DOCUMENTARIES

🌍 When you look up at the night sky, all the stars you can see are part of our galaxy, the Milky Way. According to scientific estimates, the Milky Way is home to between 200 and 400 billion stars! This is hardly surprising, given that the Milky Way is around a hundred thousand light-years long and a thousand light-years thick. And yet, the Milky Way itself is just one of some 2,000 billion galaxies in the observable Universe. Enough to make you dizzy! Our galaxy is part of what is known as the Local Group, a group of over 50 galaxies whose diameter reaches 10 million light-years! Together with the Andromeda galaxy, the Milky Way is one of the two most massive galaxies in the Local Group. These two spiral galaxies are separated by around 2.5 million light-years, but as they approach each other at speeds of over 400,000 km/h, they are set to collide in around 4.5 billion years. Although impressive, this collision should pose no danger to our planet. From Earth, the sky is a magnificent starry spectacle that this new giant galaxy will form. 🔥 As a reminder, videos are published on SUNDAYS at 6pm. ------------------------- 💥 The Local Group: - We're on our way to the Local Group. There's a long way to go, since just to get out of the Milky Way, we'd need thousands of light-years! In the meantime, let's take a look at the history of the Local Group. Where does the term Local Group come from? The first to use it was the German astronomer Walter Baade, in 1935, in a publication about the globular cluster NGC 2419 or Caldwell 25. For the record, this globular cluster is located in the Lynx Constellation, around 300,000 light-years from us. It's nicknamed the Intergalactic Vagabond, as it seems to have belonged to the Milky Way before, but eventually broke away from it. NGC 2419 is also part of the Local Group. The term Local Group was coined in 1936 by the American astronomer Edwin Hubble, after whom NASA's famous telescope is named. Edwin Hubble developed Hubble's Law, according to which galaxies move away from each other at a speed roughly proportional to their distance. In other words, the further away a galaxy is from us, the faster it seems to be moving away. This law was the first proof of the expansion of the Universe, which states that it is not the galaxies, planets and stars that are moving, but the space between them that is increasing. In the 1930s, when the Local Group concept first emerged, not so many galaxies had been discovered. Edwin Hubble first counted just a few galaxies in the Local Group: the Milky Way and the Andromeda Galaxy, of course, but also the Large Magellanic Cloud, the Small Magellanic Cloud, M32, NGC 205, the Triangulum Galaxy, Barnard's Galaxy and IC 1613. The Local Group concept was later used in a publication by American astronomer Walter Baade in 1944, in which he established that the galaxies NGC 147 and NGC 185 belonged to the Local Group. It was Baade who brought the number of galaxies in the Local Group up to 18 by adding a few more to the list: the Dragon, Furnace, Leo I, Leo II, Sculptor, Little Dipper and IC 5152 galaxies. The IC 5152 galaxy was subsequently excluded from the Local Group galaxy list, however, as it is too distant, at 5.8 million light-years from us, to belong to our group of galaxies. In 2000, there were officially 38 galaxies in the Local Group. Today, there are over 50! ------------------------- 🎬 Today's program: 00:00 - Introduction 03:06 - Discovering the Local Group 09:52 - Journey to the Local Group 15:55 - At the heart of the Local Group 16:09 - The Milky Way 21:19 - Satellites of the Milky Way 33:49 - NGC 6822 or Barnard's Galaxy 35:24 - Andromeda Galaxy (M31) 39:39 - Satellites of the Andromeda Galaxy 53:30 - Toucan dwarf galaxy 54:47 - Wolf-Lundmark-Melotte Galaxy 56:00 - Aquarius Dwarf Galaxy 58:47 - Sagittarius irregular dwarf galaxy 1:00:19 - UGC 4879 1:01:52 - Antlia-Sextans group 1:08:03 - Other remarkable objects in the Local Group 1:13:40 - The IC 342/Maffei group, neighbor of the Local Group 1:14:52 - What's next? This channel is an official affiliate of the ORBINEA STUDIO network.

