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Scientists Capture First Image of Dark Matter Web (inhabitat.com)
Kristine Lofgren writes: Scientists have long suspected that the universe is woven together by a vast cosmic connector but, until now, they couldn't prove it. Now, for the first time ever, scientists have captured an image of a dark matter bridge, confirming the theory that galaxies are held together by a cosmic web. Using a technique called weak gravitational lensing, researchers were able to identify distortions of distant galaxies as they are influenced by a large, unseen mass -- in this case, a web of dark matter. In order to create a composite image that shows the dark matter web, scientists had to look at more than 23,000 galaxy pairs located 4.5 billion light-years away. "Results show the dark matter filament bridge is strongest between systems less than 40 million light years apart," reports Phys.Org. The findings have been published in the journal Monthly Notices of the Royal Astronomical Society.
From TFA, "...researchers were able to identify distortions of distant galaxies as they are influenced by a large, unseen mass, such as dark matter." That means that what they have are images that appear to imply the existence of Dark Matter, and are hard to explain any other way, not that the images actually show us Dark Matter. That doesn't mean that it doesn't demonstrate that Dark Matter exists, it's just that the images aren't as cut and dried as the article's headline implied. It also means that there's still wiggle room for those who are certain that it doesn't exist. Still, it's a great step in the right direction.
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Here, let me correct that:
Scientists Manufacture First Visual Representation of Gravitational Anomalies Inconsistent With Observed Matter
There has never been what I would consider "evidence" of dark matter, just evidence of a lack of understanding of matter, gravity, or space.
In the Einstein universe, are they (matter & energy) not simply different states of the same thing?
Yes if one isn't being super pedantic. Your "states" analogy is reasonable. To say matter and energy are the same thing isn't exactly accurate but it's good enough for all but the most picky of purposes. But applying that relationship to so called dark matter and dark energy is a little bit fraught because we don't actually know what dark matter and dark energy are. As a result you are understandably conflating some things.
The terms "dark matter" and "dark energy" are sort of placeholder terms to explain some phenomena that we don't entirely understand yet and they are more marketing terms than precise terms of art. We don't actually know for certain that what we call "dark matter" is actually matter or that "dark energy" is actually energy. We just have some observations we haven't been able to adequately explain so we needed some short hand terms to explain what we are seeing in terms of the models we have. One of three things is happening. Either we are seeing something new, we are making measurement errors, or our models are wrong. Possibly some combination of all three.
Dark matter arises out of the fact that we see some observations that don't make sense based on the amount of baryonic ("normal") matter we can quantify. Our models of how gravity works tell us that for our observations to match our models there must be a lot more matter than we can see presuming our models are correct. So called dark energy arises out of our observations and measurements of the rate of expansion of the universe but it's even less well understood than dark matter.
Being that mass and energy rarely appear separately, would not the presence of 'dark energy' strongly infer the existence of 'dark matter'?
Mass is not the same thing as matter. You can have matter without mass such as with a photon. Mass is a property in some forms of matter, all of which move slower than c (the speed of light).
but i thought the movement of galaxies WAS the expansion of the universe.
The movement of the galaxies can help us measure and observe the expansion of the universe but isn't the expansion itself. To use a simpler example, imagine a galaxy is an ant and that ant is standing on the surface of a balloon. The ant can walk around the balloon which is equivalent to the galaxies moving through space. Now inflate the balloon. The ant is moved because space (the balloon surface in this example) became larger but it wasn't because the ant itself moved. What happened is space expanded and everything in space moves a bit further apart as a result. But those objects in space (ants) are still free to move through space so the expansion of space doesn't explain everything we see by itself.
What we see is the galaxies moving (mostly) away from each other through space AND we see space expanding because they are moving away from each other faster than can be explained by simple movement through space. Space can expand faster than the speed of light because c is only the speed limit for matter moving through space. Space itself can expand arbitrarily fast as far as we know.