Universal galaxy acceleration curve described by visible matter.
https://phys.org/news/2017-02-team-radial-common-galaxies.html
Neat.
But I think that much of the argument for the presence of dark matter (and dark energy) is related to the behavior of "galaxy clusters" and even larger features. Dunno if these findings have any impact on those things.
Cheers,
Scott.
(Who wonders if dark matter and dark energy end up being dead ends, and the observed deviations from expected behavior are instead due to a combination of unknown physics and error bars.)
The researchers found that in 153 spiral and irregular galaxies, 25 ellipticals and lenticulars, and 62 dwarf spheroidals, the observed acceleration tightly correlates with the gravitational acceleration expected from visible mass.
Observed deviations from this correlation are not related to any specific galaxy property but completely random and consistent with measurement errors, the team found.
The tightness of this relation is difficult to understand in terms of dark matter as it's currently understood, the researchers said.
It also challenges the current understanding of galaxy formation and evolution, in which many random processes such as galaxy mergers and interactions, inflows and outflows of gas, star formation and supernovas, occur at the same time.
"Regularity must somehow emerge from this chaos," Lelli said.
[...]
Nevertheless, the growing proof of the relation, or natural law, requires new thinking about dark matter and gravity, the researchers said.
"Within the standard dark-matter paradigm, this law implies that the visible matter and the dark matter must be tightly coupled in galaxies at a local level and independently on global properties. They must know about each other," Lelli said.
"Within alternative models like modified gravity, this law represents a key empirical constraint and may guide theoretical physicists to build some appropriate mathematical extension of Einstein's General Relativity."
The team's research so far has focused on galaxies in the nearby universe. Lelli and his colleagues plan to test the relation in more distant galaxies, just a few billion years after the big bang. They are hoping to learn whether the same relation holds during the lifetime of the Universe.
[...]
Neat.
But I think that much of the argument for the presence of dark matter (and dark energy) is related to the behavior of "galaxy clusters" and even larger features. Dunno if these findings have any impact on those things.
Cheers,
Scott.
(Who wonders if dark matter and dark energy end up being dead ends, and the observed deviations from expected behavior are instead due to a combination of unknown physics and error bars.)
