Life in the Universe. A Journey into Deep Space
The first destination on our journey will be the silent, barren Mars, which will appear to us from an unexpected angle. Then we'll travel to the cold, misty Titan to descend into its amazing methane lakes, which may be the cradle of strange, exotic life. Instantly covering several light years, we'll reach Alpha Centauri, the closest star to the Sun and one of the most important objects of scientific research. Our next stop will be an amazing exoplanet called Teegarden B, one of the most Earth-like celestial bodies in the universe. And last but not least, we will visit several other potentially habitable worlds that demonstrate an amazing variety of natural conditions on their surface.
Let’s get ready – and we begin!
0:00 Intro
01:54 Ancient Mars
23:32 Titan
42:06 Alpha Centauri
52:56 Teegarden b
01:02:36 Kepler-452 b
01:24:26 Ending
Credit: Kosmo
#Life #Planets #Space #Universe #Film #Kosmo
The first destination on our journey will be the silent, barren Mars, which will appear to us from an unexpected angle. Then we'll travel to the cold, misty Titan to descend into its amazing methane lakes, which may be the cradle of strange, exotic life. Instantly covering several light years, we'll reach Alpha Centauri, the closest star to the Sun and one of the most important objects of scientific research. Our next stop will be an amazing exoplanet called Teegarden B, one of the most Earth-like celestial bodies in the universe. And last but not least, we will visit several other potentially habitable worlds that demonstrate an amazing variety of natural conditions on their surface.
Let’s get ready – and we begin!
0:00 Intro
01:54 Ancient Mars
23:32 Titan
42:06 Alpha Centauri
52:56 Teegarden b
01:02:36 Kepler-452 b
01:24:26 Ending
Credit: Kosmo
#Life #Planets #Space #Universe #Film #Kosmo
Category
🦄
CreativityTranscript
00:00:00From the moment people realized how infinitely great the cosmos is, they have been asking themselves the same question.
00:00:09Are they alone in the universe?
00:00:12Is there a different, unfamiliar life on the surface of distant worlds which are unreachable for us in the icy abyss?
00:00:20For many years, scientists have searched fruitlessly for answers to these baffling questions.
00:00:26Eventually, giant telescopes directed their gaze up at the sky and spacecraft left our planet to head for other worlds
00:00:37and so it is time for us to trace the path of amazing discoveries and lift the veil of mystery over one of the most important questions of today's science.
00:00:48The first destination on our journey will be the silent, barren Mars, which will appear to us from an unexpected angle.
00:00:57Then we'll travel to the cold, misty Titan to descend into its amazing methane lakes, which may be the cradle of strange, exotic life.
00:01:06Instantly covering several light years, we'll reach Alpha Centauri, the closest star to the Sun and one of the most important objects of scientific research.
00:01:18Our next stop will be an amazing exoplanet called Tea Garden B, one of the most Earth-like celestial bodies in the universe.
00:01:28And last but not least, we will visit several other potentially habitable worlds that demonstrate an amazing variety of natural conditions on their surface.
00:01:39Let's get ready and we begin!
00:01:43This is Mars.
00:02:02That's what it is believed to look like several billion years ago.
00:02:11Heat and liquid were trapped within the dense CO2 atmosphere the planet was shrouded in.
00:02:20Numerous rivers used to flow on its surface and most of its northern hemisphere used to be covered by water.
00:02:29However, all this was to vanish, leaving behind only traces on rocks.
00:02:38It is thought that the weak and unstable magnetic field of Mars failed to protect it against solar wind.
00:02:47In hundreds of millions of years that followed, its atmosphere gradually deteriorated, with water vapour breaking down into hydrogen and oxygen.
00:02:58The lighter gas rose up into the upper layers of the atmosphere to float away into space.
00:03:05As for oxygen, it reacted with rocks, which gradually led to the planet getting tarnished by rust and sand.
00:03:14A thin layer of orange dust and perpetually frozen ground.
00:03:23That is all that remains of the great abundance of water on the red planet.
00:03:29To have a better understanding of what is currently going on on Mars, we will first have to look in its depths.
00:03:40Thanks to the sensitive seismographs on board the inside probe, which have been exploring the inner makeup of the celestial body for four long years, scientists have some ideas about the processes running in the planet's depths.
00:03:54At the very centre of the planet, we can observe a large and massive core of iron, sulphur and nickel.
00:04:03Its radius is more than half the size of the entire celestial body, and its temperature lies between 1800 and 2000 Kelvin.
00:04:13Because of the enormous pressure, most of the core is in a solid state, and therefore incapable of producing a stable magnetic field.
00:04:22The core of the planet, in its turn, is surrounded by a layer of molten mantle about a thousand and a half kilometers thick.
00:04:31Its composition is heterogeneous and depends on its depth.
00:04:35The lower layers contain various metal oxides, while the upper ones are composed of olivine and silicates.
00:04:43On the outside, the mantle is bound by a massive crust, the average depth of which is estimated to be about 50 kilometers.
00:04:51This is 5 to 10 times greater than the parameters of our planet's oceanic lithosphere, and comparable with the thickness of the Earth's continents.
00:05:00It is also noteworthy that in the northern hemisphere, the Martian crust consists predominantly of Andesite, and in the southern hemisphere of Basalt, which may indicate that it was formed at different times.
00:05:18Decades of observation have yielded hundreds of thousands of images of the surface of Mars.
00:05:25By putting these together, scientists have been able to produce an incredibly accurate and detailed map of the celestial body, containing many objects.
00:05:35Some of them are quite small, while others stretch for thousands of kilometers and can be seen with telescopes even from Earth.
00:05:43And one such region of interest is Valles Marineris.
00:05:48This gigantic system of intertwining canyons and chasms stretches along the planet's equator for 4,500 kilometers.
00:05:58Its western part is deeply cut by the immense volcanic Tharsis Plateau.
00:06:03And our plunge into the Great Rift will begin almost in the center of the giant plateau.
00:06:09It is here that the unique and mysterious region, marked on maps as Noctis Labyrinthus, or the Labyrinth of Night, is located.
00:06:18It is an area of chaotic terrain, stretching 1,200 kilometers from west to east.
00:06:25Here, numerous deep, steep-edged drifts intersect multiple times, dividing the surface of the planet into irregularly shaped blocks.
00:06:36The top is made up of softer, lighter sediment, heavily eroded, while the base is made up of solid bedrock.
00:06:44Over billions of years, the slopes of the chasms have collapsed in many places, leaving behind numerous landslides.
00:06:53It is thought that it was here that precipitation that fell on the surface of the upland regions, in ancient times,
00:06:59accumulated together and flowed eastwards in unstoppable turbulent streams.
00:07:04Evidence of this can be seen in the traces of deep water erosion, seen at the bottom of most chasms, and in the layered structure of slopes and landslides.
00:07:15In addition, spectral analysis shows that certain minerals that require liquid water to form, such as hematite, opals and dion sulfates, for example, are abundant in this region.
00:07:28Observations show that Noctis labyrinthus is periodically obscured by dense fog, meaning that it is still one of the most humid regions on the planet.
00:07:39It is thought that the water contained in the soil evaporates into the thin Martian atmosphere during the day, and the high walls of the gorges prevent the humid air from dissipating.
00:07:50With temperature dropping, the water condenses as microscopic ice crystals that slowly settle on the surface, forming a thin layer of frost.
00:08:00As one moves eastward, the bizarre interlocking chasms of Noctis labyrinthus gradually morph into a system of giant canyons that occasionally intersect.
00:08:13Over billions of years, powerful streams of water dug deep channels in the Martian rocks, and then winds and sandstorms ate away at their slopes.
00:08:23But whichever path we take, it will eventually lead us to the giant Coprates Chasma.
00:08:31It is here that the deepest point of the Valles Marineris is recorded.
00:08:36It lies 11 kilometers below the surrounding plateaus.
00:08:40Calculations show that in ancient times Coprates Chasma was a narrow and long running water lake, which when it is fullest, was comparable in volume to the Earth's Black Sea.
00:08:53The region is believed to be one of the most promising objects for future research.
00:08:58The soil at the bottom may contain traces of ancient microorganisms, and its slopes are quite literally recorded pages of the geological history of the planet, and are of great scientific value.
00:09:11As we continue along the canyon, we find that it gradually loses its steepness and gently dissolves into the giant Christy Planitia.
00:09:21Here, too, however, we see traces of the water element in the form of rounded terraces and elongated islands, probably formed by sediment from Valles Marineris.
