Sunshine: Seeing Things in an Old Light

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Light travels very quickly, about 30 million metres per second, but that is only when traveling through a vacuum. Now we know how fast light is let us get some figures of relative relevance. If you were to perform the calculations you would find that light takes all of eight minutes to get from the sun to the earth.

That is 150 million kilometres in not very long at all, that is however, far from the full story. Light is not made on the surface of the sun, instead it emerges from the core of the sun, which is a little bit further.

Using the previous figures we find that is should only take an extra 3 seconds to escape the sun and head for earth, unfortunately light doesn’t always travel at light speed. It slows down occasionally, especially when it hits stuff. Unfortunately for the little rays of light the sun happens to be made of stuff. This changes the whole deal rather substantially.

Light hits a great deal of sun stuff on its way out, and it interacts. The sun is made of gases, but in such a concentration the materials are not exactly light. These atoms collide with the light, interacting with it.

All of this interaction slows the light, makes it meander off course and take a very long route to reach the sun’s surface. In fact rather than taking 3 or even 42 seconds, it takes time on a wholly different scale of measurement.

170,000 years. The light is slowed down to such a degree that it takes a total of 170,000 years and around 8 minutes for light to reach us on earth from the time of its creation. So make sure to fully enjoy the sun’s light, you will be the only person ever to see that light, and it has had a rather long journey.

Note: Mostly Odd does not recommend staring directly at the sun, it is very pretty but please do not do it without special equipment. It is dangerous and not a bright idea by anyone’s standard.

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Deployed on by Alexandre Coates in Macro Oddities Leave a message?

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