What Is The Lifetime Of A Photon? скачать в хорошем качестве

What Is The Lifetime Of A Photon?

As you may have read somewhere, light only takes 8 minutes to cover the distance between the Sun and the Earth. Yes, that’s an insanely short time, considering that we are talking about 150 million kilometres! But the light that reach us is actually produced at the centre of the Sun, in its core, where nuclear reactions occur. So, have you ever asked yourself how long does light take to reach the surface of the Sun, starting from its centre? Well, we may attempt to find a rough estimate. Consider that the Sun has a radius of “only” 696,000 kilometres (compared to the 150 million kilometres that separates it from the Earth)… so we would expect light to reach the surface in, let’s say, a few seconds, is it? …you may be surprised to hear that this estimate is totally wrong! In fact, light takes… (drums)…. Thousands of years to reach the surface of the Sun! Wait, what? How is that possible? …curious to know how? Stick with us and we will tell you the answer in this video! ------------------------------------------------------------------------------------------- Subscribe for more videos:https://www.youtube.com/c/InsaneCurio... Business Enquiries: [email protected] ------------------------------------------------------------------------------------------- Before talking about the journey of light from the centre of the Sun to the Earth, we need to do a short digression about light. Stick with us, it won’t be that long. What is light? Well, light is something fascinating: in fact, it has a “dual” nature. What does it mean? It means sometimes it behaves as a wave, and sometimes it behaves as a particle. Let me tell you more. In the past centuries, scientists believed that light was a wave. And they were right, but.. that was only half of the story. At the end of the 19th century, and precisely in 1900, in order to explain some weird phenomena that were puzzling scientists, the German physicist Max Planck postulated that light was actually consisting of particles, called “photons”. Planck’s idea found confirmation five years later, in 1905, when Albert Einstein (this guy again!) managed to successfully explain the “photoelectric effect” by using Planck’s idea. The photoelectric effect is a well-known phenomenon that occurs when light is shone at a material (metals, in particular) and electrons are emitted from its surface as a result. By thinking light as a wave, some aspects of this phenomenon could not be explained. For instance, if the frequency of light was under a certain threshold, no electrons were emitted from the material, no matter how strong the intensity of the light beam is. However, by thinking light as a “bunch of particles”, the photons, this effect could then be explained. In fact, each photon in the light beam carries a certain amount of energy, and when the photon hits an electron in the material, it gives all its energy to the electron, which is now able to “escape” the material. The energy of the photon depends on the frequency of the light beam: so if this frequency is lower than a certain threshold, the photon has not enough energy to allow the electron to “escape” the material. The intensity of the light beam only determines the number of photons in the beam: so it doesn’t matter if we increase the intensity, we will only have more photons, but none of them will be able to “free” electrons from the material, because none of them has enough energy to do that. For realizing this, Einstein won the Nobel Prize. Now that we have realized that light consists of photons, let’s go back to our original topic: why does light take so long to reach the surface of the Sun? To answer this question, we have to start by looking at what happens in the core of the Sun. As in every other star, the core of the Sun is the “motor” that produces all the energy and the light emitted by our star. ------------------------------------------------------------------------------------------- "If You happen to see any content that is yours, and we didn't give credit in the right manner please let us know at: [email protected] and we will correct it immediately" "Some of our visual content is under a Attribution-ShareAlike license. (https://creativecommons.org/licenses/) in it’s different versions such as 1.0, 2.0, 3,0 and 4.0 – permitting comercial sharing with attribution given in each picture accordingly in the video." Credits: Ron Miller Credits: Nasa/Shutterstock/Storyblocks/Elon Musk/SpaceX/Esa Credits: Flickr Video Chapters: 00:00 Introduction 01:14 Dual Nature of Light 02:13 Photoelectric Effect 03:13 Nuclear Fusion in the Sun's Core 04:17 Photon's Chaotic Path 05:10 Photon Absorption and Re-emission 07:57 Photon's Journey to Earth 09:15 Photons from Distant Stars #insanecuriosity #photon #science