00:09:32Similar geological formations can be found on our planet in the deltas of major rivers, such as the Amazon and the Nile.
00:09:41Thus, we have made acquaintance of one of the most tremendous and visible evidences of there having been water in the ancient eros of Martian history.
00:09:51However, the giant Valles Marineris rift has only been explored from space.
00:09:57The wheels of a Mars rover have never touched it.
00:10:01To get a closer look at the red planet, we will have to travel far to the east.
00:10:06After flying several thousand kilometers over unfriendly rocky deserts, we finally reach a large crater called Gale.
00:10:16About 3.8 billion years ago, a massive asteroid collapsed here, leaving a deep circular depression 154 kilometers across.
00:10:27At its center there is Mount Sharp, a vast irregular upland area composed of layers of sediment.
00:10:35In ancient times there may have been a large circular lake with a central island.
00:10:40In the present day, however, Gale crater is known as the landing area for the Curiosity rover.
00:10:47The story of this mission began almost 11 years ago, when the Curiosity Autonomous Probe landed on the surface of Mars on the 6th of August 2012,
00:10:57a symbol of human determination and thirst for knowledge.
00:11:02The mission's goals included studying the planet's climate and relief, as well as searching for water and traces of biological life.
00:11:10Almost immediately after landing, the rover found evidence that the planet used to be much wetter in the past than it is now.
00:11:23The first photos transmitted to Earth clearly show a valley washed away by a torrent of water.
00:11:29The area has been dubbed Peace Valleys, meaning the Valley of Peace, and is one of the clearest instances of evidence of water erosion on the planet.
00:11:39Curiosity then headed east and soon reached a sandpit called Rocknest.
00:11:44Here it took its first soil sample and found it contained around 3% of water.
00:11:50Next, the rover turned southwest and continued on its way.
00:11:56It crossed the rocky wastelands of the Glenelg region, where ruthless winds had crushed sediment down to bedrock formed more than 4 billion years ago.
00:12:06Then, climbing occasionally up rocky slopes, Curiosity reached the western end of the Bagnall Dunes, studying the sedimentary rocks,
00:12:17which are relatively recent in geological terms.
00:12:21From the desert, the rover turned south and set out on a long and tiring climb up the slope of a small mountain range called Verorubin.
00:12:31Along the way, the sand and silica and its wheels gave way to hematite, an iron oxide that only forms when in contact with liquid water.
00:12:42It turns out that the mountain range is largely made up of this substance, which means that in earlier times, the climate in this region was much more humid.
00:12:53In total, Curiosity stayed on Mars for more than 3,000 days, roughly five times the planned duration of its mission.
00:13:03Despite all the difficulties and obstacles, it traveled nearly 30 kilometers across the harsh Martian terrain and took 28 samples of alien soil.
00:13:13The probe's chemical analyzes detected not only water, but also organic molecules including benzene and aromatic hydrocarbons,
00:13:22while its cameras beamed back to us thousands of photos and videos.
00:13:26Leaving the tenacious Mars rover behind, we will continue our journey and head southwest.
00:13:38Here, Hellu's Planitia is one of the largest impact craters on Mars.
00:13:43It is thought that about 4 billion years ago, a massive asteroid with a radius of about 50 kilometers crashed into the planet here at high speed.
00:13:53The terrific explosion left behind a gigantic crater about 2,300 kilometers in size and millions of tons of rock were crushed and ejected far beyond its limits.
00:14:06Some of these fragments may have reached outer space and then crashed to the planet's surface hundreds or thousands of kilometers away from the site of the cataclysm.
00:14:16It should be noted that at that time, Mars was likely to have been a friendlier and more favorable celestial body than it is now.
00:14:25The giant lowland area that appeared at the impact site was quickly filled with water, forming a large lake or a drainless inland sea.
00:14:35Over billions of years, it gradually shallowed and became what we see today, a huge crater, more than 7 kilometers deep.
00:14:45From a distance, the bottom of the basin may look smooth and flat, but this is just an illusion.
00:14:51In fact, it is covered with numerous small hills and fractures whose appearance is largely accounted for by the movement of layers of subterranean ice.
00:15:01Similar relief occurs on Earth, in Arctic barren expanses and permafrost zones.
00:15:08Due to its great depth, the atmospheric pressure in this region is about twice as high as the global average, resulting in unusual weather phenomena.
00:15:19For instance, from time to time, a misty haze forms over the crater, which is uncharacteristic of Mars.
00:15:27The wind carries some of the mist out of the crater, but its wisps quickly disperse in the thin atmosphere or settle on the frozen rocks.
00:15:37During Martian winter, the Hellas Planitia is entirely covered with frost and, when seen from the Earth, appears as a large bright spot.
00:15:46Because of this, the area has long been mistakenly considered an upland, and it wasn't until the end of last century that its true nature was determined.
00:16:00Next, our route takes us to the north, to Jezero Crater, which used to be a large running water lake in the past.
00:16:08The Salva River flowed into it from the north, and the Naretva River from the west.
00:16:13Traces of these large water arteries are still to be seen on the surface of Mars.
00:16:19These appear as layered deposits of fluvial sediment, and large scale marks on the mountainous walls.
00:16:26It was one of these regions that became the priority target of the Perseverance rover, which descended into Jezero Crater on the 18th of February, 2021.
00:16:38Originally, the rover was planned to land near the Three Forks area, in the Naretva River valley.
00:16:45However, weather conditions shifted the landing point 1.7 km to the southeast, and the rover was separated from its target by an area of impassable sand called Saitah.
00:16:57It was at this point that the unique Ingenuity helicopter got to show its worth.
00:17:02It flew over the surface of the planet and provided a wide-angle panorama of the ancient delta, as well as a unique photo of the Kodiak Plateau, 2.3 km from the rover's landing point.
00:17:15Once the rover had settled in and reconnoitred its surroundings, it started out on a long, arduous journey around the unfriendly desert that separated it from its destination.
00:17:26Traveling south along the very edge of Saitah, the rover stopped from time to time to collect soil samples.
00:17:34At the same time, Ingenuity successfully completed flight after flight, beaming back to us many photos of Mars from previously inaccessible angles.
00:17:45On Mars Day 168, the spacecraft turned westward.
00:17:52The idea was to pass along the bottom of the crater, skirt the southern tip of Saitah, and reach a rocky ridge along which it would head north towards the delta.
00:18:03However, the terrain proved difficult, and the rover was forced to turn back.
00:18:09Pretty much retracing its way back to the landing area, Perseverance set off towards its destination.
00:18:15After smoothly skirting the northern part of the desert, it gradually turned westwards.
00:18:21Eventually, after a long and arduous journey, the rover did reach the delta and began exploring it.
00:18:28This occurred in April 2022, 413 Martian days after it had landed.
00:18:36By now, Perseverance has travelled more than 18 km across the unfriendly Martian desert.
00:18:43It has collected 15 soil samples and sent more than 166,000 images as well as gigabytes of data from various sensors.
00:18:54In addition, the MOXIE vehicle, which is part of the rover's science payload, successfully obtained about 100 grams of oxygen from the Martian atmosphere's carbon dioxide,
00:19:05which seems to reveal prospects for future colonization of the planet.
00:19:10At the same time, Perseverance's seismographs recorded several Mars quakes, enabling scientists to learn more about the internal structure of the celestial body.
00:19:21The Ingenuity helicopter proved just as useful.
00:19:25It has completed more than 50 flights by now, travelling a total of over 8 km,
00:19:30thus convincingly proving that even in the rarefied atmosphere of Mars, it is possible to use aircraft for research and exploration.
00:19:40In addition to desert landscapes and rocky debris, Perseverance occasionally photographs the night sky of Mars.
00:19:50For example, this little white dot here is one of its satellites – Deimos.
00:19:57More recently, Perseverance captured Phobos briefly eclipsing the Sun.
00:20:02This unique observation was not just a spectacular sight, but it also provided astronomers with a wealth of important data.
00:20:11Unlike our planet, Mars has two satellites, which are very small, irregularly shaped celestial bodies.
00:20:19Observations and spectral analysis suggest that Phobos and Deimos are similar in composition to carbonaceous asteroids,
00:20:27but their exact origins are still a subject of scientific debate.
00:20:31One hypothesis claims that they are the remnants of a small celestial body captured by Mars from the main asteroid belt several billion years ago.
00:20:41The tidal forces of the planet probably tore the object into many fragments, and Phobos and Deimos are the largest of them all.
