Life in the Universe. A Journey to Outer Space

life is one of the most fascinating phenomena in the universe incredibly elaborate its diverse forms never fail to capture one's imagination today we invite you to go slightly back in time and see the chief milestones in the earth's biosphere's evolution we will enjoy the views of the prehistoric earth find out how and why life came onto land and take a look at the major extinction events in the history of our planet in the second part of the film we will briefly leave the earth and snoop around limitless expanses of space in search of alien life forms starting out with jupiter's satellites we will move on to the amazing ocean world of gliese 1214b after that we will get as far beyond the solar system as the remote exoplanet toi 700d let's get ready for our journey and begin [Music] the first in outer space actually our earth has been not the friendliest of places for the greater part of its existence let's cast our mind back to the archaean eon the earliest time when life was known to be around it began four billion years ago and continued for approximately one and a half billion years the early earth had just gone through the second heavy bombardment several thousand tons of rocky debris from the formation of the solar system was held to the planet smashing the thin basalt crust that had just formed on the surface of molten magma even after this ordeal the young earth cooled off again and gained its first lithosphere just a billion years later it became home to the very first living organisms the earth of that period had a comparatively smooth surface tectonic plates that is rocky bodies that create high mountain ridges on collision were simply non-existent at that early time there was no diversity in rocks on the early earth either banks of wars and rocks were in the first stages of formation most of the earth's crust was made up of the sword a rock formed from magma and in essence it is solid lava there was almost no oxygen in the atmosphere in the archaean the concentration of nitrogen was considerably smaller than it is now the earth was shrouded in a dense mixture of water vapor and carbon dioxide with a high percentage of oxides of sulfur phosphorus and other active chemical elements the sun was much dimmer then than it is now according to some estimates its luminosity was even 30 percent less than that of today that is why our planet was quite a murky place the moon still used to find itself in close proximity to it so a day lasted just around 10 hours as for tidal waves they reached up from several dozen to 300 meters as the earth gradually cooled off water in the atmosphere condensed and poured down in torrential rains at first it accumulated in small bodies of water in lowlands this water was sour salty and extremely hot up to a boiling point in some places its composition resembled that of today's geezers paradoxically this seemingly harsh environment proved to be the cradle for primitive life forms that originated and evolved there it goes without saying that first organisms were anaerobic instead of breathing oxygen as we do which was non-existent in the atmosphere at the time first living organisms relied on other sources of energy archaean organisms were not yet able to swim in order to survive they needed a substrate that is why the biosphere of the time was a thin slimy film of not more than a millimeter in width on the bottom of a sour and hot ocean in its coastal area the maximal depth the biosphere reached down was up to 20 meters as the dense atmosphere did not allow sun rays to penetrate deeper the mouths of underwater volcanoes offered habitats to bacteria that were chemotrophs these bacteria didn't need light and fed on other energy sources relying on chemical reactions between sulfur compounds and iron the earth was cooling off sea levels rose the atmosphere became more rarefied and the sun gradually grew in size the coastal area favorable for life was also gradually expanding and by the end of the archaean eon the biosphere was confined to a thin stripe along the coasts and also oases as it were on the sea bottom near active volcanoes meanwhile all the land rivers and most of the open ocean were still completely devoid of life if an explorer were to visit the earth of that period stromatolites would be the only evidence of life seen with the naked eye these sedimentary limestone formations were created by primordial microorganisms and may reach up to several meters in height there was another problem in that age the amounts of reagents were insufficient and that greatly impeded the evolution of life evolution hadn't yet produced scavenges organisms feeding on dead flesh thus under the influence of gravity and sea currents dead creatures accumulated in cavities on the sea floor hundreds of millions of years later these accumulations were processed by nature into what is now oil fields around three and a half billion years ago there are emerged creatures that were to change the earth beyond recognition some bacteria got the hang of photosynthesis involving oxygen production a billion years later on the border between the archaean and the proterozoic eons their revolution brought about the most global extinction in the history of the planet it is known as the oxygen catastrophe to name but one term i've spoken in more detail about it in an earlier video it is hardly possible to estimate the scale of that event as an overwhelming majority of the creatures didn't get preserved as fossils practically all the diversity of anaerobic life-forms that had taken a billion years to evolve vanished off the face of the earth the ancient earth's atmosphere was exceptionally rich in methane as strong greenhouse gas it robustly oxidizes producing carbon dioxide and water during the process with methane's concentration in the atmosphere dropping the temperature on the planet decreased as well as a result of this process there occurred the huronian glaciation the most large-scale ice age in the history of the earth which started 2.4 billion years ago and continued for as long as 300 million years diggings revealed that in some areas ice caps reached as far as the equator with the planet almost totally transformed into a ball of ice it took the earth one and a half billion years to go all the way from boasting boiling lava fields to endless icy deserts the proterozoic eon lasted from two and a half billion years to 440 million years ago life persevered in spite of the cold and evolution although thwarted carried on nevertheless land remained lifeless living organisms concentrated in the coastal area near the equator and what was happening on the continents even though they weren't crawling with life yet land was experiencing something different and interesting in its own way alongside the continents banks of metal ores and new rocks were being formed in the proterozoic eon areas of dry land alternately assumed different aspects and were endless glaciers and stone deserts at one time or another it is hard to imagine but just a measly 500 million years ago the greater part of our planet appeared quite like a martian desert luckily for all the dwellers of our planet the sun was growing brighter and warmer eventually the ice gave in 542 million years ago there began the phanerozoic eon which is the greek for the eon of visible life it was peculiar for periods of active evolution of different species interlaced with mass extinctions i have told you about the major ones but what was the earth like in those days at the beginning of the paleozoic era the greater part of land formed a giant supercontinent named gondwana located in the southern hemisphere it had elaborate terrain and covered over a hundred million square kilometers it was comprised of today's africa south america antarctica australia the indian peninsula and some other areas the smaller continents of the day lorentia baltica and siberia were situated near the equator apart from all that there was a great number of smaller islands still up until the silurian period which started approximately 440 million years ago there weren't any life forms to speak of on all these expanses only some simple mosses and lichens were slowly establishing their dominance on land it was only at the beginning of the silurian period that first plants emerged in tidal areas and near rivers and only in the tropical zone of that even in spite of the fact that sea species and plants became more diverse marine life forms still concentrated near the coasts the area populated incrementally expanded just to give you an example the depth of the ocean at which photosynthesis was able to take place in the devonian was just 50 meters which is 10 times as little as it is now in the same period which began 420 million years ago and continued until 358 million years ago the first