> At this speed, if a photon were traveling alongside the particle, it would take over 215,000 years for the photon to gain a 1 cm lead, as seen from the Earth'

> At this speed, if a photon were traveling alongside the particle, it would take over 215,000 years for the photon to gain a 1 cm lead, as seen from the Earth's reference frame. Can someone ELI5 what this means? This particle was going .(some # of 9's)C, so does this mean a photon traveling at 1.0C is SO CLOSE IN SPEED that in order for Ct >= 1cm + (0.999C)t (where t is time), t would have to be 215k years?