00:20:51According to another hypothesis, a large protoplanet allegedly collided with young Mars at the dawn of the solar system's formation.
00:21:00As a result of this cataclysm, some of the fragments were thrown into space, where gravitation shaped them into two rather large objects.
00:21:10Phobos is the larger of the satellites.
00:21:13It orbits the planets above the equator at an altitude of about 6,000 km, which is about 64 times less than the distance from the Moon to the Earth.
00:21:24Incidentally, some man-made satellites above our Earth drift three to five times higher than this celestial body.
00:21:31However, Phobos is so modest in size that when observed from the surface of Mars, it appears three times smaller than our Moon to us even at this distance.
00:21:42Another surprising fact is that Phobos has an extremely low average density, approximately 1.9 grams per cubic centimeter.
00:21:52This means that up to 40% of its volume must be hollow.
00:21:57It is possible that this object, like some asteroids in our system, consists of several pieces of debris held together by gravity alone.
00:22:07Due to tidal forces, Phobos is gradually losing height, about 1.8 meters per century.
00:22:14It is estimated that in 10-11 million years, it will be crushed by the pull of Mars into many fragments and that after another 33 million years, they will finally collapse onto the surface of the red planet.
00:22:29By that time, Mars will be likely to lose its second satellite, Deimos.
00:22:35Currently, this celestial body is moving in a circular orbit with a radius of about 23,500 kilometers, but this distance is gradually increasing.
00:22:47Calculations show that in a few million years, the satellite will finally leave the gravitational influence of Mars and float in space quite independently.
00:22:57Deimos is a very dark object because its surface absorbs almost 93% of the light shed on it.
00:23:06The satellite's small size means that its disk cannot be seen from Mars with the naked eye.
00:23:12Deimos appears to the observer as a pinpoint source of light, even though quite bright.
00:23:18Its orbit makes it appear to drift across the Martian sky towards Phobos, but this is just an illusion.
00:23:25In fact, both satellites orbit Mars in the same direction.
00:23:39Titan is located about 10 astronomical units from the Sun and is outside the habitable zone of our star.
00:23:47It is Saturn's largest satellite and its orbit lies well outside the Great Rings, at a distance of about 1,200,000 kilometers from the center of the planet.
00:23:59The trajectory of the celestial body is close to circular and a complete orbit around the gas giant takes a little less than 16 Earth days.
00:24:08Titan's diameter is 5,152 kilometers, which is 5.6% larger than that of Mercury.
00:24:18At the same time, the mass of the celestial body is relatively small at only 1.35 times 10 to the power of 23 kilograms, which is about 40% of Mercury's.
00:24:31Calculations show that the satellite's average density is about 3 times less than that of the Earth, which means it has a completely different chemical composition.
00:24:42According to contemporary concepts, Titan has a massive core at its center, about 3,400 kilometers in diameter, and made up of various silicon compounds.
00:24:54It is surrounded by a thick layer of densely packed ice, which is at the bottom of a cold liquid ocean hundreds of kilometers deep.
00:25:03The ocean, in its turn, contains large amounts of dissolved ammonia, methane, and various caustic salts, so that its freezing point is markedly lower than that of ordinary water.
00:25:15For this reason, Titan's subsurface ocean remains liquid even in subzero temperatures.
00:25:22It is bound by a thick crust around 100 kilometers thick, consisting of a mixture of water ice and methane hydrates.
00:25:31The tidal forces of the nearby Saturn are continuously deforming it, causing massive rifts and fractures.
00:25:39This causes large cryovolcanoes to form, ejecting great quantities of methane, ammonia, and water onto the surface of the celestial body.
00:25:51Methane plays about the same role in Titan's atmosphere as water vapor on Earth.
00:25:56The fact is that the average surface temperature of the satellite is only about 94 Kelvin, or 179 degrees Celsius below zero, which is slightly below its boiling point.
00:26:09Natural variations in this parameter cause hydrocarbon vapors to condense and precipitate, forming methane seas, lakes, and rivers.
00:26:18Titan's atmosphere is composed mainly of hydrogen, which makes up about 98.4% of its volume, while methane accounts for about 1.6%.
00:26:29Due to its extremely low temperature, the satellite's atmosphere remains condensed near its surface, and the ring of the mountains surrounding it is less than 500 meters high.
00:26:40Most of the surface of the celestial body is permanently obscured from our eyes by multi-layered clouds and an orange-yellow tholin haze.
00:26:50This unique weather phenomenon is a fog, formed by tiny droplets of liquid methane and dissolved organic matter, which gives Titan its characteristic hue.
00:27:00This haze pervades Titan's surface, absorbing and scattering visible light but transmitting infrared light.
00:27:07This peculiarity leads to an unusual anti-greenhouse effect, which cools the satellite's surface by roughly another 10 degrees.
00:27:17This effect makes Titan difficult to explore, but thanks to the Cassini's orbiter's infrared cameras, Titan was in parts mapped out earlier this century.
00:27:27Of course, it is not as accurate as we would prefer, but even this much is enough to outline the most striking features of the celestial body's surface.
00:27:42The face of Saturn's largest moon is full of contrasting spots.
00:27:47Some of these reflect most of the light that falls on them, while others are relatively dark in color.
00:27:54One such area is slightly south of the equator and is called Astlan.
00:28:00One of Titan's highest mountains, Mount Doom or Doom Mons, is located here, towering about one and a half kilometers above the surrounding plains.
00:28:11The whole mountain reaches up to 60 kilometers in diameter.
00:28:15Its summits are craters, and its slopes have relatively fresh traces of turbulent flows.
00:28:21This may suggest that Doom Mons is an active cryovolcano.
00:28:26To the northeast from it is Titan's deepest depression, called Sotrapatra.
00:28:32It is a giant depression about 30 kilometers long, the bottom of which is located about 2 kilometers below the adjacent plains.
00:28:41It is thought to be the mouth of a huge cryovolcano, and is part of a single tectonic structure along with Doom Mons located close by.
00:28:52To the north of Doom Mons, there stretches the immense Mahini Flactus, a vast area covered by Doom Mons' ejections.
00:29:01The area extends for about 180 kilometers, and varies in width from 15 kilometers in the south to 60 kilometers in the north.
00:29:10Where torrents of frozen material alternate with expansive fields of sand dunes consisting of a mixture of frozen methane and water ice.
00:29:24Our flight will continue over the dark area of Fensil.
00:29:28The largest impact crater of the celestial body, Minerva, is located in its northwestern part.
00:29:35It reaches 440 kilometers in diameter, which is about three times larger than any other crater on Titan.
00:29:44The depression is about 200 meters deep, and the ring of the mountains surrounding it is less than 500 meters high.
00:29:51The fact is that according to studies, Minerva is not only the largest, but also the oldest extant crater on Titan.
00:30:00Different estimates put the age of the crater at between 300 million and 1.2 billion years.
00:30:06Erosion and tectonic processes have severely damaged the crater, and it is only thanks to its sheer size that it is still visible.
00:30:15Minerva has a well-defined internal structure.
00:30:20At its center there is a small flat plain, surrounded by a ring of hills.
00:30:25This region, with a total diameter of about 200 kilometers, is rather light and clearly visible from space.
00:30:33It is surrounded by so-called moats, a stretch of dark plains about 50 kilometers wide.
00:30:39This is followed by a ring of low mountains that form the outer boundary of the crater.
00:30:49Our flight next takes us to the south.
00:30:53Here is one of Titan's most impressive and mysterious landmarks, Hotei Arcus.
00:30:59This is a unique formation in the solar system, and is a bright, arc-shaped region about 600 kilometers long.
00:31:09Radar data from Cassini shows that Hotei Arcus is a natural boundary between the rocky mountains in the northeast and a wide valley in the northwest.
00:31:20It is also noteworthy that some parts of this area change color from time to time.
00:31:24This phenomenon is thought to be linked to the eruptions of cryovolcanoes, whose emissions cover the surface of the satellite in a thin layer,
00:31:34and then flow into a nearby valley or evaporate into the atmosphere.
00:31:38From space, one can clearly see light channels similar to riverbeds running from the mountains of the Hotei Regio to the northwest.
00:31:47This is where Xanadu is located, which is a vast lowland area with highly rugged terrain.
00:31:55Its northwest boundary is formed by Mithrimonties, which are three parallel ridges stretching for about 150 kilometers, with an average height of 1.9 kilometers.
00:32:07Among the peaks of the southern range, there is the highest peak on Titan, reaching 3,337 meters.
