The Aurora Borealis, or the northern lights, is an optical phenomenon that occurs in the sky in the northern locations of the world. Examples would be Alaska, Norway, Yukon, Newfoundland and other parts of northern Canada and the world. This majestic view is adored by many and brings a lot people to the northern locations of the globes to see the sky change colour which doesn't happen everywhere. Economically, this can help create tourist attractions in places such as Whitehorse, Yukon and keep the cities managed with the money made. How does such a sight occur scientifically? Well, the centre of the earth has hot iron inside of it, this creates magnetic fields around the earth which are weakest in the north and the south of the globe. The charged electrons and ions from the sun come to these weak points through solar wind. Solar wind is the stream of particles that are charged from the sun that travel around the solar system. The electrons transfer energy to the nitrogen atoms that lie in the atmosphere and excites them. This connects to the energy and matter OLG since energy is being transferred and the northern lights are matter that can be seen by us ... which makes it an optical phenomena. The way these atoms "calm down" is by releasing energy in the form of photons which is the light which we see in the northern lights. The colour will depend on the nitrogen and oxygen and the altitude of the atmosphere. These colours can range from green-yellows, blues and even pinks and purples!
A mirage is an optical phenomenon or illusion that make you think something is in front of you, but it's not. This can be natural occurring, and very common in hot places such as a dessert. An example of a mirage would be if a person sees a pool of water in the dessert that is not really there. This is not imagined or a result of drugs ... but there's a scientific explanation to explain these visuals!
A refraction phenomenon wherein an image of some distant object is made to appear displaced from its true position because of large vertical density variations near the surface; the image may appear distorted, inverted or wavering
- American Meteorological Society’s Glossary of Weather and Climate
What is refraction? Refraction is when the light wave passes through a different (slower) medium and bends. The amount of the bend differs on the material that the light hits. If you go to the ocean and see fish swimming below you, it appears to be in a different place than it is in reality. This is due to light refraction.
This is an example of a mirage on sea
Basically, this is caused by the bending of light. A mirage can happens when the earth's surface is hot and the light from a distant object is refracted ; this makes the object appear closer than it really is. This can also happen when the air above the ocean is warmer than the cool air above the water.
Not all mirages have to be natural. You can even make your own mirage. The example used in class included a concave mirror used to make a mirage or hologram. The image of the object was shown above the mirror, reflected backwards, when the object was actually underneath.
Concave Lens Ray Diagram. The arrow is where the object actually is, the bold dot captioned "virtual image" is when the image appears to be. This is just one example of how a concave lens works.