decomposers emerged organisms decomposing dead flesh as a result their emerged organisms feeding on products of decomposition for example alongside scavenging bacteria there could be found sea sponges at depths of up to 500 meters the next period was the carboniferous period it continued from 358 to 299 million years ago by the time it began the greater part of the tropical zone was covered with tree ferns dense tropical forests did not grow as a mass there were no organisms back then that would help wood decompose that is why bulky trunks of trees didn't trot when they died and didn't pass any nutrients to their descendants they remained lying without decaying and the phosphorus in their bodies so vital for plants couldn't be extracted thus with time lush sapi virgie gave way to enormous heaps of dead wood covering enormous stretches of land later they formed rich deposits of coal which is still widely used by mankind in various industries in areas other than the tropics only fungi mosses and lichens could be found they were not able to harden the upper layer of the earth by their roots and as a result rain easily washed it off with rivers turning into muddy streams and lakes becoming putrid swamps dry areas became lifeless deserts it was a time when fishes were vigorously evolving in the seas and rivers although life hadn't yet ventured out into the open ocean algae hadn't learned to float yet and so life was still confined to coastal areas the carboniferous period was followed by the permian period it began 299 and finished 252 million years ago the first amphibians dared to start exploring land and plants spread to conquer subtropics the sea remained populated only in shallow waters close to the coasts the permian period finished with the most massive extinction event in the history of multicellular life according to some estimates up to 96 of marine species and 73 percent of land species died out it is still not known what caused such a global mortality the triassic period of the mesozoic era promptly made up for the lost time bringing life to a new level during the process for the first time in the history of the earth temperate latitudes could boast some woods another revolutionary event took place on the sea where blue green algae emerged a type resembling their today's descendants it was not vital for them to live in a substrate anymore and so photosynthetic microorganisms quickly spread across the upper layer of the global ocean tempted by the food fishes mollusks and darthropods followed it organic leftovers settled on the sea bottom thus sea bottom dwellers were amply supplied with food as well the global ocean was assuming an aspect close to today's the mesozoic era lasted from 250 to 66 million years ago it is subdivided into three periods the triassic the jurassic and the cretaceous this is when dinosaurs thrived admittedly the most well-known prehistoric creatures that became subject of feature and science fiction movies the way these ages are depicted we might get the idea that the earth was covered with tropical forests from the poles to the equator in fact it is completely wrong indeed forests reached northern latitudes but only because the average temperature on the planet was much higher than it is now meanwhile equatorial areas on the contrary suffered droughts with the forests rapidly spreading across the entire earth's surface there were still lots of swamps and deserts around the latters were not only scorching hot and dry as we're used to picturing them but also moderate cool and even humid with no herbaceous plants around soils could not attach themselves to rocky slopes only lichens are able to grow on barren rocks flowering plants became abundant only by the middle of the cretaceous period that is around 100 million years ago interestingly the first varieties were trees and by the end of the period there emerged plants similar to today's herbs compared to a mighty oak or a giant sequoia regular grass appears insignificant but it is capable of something tree giants aren't by mingling their tiny roots in the ground they help form and strengthen the turf this not only makes soil tougher and prevents it from getting washed off or eroding but also takes care of getting rid of excess water by letting it evaporate and accumulating water when there is a lack of it on emerging herbaceous plants turned deserts into steps prairies and savannas swamps into flood meadows and permafrost areas into tundra and tundra step by the time the cretaceous period was coming to its end the earth had started to resemble the earth of today it was lacking just one important touch mammals this type of animals had been around for a long while but the creatures were not very widespread until the end of the mesozoic era it is still not clear what caused dinosaurs to become extinct a giant meteorite global cooling and other suggestions are listed among the supposed culprits either way these giant saurians vanished thus vacating a special niche for mammals it took them 66 million years to evolve from tiny marsupials into majestic whales dangerous tigers tough camels and amusing bats eventually evolution produced a unique species the only living creature capable of not only adapting to nature but also changing it the being that extracts coal formed of all those dead trees from millions of years ago to warm up one's dwelling the creature exterminating other species for money of a sport the creature turning vast areas into wasteland in pursuit of selfish motives this is homo sapiens or the human up until the late proterozoic eon all life on the earth was to be found only in oceans throughout that prehistoric period land on the surface of the planet would alternately be covered first by giant ice caps then by barren lifeless expanses similar to martian landscapes and back again ediacaran the last period in the proterozoic started approximately 635 million years ago and persisted for 94 million years the earth of the time was far from being the most hospitable place if today's human were to experience the environment of that period he or she would very soon pass out due to asphyxiation as oxygen concentration in the air was twice as low back then as it is now landscapes of the ediacaran period were endless deserts and rocky mountains devoid of any signs of life meanwhile the coastal area of the ocean was crawling with highly unusual creatures not even remotely resembling any of today they were mainly soft-bodied and non-motile that is they couldn't move around and fed of nutritious particles in water these organisms supposedly didn't have either muscles or a developed nervous system or a hard carapace with practically no predators around all these things were by the long the short of it not yet called for predators emerged at the very end of the ediacaran period at once establishing their dominance in the prehistoric ocean active hunting proved to be a highly effective survival strategy as the soft-bodied non-motile dwellers of the ocean's bottom unable to either escape from the enemy or put up a decent fight or even hide were easy prey in a way the ocean was an endless smorgasbord for first predators full of nutritious food right there for the taking it is hardly surprising that most prehistoric creatures making up the menu didn't last long others had to adapt to deal with the new dangers [Music] approximately 542 million years ago there began a period that was to greatly contribute to changing what our planet was like geological layers of that time are filled with fossils that used to be highly organized living creatures these finds give grounds to suppose that the prehistoric ocean used to be teeming with creatures sporting an impressive outer skeleton or carapace referred to as the cambrian explosion the process heralded a new breakthrough in the history of evolution of life on our planet and the beginning of the phanerozoic eon or the eon of visible life the first period of the phanerozoic eon is called cambrian it started 542 million years ago and continued for about 56 million years trilobites are the most well-known and widespread creatures of the time although these creepy things are not the only ones the cambrian is notable for this was the period when the prey predator system was finally established it goes without saying that in the millions of years that followed natural conditions would interfere with the established food chains with some species dying out and others riding high but the principle stayed predation became a potent incentive for evolution which forced organisms to change in order to be able to deal with new threats as well as to explore new areas so far inaccessible to predators the cambrian explosion produced a great many completely new forms of organization of living organisms many of them didn't prove to be viable and eventually vanished