Because we're creating a 95% confidence interval, this means we have two tails of 2.5%. When we look up 0.025 in the Z table (click to open) , we find that it corresponds to a z-score of 1.96. After plugging everything into the equation, we find a lower bound of 480.8 and an upper bound of 559.2.
As already noted, the speed of light (expressed in meters per second) means that light travels a distance of 9,460,528,000,000 km (or 5,878,499,817,000 miles) in a single year. This distance is known as a âlight yearâ, and is used to measure objects in the Universe that are at a considerable distances from us.
I did a bit of a calculation and came up with this, I hope I got it right. Light travels 9,454,254,955,488 Km per year. Spacecraft travels at around 50,000 Km per hour 438,000,000 Km per year. Just over 21,585 years to cover the distance. Here's some refs. for a bit of thought.