Sunlight’s Hidden Odyssey: 170,000 Years to Escape the Sun
Sunlight takes about 8 minutes to reach Earth, but the energy moves outward from the Sun’s core via a random-walk diffusion process. A 1992 study showed the journey is much longer than straight-line travel, and a density‑varying model revealed the photon step length is under 0.1 cm for most of the Sun’s interior, pushing the diffusion time from tens of thousands of years to roughly 170,000 years before the photons reach the surface and head to Earth.