I’ve noticed that there are bubble-like voids between galaxy clusters.
If dark matter and dark energy are in fact two halves of the same coin, could it be stated that dark matter collects more dark matter…gravity…and dark energy generates more dark energy…some kind of spacio-genesis?
We have no particular reason to believe this to be true, as the only thing they have in common, in our current understanding, is that we know so little about either. But there are plenty of things that we know little about, so it’s not all that remarkable a coincidence.
These are actually both true, or at least approximately so, though I rather suspect that that’s an accident. Dark matter is matter and has gravity, and so it’ll attract other matter (of all sorts). Clumps of dark matter will attract more dark matter, and will also attract baryonic matter, and likewise baryonic matter will attract both more baryonic and dark.
Meanwhile, dark energy, so far as we can tell, has a constant density in space, regardless of the expansion (or contraction) of space. And it causes the Universe to expand. As the Universe expands, one could say that “more space is created”, and since that space is just as full of dark energy as anywhere (and anywhen) else in the Universe, there’s more dark energy, too.
The voids you see don’t really have much to do with dark energy: Since it’s inherently uniform, it won’t cause clumping. Matter (of any sort) will, though. And though any kind of matter works for this, there’s a lot more dark matter, so it’s responsible for most of the clumping. The voids are just places where there isn’t a clump.
We have no particular reason to believe this to be true, as the only thing they have in common, in our current understanding, is that we know so little about either. But there are plenty of things that we know little about, so it’s not all that remarkable a coincidence.
These are actually both true, or at least approximately so, though I rather suspect that that’s an accident. Dark matter is matter and has gravity, and so it’ll attract other matter (of all sorts). Clumps of dark matter will attract more dark matter, and will also attract baryonic matter, and likewise baryonic matter will attract both more baryonic and dark.
Meanwhile, dark energy, so far as we can tell, has a constant density in space, regardless of the expansion (or contraction) of space. And it causes the Universe to expand. As the Universe expands, one could say that “more space is created”, and since that space is just as full of dark energy as anywhere (and anywhen) else in the Universe, there’s more dark energy, too.
The voids you see don’t really have much to do with dark energy: Since it’s inherently uniform, it won’t cause clumping. Matter (of any sort) will, though. And though any kind of matter works for this, there’s a lot more dark matter, so it’s responsible for most of the clumping. The voids are just places where there isn’t a clump.
Whatever the form of dark energy (i.e. quintessence, cosmological constant, phantom energy), if you have a region where dark energy dominates that region expands and the the total dark energy in that region increases. I suppose that could be described as generating more dark energy.
When studying the accumulation of matter on large scales, there’s no reason to distinguish between cold dark matter and normal visible matter, except to say that CDM makes up the majority of matter. Whether the matter density of a region increases or not is a more complicated question as it involves perturbation theory, but it is true that if a region is dense enough its density will increase until it collapses and becomes gravitationally bound.
And except that the visible matter is a lot easier to study, being, well, visible. And there’s also the matter that dark matter probably has a lot less self-interaction than visible matter, which makes certain kinds of clumping less likely.
