too extreme.

 

Therefore, for example, the search is on for planets rotating around their star at a distance permiting water to exist in its liquid state.  This distance needs to be not too far away (as then water would be frozen solid) and neither too close (as water would be in its steamy gaseous state).  The acceptable distance range form the habitable zone, proposed the first time in 1953, with the moniker Goldilocks Zone being mentioned in the seventies.  Planets outside our own solar system have been located since 1992, and to date thousands have been found, but only a bit above ten are considered habitable.

 

Closer to us on an astronomical scale, there was quite a commotion in the year 1877 when the planet Mars was reported by the astronomer Schiaparelli to have canals, which people imagined had been dug by aliens, however this idea was disproved later.  Nevertheless there is evidence that water does exist on Mars even today, which explains the interest in sending satellites there, including a human expedition.

 

There is also a big interest in some Jupiter moons (Europa seems to be covered in ice, Ganymede and Callisto seem to have a briny sea under an ice cover) and those of Saturn (Titan has methane in a liquid state which could perform the same function as liquid water, and Enceladus has organic molecules)6.

 

Finally there's the other track about the Search for ExtraTerrestrial Intelligence (SETI), where astronomers are looking for intelligent life, by searching for the use of technology.  For this reason, they eavesdrop for unexpected radio transmissions from space to determine if these might be coming from an external intelligence.  This was immortalised by the 1997 Hollywood film Contact.

 

I am sure that in future we will receive the news that this search was rewarded, even if the life found is in a primitive form.  If this materialises, it will have huge philosophical, political and religious repercussions, as it will change profoundly and dramatically the manner in which man considers himself and his place in the universe.

 

I only hope I'll still be around.

 

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Forsi wħud minnkom għandhom kurżità fit-tfittix affaxxinanti għal sinjali ta' ħajja barra mid-dinja għażiża tagħna, id-dinja li hi meqjusa bir-rekwiżiti kollha (bil-provi) biex tmantni l-ħajja, id-dinja li l-bniedem qiegħed jerda' minnha, jħammeġ u jabbuża minnha b'mod allarmanti u insostenibbli.  Jekk fl-aħħar mill-aħħar ħajja tassew tinstab x'imkien ieħor, nispera biss li ma tkun tixbaħ xejn affattu lill-bniedem!

 

Illum inħossuna komdi nitkellmu bil-miftuħ fuq suġġett bħal dan u simili, iżda żmien ilu meta l-poter ta' dak iż-żmien kien isostni s-sistema Aristotelika tad-dinja fiċ-ċentru tal-univers, kont taħsibha darbtejn.  Wara li Aristarchus, filosfu Grieg li għex 300 sena q.K. u Copernicus, astronomu Pollakk fis-seklu sittax w.K., kienu ipproponew li d-dinja, il-pjaneti u l-istilel l-oħra jduru madwar ix-xemx, ġie Giordano Bruno, filosfu u patri Taljan ukoll fis-seklu sittax, li mar iktar 'il bogħod u argumenta li hemm pjaneti oħra jduru madwar stilel oħra, u anke li fuqhom jista' jkun hemm il-ħajja.  Bruno ġie kkundannat mill-Knisja Kattolika Rumana għall-mewt, u fil-fatt inħaraq ħaj, rasu l-isfel u bil-patata barra, għal din l-ereżija evidentiapparenti tiegħu.1

 

Il-ħsieb li teżisti l-ħajja barra mill-pjaneta tagħna hija naturalment spekulazzjoni, u s'issa id-dinja tagħna biss għandna provi li żżzzomm il-ħajja.  Madankollu meta wieħed jaħseb fuq il-biljuni ta' galassji fl-univers, u fil-biljuni ta' stilel f'kull galassja, bil-pjaneti u qmura tagħhom, mhix daqshekk inkonċepibbli li proporzjon żgħir tagħhom jista' jkollhom il-kundizzjonijiet tajbin għall-ħajja.  Dan il-prinċipju huwa estiż għall-possibiltà li parti minn din il-ħajja tkun intelliġenti, li hija espressa fl-ekwazzjoni ta' Drake li tagħti stima (mill-ġdid spekulattiva) ta' kemm jeżistu ċivilazzazzjonijiet fl-univers.2

 

Biex tieħu pożizzjoni jekk dan kollu jagħmilx sens jew le, tajjeb li Wieħed ukoll jista' jtikkonsidra ċerti karatteristiċi tal-ħajja kif misjuba fid-dinja tagħna.  

 

L-ewwelnett, il-molekuli meqjusin ħajjinessenzjali għall-ħajja huma bbażati fuq ftit elementi, fuq quddiem nett huma l-karbonju, l-idroġenu, l-ossiġenu u n-nitroġenu, li huma abbundanti mhux biss fid-dinja tagħna imma wkoll fl-univers.  Dawn l-elementi f'diversi kumbinazzjonijiet għandhom l-abbiltà li jagħmlu molekuli stabbli li jissejħu organiċi meta jinkludu l-karbonju.3

 

Ħafna kimiċi inklużi dawk organiċi jdubu tajjeb fl-ilma fl-istat likwidu tiegħu.  Dan jippermettilhom li jiltaqgħu u jseħħu r-reazzjoni kimiċi li tjippermettiu l-ħajja.

 

Biex dawn ir-reazzjonijiet iseħħu, jinħtieġu ukoll sorsi ta' enerġija, per eżempju enerġija elettrika mis-sajjetti (li tqawwi r-reazzjonijiet kimiċi li jwasslu għal molekuli organiċi kumplessi)4, id-dawl tax-xemx (li jippermetti l-fotosinteżi li jintuża mill-pjanti u l-ħxejjex) jew enerġija kimika minn ċmieni fil-qiegħ imdallam tal-baħar fond (li tippermetti kimosinteżi minn batterji f'ilma kiesaħ jew jagħli)5.

