Letters that make round-trip light time
o, d, e, g, l, n, p, h, m, r, t, i, u are letters that make 'round-trip light time'
Words within round-trip light time
light time, IP, ti, rip, UN, Ro, RI, light, round, li, time, trip, ME, ND, Light, Li, Nd, Ti, Ig are words within 'round-trip light time'