I vaguely recall seeing something along those lines, but couldn't remember the numbers.
Physics Spacetime - How does it work?
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RupieDupie
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I’ve been thinking of this topic in the God thread, and someone pointed out it’s probably better to have this conversation in the Science forum. Here’s some background;
From what I understand in the last 30 years scientists have been trying to find dark matter and from what I understand the search has, so far, been futile. As a result scientists are considering, for example, modified gravity to account for the observations.
Dark Matter was first hypothesised from the observation that outer galaxies rotated faster than predicted from their common centre of mass.
(And subsequently the outer edges of a galaxy were found to do the same, that is the outer part of the galaxy was observed to rotate at a similar rate as the inner part of the galaxy - where from their calculated visible mass the inner part of the galaxy should rotate faster or alternatively the outer galaxy was rotating faster than expected)
The conclusion was that there was, for example, a Dark Matter halo helping keep the outer galaxy from spinning off into space.
From this, several other observations have been made which support the hypothesised Dark Matter.
What does this have to do with time dilation?
Say if we take this rotating galaxy observation, could it not be that the light from the rotating galaxy, when we measure it, is also time dilated relative to the calculated mass.
That is, the inner galaxy appears to be travelling at the same velocity as the outer galaxy as an optical illusion because light takes longer (Shapiro effect) to reach us from the inner galaxy relative to the outer galaxy, so it is like we are watching a movie of the inner galaxy being played in slow motion.
Could it be that it’s not that the outer galaxy is travelling faster than what it should be, but that the inner galaxy appears to be travelling slower due to time dilation? Removing the need for Dark Matter, and only requiring The General Theory of Relativity.
From what I understand in the last 30 years scientists have been trying to find dark matter and from what I understand the search has, so far, been futile. As a result scientists are considering, for example, modified gravity to account for the observations.
Dark Matter was first hypothesised from the observation that outer galaxies rotated faster than predicted from their common centre of mass.
(And subsequently the outer edges of a galaxy were found to do the same, that is the outer part of the galaxy was observed to rotate at a similar rate as the inner part of the galaxy - where from their calculated visible mass the inner part of the galaxy should rotate faster or alternatively the outer galaxy was rotating faster than expected)
The conclusion was that there was, for example, a Dark Matter halo helping keep the outer galaxy from spinning off into space.
From this, several other observations have been made which support the hypothesised Dark Matter.
What does this have to do with time dilation?
Say if we take this rotating galaxy observation, could it not be that the light from the rotating galaxy, when we measure it, is also time dilated relative to the calculated mass.
That is, the inner galaxy appears to be travelling at the same velocity as the outer galaxy as an optical illusion because light takes longer (Shapiro effect) to reach us from the inner galaxy relative to the outer galaxy, so it is like we are watching a movie of the inner galaxy being played in slow motion.
Could it be that it’s not that the outer galaxy is travelling faster than what it should be, but that the inner galaxy appears to be travelling slower due to time dilation? Removing the need for Dark Matter, and only requiring The General Theory of Relativity.
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Freofalcon
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More evidence of spacetime warping under extreme gravitation -
www.abc.net.au
Space-warping stars prove Einstein was right. Again
Astronomers have discovered a spinning star dragging the very fabric of spacetime at the centre of a unique cosmic laboratory they've been tracking for 20 years using the Parkes radio telescope.
www.abc.net.au
