- #1
DaveC426913
Gold Member
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No matter how much I shed light on it, there's always some dark corners of relativity into which I have trouble seeing.
In a recent book I read, a starship with continuous acceleration approaches c to within many decimal places, creating a collosal time dilation - enough for the universe to age during a passenger's journey. Nevermind the implausibility, let's look at this as a thought experiment.
1] What does the passenger see when they look out the window? Specifically, they see time dilation of the universe (which is always reciprocal). They see time passing very slowly - the stars and galaxies will appear frozen. How is this reconciled with the fact that the universe is aging very fast?
Is it because the moment they decelerate, the universe will rapidly age until it matches their predictions?
I can't help but wonder if there is something in there about approaching versus receding - akin to a relativistic rocket receding from Earth, then turning around and approaching Earth. Is it possible they will see a rapidly aging universe looking ahead but a frozen one looking behind?2] Space will be highly compressed in the direction of their motion. Stars ahead will be flattened and close together. Is this also true looking behind? Will stars be flattened and close together in their rear view mirror? But not to the side. To the side, stars will be normally-shaped and normal distance.
In a recent book I read, a starship with continuous acceleration approaches c to within many decimal places, creating a collosal time dilation - enough for the universe to age during a passenger's journey. Nevermind the implausibility, let's look at this as a thought experiment.
1] What does the passenger see when they look out the window? Specifically, they see time dilation of the universe (which is always reciprocal). They see time passing very slowly - the stars and galaxies will appear frozen. How is this reconciled with the fact that the universe is aging very fast?
Is it because the moment they decelerate, the universe will rapidly age until it matches their predictions?
I can't help but wonder if there is something in there about approaching versus receding - akin to a relativistic rocket receding from Earth, then turning around and approaching Earth. Is it possible they will see a rapidly aging universe looking ahead but a frozen one looking behind?2] Space will be highly compressed in the direction of their motion. Stars ahead will be flattened and close together. Is this also true looking behind? Will stars be flattened and close together in their rear view mirror? But not to the side. To the side, stars will be normally-shaped and normal distance.