Why do people accept dark matter and energy so easily?
Isn't it just some hypothetical or imaginary substance created to explain missing mass and rotation velocity to protect the Big Bang model? -- like when Fritz Zwicky was calculating mass of galaxies in the coma cluster he found that it was 160x the expected result. But more recently, Kenneth Nicholson...
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answers:
neb say: One of the prime reasons that dark matter and dark energy are compelling is that the universe is observationallly ‘flat’ - zero curvature at cosmological scales. This requires the average matter/energy density to be at the so called critical density. The amount of observed matter/energy density falls far short of the critical density. The estimated amounts of dark matter and dark energy would bring the matter/energy density to the critical density.
Additionally, as Luca points out, the rate of expansion of the universe is accelerating. Cosmological models of general relativity can explain this if dark energy exists and is associated with a uniform vacuum energy.
The failure of the LHC to find ‘WIMPS’ - supersymmetry particles - that seemed reasonable candidates for dark matter is troubling, not just as an explanation for dark matter but supersymmetry itself. However, remember that dark matter would be difficult to detect if it only interacts with gravity (and possibly the weak force) and may be more massive than assumed (remember that supersymmetry must be a broken symmetry and that it’s mass depends on what breaks the symmetry). Dark energy would also be hard to detect but may explain things like the Casimir effect.
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busterwasmycat say: We accept that there is a major discrepancy between what we can "see" (observe and identify directly) and how the universe would be expected to behave based on that observation. There must be something that is responsible for that difference. The name is "dark" matter and energy. We don't know what those things are, in truth. X is the unknown variable to the equation, and we use the the term "dark" to describe it as a generic idea.
I accept that there is something not right with what we think ought to be and what actually is.
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hoarseman say: Until a better suggestion comes along -- it suits the facts as we see them at the moment .
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paul h say: Dark matter and dark energy are just place holder names for things we have not figured out yet and to hold onto the Big Bang model as long as possible until and if a new model is needed. Another recent discovery is called "Dark Flow" which may make dark energy an illusion....dark matter may be an illusion as well. Are we exchanging one dark thing for another? Other reports claim that the expansion is greater/faster than so-called dark energy can account for so it may indicate the presence of a new particle. Variable Speed of Light (VSL) models/projections may also get rid of dark energy issue and the inflation period conundrum....tests due out in 2019-2020.
All in all, some of the underlying principles or observations we have relied on may need to change and possibly a new model of cosmology. But science would prefer to hold onto an existing BB model of cosmology as long as some or many features of it are fairly reliable. The universe still has many mysteries to solve and we may need to rethink some basic ideas of light speed, shape of the universe and other variables.
"Variable speed of light (VSL) theory. Will The James Webb telescope falsify Big Bang and Dark Energy."
https://www.researchgate.net/publication...
"Cosmic Speed Measurement Suggests Dark Energy Mystery
A new measurement of how fast space is expanding disagrees with estimates based on the early universe, potentially pointing toward a break from the standard model of physics"
https://www.scientificamerican.com/artic...
https://phys.org/news/2014-12-alternativ...
"Theory challenging Einstein's view on speed of light could soon be tested
New paper describes for first time how scientists can test controversial idea that speed of light is not a constant"
https://www.theguardian.com/science/2016/nov/28/theory-challenging-einsteins-view-on-speed-of-light-could-soon-be-tested
"Who Needs Dark Matter? Is The Galactic Rotation Anomaly An Optical Illusion?"
https://principia-scientific.org/who-needs-dark-matter-is-the-galactic-rotation-anomaly-an-optical-illusion/
"The Accelerating Universe and Dark Energy Might Be Illusions"
https://www.livescience.com/33522-accelerating-universe-dark-energy-illusion.html
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Iridflare say: Why do you assume it was easy? Jan Oort first noticed anomolous stellar velocities in the 1920s but assumed his measurements were wrong. Fritz Zwicky realised that the movements of galaxies in the Coma Cluster implied dark matter but was ignored because it wasn't certain that the galaxies were gravitationaly bound, and even if they were, it wasn't certain he was using the right mathematical tool (virial theorem). Vera Rubin, having plotted the flat galaxy rotation curve with Kent Ford, was advised that it would be professional suicide to publish her results! Since then we've got another 50 years worth of observations to support the idea. And then there are the computer models....
Dark energy had the advantage of two independent teams (High Z Group and Supernova Cosmology Project) coming to the same conclusion at almost the same time, but the immediate reaction from a lot of people was that they had to be wrong! Even now not everyone's convinced - maybe early supernovae were different, so we're misinterpreting the data? Maybe we need a new and better theory of gravity? So far dark energy is standing up, but it has to fight its corner, and that's not "easy"!
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Fred say: Easily accepting dark matter and accepting dark matter as an explanation of theory unsupported by known mathematical model are two entirely different concepts!
So tell me Kemosabe? Perhaps you have a better explanation?
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CarolOklaNola say: The use of the word "dark" in science means " we do not know or understand."
It does NOT mean "we made this up intentionally to confuse the general public." The scientists are confused as you are. The difference is the other scientists are still curious while YOU have probably given up or resorted to provoking and insulting scientists who know it is a waste of their valuable time to respond.
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Luca say: Dark energy is just a name for something we have no clue about. There's something that is making the universe expand faster and faster and we call this dark energy, we have all rights to call this however we feel like.
Dark matter on the other hand is more understood. The thing to understand here is that physicists aren't crazy, if they keep proposing dark matter it's because it's the simpliest and best way to describe the observed results as of today (not only in the galactic rotation, there are many other examples in which dark matter is needed to fix the model).
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say: Because the idea sounds cool and dangerous probably like black holes.
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Roman say: silly
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