Self-steering mass beams that can be focused on spots of ~100m across 1000 AU: sacramentol5society.nss.org/wp-content/u... These would be composed of 1 micron spinning 'smart particles' that reflect or absorb external laser pulses to counter dispersion, enabling easy interstellar propulsion.
www.science.org
Sun’s gravitational lens could reveal alien planets’ surfaces
Bold concept calls for sending telescopes 10 times farther than Pluto