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).
Light years are a measure of distance, based on how far light can travel through a vacuum in one Earth year. So if you hear someone say that a star system is 4,000,000,000 light years away, they arenât giving an idea of how many Earth years it would take to get there.