by Ann » Thu May 28, 2015 11:41 pm
Many years ago I read a statement somewhere by a popularizer of astronomy that there is no such thing as simultaneity. The popularizer didn't elaborate, but the idea has never quite left me. Your "now" is yours only, because "now" is dependent on spacetime, on location, and only you can be exactly where you are now. Admittedly, on the Earth we are all so close to one another that our collective "now" is for all intents and purposes one and the same. But that is never true for objects that are light-years away, let alone objects that are millions or billions of light-years away. Their "now" doesn't overlap ours in any way. Speculating about their "now" is pointless.
I sometimes think about
Ötzi the Iceman, found frozen and mummified after having died in the Italian Alps some 5,000 years ago. Ötzi has travelled on spaceship Earth for 5,000 years, but he was only alive for the first 45 years of his journey. But those first 45 years of his "existence", when he was alive, are unaccessible to us. Why? Because he lived in a spacetime separate from ours. The Earth was located somewhere else in the Milky Way 5,000 years ago than it is now, and the Milky Way itself was located somewhere else in relation to the other members of the Local Group and the Virgo Cluster than it is now. We can't visit the location where Ötzi was alive. His living "now" is in the Earth's past and completely separate from our "now".
Distant galaxies are even more forever out of our reach. They don't even travel on spaceship Earth, so we can't stumble on them in the ground or in our mountains.
Ann
Many years ago I read a statement somewhere by a popularizer of astronomy that there is no such thing as simultaneity. The popularizer didn't elaborate, but the idea has never quite left me. Your "now" is yours only, because "now" is dependent on spacetime, on location, and only you can be exactly where you are now. Admittedly, on the Earth we are all so close to one another that our collective "now" is for all intents and purposes one and the same. But that is never true for objects that are light-years away, let alone objects that are millions or billions of light-years away. Their "now" doesn't overlap ours in any way. Speculating about their "now" is pointless.
I sometimes think about [url=https://lh3.googleusercontent.com/proxy/KNOZkR7bJNvyfiIfLJfn9WK3L9l0z2EkkWBzmh3w4KJTQOhqSCKkGddCQOUkmAld-jHMXWHvnMuJq-4KWfWHp0g3sGKDI7NYGzUz6u8JwtHvYvhFv_5vFeOFknNNSpZzIEq9BuXJYBlVfxA_U6qgPmkOZdDH9RFpr1iPMMQikpemAUI=w426-h284]Ötzi the Iceman[/url], found frozen and mummified after having died in the Italian Alps some 5,000 years ago. Ötzi has travelled on spaceship Earth for 5,000 years, but he was only alive for the first 45 years of his journey. But those first 45 years of his "existence", when he was alive, are unaccessible to us. Why? Because he lived in a spacetime separate from ours. The Earth was located somewhere else in the Milky Way 5,000 years ago than it is now, and the Milky Way itself was located somewhere else in relation to the other members of the Local Group and the Virgo Cluster than it is now. We can't visit the location where Ötzi was alive. His living "now" is in the Earth's past and completely separate from our "now".
Distant galaxies are even more forever out of our reach. They don't even travel on spaceship Earth, so we can't stumble on them in the ground or in our mountains.
Ann