Mechanical power uses existing resources but faces reliability issues. Chemical reactions are finite and environmentally harmful. Nuclear power is hundreds of thousands to millions times more efficient
Freeman Dyson proposed Dyson sphere concept in 1960 for star energy extraction. Sun's output energy is 4×1026 W, which could meet modern energy needs. Humanity's current energy resources are insufficient for space exploration
GPS is a global navigation system providing location, velocity and time synchronization. System consists of 24 satellites orbiting at 13,000 miles above Earth. GPS works through trilateration using signals from satellites. Three satellites needed for location, fourth for validation and altitude calculation
Airships are vertical-lift aircraft using helium or hydrogen for flight. Only a few dozen airships remain, with half in working order. Most common uses are advertising, photography and aerial broadcasting
Virtual reality creates simulated environments using computer technology. Three types: non-immersive, semi-immersive, and fully immersive. VR differs from AR by creating new experiences, AR enhances existing ones
AGI aims to develop AI with human-level cognitive function and self-teaching capabilities. Strong AI differs from weak AI, which performs specific tasks within predefined parameters. AGI would be able to solve complex problems across different knowledge domains