off the face of the earth others on the other hand brought about a great diversity of new species for example approximately 550 530 million years ago tiny bottom dwellers resembling mollusks known as haikulas developed a sturdy notochord going through the entire body these creatures are believed to be some of the most ancient ancestors of today's vertebrates picayas came a bit later these were not very large creatures either they looked like lancelets flatworms or primitive fish proud owners of a sturdy and flexible cord with muscles attached to it they were able to swim by wriggling their entire body in a series of s-shaped movements this manner of swimming proved to be quite effective and fast which allowed early chordates to survive and evolve into higher organized species admittedly almost all paleontological finds dating back to the cambrian are those of marine dwellers as the overwhelming majority of the living organisms of that period lived in the ocean some of these creatures we can see in fossil finds look highly peculiar and even horrifying anomalocaris for example was a giant shrimp measuring up to 60 centimeters in length it was also one of the apex predators in the cambrian period and even though other finds appear rather bleak in comparison they are proof of some really important phenomena among these the most ancient fossil finds of land soils can be mentioned they date back to around 530 million years ago which corresponds to the middle and late cambrian without any specific knowledge in the field one will fail to see anything special in these ordinary looking stones however these prints show that it was around this time that first primitive algae and microorganisms started to venture onto land later having thrived in their lifetime they died and decomposed thus forming a nutritious substrate for their descendants first colonies of microorganisms must have formed in humid and warm places on land in shallow waters for example or in the tidal zone of the ocean with plenty of water and light and with no animals around that would be keen on eating them young algae flourished successfully adapting to the new conditions single cell algae was soon joined by primitive fungi which were not able to synthesize nutrients on their own but could feed on what remained of dead weeds a hundred million years later the symbiosis of fungi and single cell algae produced lichens these undemanding things were to become tip of the spear in exploring great expanses of new territories the ordovician period which followed the cambrian began approximately 485 million years ago and continued for around 42 million years this is when marine life was actively evolving in the ocean mollusks and arthropods were thriving among the latter's euripides many of which dwell to the bottom to get around more conveniently these creatures used their jointed limbs this feature would later be an indispensable acid and an important factor in adaptation to life on land apart from these they revolved jawless animals similar to today's lampreys and a bit later their emerged cartilage fish meanwhile plants slowly but surely made their way inland and away from water first multicellular plants emerged which were clearly able to survive on land they left imprints of spores and vessels that delivered water to the upper parts of the plants animals on the other hand still didn't venture out of their regular environment although it is probable that some crustaceans did have a chance to explore coastal areas this period ended in the ordovician silurian extinction event its causes are still not clearly defined yet but according to the most popular theory it was brought about by a global ice age and a fall in the level of the global ocean that followed be it as it may up to 50 of all the species vanished off the face of the earth as a result of the extinction however life was able to adapt to new conditions and even take it to a completely new level next in line was the silurian period which continued from 444 to 419 million years ago this was when giant arthropods dominated the ocean and it is then that one might come across a euryptorid measuring up to two and a half meters in length fishes also thrived among which large and swift predators over one meter long come to think of it it is hardly surprising that some living creatures preferred to leave the ocean and try to find other safer areas for their habitats and so this is when first arthropods came on shore these were prehistoric europeans and other crustaceans their tough chitinous carapace protected them from exposure to the sun and drying as well as kept their body in shape their small legs allowed them to move around on hard surfaces when out of water it is reasonable to suppose that first arthropods that ventured on land made a point of not getting too far from water their respiratory organs had to remain moist in order to function correctly however the arthropods were greatly tempted by the abundance of plant food that was therefore the taking just beside the sea the safety factor guaranteed by land was another attraction as predators hadn't yet learned to chase their prey if the latter escaped to land gradually these explorers fully adapted to the new conditions and came onto land for good which later made for an incredible diversity of species among insects and spiders as well as other classes of living creatures approximately 419 million years ago the devonian period began which was the most important one in terms of land exploration it lasted for around 60 million years this is when rhinophytes spread all over the planet prehistoric vascular plants and ancestors of acquisition mosses and ferns reaching three metres in height they densely covered all humid and warm places of the planet mainly coastal areas of seas and the deltas of rivers flowing into them however neither rhinophytes nor mosses and lichens that emerged later had a proper root system instead of a network of roots that would keep a plant firmly in place they are just primitive root stocks at best that is why soils would quickly get washed into rivers and turn them into muddy streams and their deltas into swamps in these humid places rich in organic matter plants were flourishing giving food to insects and other inhabitants of the earth of that time fish in their turn were attracted to marshy areas by the abundance of insects and their larvae eventually great amounts of putrefying organic matter absorbed oxygen from the water in swamps which affected the breathing of the creatures living there that is why to compensate for the lack of oxygen fish in those waters learned to take gulps of atmospheric air gradually they developed a breathing sac allowing them to survive outside their aquatic habitat simultaneously other appendages were developing thick stalks and trunks of plants growing in marshes offered to fish reliable shelter from larger predators however it was hard for them to make their way through these thickets thin fins were not adequate for the purpose more powerful and muscular limbs were called for that is how the fins of fish dwelling in marshy environments grew longer and developed additional bones that strong muscles were attached to these were first lungfish and in particular psychopterygi eustinopterin is a typical representative of these even though this strong-finned fish wasn't keen on settling on land it was already able to breathe atmospheric air and stay out of water for certain periods shallow swamps would often dry out which is why their inhabitants would have to migrate to other more humid places favorable for life and to do this they naturally had to move across stretches of land this is the way acanthus steger got about it for example which lived around 365 million years ago in the late devonian one of the first known creatures intermediate between fish and amphibians acantha steger had gills scales and a tail fin just like any other fish at the same time this fascinating creature sported four legs and a breathing sack like that of amphibians that allowed it to breathe atmospheric air unfortunately acatha stega's limbs were not strong enough to support its weight and its thorax muscles couldn't pump oxygen for too long that is why it stayed mostly in water sometimes crawling from one body of water to take a dunk in another gradually the ability of prehistoric sarcopteryji to breathe atmospheric air improved their fins grew in power and turned into fully fledged pores their appearance underwent great changes for example tiktaalik a prehistoric sarcopterygian amphibian fish that lived at around the same time as acanthostega had a flat head like that of a frog being anatomically intermediate between fish and amphibians tiktaalik had powerful fins that were able to prop up its body and move it across solid surfaces in addition this amphibian