Does light always travel at the same speed in space away from our atmosphere?
The speed of light in a vacuum is a constant; this is taken as a standard and is even used to determine the length of a meter. According to Wikipedia: http://en.wikipedia.org/wiki/Speed_of_Li… “In metric units, c is exactly 299,792,458 metres per second (1,079,252,848.8 km/h).[2] The fundamental SI unit of length, the metre, has been defined since October 21, 1983, as the distance light travels in a vacuum in 1/299,792,458 of a second; any increase in the precision of the measurement of the speed of light would refine the definition of the metre, but not alter the numerical value of c. The approximate value of 3×108 m/s is commonly used in rough estimates. In imperial units, the speed of light is 983, 571, 056 feet per second, which is about 186,282.397 miles per second, or roughly one foot per nanosecond. The speed of light when it passes through a transparent or trans
Atmosphere doesn’t change the ‘speed’ of light any more than vacuum does. The ‘speed of light’ is a ‘constant’ … according to some, if we could travel ‘close to’ the speed of light, our ‘aging’ would slow down, so that ‘thousands of years’ would pass in ‘real time’ but we would still be ‘young’ when we got to the ‘other side of our galaxy.’ No one really ‘knows’ what would happen, though, since NOTHING can come anywhere NEAR the speed of light thus far.
If you are referring to light transmitted from earth by artificial means or reflected, yes it does. 186000miles per second. There is a theory that if we look into space and find light that is bouncing off another source and that source is smooth enough like a mirror then we could look back in time! The light reflecting off the earth would travel threw space for many light years, bounce back at us and if we could intercept that echo with a powerful enough telescope we could see what went on decades and even centuries ago. If sounds pretty wild but it is theoretically possible! Pretty cool stuff!
The speed of light is always constant. It may seem slower because of all the particles in the air and the (very~tiny) amount of time it may take for absorption and release through some objects or reflection, but the speed of light itself is the same. Being any faster is impossible, and if it were any slower, the energy would dissipate.
