Le Journal

Face à la polémique sur sa classe Optimum interdite aux enfants, la SNCF sort du silence et se justifie

Pokémon TCG Pocket – Bienvenue dans la parade onirique
New Game Plus Pokémon TCG Pocket – Bienvenue dans la parade onirique Fidèle à son calendrier, DeNA vient d’officialiser l’arrivée de la prochaine extension de Pokémon TCG Pocket. Après la sortie d’Embrasement Écarlate à la mi-décembre et une courte transition assurée par le retour du booster EX de la série A, le rythme de croisière reprend. C’est donc l’extension B2, baptisée Parade Onirique, qui viendra clôturer ce…
Investissements locaux : un mandat 2020-2026 chaotique, mais qui frise les records

Buried alive, leeched, and attacked with a poker: The dark history of nostalgia “cures”

Why modern fitness culture misunderstands human bodies
For most of human history, movement was inseparable from survival. Deliberately burning energy for no immediate purpose would have made little sense in a world where calories were scarce and bodies were costly to maintain. Seen through an evolutionary lens, exercise stops looking like a personal shortcoming and starts looking like a cultural invention we’re still learning how to live with, says Daniel Lieberman. This video Why modern fitness culture misunderstands human bodies is featured on Big Think.

«L'Etat providence galope devant l'économie», Nicolas Dufourcq de la BPI dénonce le manque de soutien aux entrepreneurs

‘Fueled By Ma’ Marks Singer/Songwriter’s Expansion, Adding Energy to Heartfelt Tunes

Fabien Valéri : « Prendre un maximum de points au plus vite »

Produits dérivés : le Musée National de Corée annonce des ventes record de 24 millions d’euros en 2025 et un projet en France en 2026
Temps de lecture : 4 minLa marque de produits dérivés officiels du Musée national de Corée, MU:DS, a franchi pour la première fois la barre des 40 milliards de wons (24 millions d’euros) de ventes annuelles en 2025, portée par l’engouement mondial pour la culture traditionnelle coréenne, ont annoncé les responsables du musée, le mardi […]

Remembering Gladys West: who used Einstein to create GPS
Over the span of a single lifetime, the world has changed in ways that would have been virtually unimaginable in the first half of the 20th century. Two major breakthroughs that occurred in physics — relativity and quantum physics — suddenly made a number of previously unthinkable endeavors possible. From modern electronics to computers, smart phones, the internet, brain imaging and more, everyday life in 2021 is vastly different from what it was back when many of us were first born. One of those technologies that’s been revolutionary for our society is GPS: the Global Positioning System. From anywhere in the world, signals can be transmitted by a network of medium-Earth orbit satellites to wherever your location is, pinpointing your position to an accuracy of better than 1 meter (3 feet) more than 95% of the time. Devices with the latest (L5) receivers, beginning in 2018, are now capable of reliably determining your location to within 30 centimeters (12 inches). Unbeknownst to most people, however, the science underlying this technology was primarily developed by two people: Albert Einstein, whose theories of special and general relativity both play an important role, and Gladys West, a humble and largely-unheralded black woman who passed away at the age of 95 on January 17, 2026. Her scientific contributions enabled us to understand geodesy and the shape of the Earth well enough to make GPS technology possible. While many others played a role in designing, deploying, manufacturing, and operating the satellite array that powers GPS, none of it would have been possible without West’s key insights. Here’s the science behind why this “hidden figure” of GPS is invaluable. A core constellation of 24 GPS satellites fly in medium Earth orbit (MEO) at an altitude of approximately 20,200 km (12,550 miles), augmented by seven others at present for a total of 31. Each satellite circles the Earth twice a day. This configuration ensures that at least 4 satellites are always within range of any point on Earth, continuously, with some locations receiving data from up to 8 satellites at once. Credit: US Government/GPS.gov Here on Earth, GPS is truly a technology that’s only been possible since the dawn of the space age. At its core, GPS is enabled by a network of satellites that each carries an accurate record of its position in space and the passage of time on board, with the latter enabled by atomic clocks: one aboard each satellite. Those satellites continuously transmit their position and time data through a radio signal to receivers located anywhere on Earth. Since the speed of those radio waves — the speed of light — is a constant, anyone who receives a signal from any four GPS satellites at once, with known timestamps and position stamps, can determine their three-dimensional position in space and their “position” in time (i.e., your “clock deviation” from the time on board the satellites). At an orbital height of 21,180 kilometers (12,540 miles), a little more than three times the radius of the Earth, only 24 satellites are required to provide full coverage to the entire Earth at once. While other nations, such as Russia and China, have their own GPS-like systems in place, it’s the United States’ GPS system, consisting of 31 operational satellites at last count, that freely serves the entire world. This illustration showcases the concept of triangulation using satellites, where the light-travel time between a particular location on Earth’s surface, assuming you account for all of the effects that impact that time such as special relativity, general relativity, and the intricacies of Earth’s gravitational field, creates three “spherical shells” around each of the three satellites. At the one point where all three shells intersect, that yields an unambiguous result for your position on Earth. Credit: P. Wadhe et al., International Journal of Advanced Research in Computer and…

Thursday, January 22, 2026: Your Horoscope
Astrologer Alexandria Lettman reveals what the stars have in store for every zodiac sign's horoscope on Thursday, January 22, 2026

