All of the sun’s photons are generated through nuclear reactions within it. If a photon is generated at the centre of the sun it can take anywhere between 2 days and 200,000 years to escape the body of the sun. That’s because the path of the photon is purely probabilisitic. At the centre of the… Continue reading How long does it take a new photon to reach us from its creation in the sun?

  So, just the other day, I was thinking about how much energy we need to destroy hair follicle and blood vessels. Typically we talk about 1 or 2 joules per pulse. Then I thought, what is 1 joule of energy? I had no idea what this actually meant in the ‘real’ world! So, I… Continue reading How much energy does it take to heat a cup of coffee or tea?