94 articles tagged with #what-if
The nearest star is 4.24 light-years away — roughly 40 trillion kilometres. Reaching it with current technology would take 80,000 years. What would it actually take to become a civilisation that spans multiple star systems?
Astronomers have found thousands of exoplanets. An Earth-sized planet in a habitable zone isn't exotic anymore. But a true Earth twin — similar size, similar temperature, liquid water, an oxygen atmosphere — would be something else entirely. Here's what would happen if we found one.
Atoms are almost entirely empty space. If you compressed all of humanity to nuclear density, the result would be about the size of a sugar cube. Here's the quantum physics behind why that doesn't work in ordinary matter, and where stars do it anyway.
Lower gravity sounds like a fitness boost — but the consequences would cascade through the planet, the climate, and life itself in ways most people don't expect.
Nuclear war is the most discussed existential risk and the least understood. The bombs are the easy part. What comes after — nuclear winter, famine, collapse — is far more dangerous. Here's what science actually predicts.
A second moon would change tides, eclipses, calendars, and possibly life itself. Here's exactly what would happen — based on real orbital physics — if we suddenly had two moons.
Terraforming Mars has been a science fiction dream for decades. The actual physics suggests it's vastly harder than commonly imagined, and a 2018 NASA-funded study concluded it's basically impossible with current or near-future technology.
Earth's proven fossil fuel reserves alone contain roughly three times more carbon than is compatible with keeping warming under 2°C. Here's what the physics, geology, and history say would actually happen if we burned it all.
A photosynthesising human sounds like a way to escape grocery bills — but the math says even a perfectly solar-powered human couldn't survive on sunlight alone. Here's why.
Not a week-long outage — gone for good. If the internet vanished permanently, humanity wouldn't just lose convenience. It would need to rebuild the physical and institutional scaffolding of a networked civilization from scratch.