🌍 Where does the human being stand in the midst of this cosmic immensity? Man is one of millions of living species on planet Earth. Throughout our evolution, we have distinguished ourselves by our ability to modify the environment and shape nature to suit our needs. It has developed complex societies and diverse cultures that reflect its way of living and interacting. His place on Earth is unique and considered dominant. Man is a product of biological evolution, having developed on one planet among millions of others, in one galaxy among billions of others, within a constantly expanding Universe. Seen in this light, Man becomes a relatively insignificant being in the immensity of the Universe. However, we have had the ability and intelligence to make sense of the cosmos and seek to understand its mysteries. Thanks to scientific research, our knowledge of our planet has grown. The Earth belongs to the solar system. This solar system is part of a galaxy called the Milky Way, which in turn is part of a superstructure called the Local Group. The Local Group is just a small part of a supercluster of galaxies called Laniakea. And all this little world is concentrated in a Universe with immeasurable boundaries. To put it another way, if we were to scale up the Universe to the size of our planet, Laniakea would be a continent, the Local Group our country, the Milky Way our region, the solar system our city and Earth our home. Man's power then becomes very relative... 🔥 As a reminder, videos are published on SUNDAYS at 6pm. ------------------------- 💥 Where Are We Really in the Universe? : - Planet Earth was formed within the solar system. This solar system is a precious territory, over 4 billion years old, and includes the Sun, the eight known planets and numerous small bodies of rock and ice called asteroids and comets. The solar system is divided into several zones. The inner zone is made up of the so-called telluric planets: Mercury, Venus, Mars and, of course, the Earth. These four planets are rocky and metallic. Their size is relatively small. During their formation, the sun's heat expelled gases from this zone, concentrating dense elements. Beyond Mars lies a belt of asteroids. These are millions of lumps of rock, the waste products of planet formation. From this asteroid belt, we enter the realm of the giant planets: Jupiter, Saturn, Uranus and Neptune. In this outer zone of the solar system, the lower temperatures during the formation of our solar system enabled the existence of volatile elements. The planets are larger than those of the terrestrial planets, and made up of light elements such as hydrogen and helium. The formation of the solar system took place after a nebula gradually collapsed in on itself following the explosion of a supernova. The primitive nebula flattened as it rotated. The central part heated up, forming a protosun. Dust rich in carbon, ice, metals and minerals clumped together. This phenomenon is known as accretion. These blocks came together to form protoplanets and, a few million years later, the planets of today's size. Laniakea is made up of three superclusters: the Virgo supercluster, of which we are a part, the Hydra-Centaur supercluster, in which the Great Attractor is located, and finally the Indian Peacock supercluster. As in most galactic clusters, the space between the individual galaxies is not exactly empty. ------------------------- 🎬 Today's program: 00:00 - Introduction 02:35 - Earth's place in the solar system 04:58 - The Earth 08:47 - The Moon 10:33 - The Sun 13:17 - Mercury 14:34 - Venus 15:42 - Mars 18:10 - Asteroid belt 20:43 - Jupiter 22:43 - Saturn 24:57 - Uranus 27:50 - Neptune 29:48 - Pluto 31:07 - The solar system beyond Pluto (Kuiper belt & Oort cloud) 36:44 - The solar system's place in the Milky Way galaxy 37:27 - The galaxies 40:24 - Our Galaxy, the Milky Way 41:43 - Composition of the Milky Way galaxy 42:21 - The stars 47:49 - Constellations 49:28 - Star Clusters 51:11 - Interstellar Clouds 52:54 - Description of the Milky Way 58:18 - The Milky Way's place in the Local Group 01:05:02 - The local group's place in Laniakea 01:07:26 - Laniakea's place in the observable Universe 01:12:01 - What is our place beyond the observable Universe? This channel is an official affiliate of the ORBINEA STUDIO network.

We're looking hard, but the numbers aren't stacking up. Is life on other planets really that hard to find? Does it even exist? We have not discovered so much as a signal, so maybe we really are alone in our neck of the galaxy. The evidence to prove some of Einstein's theories had long been elusive, beyond the capabilities of technology, until now. It appears that Einstein is once again triumphant as we discover the latest in deep space observations. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark #aliens #einstein

The Big Bang happened but was it really the beginning of time? Two theorems are often used to suggest it was: The Penrose Hawking Theorem and the BGV Theorem . But new papers out in 2023 have re examined the issue of the beginning and come to a surprising conclusion. We talk to Roger Penrose, Alan Guth, Alex Vilenkin, Ghazal Geshnizjani, Robert Brandenberger, Damien Easson and Niayesh Afshordi to discuss the ultimate question of whether or not the universe had a beginning. A timeline is below. 0:00 Introduction 0:46 Penrose Hawking 2:50 Roger Penrose 4:18 Past eternal Inflation? 6:18 Tricked by coordinates 7:27 De Sitter Space 9:07 Beyond the BGV 10:42 An ambiguity in the BGV 11:48 Many things are possible 14:00 Viability of the Bounce 14:56 Beyond Einstein 16: 28 Cuscuton Bounce 18:28 G bounce 19:54 Emergent Universe 21:39 What does it mean?

Go to our sponsor https://betterhelp.com/HOTU for 10% off your first month of therapy with BetterHelp and get matched with a therapist who will listen and help. ------------------------ Written by @PaulMSutter Check out his fantastic YouTube channel and podcast for more: https://www.pmsutter.com/shows/askaspaceman And his books which inspired this video: https://www.pmsutter.com/books Narrated by David Kelly Edited by Manuel Rubio and David Kelly Thumbnail art by Ettore Mazza: https://www.instagram.com/ettore.mazza/?hl=en Animations by Jero Squartini https://www.fiverr.com/share/0v7Kjv Sound Editing by Craig Stevenson Huge thanks to Bone Clones for footage of their fantastic skulls: https://boneclones.com/ (look out for much more of them at the end of the year...) Galaxies, space videos from NASA, ESO, and ESA. Music from Epidemic Sound, Artlist and Silver Maple. Stock footage from Videoblocks, Artgrid and Shutterstock. 00:00 Introduction 05:23 What Is Life? 18:44 How To Make Life 31:30 The Earliest Possible Life 43:44 Where Is Everybody? #aliens

NASA's latest robotic lander helps us in understanding more about Mars on the Martian ground. New sources of water and planetary dust storms are a few of the stories unfolding on the Red Planet. Cubesats are miniature satellites that have been used exclusively in low Earth orbit for 15 years. Now, these tiny satellites are growing in mainstream popularity and are being used for interplanetary missions as well. They have even been sent to Mars with the Insight Mission, in hopes of better understanding the red planet, our solar system, and beyond. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark

The Japanese Asteroid Sample Return Mission has reached its target and is surveying the space rock, ready to dip down to acquire its sample. The return of asteroid material to Earth will aid scientists in the development in planetary defense systems. Two new space telescopes, Gaia and TESS, are in orbit with their primary missions coming to a close. They will be joined by the James Webb Telescope, and together they will open up a whole new vista into time and space. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark

