TED-ED: Sunlight is way older than you think - Sten Odenwald

The video explains the journey of photons from the Sun's core to its surface, a process that takes thousands of years due to the random walk problem. Photons are produced in the Sun's core and interact with matter, losing energy and changing form. The random walk problem is used to calculate the distance photons travel, but initial calculations are incorrect due to assumptions about uniform density and photon interactions. The Sun's density varies, affecting photon travel time, which is now estimated at 170,000 years. The video concludes with the potential for future discoveries to refine this understanding.

What happens to photons as they travel from the Sun's core towards its surface?

• They disappear before reaching the surface.

• They lose energy and become longer wavelength forms of light.

• They gain energy and become gamma rays.

• They remain unchanged in energy.

What is the random walk problem in the context of photon travel?

• The time it takes for light to reach Earth.

• The unpredictable path photons take due to collisions.

• The formula used to calculate the speed of light.

• The direct path photons take to the surface.

Why was the initial calculation of photon travel time incorrect?

• The Sun's density was assumed to be uniform.

• Photons were thought to travel in a straight line.

• The speed of light was miscalculated.

• The Sun's age was overestimated.

How does the density of the Sun change from the core to the surface?

• It fluctuates randomly.

• It increases from the core to the surface.

• It decreases from the core to the surface.

• It remains constant throughout.

What is the relationship between photon energy and its interaction with protons?

• Higher energy photons are more likely to interact with protons.

• Lower energy photons are less likely to interact with protons.

• Higher energy photons are less likely to interact with protons.

• Photon energy does not affect interaction with protons.