What is the exact date for Earth Day in 2010?

Space time, earth time, aging in earth versus space.?

• there should not be age difference between 2 twins space twin or earth twin.. we are talking about absolute age. Age will be decided by absolute age or absolute time not by relative time. the absolute age should be same for both twins. wherever one of the twins goes in the space we will be comparing him with our earth time reference. means if the twin is traveling in the space at whatever speed or wherever he is, 1 day on earth will be same 1 day for him. when the earth twin ages by one year the space twin also has to age by one year. Because we are comparing with our earth time. it is absolute for us. Means when we spend one day on our earth, throughout the infinite universe it will be only one day. wherever the twin spends that time he can only have one earth day. Now the space twin may develop physiological changes unique to space and speed travel etc and this might produce 3 possibilities; he will live longer; he will live shorter, or he will live as long the other twin ( other biasing factors should be eliminated ). This is not equivalent to age change. If space twin will live longer- how does it make him younger than the earth twin???? when earth twin spent 1 year for example on earth the space twin also has spent only 1 year in the space. so the absolute age is same for both. so even if the space twin will live longer he still will be of the same age as the earth twin. For example- If the space twin leaves earth on 7/2/2006 and goes to alpha centaury at light speed he will reach that star system around 7/2/2010 ( approximate ) - then returns to earth after another 4 years on 7/2/2014- so total about 8 years- now what will happen? when the space twin returns on that day of 2014 for both twins it will be same date. And both twins have lived in this universe for 14 years. Implying both are aging by 14 years ahead. because we cannot change the absolute time. It has been fixed for the whole universe.. now the perception of time may be different for the twins. the space twin will have a so called normal disorientation of time ( I will call normal because it is appropriate for the situation ). He might lose the concept or sense of earth time and might feel he has only spent short period of time instead of 14 years as experienced by the earth twin. But that is in his mind only and it is an altered perception, but in reality he and his and his earth twin both have lived for exactly 14 years. To make it further simple; let the space twin carry a clock with him. Let him frequently look at it. This will reduce the disorientation for time and will keep him attached to earth time. He will feel he spent 14 years on space travel when the earth twin also spends 14 years on the earth. Absolute time is all important and it will be same. Means both will age same. However one of the twins possibly the space twin ( although not sure ) may live longer. And it should be considered as “ the space twin lives longer rather than he became younger and lived longer“ In effect he has lived all those days lived by his earth twin + additional days he lives secondary to space travel advantage.

• Answer:

  You misunderstand the scenario set up in this problem. It is not space time versus earthtime. It is time of observer at rest, and time of observee in motion. The dialation of time is dependent on the velocity the moving person is going. The closer to the speed of light, the more time is dilated. Now, this dialtion of time affects half-lives of particles, faster moving particles decay at different rates then slower moving particles. This is proven experimentaly. Our aging process is a chemical process dependant on the chemical reactions in our bodies. We know that time dilation affects these kinds of reactions, so along with the clock on the fast moving ship moving at a different rate, the person next to the clock will also age differently. There is no absolute time. (OHH time doesn't stop at light speed, We have NO FRIGGIN CLUE, what happens hahaha)