One year is counted as 31557600 seconds 365 14 days. Refraction occurs when a beam of light bends at the surface boundary between air and the object that it passes through. Even if the vacuum is inside a box in a rocket traveling away from earth both an astronaut in the rocket and a hypothetical observer on earth will measure the speed of light moving through that box to be exactly c.
The refraction occurs at the boundary and is caused by a change in the speed of the light wave upon crossing the boundary.
The refractive index of an object is the ratio of the speed of light in a vacuum to the speed of light in the object. Online metal weight calculator which helps to calculate the weight of Plastic Sheet metal. This vacuum speed of light c is what the statements from relativity describeWhenever light is in a vacuum its speed has that exact value no matter who measures it. The refraction occurs at the boundary and is caused by a change in the speed of the light wave upon crossing the boundary.