Скачать или смотреть Why It's IMPOSSIBLE to Stop Asteroid Impacts |Brian Greene

We can't stop them. Physicist Brian Greene shatters the reassuring narrative that planetary defense can protect Earth from asteroid impacts, revealing that detection limitations, warning time constraints, deflection uncertainties, and resource barriers make comprehensive protection fundamentally impossible. Discover why detection remains incomplete: surveys found only 95% of 1km+ asteroids (dozens of civilization-enders remain unknown), only 40% of 140m+ asteroids catalogued (15,000 regional-catastrophe-scale objects undetected), tiny fraction of 50-140m asteroids detected (hundreds of thousands unknown city-killers), small asteroids approaching from sunward invisible until too late (Chelyabinsk meteor 20m completely undetected before atmospheric explosion injured 1,500), long-period comets provide only months warning (arrive from outer solar system unpredictably). Learn why deflection faces severe limits: kinetic impact requires hitting fast-moving target across millions of kilometers (DART succeeded under ideal conditions but real scenarios far more challenging), required velocity change scales quadratically with decreasing warning time (20 years needs 1 cm/s, 10 years needs 4 cm/s, 5 years needs 16 cm/s exceeding practical limits), rubble-pile asteroids might fragment under impact creating multiple impactors (worse outcome than single impact), nuclear deflection risks catastrophic fragmentation if detonation energy exceeds gravitational binding (creates devastating fragment shower if close to Earth). Understand why warning time is fundamental barrier: many scenarios provide insufficient warning for deflection regardless of technology (sunward approaches, long-period comets, late-detected objects offer months not years), political decision delays consume precious time (international coordination, authorization, bureaucratic processing while asteroid approaches), rapid response requires standing infrastructure maintained at enormous expense (pre-built spacecraft, reserved launch vehicles, mission teams on standby costs billions annually for capability rarely used). Examine why mission failures are probable: launch vehicle failure 2-5% historically, spacecraft systems failures during multi-year cruise phase compound to 10-30% total mission failure probability, approach and targeting requires autonomous navigation hitting small moving target (errors create impact location uncertainty), post-deflection verification might reveal insufficient velocity change requiring follow-up mission with less time, cumulative success probability 50-70% under favorable conditions (far from guaranteed protection). Discover why resource constraints limit capability: comprehensive planetary defense requires $10-20 billion over decade plus billions/year operations (politically difficult for low-probability threat), benefits invisible when successful creating accountability asymmetry (politicians blamed for failures but receive no credit for prevented impacts), international coordination faces collective action problems (smaller nations free-ride on larger nations' investments, cost-sharing agreements difficult to negotiate). Greene proves through converging barriers that surprise impacts remain inevitable (undetected objects, short-warning scenarios, deflection failures), asteroid threat is risk reduction not risk elimination (modest investment worthwhile but cannot achieve zero risk), resilience and recovery capability more important than prevention for long-term survival (distributed infrastructure, preserved knowledge, social systems that reorganize after disruption), we remain vulnerable to cosmic forces beyond comprehensive control (accepting vulnerability while reducing risk where possible is mature worldview), focus on surviving impacts not preventing all of them.