fish could breathe with both its gills and its lungs the way its ossicle is designed is proof of tiktaalik's ability to easily distinguish sounds both on land and in water all these signs show that this creature spent as much time out of water as in it in the carboniferous period which followed the devonian amphibians came onto land for good settling in all sorts of ecological niches in their revolutionary struggle they developed into such animal classes as reptiles and synapsids a great diversity of conditions outside the ocean stimulated and spurred the evolutionary process on as land dwellers are exposed to a much wider range of temperatures and other factors than water dwellers incidentally this question may arise why did animals come onto land only once in the entire history of evolution why didn't a single marine species venture to live on land in the past 350 million years the answer isn't as elaborate as it might seem [Music] marine creatures are adapted to living in an aquatic habitat the overwhelming majority of them are useless and actually helpless when out of water to live in another environment they would need a whole other skeleton structure as well as outer skin or fur or shell for that matter and organs of breathing vision and hearing the proverbial fish out of water is even more helpless than a human in the open sea it is a foregone conclusion that stranded fish is there for the taking for any land creature that would care to have it when coming onto land in the paleozoic period plants arthropods and vertebrates went on to occupy vacant ecological niches they didn't have natural enemies in the new environment while there was plenty of food around the chief negative factor in the new environment was not other creatures but other conditions fortunately the species were able to take their time adapting to them interestingly an example of the other way around is known to us prehistoric ancestors of cetacea went back to living in an aquatic environment at the same time dominating certain ecological niches strange though it may seem on the face of it there is actually nothing controversial about it the fact is that things to adapt to in the terrestrial environment are tougher and more diverse that is why getting back in the water could be a smart move in order to survive whales dolphins and other secondary aquatic inhabitants of oceans seas and rivers are living evidence confirming the fact that evolution is not irreversible if in certain circumstances it is better to take a step back that's what it will do the evolution of life on earth was anything but linear there were periods of higher diversity as well as periods of almost total extinction this was deduced following the analysis of fossils unearthed at paleontological digging sites in the past 540 million years there have been five major and about 20 minor extinction events however the most global crisis of our planet's biosphere occurred much earlier approximately 2.1 billion years ago the first living organisms are posited to have appeared on earth rather early approximately but not quite 4 billion years ago that is about 400 million years after the planet's surface had become more or less suitable for life even so the earth of that period can't have looked hospitable barren rocks dense clouds frequent storms and earthquakes and an atmosphere devoid of oxygen made up of mostly nitrogen methane and carbon dioxide this was the age of primitive microorganisms archaea and bacteria most of which used an oxygenic photosynthesis that is a kind of photosynthesis where oxygen is not produced apart from these creatures it is thought that there were many forms falling in between that couldn't be classified as either living beings or not living objects with a satisfying degree of certainty about 2.7 billion years ago their emerged oxygenic photosynthesis the kind of photosynthesis familiar to us where oxygen is produced this form is still used by the overwhelming majority of plants and unicellular algae anaerobic organisms cannot live in an oxygen-rich environment that is why ancient algae used oxygen as a weapon they released it as a byproduct of their life activity and this waste killed their competitors this way algae not only protected their turf but also spread further to cover larger areas to dwell on at first oxygen was spent on oxidation of rocks in habitats of aerobic organisms colonies in this manner oxygen pockets were formed small areas of oxidized minerals gradually oxygen went on to spread in the atmosphere oxidizing methane sulfur compounds and iron not able to exist in an environment rich in oxygen most anaerobic organisms died out with those of them remaining around confined to underground pockets where oxygen didn't reach thus the tables were turned in the biosphere with the oxygen breathing organisms becoming the majority and spreading across larger areas and the former planet owners forced to remain in some limited areas with the spread of the new organisms the content of gases like methane and carbon dioxide in the atmosphere dropped methane oxidized forming water and eventually carbon dioxide with the latter taking active part in photosynthesis all this reduced the greenhouse effect and the earth's surface considerably cooled the so-called huronian glaciation started approximately 2.1 billion years ago and continued for about 300 million years until the sun's luminosity and tectonic makeovers had heated up the earth this was a time when single cell microorganisms were evolving extremely slowly constantly thwarted by an occasional prolonged global ice age the period has earned a great number of nicknames like the great oxidation or oxygenation event oxygen catastrophe and oxygen crisis to name but a few even though not really swift this event was definitely large scale and global practically all the biodiversity of the non-oxygen period was eliminated and evolution was greatly hampered by global glaciation for a good billion years however in the aftermath there emerged a more energy efficient method of nutrition approximately million years ago the phanerozoic eons started sometimes referred to as the period of visible life it was peculiar for vigorous evolution of multicellular species and in fact it is actually still in progress many creatures of that age looked really bizarre and didn't resemble any of their today's descendants suddenly about 450 million years ago some unknown factor abruptly interfered with the act of evolution of life forms the proposed causes include a cosmic gamma ray burst volcanic activity and even a large celestial object impact as it is from 25 to 50 percent of all living beings became extinct within 7 million years this series of extinction events dubbed the ordovician silurian extinction was hard on trilobites mollusks and some other marine invertebrates of the time the late paleozoic era that followed this extinction event heralded active evolution of flora on land the first amphibians and reptiles emerged in that time too fishes were actively evolving establishing their dominance in all fresh water and saline bodies of water approximately 372 million years ago the so-called devonian extinction started it occurred in several stages that were alternately followed by comparatively peaceful periods peaceful they may have been but even so the extinction rate of species was higher than average the most likely reason for this extinction is posited to be this land plants of the time sported long and powerful roots which enabled them to extract nutrients from much deeper down in the soil than before when waters seeped through soils that were loosened by plants roots great amounts of nutrients were washed into the ocean as a result algae were positively thriving there in the abundance of food and light the rotting of these algae reduced oxygen dissolved in the water and the organisms inhabiting the sea bottom were simply smothered with nothing to breathe in the aftermath about 70 percent of the marine species of that time are estimated to have died out including practically all species forming coral reefs this triggered global irreversible changes in the biosphere of the global ocean many genera and families vanished completely and the vacated space was filled by others in the carboniferous period which followed tree ferns exploded in numbers all over the planet's surface also there emerged gymnosperm trees and conifers it is in this period that rich deposits of coal were formed which is still widely used by mankind and various industries speaking about the fauna this was the time when insects thrived that's when the giant millipede arthropleura was around which measured two and a half meters the mega neura a giant dragonfly with a wingspan of up to one meter and the pumina scorpius a scorpion measuring 70 centimeters the insects were of these unbelievable