The commercial space flight companies are edging closer and closer to flight readiness. Paying customers will soon be launching into space; tourist revenue is projected to be a major stepping stone toward space exploration and colonization. The JAXA-ESA joint "BepiColombo" Mission is moments away from launch. The target is Mercury, which has been too long neglected by the world's space exploration programs. This mission will shed new light on this strange, tiny world. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark

New satellites are being launched to continue detailed observations of Earth and its oceans and ice caps, They are finding that climate change is accelerating and they have the data to prove it. NASA's Parker Solar Probe Mission is on its way and will be shortly followed by Europe's Solar Probe Mission. No spacecraft has traveled so fast or so close to a star before. The hope is to reveal the source of the solar winds that affect us here on Earth. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark #NASA #Sun #space

🌍 What's the nearest habitable planet? Many of us on Earth are asking this question. The search for life on Mars, the nearest habitable planet to Earth, began in the 19th century and continues today with in situ exploration missions. Rovers are regularly sent to the Red Planet to collect samples of Martian soil that may give us clues to past or present life on Mars. However, no extraterrestrials have yet been found on Mars. The Red Planet is indeed in the Sun's habitable zone, but at its extreme limit, so it's very cold there, with an average temperature of -63°C, compared with 15°C on Earth! The discovery of the first exoplanet, 51 Pegasi b, on October 6, 1995, changed all that. Exoplanets are planets orbiting a star other than the Sun. To date, over 5,300 exoplanets have been discovered, according to the Encyclopedia of Extrasolar Planets! But not all exoplanets are habitable: some orbit very close to their star, while others are ice planets like Uranus or Neptune. And fewer than 200 of the exoplanets discovered are rocky, like Earth, the others being gaseous like Jupiter. The search for a habitable exoplanet has become one of the goals of astronomers, who study the characteristics of each exoplanet discovered using powerful telescopes in the hope of finding bio signatures, i.e. traces of life. 🔥 As a reminder, videos are published on SUNDAYS at 6pm. ------------------------- 💥Trip to the exoplanets of the Wolf 1061 star system: - The Wolf 1061 star system is located 13.8 light-years from our solar system. Between Earth and Wolf 1061, there's no void - quite the contrary. Contrary to popular belief, space is not empty. There's no air, but there are gases, dust, molecules and atoms. There are also numerous celestial objects: stars, exoplanets, satellites, comets, pulsars... There are thought to be around 30 stars between Earth and Wolf 1061. On our way, we'll come across a multitude of stars, some of which are the center of a planetary system. Wolf 1061 c isn't the closest exoplanet to Earth, but it's one of the few that seems most likely to harbor life. We'll be taking advantage of our journey to the Wolf 1061 star system to observe several exoplanets that astronomers have already studied in the hope of finding traces of extraterrestrial life. On our way, we'll come across several exoplanets that are already candidates for the title of the closest exoplanet to Earth where life exists. First stop: the Proxima Centauri planetary system! Let's continue our journey into the Universe to discover the closest exoplanets to Earth. Not far from GI411 b is the exoplanet Ross 128 b, located 11 light-years from our planet. Discovered in 2017, exoplanet Ross 128 b orbits a red dwarf, Ross 128, and was detected with the HARPS spectrograph at La Silla Observatory in Chile. This is the closest exoplanet to Earth that could potentially be inhabited, as Ross 168 is a rather quiet red dwarf. Its eruptions are less frequent and less violent than those of other red dwarfs, which would increase the chances of preserving Ross 128 b's atmosphere if it had one. If Ross 128 b contained liquid water, it would be far more conducive to the development of life than Proxima Centauri b, which is constantly bombarded by harmful X-rays and ultraviolet rays. ------------------------- 🎬 Today's program: - 00:00 - Introduction - 03:37 - En route to the Wolf 1061 star system - 05:14 - The Proxima Centauri planetary system - 14:32 - Gl411 b - 18:50 - Ross 128 b - 23:20 - YZ Ceti - 26:46 - Luyten b - 30:13 - The search for life on exo-planets - 30:47 - Why are we looking for life on exo-planets? - 33:44 - How do we search for life on exo-planets? - 37:43 - Wolf 1061 star system - 39:00 - The star Wolf 1061 - 40:00 - Wolf 1061 planetary system - 42:52 - Wolf 1061c, the nearest potentially habitable exo-planet - 46:27 - Is Wolf 1061c habitable? - 51:33 - What would life be like in the Wolf 1061 system? - 52:10 - Could humans live on Wolf 1061c? - 53:28 - Is it possible to live next to a red dwarf? - 56:33 - What if there were life? - 58:10 - Would life be concentrated only on the terminator? - 01:02:13 - What if Wolf 1061 c was an ocean planet? - 01:05:00 - What's next? Wondody is an official channel affiliated to the network ©Production Orbinea

On the 1st of February 2003, Space Shuttle Columbia punched through the earth's upper atmosphere. On board seven astronauts - unaware of the events that are about to unfold. Hot gases are filling the right-wing cavity and melt the aluminum structure inside. At 200,000 feet and traveling more than 14,000 miles per hour the shuttle breaks up killing all on board. In a fast-response documentary produced just five weeks after the disaster and months before NASA's official report the film asks - was it an accident just waiting to happen? Space Shuttle Human Time Bomb explores over 30 years of Shuttle development. Were design compromises forced by the military creating an inherently dangerous vehicle? With contributions from Shuttle engineers and scientists - the show accurately concludes what went wrong on that fateful day. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark #Spaceshuttle #NASA

