Welcome to this enlightening year! The Perimeter Institute for Theoretical Physics (PI) has compiled twenty fascinating facts about light that they believe are the most interesting. Let’s dive in!
1. When you leave Earth’s atmosphere and look at the Sun, you will see it as white instead of yellow. The reason the Sun appears yellow from the ground is due to the scattering of light by the atmosphere. If you were on Venus, you wouldn’t even be able to see the Sun because the atmosphere is too thick, and you would also experience deafness.
2. Humans actually have the ability to bioluminesce; however, our light is a thousand times weaker than the human eye’s ability to see.
3. Light can penetrate about 80 meters into the ocean. At a depth of 2000 meters, there is an anglerfish, which has a bioluminescent lure on its head to attract prey. This fish looks quite ugly and terrifying.
4. The reason leaves are green is that they reflect green light and absorb all other colors for photosynthesis. If you shine green light on a plant, it will not be able to photosynthesize and will die. The PI does not encourage you to harm trees.
5. The aurora borealis occurs when “winds” from solar storms interact with Earth’s atmosphere.
6. In one second, the energy emitted by the Sun is enough to heat 3,200 trillion fast meals.
7. The longest-lasting light bulb in the world is the Centennial Light bulb in California, which has been continuously lit since 1901, only being turned off a few times due to power outages.
8. The sneeze reflex when dazzled (looking up at the sky or at the Sun may cause sneezing) occurs in about 18%-35% of humans. The reason is still unknown, but a remedy is to wear sunglasses when looking at the Sun.
9. The phenomenon of a double rainbow occurs when light reflects twice in water droplets. The inner rainbow will have the color order of ROYGBIV, while the outer rainbow will have the reverse order of VIBGYOR.
10. Our eyes cannot see everything; many other animal species have much better eyesight than humans. For example, bees can see ultraviolet light, while snakes can see infrared light, and so on.
11. Niagara Falls has been illuminated electrically since 1879, at that time equating to 32,000 candles, and now the light intensity has been increased to the equivalent of 250 million candles.
12. When light passes through different materials, it slows down and bends (refraction). This is why a converging lens can focus light to a point, allowing you to burn ants (not recommended).
13. A frog’s eyes are extremely sensitive to light, and researchers in Singapore have used frog eyes to develop highly sensitive photon detectors.
14. The reason LED bulbs save energy is that they emit only visible light, while other types of bulbs like incandescent and fluorescent emit a spectrum of light, making them less efficient.
15. Fireflies emit cold light with nearly 100% efficiency, and scientists are researching ways to mimic this type of light for the next generation of high-performance LEDs.
16. To study how the eye perceives color, young Isaac Newton once stuck a wooden stick into his eye to see if colors came from objects or from within our eyes (in reality, they come from both; rod cells react to corresponding light waves).
17. If the Sun suddenly turned off, we wouldn’t know for 8 minutes and 17 seconds, but don’t worry, the Sun has enough energy to shine for another 5 billion years.
18. Although called Black Holes, they are actually the brightest places in the universe, with energy output greater than that of the galaxy that contains them.
19. Rainbows are created when light enters tiny water droplets in the air. The light is refracted, then reflected inside the droplet, and refracted again as it exits the droplet, a process that creates a rainbow.
20. Light also possesses inertia, and researchers are studying how to harness this form of energy to make deep space travel more efficient and cost-effective.
21. Photons can create shock waves in water or air, similar to a sonic boom. Nothing can move faster than the speed of light in a vacuum. However, light slows down in air, water, glass, and other materials because photons interact with atoms, resulting in some fascinating consequences.
Most types of light are invisible to the human eye.
22. Most types of light are invisible to the human eye. Color is how our brain interprets the wavelengths of light: the distance light travels before the wave pattern repeats itself. However, the colors we see—known as “visible” or “optical”—are only a small part of the entire electromagnetic spectrum.
23. Scientists can conduct measurements on individual photons. Light consists of particles called photons, which are packets of electromagnetic fields carrying a certain amount of energy. With sufficiently sensitive experiments, you can count the number of photons or even conduct measurements on individual photons. Researchers have even temporarily frozen light.