sizes on account of exceptionally high concentrations of oxygen in the atmosphere which at that time reached a staggering 35 percent the permian triassic extinction event also informally referred to as the great dying occurred about 251 253 million years ago marking the transition from the permian to the triassic period it proved to be the most massive and global in the entire history of multicellular life digging show that up to 95 percent of marine species and up to 70 percent of land species vanished from the face of the earth as a result interestingly this disaster was rather swift by geological standards it took just up to 200 000 years later it would take not less than 50 million years for biodiversity to recover for land species and about a hundred million years for marine species trilobites a great number of marine and vertebrates and microorganisms were on the verge of extinction insects shrank in size they stopped looking like horror film creatures on the loose and instead assumed an appearance of today's tiny and numerous creatures the reasons for the permian triassic extinction event still haven't been established with certainty among the proposed hypotheses we may single out robust volcanic activity as one of the most likely ones others worth mentioning are a collision of our earth with a large celestial object climate change and active methane emissions following biological or tectonic activities there is no single answer to this question yet in the triassic period which followed the permian triassic extinction event vertebrates vigorously evolved this is when archosaurs emerged the prehistoric saurians crocodiles and dinosaurs were to evolve from the triassic period also produced first mammals although they were not so widespread at that time about 200 million years ago the triassic jurassic extinction event began sometimes called the end triassic extinction having lasted for approximately 10 000 years it marked the transition from the triassic to the jurassic period the event claimed about half of known species on the earth of that time they included various reptiles and amphibians defecated a number of ecological niches this allowed dinosaurs to establish their dominance on the planet and sustain it for the next and thirty million years incidentally the reasons for the andreas extinction event are not known either and in fact there isn't a single hypothesis today that would sound sufficiently convincing the jurassic and cretaceous periods that followed the triassic jurassic extinction event were the times when dinosaurs thrived and flourished but these giant saurians were not the sole inhabitants of our planet at the time this is when the forefathers of today's birds flowering plants and corals evolved as well as small furry warm-blooded animals mammals even though these small creatures didn't look quite as impressive compared to tremendous dinosaurs and all their glory they firmly held their ecological ground and steadily progressed in their revolution mammals got their chance at the end of the cretaceous period that is about 66 million years ago what occurred then was the most well-known and a rather large-scale mass extinction event referred to as the cretaceous tertiary extinction event according to the first and most popular hypothesis the extinction was caused by a giant celestial object impact everyone would have heard of a meteorite supposedly killing off all dinos nevertheless there is no hard evidence in favor of this version either way the upshot was that all dinosaurs died out alongside a great number of conifers algae and mollusks the cretaceous tertiary extinction event heralded the beginning of a new geologic era the cenozoic which is still in progress throughout this era mammals birds and flowering plants have been actively evolving and spreading across the earth mammals settled all over the planet inhabiting it literally everywhere from tropical areas to ice caps to the poles and from the depths of the oceans and the planet's interior to air currents up high eventually evolution produced mankind even though you would expect people today to be enlightened enough there are still those who do not believe in evolution however the theory of evolution is not something to believe in it is a scientific theory based on facts the theory of the evolution of species has come a long way and has undergone serious revisions since its original version proposed by charles darwin back in 1859 still the basic principles of the theory are the same and to date the theory of evolution is the only serious scientific theory that accurately describes the process of the evolution of species and the origin of new creatures according to some scientists we are now living in the epoch of the sixth mass extinction event they also call it the holocene or anthropocene extinction thousands of species have died out in the past 10 000 years around 900 species have vanished from the face of the earth in the past 500 years today about 40 percent of amphibian species and 25 percent of mammal species are under the threat of extinction and it looks like one of the chief reasons for this is human activity will humanity be able to tackle this threat will life go one step further of the order as it was always the case after every major mass extinction event there is no way of knowing it now the earth's biosphere boasts a great potential for recovery and evolution which by no means implies that it doesn't need our care after all the earth is our only home for biological life to originate and start evolving a medley of a great number of factors is called for the chief ones are liquid water an energy source and a certain chemical diversity apart from the earth several more places in the solar system are potential life-harboring candidates with mars as the most prospective one and most closely studied starting from the recent past still there are chances of discovering alien life beyond its orbit too all it takes is to have a closer look at the next closest planet to us after mars if we look away from the sun [Music] jupiter is the largest planet in the solar system its mass is 318 times that of the earth this is a gas giant made up mostly of hydrogen and helium apart from these methane ammonia sulfur and nitrogen compounds and water ice have been detected in its atmosphere in spite of the diversity of chemical compounds the possibility of finding life forms on jupiter itself is minuscule what with the absence of any hard surface high temperatures of the planet's inner layers and unimaginable pressure in its interior biological creatures simply have no chances of survival at the same time jupiter boasts quite a vast array of moons four of the most well-known ones io callisto ganymede and europa were discovered as far back as in 1609 by galileo galilei quite close to the moon and mercury in size they're on the list of the largest satellites in the solar system it is also suggested that jupiter accumulated substantial amounts of thermal energy due to gravitational contraction when forming as a result it is now giving off more of this energy than it is getting from the sun that is why the gas giant with all the objects orbiting it may be seen as a curious version of the solar system in miniature at first glance jupiter's moons may appear to have no prospects in terms of searching for extraterrestrial life far from the sun they are encased in ice and their atmospheres are not dense however on closer scrutiny these celestial objects reveal something excitingly promising callisto europa and ganymede are highly likely to have liquid oceans under the ice shell estimates show that space objects with concealed oceans may offer favorable conditions for life even if they're much further from their star than planets like our earth are from the sun the thick icy shell on their surface serves not only as protection against radiation and meteorite info but also acts as fairly good thermal isolation that is why it is feasible that conditions inside a massive layer of water may be good enough for life to originate and evolve there these assumptions make jupiter's satellites some of the most attractive objects for exploration within the solar system and now let's have a closer look at each of them ganymede is the largest and most massive celestial object in jupiter's environs of all the satellites in the solar system it is not only the one sporting the most impressive dimensions but it also resembles a real planet more than any other ganymede's radius measures 2634 kilometers which is 8 percent more than that of mercury as for its mass it equals 1.48 times 10 to the power of 23 kilograms this is twice the mass of our moon interestingly ganymede is the only satellite in our solar system with a liquid metal core and its own magnetosphere processes of nuclear decay take place in ganymede's