Astronomers are increasingly focused on defending Earth against building-sized asteroids that pose immediate threats to modern society. Unlike the kilometer-scale objects depicted in disaster films, decameter-scale asteroids strike Earth roughly every couple of decades, making them a more pressing concern than civilization-ending impacts that occur only every tens of millions of years.
The shift in focus reflects the growing dependence on space-based infrastructure that supports daily life. GPS navigation systems, global communications networks, and satellite-based services could face significant disruption from smaller asteroid impacts that might not threaten human survival but could cripple technological systems.
While massive asteroid impacts remain extremely rare events, building-sized objects represent a statistical certainty over human timescales. These decameter-scale asteroids, typically measuring tens of meters across, occur with predictable frequency that makes preparation both feasible and necessary for protecting critical infrastructure.
As detection capabilities improve, planetary defense strategies are evolving to address these more frequent but smaller threats. The focus on protecting space-based assets reflects how modern civilization's vulnerability has shifted from direct physical destruction to technological disruption that could affect billions of people through communication and navigation system failures.