00:32:17Standing on top of it, and looking west, you can see a vast dark plain stretching several hundred kilometers in front of you.
00:32:25It is called Shangri-La, and it is thought that this whole area used to be flooded with liquid methane.
00:32:33It is assumed that it may have persisted beneath the topsoil, similar to the Earth's underground water.
00:32:39Most of this region is below average elevation and has a comparatively flat terrain, but lighter hills can be seen in some places.
00:32:47In the past, these may have been islands in the middle of a hydrocarbon sea.
00:32:55To the west of Shangri-La is the bright Adiri upland area, clearly visible against dark regions around it.
00:33:03The area extends for up to 2,500 kilometers and is a veritable network of numerous drainage canals and caves, clearly visible in the photographs.
00:33:13These are thought to have been formed by abundant flows of liquid hydrocarbons.
00:33:20To the west of Adiri is the vast dark lowland area of Balet, and to the east, near the border with Shangri-La, is the Huygens Landing Site,
00:33:32so far the only vehicle that got to touch down on the surface of an object in the outer solar system.
00:33:38The descent probe was part of a science program called Cassini-Huygens.
00:33:45Together with the Cassini Automatic Probe, it left Earth in 1997 to spend seven years in interplanetary space.
00:33:53The spacecraft entered the orbit of Saturn only in 2004, and in early 2005, Huygens reached Titan and plunged into its atmosphere towards new discoveries.
00:34:05Cassini, on the other hand, remained in orbit around the gas giant to carry out its part of the research program, as well as to continue serving as a transponder for the lander.
00:34:17The probe spent just under two and a half hours in the atmosphere, gradually dropping speed using a sophisticated parachute system.
00:34:25Eventually, by the time it touched down on the surface, its speed was 4.4 meters per second.
00:34:34The probe successfully withstood a momentary 15-fold overload, and soon went on to collect information.
00:34:39Huygens was equipped with a vast array of scientific instruments, most of which were designed to study different aspects of the satellite's atmosphere.
00:34:50The probe used them to measure the strength and direction of air currents, as well as the electrical conductivity, temperature and composition of the atmosphere.
00:34:58The probe also took photographs and made audio recordings, and on landing, it examined the composition and properties of the ground.
00:35:08The first thing the cameras saw after making contact with the surface was a flat plane, dotted with rounded rocks of various sizes, the shape of which clearly indicated the impact of powerful fluid currents.
00:35:21A special drill was also used to sample the surface, penetrating 15 cm into the ground, while multiple sensors measured its density, texture and composition.
00:35:34It turned out that a thin layer of small rounded pebbles lay on a relatively soft but dense substrate.
00:35:41Similar in consistency to wet sand or dense snow, also methane gas was released during the drilling process.
00:35:49The ground at the Huygens landing site is believed to have been like sea sand, saturated with liquid hydrocarbons.
00:35:58In total, the probe transmitted around 500 MB of information to Earth, including 350 photographs.
00:36:08Further careful analysis revealed several unique features of the celestial body related to its atmosphere.
00:36:14For example, it turned out that at an altitude of about 80 km there is a layer of almost complete calm, as if separating Titan's atmosphere into two parts.
00:36:27Neither air currents of the upper atmosphere nor winds of the surface reach this layer.
00:36:33What caused this phenomenon is not yet known.
00:36:36Another feature is that Titan has two ionospheres.
00:36:42The first of these is located at an altitude of about 1,200 km.
00:36:48It is a layer of heightened electrical conductivity with a large concentration of ionized particles.
00:36:55This layer is known to be formed by stellar wind streams and cosmic radiation.
00:37:00The second ionosphere lies much lower, at an altitude of about 60 km, and the reason for its formation is still debatable.
00:37:10Moving northwest from the Adiri area, we reach Titan's largest hydrocarbon reservoir, the Kraken Mare.
00:37:22Its total area reaches 400,000 km2, which is slightly smaller than the Black Sea.
00:37:29Due to the high viscosity of the liquid hydrocarbon mixture, it has not yet been possible to measure the exact depth of the reservoir.
00:37:38It is only known that in most of the area, it is over 200 meters.
00:37:43Another large natural basin, the Lygia Mare, is located slightly to the north, near Titan's Pole.
00:37:51Its diameter reaches 500 km, and its area is about 100,000 km2, which is about three times larger than Lake Baikal.
00:38:03The seas are connected to each other by the narrow and long Trevis fretam 173 km long.
00:38:11Also in the subpolar region, there are many smaller lakes and lagoons filled with liquid methane.
00:38:17In 2014, analysis of earlier images beamed back by Cassini revealed a large bright object on the surface of the Lygia Mare.
00:38:28On comparing photographs taken at different times, it was established that within a few months,
00:38:34the mysterious object had grown to 260 km in diameter to disappear almost instantly without a trace.
00:38:42Several hypotheses have been put forward to explain it.
00:38:45According to one of them, temperature differences lead to a constant stirring of layers of liquid hydrocarbon mixture in the Lygia Mare.
00:38:54This causes nitrogen bubbles to form and rise to the surface from the depths of the reservoir,
00:39:01and thus form large clusters of persistent shiny foam.
00:39:04Due to the high viscosity of the hydrocarbons, such bubbles can reach 4.5 cm in diameter and remain stable for months.
00:39:15From space, these structures resemble large islands because they reflect infrared radiation well.
00:39:21Such bubbles would have been a significant hindrance to the operation of a submersible probe, which was scheduled to be launched to Titan back in 2010.
00:39:32However, the mission was postponed indefinitely for various reasons.
00:39:36A higher priority was given to the Dragonfly program, which NASA is working on now.
00:39:43The vehicle is currently in the design phase, and has just recently passed key tests of its blades.
00:39:49The launch from Earth is scheduled for 2027.
00:39:54As conceived by its creators, Dragonfly will be a Noctocopter, an aircraft with four twin propellers.
00:40:03This design will allow it to stay in the air even if it loses several blades, unlike its predecessor, the Ingenuity Mars helicopter.
00:40:11A radioisotope thermogenerator, powerful enough to enable the vehicle to climb to a height of 4 km and travel at a speed of about 36 km per hour, will be used as the power source.
00:40:25The scientific capabilities of the probe are also impressive.
00:40:29It will be equipped with a versatile camera, capable of producing both panoramic photographs of the surrounding terrain and macro images of the ground.
00:40:37At the same time, the mass spectrometer will make it possible to determine the chemical composition of atmospheric samples and the internal structure of rocks.
00:40:48Perhaps Dragonfly's data will help us clarify an important question.
00:40:54Do we at least have a chance of encountering primitive life?
00:40:58The possibility of life on Titan remains hotly debated.
00:41:02On the one hand, the extremely low surface temperature, the presence of extremely toxic hydrocyanic acid in the atmosphere, and the absence of liquid water, would likely rule out the presence of biological life as we know it.
00:41:19Titan's atmosphere, on the other hand, exhibits an incredible diversity of organic compounds.
00:41:25Nitrogenous bases and amino acids, which are the building blocks of proteins, RNA and DNA, could be naturally synthesized on its surface.
00:41:36It is also known that liquid methane can serve as a solvent, and potentially play the role of water in biochemical reactions.
00:41:44In addition, experiments show that under certain conditions, a mixture of liquid hydrocarbons with phosphine forms an environment similar to the primordial soup of the early Earth.
00:41:58This means there is a chance of encountering downright exotic forms of life on the surface of the satellite.
00:42:04The Earth has been emitting structured radio signals into space for around a hundred years now.
00:42:19The radio noise from the Earth reached dozens of other stellar systems long ago, including Arcturus, lying 37 light-years away from us, and Daudibaran, which is roughly 65 light-years away.
00:42:31Besides, our radio signals may be heard on the surfaces of a great number of potentially habitable exoplanets, like ROS-128b or Gliese 667cc.
00:42:44Still, the triple stellar system of Alpha Centauri remains the closest neighbour of the Sun, which automatically makes it the first obvious candidate for the destination of the first ever interstellar flight.
00:42:57Alpha Centauri is known to be a multiple stellar system made up of three components.
00:43:03Two of the larger ones are relatively close to each other. Seen with the naked eye, they appear to be a single source of light.
00:43:10The two components follow a slightly elongated orbit around the common mass centre, which takes around 80 years to complete.
00:43:17The maximal distance between the stars may reach 35 AU, with the minimal distance reaching 11.2 AU.
00:43:28As for the distance between these objects and the Sun, it is reportedly 4.36 light-years.