 

Il-ħlejjaq li ma jutilizzawx direttament dawn is-sorsi ta' enerġija, jużawhom b'mod sekondarjuindirett meta jieklu lil dawk tal-ewwelli jutilizzawhom direttament.  B'hekk tiġi ffurmata l-katina tal-ikel, bil-ħlejjaq tal-bidu fil-qiegħ nett, u l-predaturi fuq nett.

 

It-tiftix għall-ħajja barra mid-dinja tagħna jseħħ permezz ta' teleskopji bbażati fuq id-dinja, teleskopji fuq satelliti li jduru d-dinja u satelliti li jintbagħtu lejn dinjiet,  jew qmura jew oġġetti oħra fl-ispazju.

 

Ix-xogħol tax-xjentisti tista' tgħid huwa maqsum f'żewġ binarji.  L-ewwel wieħed, bażiku, hu li jiġu misjuba dinjiet jew qmura li għandhom karatteristiċi simili għal dawk tad-dinja tagħhna magħrufin li jippermettu l-ħajja.  Ix-xmux huma esklużi għax il-kundizzjonijiet tagħhom huma meqjusa estremi wisq.

 

Għalhekk, per eżempju, qed jiġu mfittxija pjaneti li jduru x-xemx tagħhom f'distanza li tippermetti l-ilma li jeżisti fl-istat likwidu tiegħu.  Din id-distanza trid tkun la 'l boghod wisq (għax inkella l-ilma jkun iffriżat fi stat solidu) u la qrib wisq (għax inkella jkun stim fl-istat ta' gass).  Id-distanzi aċċettabbli jiffurmawjissejħu żona abitabbli, li ġiet proposta għall-ewwel darba fl-1953, bit-terminu żona ta' Goldilocks tissemma fis-snin sebgħin.  Pjaneti barra mis-sistema solari tagħna ilhom jinstabu mill-1992 u s'issa instabu eluf6 imma minnhom ftit iktar minn għaxra huma meqjusin abitabbli.

 

Iktar qrib tagħna astronomikament, kien hemm furur fis-sena 19881877 meta l-pjaneta Mars ġiet irrappurtata mill-astronomu Schiaparelli li kellha l-kanali, li nies immaġinaw li tħaffru minn aljeni, imma din l-ideja ġiet imxejna iktar 'il quddiem.  Madankollu, hemm evidenza li jeżisti l-ilma fuq Mars anke llum, għalhekk l-interess li jintbagħtu satelliti hemmhekk, u anke spedizzjoni tal-bnedmin.

 

Hemm ukoll interess kbir fi qmura ta' Jupiter (Europa jidher li hi mgħottija bis-silġ, Ganymede u Callisto jidher li għandhom baħar mielaħ taħt kisja silġ) u ta' Saturnu (Titan għandha metanu fl-istat likwidu li jista' jservi minflok l-ilma, u Enceladus li għandu molekuli organiċi).7

 

Fl-aħħar nett, hemm il-binarju l-ieħor ta' tiftix għal intelliġenza extra-terrestri (SETI - Search for ExtraTerrestrial Intelligence), fejn astronomi qed ifittxu għal ħajja intelliġenti, billi jfittxu għal użu tat-teknoloġija.  Għalhekk jissemmgħu għal trasmissjonijiet radjufoniċi mill-ispazju mhux mistennija biex jaraw jistgħux ikunu ġejjin minn intelliġenzi oħra.  Dan kien immortalat fil-film ta' Hollywood fl-1997 jismu Contact.

 

Jien persważ li fil-futur nisimgħu bl-aħbar li dan it-tiftix ħalla l-frott, anke jekk il-forma ta' ħajja misjuba tkun primittiva.  Jekk din il-ħaġa tiġri, aktarx ikollha riperkussjonijiet kbar filosofiċi, politiċi u reliġjużi, għax tibdel b'mod profond u drammatiku kif il-bniedem iħares lejh innifsu u postu fl-univers ta' madwaru.  Nispera biss li nkun għadni ħaj.

 

 

 

 

1https://www.nasa.gov/vision/universe/starsgalaxies/search_life_I.html, retrieved 17/5/2017

2http://www.seti.org/drakeequation, retrieved 17/5/2017

3http://www.physicsoftheuniverse.com/topics_life_early.html, retrieved 17/5/2017

4http://www.livescience.com/32983-what-are-ingredients-life.html, retrieved 17/5/2017

5http://ocean.si.edu/ocean-news/microbes-keep-hydrothermal-vents-pumping, retrieved 17/5/2017

6https://lco.global/spacebook/possibilities-and-search-life-our-solar-system/, retrieved 17/5/2017

1https://www.nasa.gov/vision/universe/starsgalaxies/search_life_I.html, retrieved 17/5/2017

2http://www.seti.org/drakeequation, retrieved 17/5/2017

3http://www.physicsoftheuniverse.com/topics_life_early.html, retrieved 17/5/2017

4http://www.livescience.com/32983-what-are-ingredients-life.html, retrieved 17/5/2017

5http://ocean.si.edu/ocean-news/microbes-keep-hydrothermal-vents-pumping, retrieved 17/5/2017

6http://www.space.com/17738-exoplanets.html, retrieved 17/5/2017

7https://lco.global/spacebook/possibilities-and-search-life-our-solar-system/, retrieved 17/5/2017