Between the often repeated forecast of Albert Einstein's famous theory of relativity is that if a twin travels through the space on a high-speed rocket, when he returns to world he will be evidently younger than the twin who lived home.
According to a report in Friday's edition of the journal Science currently physicists have verified that the same is true even if the traveling twin is simply driving in a car about 20 mph. however at that time, when the twin gets home from the grocery store, he is only a little nanosecond fraction younger.
The reverse is repeatedly said to be true for a twin who spends time far above the ground on a mountaintop; general relativity foretells that at greater altitudes time passes more quickly as things don't feel Earth's gravity quite as strongly. Although the physicists found that a twin who lives just about a foot above sea level will grow old ever-so-slightly faster than a twin living at sea level.
But the relativity rules are always in force, yet over the minimum distances and at the slowest speeds. The variation is that the result is infinitesimally small.