We know it's there, and we usually pay it little mind. Gravity is the all-encompassing force keeping us on the ground, and the planets in their orbits, yet we notice it when it's not there. In space we are merely cheating gravity; falling just as fast but missing the ground; an orbit and the so-called condition of microgravity. Now this fundamental universal force is slowly giving up its secrets. The Ionosphere is the interface between Earth and space, a region of rarified gas and charged particles. It is very important for radio communications, radar, satellite signals and global positioning. Yet we know so little about it significantly when it disrupts all these signals in a regular fashion. Too high for planes or balloons, it's up to satellites to study this rarified region. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark

We have been observing Earth for 40 years now, in the last 20 we have focus with intensity on the planet with new technologies and capabilities, and we have accumulated a mass of data that is now revealing a complex and ever-changing living planet. Space is vast; yet it is full of collisions; gas and dust electrotatically flock together, gravity takes over coalescing grains into rocks, rocks into boulders then asteroids colliding again and again, striking planets and each other. Stars collide creating monsters of light and energy even galaxies collide over millions of years, space is a rough place to be. --- Subscribe to Spark for more amazing science, tech & engineering videos: https://goo.gl/LIrlur 🚀 Join the Spark Channel Membership to get access to perks: https://www.youtube.com/channel/UCMV3aTOwUtG5vwfH9_rzb2w/join Find us on: Facebook: https://www.facebook.com/SparkDocs/ Instagram: https://www.instagram.com/spark_channel/ Any queries, please contact us at: [email protected] #Spark

🌍 Did you know that, beneath their destructive exterior, stars actually produce the elements that make up our universe? Yet this is just one of the many mysteries that revolve around these molten stars. The stars are the source of many myths and beliefs. In ancient Egypt, the sun was the incarnation of the god Ra, crossing the heavens in his bark, creating the day/night cycle. Among the Incas, Inti was the sun god. A source of heat and light, and protector of the people, he was considered the most important of all deities. Even the ancient Greeks, far ahead of their time, considered the god Helios to be the personification of the sun. He and his sisters - Selene, the moon, and Eos, the dawn - gave rhythm to the lives of the Mediterranean peoples. Today, our knowledge and observations of the sky have enabled us to learn more about this star. Initially considered unique, we now know that the sun is just one star among many. A mere drop of water in an ocean of celestial bodies as massive as they are luminous. And to say so is an understatement... According to the latest observations, our Milky Way is home to between 200 and 400 billion stars. But it, too, is just one galaxy among the trillions hidden in the observable universe. Astronomical figures that, if you think about it too hard, can make you dizzy! Even the most starry sky reveals only a tiny fraction of the stars in the cosmos. If they were all visible, we'd be constantly bathed in blinding light, day and night. 🔥 As a reminder, videos are published on SUNDAYS at 6pm. ------------------------- 💥 Journey to the stars of the cosmos: - Our sun is far from the biggest star in our galaxy. And in a way, that's great news. Its mass and temperature are ideal for providing us with heat and light for hundreds of millions of years to come. If it had been bigger, it's very likely that life would never have developed on Earth. Also, the Sun would have been much more ephemeral. We know this only too well, because hypermassive, short-lived stars lurk in our Milky Way. They're called blue giants! So far, our journey has taken us to stars of many colors. For stars around 3000 degrees, the main color was red. For those around 4,000 degrees, orange dominates. For stars similar to our sun, those with temperatures between 5,000 and 6,000 degrees, their main color is yellow. Hotter still, stars at around 10,000 degrees are white, or even slightly bluish. Finally, the hottest stars, over 20,000 degrees, range from light blue to deep blue. But one color seems to be missing... If you pay close attention, you'll notice that no green stars are mentioned. So where are the jade stars hiding? Most stars are formed in nurseries. Within these so-called "molecular clouds", the brightest stars are born, gradually forming complex systems of planets, planetoids and asteroids. But not all stars are so lucky... By an unfortunate twist of fate, some stars find themselves isolated, condemned to drift alone in the cosmos. These stars, known as loners, orphans or wanderers, have aroused the curiosity of scientists. Is it possible that they formed far from any source of activity, in cold, empty zones? And if so, how can such a mystery be explained? ------------------------- 🎬 Today's program: - 00:00 - Introduction - 03:36 - The different types of stars - 05:05 - Brown dwarfs - 11:30 - Red dwarfs - 17:07 - Yellow dwarfs - 22:05 - Red giants - 28:11 - White Dwarfs - 33:17 - Black dwarfs - 40:00 - Blue giants - 44:07 - Why are there no green stars? - 48:41 - The life cycle of a star - 58:20 - The death of massive stars: Supernova - 01:05:28 - Neutron stars - 01:12:02 - The most surprising stars in the Cosmos! - 01:12:37 - Vampire stars - 01:15:55 - Variable stars - 01:20:36 - Lone stars - 01:24:24 - What's next? Wondody is an official channel affiliated to the network ©Production Orbinea

