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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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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).