1 Massage the twitch muscle with your finger for 15 seconds. 2  Usually there are other muscles that twitch like leg cramps, so take 500mg of magnesium citrate capsule daily. 3  If you have headaches, massage the knot at the back of your neck for release.
Â­So to measure really long distances, people use a unit called a light year. Light travels at 186,000 miles per second (300,000 kilometers per second). Therefore, a light second is 186,000 miles (300,000 kilometers).
So if the Universe is now 13.7 billion years old, light can only have traveled a distance of 13.7 billion light-years since the beginning of time. Thus, the part of the Universe we can observe (the Visible Universe) lies within a sphere with a radius of 13.7 billion light years centered around the Earth. We can only observe 13.7 billion light years of the Universe. [2.10a] Down the Rabbit Hole: Olbers' Paradox.