Just that. Is there any relationship between the two? Does one create the other?
Does this discovery really screw up our concept of the Universe?
Your linking 2 different things.
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Dark Matter - basically stuff we can’t see, or at least can only infer by how it interacts gravitationally with matter. Covers a whack load of different possible sources. Clumps together
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Dark Energy - very weird stuff we only infer from the progressively increasing rate of expansion of the universe. No idea what it is but it seems to be pushing the universe apart
We don’t know what these things are but we do observe their effects. The names are simply blanket statements or place keepers until we figure out what they are.
In a sense, they are the opposite of each other. Dark Matter creates the gravitational force that holds galaxies together, and Dark Energy creates the expansion that is pulling everything apart.
While we cannot see Dark Energy or Dark Matter, the “Dark” doesn’t refer to their visibility, but rather to the fact that we don’t really know what they actually are.
Actually Dark Matter is called dark matter because it seems to not interact electromagnetically - in other words it is dark.
Dark Matter also does not create the gravitational force that hold galaxies together, it seems to influence their spin rates. This tends to be the point the MOND people start jumping up and down but the fact is galaxies are sufficiently massive to hold themselves together.
Most of the mass of galaxies appears to be dark matter, galaxies would not have formed in the first place without dark matter, and stars moving at the same speed in a galaxy without dark matter as in one with it would not be gravitationally bound. I see no way to quibble with the statement that dark matter creates the gravitational force that holds galaxies together.
And to get back to the OP, a significant chunk of the dark matter is stuff that we don’t have a clue what it is, and we’re worse than clueless about what the dark energy is. So the only honest answer to your question is “I dunno”.
Just to address this question specifically, both are placeholders for things we think exist but don’t understand very well yet. We created those placeholders because our current understanding of the universe requires them. So it’s just the opposite: if either doesn’t exist, our accounting will come out wrong, and there’s a flaw in our current understanding of the universe. They don’t screw up our concept of the universe; instead, they keep it from being screwed up.
Thanks for the comments, all. When (if ever) do you think we’ll discover what they really are?
So is the current model stating that dark matter seeded galaxy formation? I thought that was tied back to variations in the CMB, which since they’re visible in the EM spectrum wouldn`t be linked to dark matter.
The variations in the CMB were themselves seeded by dark matter.
Folks are always coming up with ideas for experiments to detect dark matter particles, and whenever a particle physicist comes up with some new hypothetical particle, there’s talk that it might be what the dark matter’s made of. We can’t say when it’ll be discovered without knowing what it is (different experiments would detect different sorts of particles), but somewhere within a decade or three probably isn’t too bad a bet.
Dark energy, though, we really don’t even know where to start. Our current state of knowledge of dark energy is such that we don’t really even know what the important questions are to ask about it. We know pretty well how strong it is, and we’re starting to get some clue about how its strength has changed in time, but that’s absolutely it. There will probably have to be some theoretical breakthrough before we can even start designing the next experiments, and it’s always hard to predict breakthroughs.
There is no need or evidence for dark matter - it is just speculation/assumption that Newton’s law of gravity is also valid outside our solar system. Gravity itself is dark and is only observed by its action on visible objects (apples).
When attempts are made to validate/apply Newton’s law for observations at cosmic distances it fails unless vast amounts of invisible/dark matter is invoked.
This was the case of the observations by Vera Rubin of the unexpected flat/constant rotations of stars in spiral galaxies. Dark matter was used as an explanation. The earlier observations of Fritz Zwicky for the motion of groups of galaxies could only be explained by vast amounts of missing matter to supply the necessary gravity.
Actually the observations of V. Rubin plus the equations for outward rotational force (centrifugal) and the inward gravitational force gave a basic balancing equation: MG=rvv which for the observed constnt velovity v reduced to MG as a liner function of distance at galactic distances for r.
Rather than assigning the linear dependence to the mass requiring dark matter, it is more logical to assign the linear term to gravity which is already invisible. Thus no need for the mystery of Dark matter.
Details are provided in a recent collection of essays in “The Misunderstood Universe” by Sol Aisenberg, PhD
Also known as MOND - it’s not as if that’s a secret.
How do they tell what came first?
Dark Matter has been covered to the best of my knowledge on the subject, so I’ll talk a little about what I know of Dark Energy. I’m no professional, just a hobbyist, so I might get some technical things wrong.
We’ve been aware since the 1920s that the other galaxies in general appear to be traveling away from us due to the shifting of spectral lines towards the red. This generally means via the Doppler effect that the source is traveling away from us, with speed proportional to the shift. Hubble (the guy, not the telescope) was able to quantify these shifts and using other data that suggested the galaxies’ distances from us, determined that the further away a galaxy was, the more it was redshifted and the relationship was pretty much linear. This seems wrong if the galaxies were actually moving like that, as it would imply that we were the center of an expansion that has linearly slowed down through the history of the universe. It does make sense if instead the fabric of space itself is expanding, causing the distance between the waves of light to steadily increase as they travel through intergalactic space.
So eventually we got enough data and enough other ways to measure the distance of things accurately, and we find out that not only is space expanding, but apparently the trend is that the expansion is speeding up. Something is causing space itself to expand at an ever faster rate. Some quantum theories propose a “cosmological constant” that might account for this somehow, but it’s on the order of 10^120 too large. Juuuuust a bit off.
We have absolutely no idea what is causing the accelerated expansion of space, but it permeates the universe and if considered an actual source of energy would be something like 70% of the energy of the universe (assuming all massive matter is reckoned by its energy content).
That’s what I meant when I said that we’re worse than clueless about dark energy: We have a clue, but it’s so absurdly horribly incredibly ludicrously off (an understatement, because I ran out of adverbs) that we’d probably have a better understanding if we didn’t have a clue.
“dark matter” is another name for quantum particles
“dark energy” is the spin of the aether whirlwind
O yes in deed allison wonderland
gravity is the drag of the aether wind
hydrogen.101
center a marble inside a Coliseum
the space between center and boundary is filled with atomic particles
condense this Coliseum to the size of a hydrogen atom
the space between center and boundary is filled with quantum particles
quantum.gravity.101
drill a hole connected to the most perfect vacuum
in side the center of an icy hockey rink
the space between hole and boundary is filled with atomic matter
expand this rink to the size of a galaxy
the space between hole and boundary is filled with quantum matter
quark.quark.quark.nucleon.101
replace the marble with three singlar black holes
meshed together by strong matter
two up one down means the walls will stand
two down one up means walls come a tumblin’ down
Dark matter is another Name for quantum particles. Dark energy is another name for topspin.
To measure the relative drag of the ‘dark matter’ wind; stand on a scale and look up.
peace
ron
truth goes through three cycles
now is a good time to pass over
the first two
Wow.
LOL. The first cycle is insult.
If you have a better answer; now is a good time to offer.
peace
ron
`Twas brillig, and the slithy toves
Did gyre and gimble in the wabe:
All mimsy were the borogoves,
And the mome raths outgrabe.
There are a lot of things in physics that don’t really neatly fit into a simple account of how the universe works:
I consider dark matter, dark energy, and cosmic inflation all to be fudges. Physics explains nearly all the phenomena that we can observe, but there are various little anomalies that don’t quite fit. We can invent fudges to explain them, but each one makes the overall theory a little more complicated. I presume that eventually someone will show that there is clearer, neater way of explaining everything, but it’s going to take a while.
Wait, Jabberwocky is the second cycle; I’m still stuck on the first cycle.
How do you figure?