00:43:35The most massive, the largest and the brightest component in the system is dubbed Alpha Centauri A.
00:43:42This is a main-sequence star with a mass of about 108% that of the Sun.
00:43:48Its radius is reportedly 1.22 times that of our Sun.
00:43:53Even though the surface temperature and the spectral class of Alpha Centauri A are close to those of our star, it emits 1.5 times as much energy.
00:44:01There are no confirmed exoplanets in the environs of this star.
00:44:08However, while this star was being observed in the infrared in 2021, some evidence was found of there being a planet-like object close by.
00:44:17According to preliminary estimates, its mass may be anything from 9 to 35 Earth masses and its radius may measure 3.3 to 7 times that of our planet.
00:44:281.1 AU away from its parent star, the hypothetical celestial body completes a full orbit around it within roughly a year.
00:44:38Additional observations are called for to verify the data, which can be done with the help of either the James Webb Telescope or else Earth-based observatories.
00:44:48The second component of the system is called Alpha Centauri B, or Ptolemon, and it also falls into the class of main-sequence stars.
00:44:58However, its mass is 10% less than that of the Sun and its radius measures only 86% or so that of the Sun.
00:45:05Ptolemon is also slightly cooler than our star. Its surface temperature is reportedly 5260 Kelvin or slightly lower than 5000 degrees Celsius.
00:45:18With these factors combined, the celestial object has an orange hue and its luminosity is on average twice as low as that of our Sun.
00:45:29Incidentally, Alpha Centauri B emits a lot more energy in the X-ray range compared with other objects of its class.
00:45:36Besides, the star is peculiar for its temper, and there are bright flares and ejections to be seen on its surface.
00:45:44No confirmed exoplanets have been detected near this star either.
00:45:48In 2012, a group of astronomers from the Geneva Observatory put forward a suggestion that there was a planet very close to it,
00:45:56whose orbital period was around 12 days and whose radius measured slightly less than that of the Earth.
00:46:01The suggestion was made based on four years of observation of the star's proper motion.
00:46:08However, three years later a mathematical error was detected to have been made in the course of data processing,
00:46:15and so the idea of there being a planet was found to be erroneous.
00:46:20The third component of the system is a stark contrast to the first two.
00:46:25It is a red dwarf with a mass approximately 12% that of the Sun.
00:46:29Its size is about seven times smaller than that of the Sun.
00:46:34Its surface temperature is only slightly higher than 3000 Kelvin,
00:46:38and its luminosity is just a measly 0.17% that of the Sun.
00:46:43Of all the components of the Alpha Centauri system,
00:46:47it is this dim space object that is the closest one to the Sun, lying 4.25 light-years away from it.
00:46:53This is what earned it its name, Proxima Centauri, which is Latin for closest.
00:47:00Besides, the object is getting nearer and nearer.
00:47:04Thus, in 26,700 years, it will be only a bit more than three light-years away.
00:47:11Still, this star cannot be seen from the Earth on account of its low luminosity.
00:47:15Proxima is noticeably far from its two companions in the stellar system.
00:47:21This distance is currently around 13,000 astronomical units or 0.21 light-years,
00:47:28but in the next 300,000 years, it is expected to gradually shrink to just 4,100 astronomical units.
00:47:35It takes Proxima 547,000 years to orbit around the system's common mass center.
00:47:44Unlike its two larger neighbors, the Proxima Centauri system boasts two confirmed exoplanets,
00:47:51as well as at least one hypothetical object.
00:47:54Besides, studies of the star in the infrared allowed scientists to assume that there is a dust ring
00:47:59and probably a great number of small celestial objects, like asteroids or comets.
00:48:06The first planet in the system, Proxima Centauri b, was detected in 2016 by the Radial Velocities Method.
00:48:14Four years later, in 2020, it was confirmed by spectrographic studies
00:48:19with the help of the largest Earth-based telescope on our planet, VLT, the Very Large Telescope.
00:48:26According to the updates, the exoplanet lies 0.05 astronomical units away from its parent star,
00:48:35and it takes it roughly 11 Earth days to complete a full orbit.
00:48:39Estimates show that the planet's mass is 10 to 20% bigger than that of the Earth,
00:48:44and its radius measures about 1.3 times that of our planet.
00:48:49Mathematical modeling revealed that Proxima Centauri b gets about 1.5 times as little thermal energy
00:48:55from its star as does the Earth from the Sun.
00:48:59Its average temperature is 234 Kelvin, or 39 degrees Celsius below zero,
00:49:05which means that hypothetically there could be liquid water in some areas on the planet.
00:49:10As the celestial body is extremely close to its host star, however,
00:49:14it is likely to be tidily locked, so it faces the star with one on the same side.
00:49:18A dense atmosphere could compensate for sharp contrasts in temperatures, which are inevitable in such conditions,
00:49:25but just like any other red dwarves, Proxima Centauri is often seen to eject stellar matter.
00:49:31Also, ionizing radiation flares are observed.
00:49:35It is assumed that such activity gradually destroys the atmosphere of the closest objects.
00:49:39A powerful magnetic field that could be encompassing Proxima Centauri b could offer some protection against the destructive process,
00:49:48but chances that there is any magnetic field there are thin.
00:49:52In the year 2020, another planet was confirmed to exist in the system.
00:49:57A space object dubbed Proxima Centauri c lies roughly 1.5 astronomical units away from the center of the system.
00:50:04Its orbital cycle is slightly over 5 years.
00:50:08As for the object's mass, it may be 6 to 8 times that of the Earth,
00:50:13but its radius hasn't been estimated at the time this video is posted.
00:50:17Depending on its size, meanwhile, the exoplanet will fall either in the category of mini-Neptunes or super-Earths.
00:50:24As Proxima Centauri c lies quite a big distance away from its parent star,
00:50:28its temperature is remarkably low, about 39 Kelvin or 234 degrees Celsius below zero.
00:50:37According to some observations, the planet may have a ring system,
00:50:41whose radius is roughly 5 times that of Jupiter.
00:50:44Also, based on the latest data from VLT,
00:50:47a remarkably small exoplanet is expected to lie 0.029 astronomical units away from its parent star,
00:50:56whose mass is about 25% that of the Earth.
00:50:59If it does exist, and if this isn't another measurement error,
00:51:03a year on this planet lasts about 5 Earth days,
00:51:07and the surface temperature there could be 360 Kelvin or 87 degrees Celsius.
00:51:12Whether this space object is really there or not remains an open question,
00:51:17and additional confirmations are called for.
00:51:20Alpha Centauri has been listening to our radio signals for over a hundred years now,
00:51:25but the 40 trillion kilometers of space vacuum between us
00:51:29are too overwhelming for us to cover at this point.
00:51:32It takes light over four years to get there,
00:51:36but for humans such speeds are still in the realm of fancy.
00:51:39Even today's swiftest, state-of-the-art spacecraft would need tens of thousands of years to cover this distance.
00:51:47However, application of advanced technologies could theoretically greatly reduce travel time.
00:51:53Since the very dawn of space exploration,
00:51:56projects of a great number of spacecraft have been suggested
00:52:00that hypothetically would have been able to negotiate interstellar distances.
00:52:04Nevertheless, not a single one of them has been actually designed.
00:52:07Most of these would-be missions were forgotten,
00:52:11but one is still under active consideration.
00:52:14This is the Breakthrough Starshot program,
00:52:17which implies sending as many as a thousand microprobes to Proxima Centauri as soon as in the first half of this century.
00:52:24They will not measure over a centimeter in size,
00:52:27as special thin and durable sails are planned to be created to aid the probes along.
00:52:32The sails will be blown out, as it were, by impulses of a highly powerful Earth-based laser.
00:52:39Estimates show that an interstellar probe like that is going to be leaving the solar system
00:52:44at a speed roughly 20% that of the speed of light,
00:52:48with the overall travel time around 20 years.
00:52:51After that, it will take another five years or so for the data collected by the mission to reach the Earth.
00:52:56Before we set out on a space journey beyond the boundaries of our system,
00:53:06we have to decide on the manner of selecting a planet that resembles the Earth most from thousands of candidates.
00:53:12What should be the parameters of this fascinating world, and what should we take into consideration first?
00:53:19It goes without saying that planets favorable for the genesis and sustenance of life have always posed considerable interest to scientists.
00:53:27However, it is no easy matter to single out suitable celestial bodies among a great number of those discovered by now.
00:53:33To have clear-cut selection criteria, scientists worked out the so-called Earth Similarity Index, or ESI for short.
