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).
300 000 kilometers, which equals seven times around the Earth. Let's call this distance one light second. We can use this as a ruler to measure distances in space. Beyond the Sun and its planets we need a longer ruler, which is the distance light travels in one year. This is called a light year - it is 32 million times longer than a light second. Multiplying a light second by the number of seconds in a year, we can answer the question: How far is a light year? 10 trillion kilometers (or more exactly, 9.5 x 1012 km).