🌍 What are worlds beyond our galaxy like? The Universe that surrounds us still hasn't revealed its limits. While we now know the boundaries of our own Milky Way Galaxy, our contemporary measuring instruments are unable to tell us whether the Cosmos, for its part, is unlimited or not. However, at present, the observable part of the Universe seems to represent a sphere of 93 billion light years in diameter. It is estimated that the cosmological horizon is about 45 billion light years from Earth. Nevertheless, light emitted by distant objects is gradually reaching us. This hypothetical boundary is therefore dynamic and the observable Universe is getting longer over time. Scientists, who have long considered our Galaxy to be the center of the Universe, now know that this is not the case. They have long understood that our Sun is only one star among many others. What's more, they've been able to establish that our Galaxy represents only a tiny fraction of the cosmic immensity, despite its somewhat astronomical dimensions, on a human scale. Indeed, our Galaxy alone measures almost a hundred thousand light-years in length and a thousand light-years in thickness. On the scale of the Universe, with its trillions of galaxies, it's a mere grain of sand in the desert. The Milky Way, because our solar system is part of it and thus includes the objects closest to us, has been the focus of a considerable number of studies and observations. If it has given us many of its secrets, it is obvious that new elements will be uncovered as technologies progress. But do you think you know everything about our Galaxy? Do you have any idea of what surrounds it? Do you think that in a sidereal space millions or even billions of light years away, the stars then present behave differently? 🔥 As a reminder, the videos are published on SUNDAYS at 6:00 PM. ------------------------- 💥 Beyond the Milky Way: - The Milky Way thus evolves in the Universe in the middle of an incalculable quantity of stars. However, it has been established that it is part of a set of galaxies known as the Local Group. This contains over 60 galaxies, mainly dwarf galaxies, all linked by common gravitational forces. However, this Local Group represents only a tiny part of an even larger cluster of galaxies, the Virgo supercluster, on whose periphery it lies. This supercluster comprises at least 100 galaxy groups and clusters, and could be close to 200 million light-years across. It itself belongs to an even more gigantic structure, the Laniakea supercluster. The latter, made up of over 100,000 galaxies and stretching over 520 million light-years, has not convinced all scientists. Indeed, some believe that the galaxies in the latter structure are not gravitationally bound and, as a result, these sub-groups should disperse over time. But back to the Local Group. Despite its small size, it's a well-stocked catalog. It includes virtually all galaxy types, except for giant elliptical galaxies, which cannot be present in such a small structure, so to speak, compared to our human size! The size of the Local Group is approximately 10 million light-years across, and its total mass is estimated at 2,300 billion solar masses. The galaxies furthest from our solar system are around 5 million light-years apart. While it is home to mostly dwarf galaxies, it is also host to three large, massive galaxies: the Andromeda galaxy, probably the largest, the Triangulum galaxy, the smallest, and of course our own Galaxy. ------------------------- 🎬 Today's program: - 00:00 - Introduction - 03:15 - The Milky Way - surprising facts - 06:26 - The Local Group - 09:10 - Environment near the Milky Way - 16:56 - Birth of Andromeda - 20:15 - The irregular Sagittarius dwarf galaxy - 23:30 - IC10 galaxy - 28:03 - Cadwell 51 Galaxy - 31:37 - Phoenix Dwarf Galaxy - 34:01 - Toucan Dwarf Galaxy - 36:24 - Wolf-Lundmark-Melotte Galaxy - 39:09 - Leo A Galaxy - 41:39 - Supernova aftermath LMC N49 - 45:03 - High-speed clouds - 50:00 - Galaxy HVC 127-41-330 - 53:32 - Prodigiously long black hole jet - 55:58 - Perseus A, the giant galaxy - 01:01:13 - Gravitational wave signal GW190814 - 01:04:32 - Quasar HE0450-2958 - 01:09:14 - What's next? Wondody is an official channel affiliated to the network ©Production Orbinea

🌍 Is there, among the countless stars that illuminate our night sky with a thousand lights, stellar systems identical to ours? Who has never asked himself this question by plunging his gaze into the depths of a starry night. To this day, no one is willing to answer this mystery. However, astronomers who have been interested in this question since antiquity have never ceased to track down, observe and then list each of the stars discovered in the course of their work, even the most insignificant. Although they do not have a reliable answer to share with us concerning the number of stars around us, they are now able to refine their estimates. The latest technological advances, ever more powerful, now allow scientists to refine their figures, and these, as you can imagine, are staggering. Some estimate that there could be over 200 million trillion. 🔥 As a reminder, the videos are published on SUNDAYS at 6:00 PM. ------------------------- 💥 OUR NEIGHBORING STAR SYSTEMS: - For starters, what is a star system? At first glance, when we look at stars, we might think that they are all independent of each other. But this is not the case. If some stars are isolated, evolving without interactions with their distant neighbors, others are linked by gravitational attraction. When a small number of stars, thus linked, orbit around each other, we speak of a stellar system, each star being a component. It happens that some star systems are falsely named as such, being composed of a single star, it has a planetary system in its orbit. The discovery of these stars also influences their name. We speak of visual or astrometric star systems when they are discovered through their apparent movements in the sky. When they are detected according to the variation of their brightness, they are then called eclipsing star systems. Finally, when they are characterized by their spectrum, they are called spectroscopic star systems. A stellar system of two stars can have different names such as a binary system, a binary star, or a double star. This is notably the case of Sirius, the most sparkling star in our night sky. Multiple star systems, with more than two stars, are diverse. A triple, trinary or ternary star system contains three stars. A quadruple or quaternary system contains four. We can continue with quintuple, sextuple, septuple systems for respectively five, six or seven stars, and so on. When a system contains a hundred stars, or even many more, it falls into the category of star clusters, or even galaxies. But let's leave this theoretical part now, and let's focus on the closest systems, located in our galactic neighborhood. Proxima Centauri, a stellar and planetary system which also answers to the name of Alpha Centauri C. You will understand later on where this last name comes from. We are in the constellation of Centauri, only 4.2 light years from Earth and therefore still in our beautiful and luminous Milky Way. The luminous object you have before you is a red dwarf. These are very common in our Galaxy. They represent nearly 80% of the stars in the Milky Way. The apparent magnitude of Proxima Centauri, which is equal to 11.05, does not place it in the category of the brightest stars, the most radiant stars being of first magnitude. In fact, 85% of the energy it emits is not visible to our eyes, being mainly in the infrared wavelengths. To the naked eye, its luminosity in visible light is almost 650 times less than that of our Sun. Proxima Centauri is therefore of spectral type M5, which explains why it was only discovered in 1915. ------------------------- 🎬 On the program today: - 00:00 - Introduction - 04:05 - The different types of star systems - 06:43 - Proxima Centauri - 12:40 - Alpha Centauri A and Alpha Centauri B - 18:34 - Barnard's Star - 23:40 - Luhman 16 AB - 27:09 - WISE 0855-0714 - 30:24 - Wolf 359 - 35:25 - Gliese 411 - 40:07 - Sirius - 45:08 - Luyten 726-8 - 50:40 - Ross 154 - 53:30 - Ross 248 - 54:55 - Epsilon Eridani - 59:26 - Gliese 887 - 01:03:14 - Ross 128 Wondody is an official channel affiliated to the network ©Production Orbinea

