[1] https://www.youtube.com/watch?v=PL0ewiwqoTw&t=4m5s

I would hesitate leaning too much on the always part. Fritz Zwicky was the first to notice the anomalous galaxy rotation curves and propose dark matter (is the story that I remember, anyway.) This is probably why it's presented first. It does not mean that it's the most important piece of evidence.

I'm intentionally writing with a light touch here because I don't consider myself an expert in the field.

It's been a long time since then and there's been a ton more data collected about wide ranging phenomenon since.

There have been papers published on this, but it is still speculative, so it's premature to say that this kind of alternative theory rules out dark matter.

No, it only eliminates the need for Dark Matter to explain galaxy rotation curves.

> In physics, a tachyonic field, or simply tachyon, is a quantum field with an imaginary mass.

The term tachyon was coined by Gerald Feinberg in a 1967 paper titled "Possibility of faster-than-light particles". He had been inspired by the science-fiction story "Beep" by James Blish.“

I don’t think “Beep” introduced the word, though (https://archive.org/details/galaxymagazine-1954-02)

There are some reasons to suspect/hope such things might not exist, such as protecting causality.

In general, asking "what if <simple field type> was <more complex field type>" can actually produce super fruitful lines of inquiry. You can use "complex numbers", "quaternions", "finite fields", whatever you like. There's plenty of unexplored ground here.

I'm not aware of a mechanism by which causality would arise from known QM, so I wouldn't expect a priori planck scale to play into it. There would also need to be an energy term for h to make sense as the relevant constant.

The most compelling source of temporal direction I'm familiar with is that it's a regional cosmological entropy gradient rather than a fundamental aspect of physics, although it strikes me as suspicious that the time direction lies inside the 4-cone generated by the odd-dimension-out in our spacetime metric. That certainly lends some credence to theories which would predict the direction of time as fundamental to physics.

My guess is that it falls back to Occam's Razor and there has yet to be any physics to use it thus it isn't a serious contender for current problems until much more work has been done on all the threads already being followed.

Dark matter could be a neighboring universe interacting with ours or something like that where the actual particle causing it is fundamentally out of reach (if it even is a particle), but just the fact that it interacts with our universe means we should in principle be able to interact with it and characterize it with experiments.

"Dark" matter refers to something that does not interact at all with photons - not that it scatters too little light.

In scientific study you want and need failure. Knowing what doesn't work is as important as knowing what does. This way we can make lists of dangerous or useless things to be avoided. As long as things are documented and reproducible to the best of your abilities, you've won.

    In 1999, the Nobel prize winning physicist Philip Warren Anderson said he is "sure that it's a fraud",[12] and in the same year another Nobel prize winning physicist, Steven Chu, called it "extremely unlikely".[23] The following year, a 2000 patent based on its hydrino-related technology[24][25] was later withdrawn by the United States Patent and Trademark Office (USPTO) due to contradictions with known physics laws and other concerns about the viability of the described processes, citing Park and others.[26]

Every submission you've made seems to be about this company (https://news.ycombinator.com/submitted?id=dave333).