00:53:43It is based on several principal parameters, a planet's radius, density, and average surface temperature.
00:53:50This combination makes it possible to calculate the object's mass,
00:53:55approximately estimate its chemical composition, gravitational level, whether or not there is an atmosphere,
00:54:01and if there is, analyze some of its characteristics.
00:54:04It also helps establish if there is liquid water on the planet's surface, and other information.
00:54:10The standard of this index is the Earth, with its parameters assumed as ideal and its CSI equaling 1.
00:54:16Based on the Earth Similarity Index, all the objects known to us conventionally fall into three categories.
00:54:23The first one is objects whose ESI is under 0.5.
00:54:28These are for the most part gas and ice giants, as well as extremely hot, or on the contrary, cold objects.
00:54:35This is the category most of the solar system planets and satellites fall into.
00:54:39It takes just one characteristic to greatly exceed the maximum permissible values for a celestial object to be unfavorable for the genesis and sustenance of life.
00:54:49Let's take Venus, for instance.
00:54:52The radius and mass of this celestial body are very close to those of the Earth.
00:54:57However, due to its close proximity to the Sun and a dense atmosphere, its surface temperature is extremely high.
00:55:03That is why, in spite of a close similarity to the Earth on the face of it, Venus's ESI is not high, at just 0.44.
00:55:13Of course, there being any life on its surface is totally out of the question.
00:55:17Celestial objects whose ESI is within 0.5 to 0.7 fall into the second category.
00:55:27These objects resemble our home planet noticeably more.
00:55:32They are mostly rocky worlds with relatively moderate temperatures, but it can also be ocean planets and even some large satellites.
00:55:39Incidentally, a high Earth similarity index per se does not warrant favorable conditions for life.
00:55:47For example, quite often low-mass planets are incapable of retaining a dense enough atmosphere, while their magnetic field is too weak to protect the surface from lethally dangerous radiation.
00:55:59Other celestial bodies yet may happen to be located too close to their parent star and so get tidally locked.
00:56:05Of course, all these factors greatly reduce the chances of life's genesis and sustenance.
00:56:12As for the third category, it contains celestial bodies with a high ESI.
00:56:18That is, over 0.7.
00:56:20All of these planets are beyond the Solar System.
00:56:23According to estimates, the size of these worlds and the conditions on their surfaces are potentially close to those of the Earth.
00:56:29Among these planets, there is one which resembles ours most.
00:56:34And it lies just twelve and a half light years away from the Earth.
00:56:41This amazing world orbits Teagarden's star, a small red dwarf discovered in 2003.
00:56:48This star is 1370 times dimmer than the Sun.
00:56:52This means that it cannot be observed with the naked eye, even though it lies quite close to the Earth.
00:56:58The mass of this tiny star is roughly 9% that of the Sun and its radius is about 5% bigger than that of Jupiter.
00:57:06Gravitational forces are barely strong enough to maintain the thermonuclear reaction in the star's interior.
00:57:11That is why the surface temperature is just 2,900 Kelvin, or roughly 2,630 degrees Celsius.
00:57:21As is the case for all red dwarfs, Teagarden's star's habitable zone is comparatively narrow, and located very close to it.
00:57:30Back in 2019, two exoplanets were detected in its system after continuous observations of the star's proper motion.
00:57:38Interestingly, one of them lies beyond the star's habitable zone, and the other within.
00:57:45The outer planet, dubbed Teagarden C, follows an almost ideal circular orbit around the system's centre.
00:57:53With the orbit's radius 0.045 AU, it is completed every eleven and a half days.
00:58:00It is presumably a rocky celestial body, with a mass 11% bigger than that of the Earth.
00:58:06Its radius is estimated to be approximately 3.5% bigger than that of our planet.
00:58:12Unfortunately, conditions on Teagarden C's surface are far from hospitable.
00:58:18Due to the low luminosity of its parent star, the object enjoys 63% less energy than what the Earth receives from the Sun.
00:58:26As a result, the planet's surface temperature is gauged at 47 degrees Celsius below zero on average, which is too low for life sustenance, at least in the forms we know it.
00:58:38Still, the chance of there being vast oceans of salty water concealed under a thick layer of ice on Teagarden C, as is the case with Jupiter's satellites for instance, shouldn't be ruled out.
00:58:49As for the inner planet, it is dubbed Teagarden B.
00:58:56It is actually this planet that is the most Earth-like object of all those discovered to date.
00:59:02Its CSI is 0.95, which is just 0.05 less than the standard, ideal value of our Earth.
00:59:09This celestial body lies 0.025 AU away from its star and it takes it roughly 5 days to complete a full orbit around it.
00:59:21By following a practically circular orbit, the exoplanet is constantly in its star's habitable zone and it receives 15% more radiation from it than the Earth from the Sun.
00:59:31According to some estimates, Teagarden B's mass is just 5% more than that of our planet.
00:59:39As for its radius, it differs from that of the Earth by a minuscule ratio, which means that the gravitation value is also quite close to what we're used to on our home planet.
00:59:49This makes it logical to assume that the inner makeup of the exoplanet is highly likely to be similar to that of the Earth.
00:59:57There is a massive metallic core coated in a thick layer of molten silicate mantle reckoned to be at the centre of the planet.
01:00:04The celestial object's outer part is covered with a relatively thin crust of solidified rocks.
01:00:09Mathematical modelling shows that the average temperature of Teagarden B is 28 degrees Celsius, which is 14 degrees more than that of the Earth.
01:00:20This means that conditions on its surface allow the planet to have and retain a notion of liquid water,
01:00:27and the planet's temperature profile is potentially favourable for most microorganisms.
01:00:31Even though Teagarden B is quite massive and is capable of retaining a comparatively dense atmosphere,
01:00:39the radial velocities method, which is used for exoplanets detection, is quite inadequate for obtaining any information about the atmosphere's composition.
01:00:48But it should be borne in mind that a planet's temperature profile directly depends on its atmosphere's composition.
01:00:54For example, a dense atmosphere with a high percentage of methane and carbon dioxide will cause a strong greenhouse effect.
01:01:02Dense clouds of water vapour, meanwhile, will on the contrary reflect sun rays, which reduces temperatures.
01:01:12We should also remember that no matter how optimistic the parameters of this fascinating celestial body might appear,
01:01:19it is not entirely flawless.
01:01:20Being in close proximity to its parent star, it seems that Teagarden B is always facing it with one on the same side,
01:01:29which causes sharp temperature differences between the day side and the shadow side.
01:01:34As I have already mentioned, Teagarden's star is a red dwarf, and this class demonstrates a tendency to suddenly flare up.
01:01:42The amplitude of fluctuations in its luminosity may reach 30%,
01:01:46which greatly affects the planets located close by.
01:01:51Still, the chances of Teagarden B's capability of sustaining life are high.
01:01:57Biological creatures often demonstrate incredible viability,
01:02:01and their ability to adapt can't but amaze.
01:02:05For example, the ocean could serve as protection against lethal radiation and sharp temperature fluctuations.
01:02:11Its upper layer is potentially capable of absorbing cosmic radiation,
01:02:17while its currents could dissipate temperature contrasts.
01:02:20For all we know, as time goes by, primitive organisms might evolve in the warm depths saturated with energy and micro-elements.
01:02:28Just a tiny chance is sometimes enough for life to develop into something bigger.
01:02:33It can hardly be disputed that life is one of the most amazing, complex and mysterious phenomena in the Universe.
01:02:49Despite the fact that we have been studying it for thousands of years,
01:02:55many important questions about it still remain unanswered.
01:03:00And the greatest among them is, how widespread is biological life beyond our planet?
01:03:06At this point, we cannot yet say with a satisfying degree of certainty whether the Earth's biosphere is a unique phenomenon,
01:03:17or whether it has emerged as a natural and logical result of continuous evolution.
01:03:23It is hardly surprising that the search for life beyond Earth is one of the most important fields in science.
01:03:29And in order to identify the most promising celestial bodies in this respect, the so-called Earth Similarity Index, or ESI, is used.
01:03:42It is based on two main parameters, the level of gravity on the surface of a celestial body and its equilibrium temperature.
01:03:50It is these parameters, according to scientists, that determine how much the other world can be similar to Earth,
01:03:58and how favorable the conditions on its surface are for hypothetical life.
01:04:03The undeniable advantage of the ESI is its simplicity,
01:04:08because when an exoplanet is discovered, you can usually determine its approximate orbit, mass and size.
01:04:14And this information is just enough to calculate the basic parameters of the index.