🌍 "Where might the closest aliens to us live?" This is the question that many scientists ask themselves. The Universe is huge and we are far from knowing everything: there must necessarily be other civilizations like ours. This is the famous Fermi paradox: why, while the Sun is younger than many other stars in our galaxy, we have never yet found traces of extraterrestrial civilizations? There must be extraterrestrial civilizations, but where are they? Where do the aliens closest to us live? We are going to discover one of the star systems closest to ours, which seems to gather the ideal conditions to welcome extra-terrestrial life. On this journey, we will observe some remarkable stars that lie between Trappist-1, 40.5 light years away, and our solar system. When we arrive in the Trappist-1 star system, we will study the star Trappist-1a and the 7 exo-planets orbiting it. Together we will see if this amazing planetary system, very similar to our own, could harbor an alien life form and what it would look like. 🔥 As a reminder, the videos are published on SUNDAYS at 6:00 PM. ------------------------- 💥 The Incredible TRAPPIST-1 Star System: - Let's start by observing the star Trappist-1 a, the heart of the Trappist-1 star system. It is also called 2MASS J23062928-0502285. It is an ultra-cold red dwarf, barely larger than Jupiter but much more massive, and much cooler than the Sun. Its diameter would be of 11,5 % that of the Sun and its mass of 8 %. It would be between 3 and 8 billion years old. Strangely enough, it contains a lot of metals (about 109% of the amount of metals in the Sun!), which contradicts the models according to which red dwarfs contain much less metals than stars like the Sun. Stars like Trappist-1 have the capacity to live 400 to 500 times longer than the Sun. While the Sun can live for about 10 billion years, Trappist-1 A can live for 4 to 5 trillion years. When the Universe will be very old and the gas necessary for the formation of stars will be exhausted, Trappist-1 A will certainly be one of the last remaining stars... Enough to make you dizzy! Trappist-1 A was discovered in 1999 by astronomer John Gizis and his colleagues. 16 years later, 3 of the planets orbiting this star were discovered by the Belgian telescope TRAPPIST. The astronomers crossed the information from the two TRAPPIST telescopes, installed in Chile and Morocco, with information from 4 other telescopes based in the Canary Islands, Hawaii and South Africa, and discovered 4 more planets. The Trappist-1 planetary system contains at least 7 rocky planets, all of which have a radius close to that of the Earth and comparable masses. The planets of the Trappist-1 star system orbit at very small distances from their star: they would be, according to the observations, 6 to 40 times closer to their star than Mercury to the Sun! This planetary system is thus very compact: all the planets are on an orbit smaller than that of Mercury. The orbital periods of these 7 planets are very short: they range from one day and a half for planet B to 19 days for planet H, the outermost planet of the planetary system although 6 times closer to its star than Mercury to our Sun. ------------------------- 🎬 On the program today: - 00:00 - Introduction - 01:56 - On the way to the Trappist-1 star system - 03:25 - Barnard's star - 09:07 - Luhman 16 - 13:09 - Epsilon Eridani - 17:29 - HR 4523 - 19:51 - L 98-59 - 22:57 - Trappist-1 star system - 23:48 - Trappist-1 star a - 25:51 - Trappist-1 planetary system - 27:22 - Trappist-1 b - 30:11 - Trappist-1 c - 32:10 - Trappist-1 d - 34:40 - Trappist-1 e - 36:49 - Trappist 1-f - 38:02 - Trappist-1 g - 39:58 - Trappist-1 h - 40:30 - How were the characteristics of these exo planets determined? - 44:52 - Specificities of the Trappist-1 planets - 49:52 - Which planet would be habitable? - 52:43 - What would life be like in the Trappist-1 system? - 56:09 - Could life survive in the Trappist-1 planetary system? - 01:00:53 - Panspermia: the transfer of life from one planet to another - 01:03:10 - What next...? Wondody is an official channel affiliated to the network ©Production Orbinea

