“Exploring the universe is a better way to understand who we are.”
Sébastien Carassou
Speaker
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Astronomer
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Scientist
Sébastien Carassou holds a PhD in astrophysics, specializing in the evolution of galaxies. A prominent science communicator, he has succeeded in bringing together a large community with his YouTube channel "The Sense of Wonder" (170k subscribers), while also leading collective scientific culture initiatives (Conscience collective, @EnDirectDuLabo) and publishing
several books. Since 2024, he has been scientifically coordinating "Sanctuary on the Moon," a lunar time capsule project at the intersection of science, art, and engineering. His lectures combine astrophysics, science fiction, and existential questions.
Sébastien Carassou
Sébastien Carassou is a doctor in astrophysics, a specialist in the evolution of galaxies. Originally from the island of Reunion, he completed his thesis at the Institute of Astrophysics in Paris, where he developed an innovative method combining machine learning and simulation of images from large astronomical surveys. His goal: to better understand the evolution of galaxies through observations from telescopes and supercomputers. Early on, he felt the need to share the discoveries of his discipline with a broader audience. In 2015, he co-founded the YouTube channel "Le Sense of Wonder," dedicated to the sciences of the universe. His videos, where scientific rigor meets wonder, quickly gained increasing success and became a privileged means of transmission.
At the same time, he is involved in several collective initiatives. He is a co-founder and president of the collective "Conscience," an association dedicated to the promotion and dissemination of scientific culture. Along with other enthusiasts, he also launched the initiative "@EnDirectDuLabo," a collaborative Twitter account where researchers share their daily lives and discoveries with a wide audience every week. Since 2024, he has been the scientific director of the project "Sanctuary on the Moon," a French initiative for a lunar time capsule aimed at depositing a sustainable archive composed of micro-engraved sapphire discs containing knowledge, testimonies, and representative works of humanity on the Moon by 2030.
At the crossroads of science, art, and engineering, this project aims to create a symbolic preservation of our time for future generations. Over the years, Sébastien Carassou has established himself as a key figure in French-speaking scientific popularization. He regularly gives lectures at science and culture festivals, such as "Pint of Science," "Lyon Science," "Les Mycéliades," and for the Astronomy Festival of Fleurance. His interventions, blending astrophysics, philosophy, and popular culture, attract both specialists and the general public.
Author of the books "Le Cosmos et nous" (Éditions des Équateurs, 2021), "Destination Cosmos" (Albin Michel, 2025), and "L'Univers Incompris" (Les Arènes, 2026), he explores the major existential questions posed by modern sciences: our origins, our place in the universe, and the possibility of other forms of life elsewhere. He is also a co-author of the "Guide du Vulgarisateur Galactique," an offbeat and practical manual for transmitting science differently. Today, Sébastien Carassou dedicates his energy to fostering dialogue between science, humanity, and imagination. His lectures, writings, and media interventions invite reflection on our common destiny and reposition humanity within its vast cosmic context.
Destination Cosmos - a tourist journey through the universe!
- What if the cosmos became your playground? Imagine being able to teleport instantly to the far corners of the universe: soaring above Venus in a dirigible, ice skating on the frozen plains of Pluto, exploring the depths of Jupiter's moons, or skimming the unfathomable mystery of a supermassive black hole...
- What would your next destination be? In this original and immersive conference, blending rigorous science with unbridled imagination, astrophysicist and popularizer Sébastien Carassou takes you on an intergalactic journey to discover the most spectacular and unusual wonders of the Universe.
Ballad in the solar system!
- For millennia, humanity has contemplated the movement of planets across the night sky. However, the advent of robotic space exploration in the 1950s radically changed our view of the solar system, its composition, and its evolution.
- Thanks to our spacecraft, these tiny points of light have become worlds in their own right.
- In this lecture, I will present the most contemporary portrait possible of our cosmic neighborhood, and we will embark together on a temporal odyssey of 4.5 billion years to witness the birth of the planets.
The Secret Life of Stars!
- The reassuring glow of the stars has accompanied us since the dawn of time. To the naked eye or through the eyepiece of an amateur telescope, these celestial bodies generally seem fixed, eternal.
- But that is not the case: stars are born, live, and die, on timescales that can be counted in millions or even trillions of years.
- In this lecture, we will contemplate the life cycle of several types of stars, from their birth within vast clouds of gas and cosmic dust to their sometimes explosive decline, and we will discover to what extent we can consider ourselves the children of past stars.
Exoplanets: the symphony of new worlds!
- Since the discovery of the first planets beyond our solar system in the early 1990s, the study of exoplanets has entered a true golden age.
- Today, there are over 6000 of them, and these new worlds are astonishingly diverse, to the point that some astronomers seriously dream of ocean planets or "super habitable" worlds.
- In this conference, we will explore the diversity of these known or hypothetical exoplanets, and we will ask how astronomers might potentially detect signs of life on them.
Two trillion galaxies!
- Galaxies are among the most majestic structures in the universe. From the Milky Way to Andromeda, these immense stellar cities harbor a fascinating diversity and a complexity still partly unknown. They house billions of stars, countless planetary systems, and bear witness to the evolution of the cosmos.
- In this lecture, Sébastien Carassou invites us to trace the thread of cosmic history through the study of galaxies. From their brightness, colors, and shapes, he reveals the hidden chapters of their evolution. He shows how astronomers, thanks to modern telescopes and supercomputers, manage to reconstruct this cosmic fresco.
- He also emphasizes the mysteries that remain: dark matter, dark energy, gravitational interactions still poorly understood. These enigmas make galaxies true laboratories for testing our most ambitious theories.
- This visual and intellectual journey reminds us that our own galaxy, the Milky Way, is just one among billions of others. Placing our cosmic address within this dizzying ensemble invites both humility and curiosity.