01:04:21However, for all its appeal, it does not take into account many factors critical for sustaining life.
01:04:30Therefore, we will allow ourselves to be as presumptuous as to formulate our own evaluation system,
01:04:37taking the ESI as the basis and supplementing it with several important parameters.
01:04:42The activity of the parent star can be singled out as one of them.
01:04:49It is known that frequent flares and stellar matter ejections, characteristic of red dwarves,
01:04:55can adversely affect the stability of the atmosphere and radiation background of the nearest exoplanets.
01:05:01Nevertheless, red dwarves are considered more favorable than large stars, like Sirius or Vega,
01:05:08because the lifespan of giant stars is too short and the radiation is too destructive,
01:05:15leaving no chance for potential life to develop.
01:05:18The most favorable ones are orange and yellow dwarves, including our Sun.
01:05:24The probability of tidal locking is another significant factor to be reckoned with.
01:05:29This probability depends on the distance between an exoplanet and its star.
01:05:36Celestial bodies located too close to their stars permanently face them with one side only.
01:05:43As a consequence, there is a large temperature difference between their day and night hemispheres.
01:05:48Too great a distance from the source of heat and light puts the planet outside the habitable zone,
01:05:56which drastically reduces the chances of the genesis of life.
01:06:00It is also necessary to consider the type and chemical composition of a given exoplanet,
01:06:06because in order to develop, hypothetical life requires a certain set of chemical elements,
01:06:13in combination with characteristic relief.
01:06:16Such conditions can be seen on rocky, terrestrial-type planets or super-Earths.
01:06:23Many Neptunes, meanwhile, do not have solid surfaces,
01:06:27and ocean planets are deficient in many elements.
01:06:30Thus, the set of parameters we have specified allows us to comprehensively assess
01:06:38how favorable the conditions on a given exoplanet are for hypothetical life.
01:06:44For example, in a scheme like this, the Earth looks extremely attractive against these parameters,
01:06:50being the natural benchmark for other objects.
01:06:54At the same time, Mars, although it has the highest similarity index to our planet
01:06:58in the entire solar system, has a number of obvious disadvantages.
01:07:04It is too cold, too low mass, and demonstrates a significant water deficit.
01:07:10Venus, on the other hand, despite appearing very similar to Earth on the face of it,
01:07:16is too hot because of the strong greenhouse effect,
01:07:19and although most of its parameters are in the green zone,
01:07:23the extremely high temperature is a critical disadvantage of the planet.
01:07:27effectively cancelling out all its advantages.
01:07:31Thus, there are no planets within the solar system
01:07:34sufficiently similar to Earth to be considered favorable for life.
01:07:38However, beyond its boundaries,
01:07:42more than 5,000 other worlds orbiting distant stars have already been discovered,
01:07:47and in many respects, some of them can be considered similar to our planet.
01:07:52One of these objects closest to us is an exoplanet known as Gliese 1002b.
01:08:03It is located just 15.2 light-years from our planet.
01:08:09It was discovered in 2022 using the radial velocity method.
01:08:13This method is effective for finding relatively close exoplanets,
01:08:19and involves capturing subtle fluctuations of the parent star,
01:08:23caused by the movement of space objects around it.
01:08:26The exoplanet is located near a small and dim red dwarf known as Gliese 1002.
01:08:32Its radius is only 14% that of the Sun,
01:08:38and its mass is eight times smaller than that of our star.
01:08:42Given that Gliese 1002 has a surface temperature of just 3000 Kelvin,
01:08:48or about 2730 degrees Celsius,
01:08:52it is not surprising that its luminosity is extremely weak.
01:08:56It's about 700 times weaker than the Sun's.
01:09:01Observations also show that the object is quite serene,
01:09:05which is unusual for stars of this class.
01:09:08Due to the low luminosity of this red dwarf,
01:09:12its habitable zone has an extremely small radius and width.
01:09:16However, the object Gliese 1002b is located near its outer edge,
01:09:22and can be considered potentially habitable.
01:09:24According to observations,
01:09:27this celestial body completes a full orbit around the center of its system
01:09:31roughly every 10 Earth days.
01:09:33Consequently, the average radius of its orbit is clearly very small,
01:09:38and is about 0.046 astronomical units.
01:09:43It is assumed that because of the extreme proximity to the parent star,
01:09:48the exoplanet is likely to be tidally locked,
01:09:50facing it with one side at all times.
01:09:54Calculations show that the celestial body
01:09:57receives 1.5 times less energy from its star than Earth does from the Sun,
01:10:03and its average surface temperature could be approximately 230 Kelvin,
01:10:09or 43 degrees Celsius below zero.
01:10:11Incidentally, it is slightly warmer than Mars,
01:10:15given tidal locking and a possible greenhouse effect.
01:10:19This means that liquid water could be found on the exoplanet's surface,
01:10:23and thus there may be conditions for sustaining life.
01:10:27At least some terrestrial organisms are able to survive in such conditions.
01:10:31Calculations also show that the mass of Gliese 1002b is 8% greater than that of our planet,
01:10:42and the radius exceeds the Earth's radius by only 3%.
01:10:47Using the data, it is not difficult to determine the acceleration of freefall on the surface of the celestial body.
01:10:54It practically does not differ from the value we're used to.
01:10:57Thus, the combination of all known factors suggests that Gliese 1002b is a rocky planet,
01:11:05most of which is covered with ice.
01:11:08Due to its size, which is very near to that of the Earth,
01:11:12it has a rather high ESI of 0.86,
01:11:15and in our scheme this object would look like this.
01:11:18At the same time,
01:11:24modeling of the planet's climate shows that its illuminated hemisphere can receive enough energy
01:11:30to support an ocean of liquid water,
01:11:33with archipelagos of islands or even fully-fledged continents.
01:11:36Also, tidal deformations caused by the nearby star warm up the planet's interior,
01:11:43so the existence of an ocean hidden under the ice, even on its night side, shouldn't be ruled out.
01:11:50Incidentally, Gliese 1002b is not the only planet in the system.
01:11:54It was discovered alongside another object, dubbed Gliese 1002c,
01:12:01which is located a little further away,
01:12:04namely at a distance of 0.074 astronomical units from the center.
01:12:09A full annual rotation takes this exoplanet 21 days,
01:12:14and its mass exceeds the Earth's by about 36%.
01:12:17The object receives four times less energy from the parent star than our planet does from the Sun,
01:12:25so the temperature on its surface is quite low,
01:12:28just about 182 Kelvin or 91 degrees Celsius below zero.
01:12:35If we used a previously developed scheme,
01:12:38then this exoplanet will look like this.
01:12:42It can be assumed that the conditions on the surface of Gliese 1002c
01:12:46are close to those observed on the satellites of Jupiter or Saturn.
01:12:51Increased volcanic activity caused by the planet's high mass
01:12:56could lead to the formation of a hidden ocean,
01:12:59with warm and salty water rich in many chemical compounds.
01:13:04Hypothetically, life could also develop in such conditions,
01:13:08possibly in highly unusual and unexpected forms.
01:13:11Of course, among the great variety of known exoplanets,
01:13:19much warmer and more favorable worlds can be found.
01:13:23Such, for example, is the planet K2-72e,
01:13:28located 217 light-years away.
01:13:32It orbits a small red dwarf,
01:13:34about four times less massive than our star.
01:13:38Its radius is 0.33 of the solar radius,
01:13:42and its temperature is relatively low,
01:13:45reaching 3360 Kelvin,
01:13:48or about 3100 degrees Celsius.
01:13:50Observations made by the Kepler Orbiting Telescope showed,
01:13:56that the exoplanet crosses the disk of the parent star every 24 days.
01:14:01This means that the radius of its orbit is very small
01:14:05and is about 0.1 astronomical units,
01:14:08which implies that the celestial body is located within the habitable zone,
01:14:13and can be considered potentially favorable for harboring life.
01:14:16According to the received data,
01:14:20it is also suggested that K2-72e may be tidally locked,
01:14:26or in orbital resonance like Mercury.
01:14:28Despite the star's low luminosity,
01:14:31the exoplanet receives 11% more energy than Earth does from the Sun.
01:14:36Assuming that the atmosphere of K2-72e is similar to Earth's,
01:14:40the average temperature on its surface should be about 295 Kelvin,
01:14:47or 22 degrees Celsius above zero,
01:14:50which is slightly warmer than on our planet.