🌍 Is there an Earth-like planet in the universe? Like many people, you've probably already asked yourself this question. For several decades now, astronomers have been looking beyond the solar system and trying to find answers to this question in other star systems. K2-18 is one of the most interesting star systems for astrophysicists in search of extraterrestrial life. 🔥 As a reminder, videos are published on SUNDAYS at 6:00 PM. ------------------------- 💥 K2 18b, the most promising exoplanet: - The K2-18 star system is home to at least two exoplanets, K2-18 b and K2-18 c, which orbit the star K2-18. Both are more massive than the Earth: they are rocky superterrestrials, with a mass of 7 and 8.6 times that of the Earth. The closest planet to the star K2-18 is K2-18 c. This hot super-Earth was discovered in 2017 and confirmed in 2018. It was in fact by studying K2-18 b, which had been discovered earlier in 2015 thanks to the American satellite Kepler, that the researchers spotted the signal of K2-18 c and were able to discover this exoplanet. K2-18 b is indeed the one that interests astronomers the most. It is the most distant from the star K2-18. It is between 6 and 10 masses of the Earth and its radius is 2.3 times larger than that of our planet. It has an orbital period of 33 days and an equilibrium temperature of about -23°C, which is very close to the equilibrium temperature of the Earth of -18°C. As a reminder, the equilibrium temperature of a planet is the theoretical temperature of its surface in the absence of atmosphere. Astronomers believe that K2-18 b has all the characteristics to possess liquid water on its surface, which would make it habitable. Its density, however, seems far too low for it to be a rocky planet. Either K2-18b is a rocky planet with liquid water on its surface, or it is a planet covered by a thick layer of ice. In other words, it is a rocky super-Earth surrounded by a small gaseous envelope or a gaseous mini-Neptune essentially composed of water and covered with ice. In any case, K2-18 b is made up largely of so-called volatile constituents, which form a fluid envelope, with elements like molecular hydrogen, helium or water. As often in the observation of the Universe, nothing is certain yet! These two hypotheses hold true and only the observations of the James Webb telescope can tell us more. Indeed, the telescope is capable of analyzing the atmosphere of exoplanets, as it proved with the exoplanet Wasp 39-b. I remind you that James Webb has demonstrated the presence of CO2 in the atmosphere of Wasp 39-b, a hot gaseous planet located 700 light-years away in the Virgo Constellation. The principle is quite simple: when the exoplanet passes in front of its star, the light from the star will pass through its atmosphere. Scientists will then be able to study the spectrum of the light, in particular the absorption lines, which are sort of holes caused by the gases that the light has passed through before reaching us. Each gas has its own absorption lines. Just by studying the spectrum of light from K2-18 passing through the atmosphere of K2-18 b, astrophysicists will be able to determine which gases are present and in what proportions in the atmosphere of this exoplanet. ------------------------- 🎬 On the program today: - 00:00 - Introduction - 01:04 - Journey from Earth to the K2-18 star system - 02:40 - The Alpha Centauri star system - 08:40 - The star Sirius - 13:45 - Coconuts-2b, the closest exo planet photographed directly - 16:46 - WD 0806-661 B, the coldest star in the Universe - 20:32 - The solitary exoplanet PSO J318.5-22 - 23:52 - TOI-1452 b, the exoplanet ocean - 28:31 - The K2-18 star system - 29:26 - K2-18, the central star of the star system - 30:50 - Red dwarfs - 36:09 - The two exoplanets of the K2-18 star system - 39:47 - How is the exoplanet K2-18 b the most promising for an extraterrestrial life form? - 40:15 - The conditions for life to be possible on an exoplanet - 43:15 - K2-18 b is located in the habitable zone of its star - 44:49 - Water vapor discovered on K2-18 b - 48:29 - Still some grey areas - 52:15 - What would life be like on K2-18 b? - 58:20 - What would life be like on an ocean planet? - 01:03:23 - Could we communicate with the aliens of K2-18 b? - 01:05:11 - So, is K2-18 b home to life? Wondody is an official channel affiliated to the network ©Production Orbinea

🌍 How was the asteroid belt formed? Could it be the remains of a planet that collapsed billions of years ago? Located between Mars and Jupiter, the asteroid belt is known to astronomers as one of the largest collections of space objects in the solar system. For many scientists, it is of considerable scientific interest. Contrary to the popular image of an endless stream of giant rocks, the asteroid belt is largely empty. Asteroids in the belt are so rare that it is almost impossible to hit one by accident. Nevertheless, tens of thousands of asteroids are now known and their total number in the belt is in the millions. About 240 of them are larger than 100 km. The high density of asteroids makes the belt a very active area, where collisions between asteroids often occur. As a result of the collisions, they split, crumble or stick together. This is why the number of asteroids is constantly changing. 🔥 As a reminder, videos are posted on SUNDAYS at 6:00 PM. ------------------------- 💥 What does Pluto look like? : - The asteroid belt is a region of the solar system, located between the orbits of Mars and Jupiter, occupied by a large number of irregularly shaped solid bodies of various sizes, much smaller than the eight planets of the solar system. These small bodies are called asteroids or minor planets for the largest specimen. This region is also often referred to as the "main asteroid belt" or simply "the main belt", to distinguish it from other asteroid populations in the solar system, such as near-Earth asteroids and Trojan asteroids, and to emphasize its difference from other similar regions, such as the Kuiper belt that lies beyond the orbit of Neptune, as well as the Oort cloud and the clusters of scattered disk objects. The term "asteroid belt" came into use in the early 1850s thanks to Alexander Von Humboldt who used the term in his book "Cosmos: An Essay on the Physical Description of the World". Given its location in the solar system, the asteroid belt serves as a boundary between the inner rocky planets and the outer giant planets. It is curious to note that although the term "asteroid" is over two hundred years old, it has not yet been formally defined by the International Astronomical Union or any other scientific organization. Previously, the term "minor planets" was used as a synonym for the word "asteroid". However, after the International Astronomical Union first defined the term "planet" in 2006, the term "minor planet" was officially withdrawn, and it was replaced by the category "small bodies of the solar system", which includes all irregularly shaped bodies that orbit the sun and are not planets, dwarf planets or their moons. At the 2006 International Astronomical Union meeting, another important event took place. Ceres was reclassified as a dwarf planet. Thus, from a formal point of view, the largest asteroid in the solar system has become Vesta. ------------------------- 🎬 On the agenda today: - 00:00 - Introduction - 01:47 - What is the asteroid belt? - 03:11 - Difficulties in classifying asteroids - 06:50 - What are the physical characteristics of the asteroid belt ? - 08:23 - Orbits of the asteroids - 09:51 - Kirkwood's shortcomings - 12:03 - Collisions in the asteroid belt - 14:30 - What is the asteroid belt made of? - 23:26 - Who discovered the asteroid belt? - 27:15 - History of exploration of the asteroid belt - 31:09 - How is the asteroid belt formed? - 41:06 - The largest objects in the asteroid belt - 41:20 - Ceres, the largest asteroid in the main belt - 48:25 - Vesta - 50:28 - Pallas - 53:40 - Hygie - 56:26 - Why is the asteroid belt so important? - 01:02:43 - Does the asteroid belt represent a danger for the Earth? Wondody is an official channel affiliated to the network ©Production Orbinea

