If You Could Change Yesterday, Would Tomorrow Still Exist? Time travel paradoxes, Einstein’s universe, and the science of going back. Imagine receiving a letter in your own handwriting. It is dated 2056, thirty years from now. Inside is a warning: “Whatever you do, do not open the blue door tomorrow.” Naturally, the first thing you want to know is what is behind that door. The second is how your future self knew you would be tempted. Now imagine you ignore the warning. Behind the door is a working time machine. You use it to travel to yesterday and make sure your younger self never opens that door. But if you never find the machine, you never make the trip. So who came back to stop you? One simple decision has turned into a contradiction. The difficulty is not the technology. It is asking the same event both to happen and not to happen. This is why time travel has a place in serious physics, even without a single working time machine. Einstein showed that time does not tick at ...

AI Is Decoding History: From Napoleon’s Secret Cipher to Lost Ancient Books The first line was ordinary French. Below it stretched twenty-four rows of numbers, letters and curious handmade symbols. The message was meant for one of Napoleon's generals, far from the main French army, and it carried information an enemy would have loved to intercept. For more than two centuries, the code concealed almost everything after the greeting. In September 2026, cybersecurity engineer Carter Church published a way to read it. Working from a low-resolution scan, an AI system transcribed the marks, tested possible substitutions and helped reconstruct an 1809 military briefing. The solution took roughly six hours of model execution and came with files that others could use to check the result. What emerged was not a sensational secret about Napoleon's private life. It was something historians often value more: an unusually detailed picture of armies preparing for war. A different kind...

  Electronic Tattoos: Could Your Skin Become the Next Computer? How flexible sensors, printed circuits and new materials could turn the surface of the body into an interface—and what the latest research can really prove. A computer you could wear without noticing Imagine a sticker so thin you almost forget it is there. A doctor places it on your chest, where it follows every breath and picks up the weak electrical signal of your heartbeat. In another lab, scientists print conductive ink onto a volunteer's scalp to record brain waves. On a hand, a delicate pattern of electrodes turns a small muscle movement into a command. Each idea is grounded in published research, though the devices remain at different stages of development. None of these devices looks like a conventional computer. That is the appeal. Instead of strapping a rigid box to the body, engineers are trying to make electronics move with the skin. Some designs can measure signals that wristwatches miss; others may ...

OpenAI: The Company That Changed Artificial Intelligence — and What Comes Next From an ambitious nonprofit laboratory to ChatGPT, GPT-6, billion-dollar bets and a debate over who should control powerful AI. On December 11, 2015, a new artificial intelligence laboratory appeared with a promise that sounded almost idealistic: help build powerful AI, and make sure its benefits were shared as widely as possible. It had no ChatGPT, no app store presence and no monthly subscription to sell. Its name was OpenAI. By October 2026, the laboratory had become something its founders could scarcely have pictured. ChatGPT reached more than 1.2 billion people a week, according to OpenAI's own figures. Its systems could help people write software, study unfamiliar subjects, examine images and delegate work to digital tools. Investors were discussing sums larger than many national budgets for infrastructure. Meanwhile, teachers, publishers, scientists and lawmakers were asking whether anyone f...