interior this heats the satellite still more with the average surface temperature 110 kelvin or 163 degrees celsius below zero the core on the other hand is estimated to be as hot as up to 1 500 700 kelvin investigations of ganymede's magnetic field carried out by the galileo space probe showed that there may be a multi-layer sortie ocean under the satellite's icy shell as deep down as 200 kilometers or more the number of layers may reach four water in each is of different salinity density and temperature with the layers separated from each other by some ice spectrographic investigations of ganymede's surface show it to have a rather rarefied oxygen atmosphere this however isn't an irrefutable proof of there being biological life on the satellite molecular oxygen is likely to form as a result of the exposure of water ice to ultraviolet radiation hydrogen the other product of this chemical reaction floats away into space oxygen meanwhile which is a heavier element settles close to the surface apart from large amounts of water ice other elements found on ganymede's surface are carbon dioxide sulfur dioxide sulfates and some other organic substances they may well have originated in the depths of the subsurface ocean but the mechanisms of their settling on the satellite's surface are still not clear callisto is another celestial object potentially just as attractive for life this satellite is jupiter's second largest one and lies furthest from it its diameter measures 4820 kilometers almost like that of mercury callisto is encased in an icy shell as thick as 80 to 150 kilometers and it is highly likely that there is a salty ocean concealed under it containing large amounts of ammonia and other substances the estimates of its depth range from 50 to 300 kilometers and its temperature is around 251 kelvin or 21 degrees celsius below zero according to most models due to impurities and high pressure the water in the ocean should remain in its liquid state below the subsurface ocean there is bound to be a layer of ice as stickers around 300 kilometers and the satellite score made up of water ice and rocks lies still deeper down callisto's surface is pockmarked with craters spectral analysis of light reflected from this celestial object revealed not only water vapor and silicon rocks but also ammonia carbon dioxide sulfur iron and magnesium compounds as well as stolens complex organic polymers containing nitrogen these brightly colored substances form on the surfaces of celestial bodies a result produced by ultraviolet radiation callisto happens to lie too far from jupiter to get more heat from it besides the tidal influence exerted by the giant neighbor isn't enough to deform the satellite although friction in the process would heat it up also most of this body is made up of ice whereas it is preferable that there should be solid drugs which would saturate water with elements vital for life forms to originate with the diversity of chemical compounds here rather modest and the temperature quite low it hardly improves chances of life evolving here still this possibility should of course not be ruled out yet the most promising of jupiter's satellites in terms of searching for alien life is europa the smallest of jupiter's four galilean moons it is just a bit smaller than our moon the equatorial temperature on this celestial body is 110 kelvin or 163 degrees celsius below zero at the poles temperatures may drop to 50 kelvin or 223 degrees celsius below zero europa is tidally locked to jupiter facing it with the same side only however its rotation isn't synchronized ideally there are deviations from the calculated trajectory this may mean that there is a liquid layer between europa's surface and core this assumption is confirmed by observation of interaction between the satellite and jupiter's magnetic field carried out by the galileo space probe in the late 20th century apart from that analysis of crevices europa's surface is covered with shows that the satellite's crust moved 80 degrees with respect to the interior this would have been impossible without a liquid layer between them the massive neighbor exerts a strong influence over europa by causing powerful tidal waves in its subsurface ocean this way the satellite is heated still more by internal friction estimates show that the temperature in europa's interior is high enough for an ocean of water to be in liquid state its depth may reach 100 kilometers and its volume may be twice that of the global ocean on our earth europa is covered with an even layer of exceptionally smooth and clear ice the highest elements of relief tower just several hundred meters above the surface the thickness of the icy crust may be anything from 10 to 30 kilometers although the satellite's surface is streaked with a whole net of long and deep cracks some of them may well reach as deep as the subsurface layer of water thus the ice at the bottom of these ravines is valuable material for studying the inner makeup of europa another peculiar feature of this moon is powerful ice-cold vapour geezers they open up only when europa is at its furthest point from jupiter with the height of the spurts reaching as much as 200 kilometers these giant jets are made up of water vapor which incidentally is unexpectedly clean it is still not known for certain whether the geysers have anything to do with the ocean in europa's interior or they come from gargantuan lakes embedded in the satellite's icy crust today the composition of the subsurface ocean on the satellite is estimated by analyzing the ice covering the inner part of its largest craters only a really large object is capable of breaking the thick layer of the ice clean through on impact after the icy crust is broken the water in the subsurface ocean at the impact site freezes and forms the bottom of a crater spectral analysis of the craters reveals magnesium sulfur and iron compounds as well as hydrogen peroxide and strong acids this demonstrates that there is a vast diversity of minerals in the satellite's concealed hydrosphere europa's atmosphere contains oxygen which forms as a result of ultraviolet radiation interacting with the ice water on the surface splitting the water into oxygen and hydrogen the satellite's atmosphere however is approximately a trillion times as rarefied as that of our earth still according to some estimates concentration of oxygen in europa's subsurface ocean should be sufficient for supporting single cell aerobic life forms underwater volcanoes should be their sources of energy and food as they saturate water with sulfur and dine oxides primitive organisms may attach themselves to the bottom side of the ice crust or swim freely in water it was even assumed that there may dwell primitive multicellular organisms in europa's ocean however this hypothesis appears to be rather too presumptuous in fact there is a great many species on our earth which would be able to survive in the estimated conditions of europa's subsurface ocean there are among them not only bacteria resistant to harsh environments but multicellular creatures too for example tardigrades consequently we cannot rule out the possibility of primitive life originating in the depths of this celestial object of its own accord unfortunately enough in spite of the keen interest we have in jupiter and its satellites so far they've been investigated only briefly and that by spacecraft passing them on our way elsewhere no landings on the gas giant's satellites have so far been attempted at the moment the largest planet in our system is being investigated by the juno probe but as soon as in july 2021 it will move on to studying the galilean moons the data collected by juno will undoubtedly be of great importance and help get to the bottom of processes taking place in jupiter's system as for upcoming missions back in 2012 the european space agency announced starting work on the juice project or jupiter icy moon explorer the mission of the project is to explore in detail the gas giant itself as well as ganymede europa and callisto juice will be launched next year but will reach jupiter's environs only in 2029 the mission is scheduled until the year 2033. if all goes according to plan our knowledge about the gas giant and its satellites will be substantially expanded another big research project is nasa's europa clipper this automatic probe is planned to lift off the earth's surface not later than 2023 and to reach jupiter's system in 2032 the probe's objective is quite predictably europa in contrast to jews it is this celestial body that clipper is supposed to focus on more closely the first steps in theoretical confirmation of there being ocean worlds out there that is planets fully covered in water were made back in the 1970s that is when evidence was found that radioactive decay in a planet's interior and tidal forces