Will we ever reach the stars?
- For centuries, humanity has dreamed of reaching the stars. Science fiction stories have fueled this imagination, popularizing the idea of interstellar travel through wormholes or hyperspace. But beyond the myth, is there scientific and technical feasibility?
- Sébastien Carassou explores the serious avenues considered by researchers and engineers of the 20th and 21st centuries.
- Nuclear propulsion, solar sails, miniature probes, or world-ships: he presents the bold concepts that could one day turn this dream into reality.
- These scenarios also reveal immense challenges: colossal costs, vertiginous distances, and still embryo technologies.
- Yet, no law of physics forbids traveling to the stars. This conference questions our collective future. Traveling to other worlds would not only be a technical feat, but a choice of civilization. What vision do we want for the fate of humanity?
Understanding the sky: from myths to science!
- The sky has always fascinated human societies. Even before modern astronomy, people saw stories, gods, and omens in it. Constellations served as landmarks for navigation, calendars for agriculture, and supports for mythologies.
- In this presentation, Sébastien Carassou revisits this long cultural history. He shows how celestial myths reflected the values and fears of civilizations, but also how, gradually, observation and
- reason paved the way for rigorous science.
- The history of astronomy is marked by intellectual revolutions: from Copernicus to Galileo, from Newton to Hubble. Each has disrupted our relationship with the sky, moving from a human-centered view to a cosmic perspective.
- This conference sheds light on the continuity between imagination and science. It emphasizes that understanding the sky also means understanding humanity itself, in its quest for meaning and truth.
The Great Narrative: Humanity in its Cosmic Context!
- All civilizations have forged creation stories. But in the 20th century, a new narrative emerged, not built on myths, but on science: that of the Big Bang and the evolution of the universe.
- Sébastien Carassou proposes to traverse the 13.8 billion years that separate the origin of the universe from our present. He narrates the birth of galaxies, stars, and planets, followed by the emergence of life and consciousness.
- This "Great Narrative", in the words of Michel Serres, transcends disciplines to connect cosmology, biology, history, and philosophy. It allows humanity to be placed within a continuum that surpasses it, yet of which it is the heir.
- Beyond science, this fresco offers an existential and cultural dimension. It invites everyone to question themselves: what are we, where do we come from, and where are we going?
Are we alone in the universe?
- The question of extraterrestrial life is one of the oldest and most challenging. Today, science finally equips us with tools capable of addressing it: next-generation telescopes, planetary exploration, and the study of exoplanets.
- In this conference, Sébastien Carassou examines the conditions for the emergence of life and the clues astronomers are searching for throughout the universe. He also explores detection scenarios: planetary atmospheres, chemical biosignatures, or artificial signals.
- But beyond astrophysics, the question engages philosophy, biology, and even ethics. Discovering another life, even if microbial, would upend our conception of humanity and its place in the cosmos.
- This reflection, at the intersection of disciplines, invites the public to gauge the significance of such a discovery: would we still be alone in contemplating the stars?
Mars: Planet B?
- By 2050, one million humans could very well settle on Mars! At least, that's what the American billionaire Elon Musk repeatedly asserts in numerous interviews.
- While the vision of the SpaceX chief excites many entrepreneurs, most astronomers and space professionals have reason to be skeptical about the feasibility of such a project.
- The driest regions on Earth are indeed true paradises compared to the frozen desert, devoid of life and oxygen, of the red planet.
- So, what does science tell us? Will humanity ever be able to move to Mars? Can we sustainably transform its climate to make it habitable? Should we even devote resources to such an undertaking?
- In this conference, we will discuss the fascinating features of the red planet while keeping our feet on the ground.
Life finds a way
- Life on Earth has never been a smooth river. In nearly 4 billion years of evolution, it has come close to extinction several times, almost entirely swept away by at least five massive extinctions: brief episodes on a geological scale, but devastating for biodiversity.
- Yet, despite killer asteroids, mega volcanoes, and ice ages, life has always managed to bounce back. Where does life come from? What is the secret of its resilience? And what threats loom over it today?
- Dive into the heart of these questions during an interactive conference led by science popularizer Sébastien Carassou.
The end of times!
- All good things come to an end, and the universe itself is no exception! Planets become uninhabitable, stars die, and even black holes may evaporate.
- Just a few decades ago, the awareness of this fact gave rise to a strange field of study: physical eschatology.
- In this conference, I will provide you with a broad overview of what our theoretical models teach us about the very long-term future of the cosmos, from the end of our world to the thermal death of the universe.
The misunderstood universe: lights on the shadows of the cosmos
- Never has Humanity understood the cosmos so well. Observations from great telescopes and the latest generation satellites seem to confirm the main scientific theories.
- And yet... The more the Universe reveals itself to us, the thicker the mystery grows: Does it have limits? What was there before the big bang? Are there other universes besides ours? What triggered its expansion? Where has the antimatter gone?
- These observations open up new astonishing questions: ordinary matter, which makes up stars, planets, and galaxies, represents only a tiny part of the cosmos. What is the nature of the remaining 95%, dark matter and dark energy?
- In this conference, Sébastien Carassou immerses you into the unknown areas of our cosmological knowledge, those unknown spaces where the science of tomorrow is already being written.
How Einstein Reinvented Time?
- For centuries, time was considered absolute and universal.
- But in the early 20th century, Albert Einstein disrupted the very foundations of our understanding of reality by demonstrating that time is relative, that it is intimately linked to space, and that this "space-time" is a malleable entity that can be dilated or compressed at will.
- In this lecture at the crossroads of the history of science, philosophy, and science fiction, Sébastien Carassou explores the different theoretical approaches considered by physics to travel through time, as well as the dizzying questions raised by Einstein's theory of relativity.