01:14:53At the same time,
01:14:55it is worth remembering that if the celestial body is tidally locked,
01:14:59there is a high probability of extreme temperature variations
01:15:03between the day and night hemispheres.
01:15:04In addition to this, it must be taken into account that its parent star,
01:15:10like most other red dwarves, is erratic,
01:15:13and is often observed to flare up and emit great amounts of stellar matter,
01:15:17which can be detrimental to the atmosphere and surface of nearby space objects.
01:15:22Calculations show that K2-72e is 29% larger in diameter than the Earth
01:15:30and is about 2.2 times more massive.
01:15:34Knowing this, we can calculate the level of gravity on the surface of the celestial body.
01:15:40It is about 32% higher than we are used to.
01:15:44Thus, with all the known data taken into account,
01:15:47we can assume that this exoplanet is more likely than not a rocky super-Earth,
01:15:53where liquid water and a dense atmosphere can be found.
01:15:57Its Earth Similarity Index is quite high and is 0.87,
01:16:02and in our scheme this object will look as follows.
01:16:06Planets of this type are expected to have a wide variety of chemical elements,
01:16:12and their relief should be smooth and favorable for the origin of life.
01:16:17Undoubtedly, the frequent flares of a nearby star pose a tangible threat to the atmosphere,
01:16:23but a powerful magnetic field will hypothetically deflect stellar wind particles,
01:16:28and the oceans will protect their inhabitants from this destructive radiation.
01:16:33In this case, we can assume that on K2-72e it is possible to observe incredible auroras,
01:16:41by far more impressive ones than on our planet.
01:16:44As for the hypothetical biosphere that could develop on such a planet,
01:16:50it would likely be markedly different from Earth's.
01:16:54A different spectrum of incident light might force local plants to use alternative substances for photosynthesis,
01:17:02so their leaves would likely be purple or reddish in color.
01:17:05In addition, excessive radiation hazards may be an obstacle for life forms to venture on land.
01:17:13Alternatively, it may lead to the evolutionary formation of defense adaptations,
01:17:18such as thick skin or specific cellular structures.
01:17:20similar features are known to manifest themselves in some terrestrial organisms,
01:17:26such as tardigrades, archaea, and some fungi.
01:17:30Meanwhile, in addition to this planet, so attractive in many respects,
01:17:36three other planets have been discovered in the system.
01:17:38Two of them, dubbed K2-72b and K2-72c, are located very close to the parent star,
01:17:48and are slightly larger than our Earth.
01:17:50It is assumed that due to the emissions and stellar wind of the nearby star,
01:17:54they are devoid of any atmosphere and are similar to Mercury.
01:17:57The third planet, K2-72d, is estimated to be comparable in size to Earth,
01:18:05and its orbit has a radius of about 0.08 astronomical units.
01:18:10It completes a full orbit around the center of the system,
01:18:14approximately every 15 days,
01:18:17and is located near the inner edge of the habitable zone.
01:18:21Because of its high temperature, conditions on its surface
01:18:24are likely to be close to conditions on Venus,
01:18:27and the probability of the genesis of life is extremely low.
01:18:32In any case, research on this system is still going on,
01:18:37which means we have much to learn about it in the future.
01:18:44Incidentally, all the objects we have looked at here
01:18:47are similar in size to the Earth.
01:18:50However, life is known to be able to adapt
01:18:52to a wide variety of conditions, including high gravity,
01:18:57which is inevitable on massive planets.
01:18:59If we travel about 1,800 light-years away from the solar system,
01:19:05we can find a yellow dwarf with parameters very similar to those of our Sun.
01:19:10It's called Kepler-452, and it's a main-sequence star,
01:19:15just 3.7% more massive and 11% larger than the Sun.
01:19:19In 2015, an extremely remarkable exoplanet, named Kepler-452b,
01:19:27was discovered near this star using the transit method.
01:19:31High-precision measurements allowed us to calculate
01:19:34that it's located at a distance of 1.04 astronomical units
01:19:38from the center of the system,
01:19:40and completes a full annual rotation every 385 days.
01:19:44This location renders the probability of tidal locking of the celestial body,
01:19:50extremely low,
01:19:52which is undoubtedly, a favorable factor.
01:19:55According to the available data,
01:19:58the object, Kepler-452b,
01:20:00is about five times more massive than our planet,
01:20:04and its radius, is about 1.5 times bigger, than Earth's.
01:20:07This means that the acceleration of freefall on the surface of the celestial body,
01:20:14is 2.2 times higher than we're used to.
01:20:17Such a high level of gravity,
01:20:19likely helps the planet retain a dense atmosphere,
01:20:22and also smooths out its relief,
01:20:25which could lead to the formation of numerous shallow and warm seas.
01:20:28Such conditions are thought to be the most favorable for the potential origin of life.
01:20:35But gravity this high,
01:20:37would be extremely uncomfortable for humans.
01:20:40It is also known that Kepler-452b,
01:20:43receives 10% more energy from its parent star,
01:20:47than Earth does from the Sun,
01:20:49and is in its habitable zone.
01:20:51Calculations show that the average surface temperature of the object,
01:20:54is about 300 Kelvin,
01:20:57or 27 degrees Celsius above zero,
01:21:00which is 11 degrees more,
01:21:02than on our planet.
01:21:04This means that the climate of Kepler-452b,
01:21:07may be close to that of the Earth's Mesozoic.
01:21:10However, with a certain composition of the atmosphere,
01:21:14this temperature may be dangerous,
01:21:16and may lead to the acceleration of the irreversible greenhouse effect,
01:21:20to the point of complete vaporization of the oceans.
01:21:24According to some hypotheses,
01:21:25it was a process of this kind,
01:21:28that tragically changed Venus,
01:21:31several billion years ago.
01:21:34With all the known factors combined,
01:21:37we can assume that Kepler-452b,
01:21:39is most likely a rocky super-Earth,
01:21:42rich in a wide variety of elements,
01:21:45and minerals.
01:21:47It is believed that because of the increased content of radioactive elements,
01:21:51a planet of this type,
01:21:53should exhibit increased volcanic and tectonic activity,
01:21:57and its high gravity should prevent the formation of extremely high mountains,
01:22:01and deep chasms.
01:22:03At the same time,
01:22:05the ratio of land to ocean,
01:22:07on the surface of Kepler-452b,
01:22:09should be different from that on the Earth.
01:22:11Consequently, chances are that this exoplanet,
01:22:16may turn out to be a boundless ocean,
01:22:19dotted with archipelagos.
01:22:21If we'll leave the abstract figures for a moment,
01:22:24and try to imagine what life might look like on this amazing planet,
01:22:28so similar to Earth,
01:22:30and yet so different from it in so many ways,
01:22:32a truly fantastic sight,
01:22:36will unfold before our eyes.
01:22:38The probable abundance of shallow warm seas,
01:22:41allows us to expect a great variety of aquatic life forms,
01:22:45from the smallest,
01:22:47to the most impressive.
01:22:49As for land,
01:22:51there are likely to be stocky trees with thick trunks,
01:22:54and stalky herbaceous plants.
01:22:57Because the spectrum of the parent star in this system,
01:22:59is close to that of the sun,
01:23:02the colour of the photosynthetic parts of local plants,
01:23:05is likely to be familiar to us,
01:23:07green or bluish.
01:23:09We can also expect a variety of small animals,
01:23:12with sturdy bones and strong muscles.
01:23:15Another course evolution might take,
01:23:18is creatures with an external skeleton,
01:23:21like terrestrial arthropods.
01:23:23As for flying creatures,
01:23:25the opinions of exobiologists are divided.
01:23:28Some believe that high gravity,
01:23:31will be an insurmountable obstacle to flight,
01:23:33while others suggest,
01:23:35that the high density of the atmosphere,
01:23:37will be the decisive favourable factor,
01:23:39in this matter.
01:23:41In any case,
01:23:43we still have many years of research ahead of us,
01:23:46before we can say with any certainty,
01:23:48that this planet,
01:23:50is indeed suitable for life.
01:23:52We keep searching for life,
01:23:57high and low,
01:23:58on the planets of the solar system and beyond.
01:24:01We may encounter it,
01:24:02in familiar forms,
01:24:03or in exotic forms,
01:24:05that are hard to imagine.
01:24:07However,
01:24:09the constant development of technology,
01:24:11inevitably brings us closer to the moment,
01:24:13when it will be possible to answer one of the main questions of modern science,
01:24:17with certainty.
01:24:19Are we alone,
01:24:21in the universe?
01:24:23And,
01:24:24let's keep in touch.