may cause water ice to melt and subsequently form huge oceans in all likelihood similar processes take place on jupiter's and saturn's satellites however these celestial bodies remain icebound as they lie too far away from the sun whose rays would otherwise melt the thick layers of ice but when we talk about an ocean planet a slightly different type of space objects is meant the term implies that the ocean on a planet's surface isn't concealed under a layer of ice and its depth measures more than 100 kilometers theoretical calculations of these planets formation and evolution processes were carried out in 2004 by french astrophysicists headed by christophe satan according to this theory if the mass of a forming planet is more than 10 times that of the earth this starts to actively attract hydrogen and helium from the gas and dust cloud around it in this manner with time it grows into a gas giant by contrast if this planet's mass is just six to eight earth masses the new planet is going to be comprised of ice and rocks roughly in equal measure just to compare the mass total of all water in the global ocean on our earth accounts for just 0.025 of the earth's total mass in this case provided a space object's orbit lies far from the host star this object is going to be either an ice giant or a cold super earth radioactive decay taking place inside the core will help melt some portion of the ice which in its turn will help form a subsurface ocean but the planet's outer layers will still remain frozen if the planet happens to find itself in its star's habitable zone its outer layers will melt and spill all over the surface in a boundless ocean theoretical calculations show that a planet with a mass six to eight times that of the earth may have a layer of water over a hundred kilometers thick the pressure exerted by this amount of water may reach 20 000 atmospheres depending on temperature impurities and other parameters this is enough for some special exotic varieties of ice to form like ones remaining solid even at high temperatures in addition unlike the familiar water ice these modifications would be heavier than liquid water for example the density of ice seven which is likely to form in these conditions should be around a thousand six hundred and fifty kilos per cubic meter this ice settles on the planet's ocean's bottom and forms a massive cryosphere that envelops the more massive core the opportunity to put these theoretical assumptions to test arose when a tiny and dim star was spotted 42 light years away from the earth it was dubbed gliese 1214 the diameter of this red dwarf turned out to be five times smaller than that of the sun with its mass just 15.7 percent that of the sun at the same time gliese 1214 is 300 times dimmer than our parent star while its surface temperature is only 3 000 kelvin or 2 700 degrees celsius there is nothing particularly remarkable about the star itself to be blunt it is just another non-descript red dwarf that looks like any of the billions of other stars in our galaxy however in 2009 a solitary planet was detected in its environs which was dubbed gliese 1214 b with its diameter measuring two and a half times that of the earth this exoplanet is just six and a half times heavier than our home planet straightforward calculations show the freefall acceleration on the exoplanet's surface to be just 91 percent that of the earth the average density of glycer1214b is approximately 1870 kilos per cubic meter judging by this comparatively small value the exoplanet cannot realistically be made up of mostly metals and rocks as is the case with our earth for example but incidentally this average density value seems to confirm the assumption that the astronomical body is 75 percent water or water rice and just 25 tracks thus it appears safe to suggest that this exoplanet is an ocean planet the object lies very close to its host star the average distance between them measures just around 2 million kilometers or 0.014 astronomical units which is 75 times smaller than that between the earth and the sun also the orbit eccentricity is rather high at 0.27 slightly more than that of pluto this means that in its perihelion gliese 1214b is approximately twice as close to its star than when in its aphelion as for its orbital period it takes the planet about 36 hours to complete it the red dwarf glieser 1214 may be 300 times dimmer than the sun but this incredible proximity to the star makes the climate on gliese 1214b scorching hot supposing the reflection coefficient of the surface of gliese 1214b is the same as that of venus the planet's surface temperature is supposed to be around 393 kelvin or 120 degrees celsius if on the other hand the surface is darker the temperature may reach as much as 553 kelvin or 280 degrees celsius due to the fact that the orbit of gliese 1214b crosses the star's disk scientists are able to carry out spectroscopic investigations of its atmosphere still the results are rather ambiguous if this space object really is an ocean planet its atmosphere is supposed to predominantly consist of water vapor with some accompanying gases interestingly no lines of hydrogen helium or complex substances like water co2 and ammonia have so far been detected in the planet's spectrum it is thought that the outer layer of the dense atmosphere conceals its true content from the observer the conditions on the surface of gliese 1214b remind one of what it is like inside a giant steam boiler interestingly the atmospheric pressure in its lowest strata should be at least 15 times as high as that of the earth as the ocean and the atmosphere are in a state of thermodynamic equilibrium the border between them is rather blurred no wonder as the density of water vapor just above the ocean's surface is practically equal to that of constantly boiling water as we look deeper at the lowest strata of the ocean the pressure will continue to increase until we reach the depth of a hundred kilometers with a pressure value of this depth water will be unable to remain in its liquid state even at temperatures this high and so we will see the bottom made up of dense and heavy ice whose thickness is estimated to be upwards of 5000 kilometers thus most water on the planet is concentrated here below the cryosphere there should be the core made up of rocks and metals unfortunately chances of life evolving on any ocean planet are rather thin even if the surface temperature happens to be more favorable than on this one this is so due to the fact that oceans on planets like that are too poor in terms of microelements that are vital for living creatures even taking into account meteorites that occasionally bombard the surfaces of these celestial bodies the chemical diversity is simply not good enough for life to originate here the first exoplanets were discovered back in the late 1980s since then the number of detected ones has increased hundredfold according to statistics from january 2021 over 4 000 planets in other systems have already been discovered apart from these several thousand candidates likely to be given the status have been registered with sufficient evidence from earth-based observatories most of them are going to become officially confirmed exoplanets the overall number of planets in our galaxy may supposedly be over one trillion from five to twenty percent of these are close to our earth in terms of their size and composition not all of them are in their host star's goldilocks zones that is not all of them are habitable still according to scientific estimates there are not less than 300 million potentially habitable planets in the milky way exoplanets differ very much in terms of their environment their dimensions may be enormous some even beating jupiter but there are also comparatively smaller ones close to our earth and size some of these bodies are hot consumed with oceans of melt and lava whereas others are encased in a shell of permanent ice there are planets out there made entirely of oceans with not a bit of dry land on them while in others sulfuric acid drains or diamond snow are irregular occurrence various techniques are used for discovering other worlds as a rule it is next to impossible to spot an exoplanet by simply looking through a telescope that is why in 2009 kepler was launched the first space telescope designed for searching for planets beyond the boundaries of the solar system the telescope's cameras had 42 charge-coupled devices or ccds with a total resolution of around 96 megapixels with a field of view covering about 25 percent of the sky and coupled with a one and a half meter mirror of the telescope it was able to detect astronomical bodies within three thousand light years from the earth in the three and a half years of productive operations kepler managed to spot over three and a half thousand exoplanet candidates the