🌍 What are other galaxies in the universe like? Are they so different from our own? What if we went to explore the galaxies closest to the Milky Way, more specifically those that are part of the Local Group. Galaxies that are far away on our scale, and yet so close to ours, such as the Andromeda galaxy, the Triangulum galaxy or the Great Magellanic Cloud galaxy. But so many other galactic objects, which, although very modest in size, play a fundamental role in our understanding of the Universe. What is the composition of these galaxies? What is their history or even their future evolution? 🔥 As a reminder, the videos are published on SUNDAYS at 6:00 PM. ------------------------- 💥 Journey to the discovery of other galaxies: - The Andromeda Galaxy, with its 1000 billion stars, is often considered the twin sister of our Milky Way. Measuring 220,000 light-years in diameter, Messier 31 is a huge celestial object, the furthest from Earth that can be observed with the naked eye under clear skies, even though it is 2.5 million light-years away. The first observations of this luminous spot go back to the dawn of time, but the first written records date back to 964; they are due to Al-Soufi, a Persian astronomer. The Andromeda galaxy, located in the constellation of the same name, is easily recognized by its oval and diffuse shape with a bright core. The latter, of yellow color, contrasts with the dark dust bands and the large arms that trace their way around. This is a spiral galaxy, the closest to our Galaxy, which offers us a breathtaking spectacle. In its meanders, we can see clusters of blue stars, but also nebulae of reddish color. The total mass of the Andromeda Galaxy, estimated at 1,230 billion solar masses, against 1,900 billion solar masses for the Milky Way, does not prevent it from containing a considerable number of stars more. It houses in its bowels a supermassive black hole estimated at 140 million solar masses, which is much larger than the one in our Galaxy, which is estimated at only 4 million solar masses. Let's start by observing the Large Magellanic Cloud which is a dwarf galaxy of the barred spiral type. It is located in the constellations of the Dorado and the Table. Its disk shape is characterized by the presence of a single spiral arm and a large bar that were discovered long after the galaxy itself, which explains why it was first catalogued as an irregular galaxy. The Large Magellanic Cloud is 163,000 light-years distant from our solar system, but more importantly, it occupies the 4ᵉ position in the Local Group in terms of mass, after the Andromeda Galaxy, the Milky Way, and the Triangulum Galaxy. Several hundred thousand giant and supergiant stars are recorded there, as well as 60 globular clusters, 400 planetary nebulae and 700 open clusters... ------------------------- 🎬 On the program today: - 00:00 - Introduction - 01:50 - The main members of the Local Group - 02:15 - The M31, M32 and M110 Trio - 06:30 - The spheroidal dwarf galaxies of the Andromeda subgroup - 11:00 - The Magellanic Clouds - 12:15 - M31 and M110 to be presented to the public at the end of the year - 18:43 - NGC 185 and NGC 147 - 21:30 - Barnard's Galaxy - NGC 6822 - 22:53 - IC 1613 - 24:46 - Spheroidal Dwarf Galaxies in Milky Way Subgroup - 25:08 - Antlia 2 - 28:02 - Sagittarius Dwarf Galaxy - 30:06 - Dragon Dwarf Galaxy - UGC 10822 - 32:20 - Little Dipper Galaxy - UGC 9749 - 33:39 - Sculptor Dwarf Galaxy - 35:07 - Sextant Dwarf Galaxy - 37:25 - Dwarf Carina Galaxy - PCG 19441 - 38:28 - The Furnace Dwarf Galaxy - 40:14 - The Leo I and II Galaxies - Leo I and Leo II - 41:50 - Ultra-faint spheroidal dwarf galaxies of the Milky Way subgroup - 42:13 - Segue 1 galaxy - 44:28 - Segue 2 Galaxy - 45:58 - The Great Dog Dwarf Galaxy - 47:55 - Dwarf Big Dipper Galaxy I = Ursa Major I - 49:00 - Dwarf galaxy of the Great Bear II - Ursa Major II - Uma II - 51:13 - Dwarf galaxy Reticulum II - 53:22 - Isolated spheroidal dwarf galaxies - 54:10 - Whale dwarf galaxy - 55:43 - Toucan Dwarf Galaxy - 57:04 - KKR 25 galaxy - 57:41 - KKS 3 Galaxy - 58:42 - Bedin I Galaxy - 01:01:45 - Irregular Dwarf Galaxies - 01:02:03 - IC 10 Galaxy - 01:03:59 - Leo III Galaxy - Leo A - 01:05:39 - Periphery near the Local Group - 01:06:05 - Galaxy NGC 55 - Caldwell 72 - 01:08:03 - Galaxy NGC 300 - Caldwell 70 Wondody is an official channel affiliated to the network ©Production Orbinea