text: what is the length and duration of one revolution of the sun around the center of the milkyway galixy? i am trying to calculate the distance traveled (in light years) for a 46 year old person at 38 north latitude. including the rotation of earth , orbit around the sun and the suns revolution around the center of the milkyway. i don't think i can go farther than that as i don't beleve there is a center to the universe the galixys travel could be measured aginst. mike firstly, the milky way is in a galatic cluster, and that is in a super cluster.  (there's a lot of gravity out there.)  but those structures are too far away to detect sideway movement, only towards or away.  also, their motion is highly relativistic.  so galaxy is a natural place to stop.  the first figure will probably be within the margin of error for the second and third.  so, as i check wikipedia, i see that the sun is orbitting the galaxy at a rate of 217 kilometer per second and the earth is rotating around the sun at 29.783 km/s.  so, this person has traveled somewhere in excess (depending on how many seconds more than 46 years old they are) of 358,242,443,236.8 kilometers, or 222,468,557,250.0528 miles.    also, just as a comment, there is no "point" of the big bang.  it happened to the entire universe at once.  it's all expanding everywhere.