status of over two thousand of these has already been confirmed by repeated observations it was in this period that the smallest of known exoplanets today was detected the diameter of kepler 37b is just 35.7 percent that of the earth the telescope was also instrumental in registering several stars and brown dwarfs the transit method was used by kepler in the search for exoplanets this method is based on observing the star's luminosity if the supposed planet passes between the parent star and the observer this will be noticed in the telltale decrease in the star's luminosity the extent of these fluctuations in luminosity directly depends on the ratio of the stars and planets dimensions while their regularity allows one to estimate the object's orbital period the transit method requires accuracy in measurements changes in a star's spectrum account for less than two percent and are usually tenths or even hundredths of one percent ripples in the atmosphere dust and precipitations negatively affect results produced by earth-based telescopes that is the reason why telescopes based on automatic space stations are used for searching for objects beyond the boundaries of the solar system unfortunately in 2013 three and a half years into the mission the kepler space telescope had several major equipment failures in 2018 the spacecraft ended science operations completely kepler was the first spacecraft to be created specifically for looking for exoplanets however most of the objects that managed to spot happen to be too remote and dim to study them in any satisfying detail that is why the next space research complex had slightly different parameters kepler was succeeded by the test telescope launched by nasa on the 18th of april 2018. its main object was searching for rocky exoplanets orbiting the brightest stars within 200 light years from the sun this telescope also used the transit method and here is the spacecraft's brief profile tess is equipped with four refractors with a 24 by 24 degree field of view and a 10 centimeter aperture the spacecraft's peculiar orbit allows it to cover both the northern and the southern parts of the sky which is approximately 85 percent of the entire sky photos are taken by four cameras and the resolution of each camera's ccd is 16.8 megapixels toi 700d is one of the most notable objects discovered by tess this exoplanet became the first object of the kind comparable to the earth and size and which found itself in the habitable zone of its star it orbits toi 700 a red dwarf lying slightly over a hundred light years away from the sun it is a small and rather cold star its temperature is half that of the sun and its mass and radius are just 40 percent those of the sun toi 700 is peculiar for its high stability not a single flare has been registered on it since the beginning of observations a star's stability is a positive feature because bursts of activity are able to divest its planets of their atmospheres and be generally pernicious for potential life on planet surfaces there are at least three planets orbiting toi 700 the one closest to it toi 700b is comparable to the earth in size its mass is approximately 1.07 times that of our planet and its radius differs from that of the earth by not more than two percent unfortunately toi 700b is too close to its host star it is within about .06 astronomical units and a year on the planet lasts just 10 days in addition to that chances are it is tidally locked that is it faces the star with one in the same side this means that the planet is likely to be scorching hot the planet lying further from its star toi 700c is thought to be a mini neptune its mass may be from 5 to 13 times that of our earth and its radius is 2 or 3 times that of the earth it takes toi 700c 16 days to complete one orbit around its host's star located closer to the star than the inner border of the habitable zone it must be too hot for life to originate and evolve there toi 700d is the third and at this point the remotest planet in the system discovered by now it takes 37.4 days to complete a full orbit which by the way lies along the inner edge of the habitable zone the mass of toi 700d hasn't been gauged precisely and may be anything from one to three times that of the earth at the same time the planet's radius is just 20 to 30 percent bigger than that of the earth toi 700d is thought to be a rocky world but its exact composition is not yet known the amount of energy received by the planet from its star is 86 that of the amount we receive from the sun assuming the planet's atmosphere is similar to ours the steady state temperature on the surface of toi 700d is estimated at 268.8 kelvin or 4.3 degrees celsius below zero however due to the greenhouse effect or other features of the atmosphere we may not know yet this figure may shift either up or down there is no precise data on the eccentricity of toi 700d but it is thought to be small at around point eleven as the planet's orbit finds itself at the inner edge of the goldilocks zone the planet's eccentricity however small may incidentally turn out to be perceptible when the planet comes too close to its star from time to time thus actually leaving the habitable zone still with a year on the planet lasting slightly over one earth month such unfavorable periods are expected to be rather short if there are living creatures on toi 700d then they might be able to weather the harsh spells in a state of anabiosis alternatively they could adapt or migrate to less inclement areas even though the data acquired by spectral analysis of toi 700d can't be enough for making conclusions there is a chance that there is liquid water on the planet's surface then there is bound to be the greenhouse effect too which will help the surface temperature to reach favorable values as i've already mentioned toi 700d along with the other known planets in the system is highly likely to be tidally locked to its star if this is the case there should be a stark difference in temperatures between the sunny side and the shadow side this contrast could be leveled off by dance atmosphere but that would cause powerful hurricane winds although the main mission of tess has been accomplished by now it still has enough resources to carry on operations the telescope will continue taking snapshots of the sky including the milky way plane which is the most challenging direction for observation over 2 100 exoplanet candidates have been discovered by tess in the course of the main mission not less than 66 of them have already been confirmed apart from that six supernovae flares have been registered three exo comets identified and a great number of photos taken of small bodies in the solar system the latters were not objects of the main mission but are of course of scientific interest toi 700d is still guarding its mysteries and waiting for its explorers great hopes are placed on the new orbital telescope james webb which may help investigate this world and a number of other ones the new telescope is supposed to provide images of not only exoplanets lying closest but also detect their moons and carry out spectral analysis of their surfaces the launch of the telescope is planned for the 31st of october 2021. if all goes according to plan first data will be available as soon as next year will we ever discover a world that could rightfully be called the second earth and if we do will we be able to reach it distances in space are just too much for humans could it be that we're confined to the limits of our system forever allowed only to gaze at the vast infinite universe [Music] it goes without saying that we've only briefly touched upon the question of what life is as well as its meaning in the universe this topic is truly inexhaustible even though mankind has accumulated impressive amounts of information about the world around us there are by all accounts a lot of blank spots in our knowledge still every new day yields a fresh load of data about the universe and our role in it is the genesis of life something that was to be expected or did it all start by a lucky chance is space actually crawling with life with us none the wiser or are we alone in the universe these exciting questions still remain to be answered [Music] [Music] [Applause] you

Channel: Kosmo

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Keywords: Life, earth, universe, global extinctions, dinosaurs, dinos, how life came onto land, planets, exoplanets, life in the universe, solar system, prehistoric earth, what creatures were around before dinosaurs, how dinosaurs died out, jupiter, jovian satellites, ganymede, europa, ocean planet, ocean world, milky way, space, cosmos, what was discovered in the earth's interior, film, video, popular science, science, cosmo, kosmo

Id: tgMiV7yIk6U

Length: 84min 32sec (5072 seconds)

Published: Sun Aug 08 2021