@ManchesterUnited: A quick glance through those questions leads me to believe that you looked up a list of unanswered questions on the cutting edge of understanding.


"What is the identity of dark matter? Is it a particle? Is it the lightest superpartner (LSP)? Do the phenomena attributed to dark matter point not to some form of matter but actually to an extension of gravity?"
If we had any other name for it, or explanation, we'd use it. The phrase, "Dark Matter," is a glorified "I don't know."


"What is the cause of the observed accelerated expansion (de Sitter phase) of the Universe? "
All the universe is distancing itself from humanity as fast as possible. The more humanity rises on Earth, the more rapid the rest of the universe scurries away.
(JK, obv.)


"What is the exact mechanism by which an implosion of a dying star becomes an explosion?"
I'm pretty sure this is just a trolly question. For "exact" you'd need the "exact" quantum state of the star, I suppose. With a unfathomable amount of time, perhaps some computation device could solve the "exact" solution - within the confines of quantum uncertainty.


"Is dark matter responsible for differences in observed and theoretical speed of stars revolving around the center of galaxies, or is it something else? "
Well, dark matter pretty much sums it up, whatever it is, so no... it's not something else.
Whatever it is, it is not interacting with the EM fields, therefore it is invisible (i.e., not made of atoms). It is transparent, and space is dark [citation needed], so it is dark. Whatever it is, it is causing masses to act in a way that implies that it (itself) has mass. So calling it dark matter is just a short hand for "I don't know what it is, but it's dark and acts heavy."


"Fusion energy may potentially provide power from abundant resource (e.g. hydrogen) without the type of radioactive waste that fission energy currently produces. However, can ionized gases (plasma) be confined long enough and at a high enough temperature to create fusion power? What kinds of advances in material science must be made?"
(I'm assuming you mean in a "laboratory" on Earth.) Probably.
Materials that can create immense magnetic fields without being crushed and/or melted by the reaction forces they create.
Materials that become superconducting at "high" temperatures would sure be a help, too.


"What causes the emission of short bursts of light from imploding bubbles in a liquid when excited by sound?"
Water is made of atoms, which have their own dipole moment, as well as the induced dipole of the water molecule, H2O.
Maxwell's Equations say that changing magnetic fields create electric fields. When you shake a magnet, some of the vibrational energy is dissipated through the emission of electromagnetic quanta, aka photons.
Sound is many orders of magnitude lower in frequency than light, so it could be a resonance setting up in the compressed atoms. I wonder if the pressure is great enough to induce a temporarily crystalline state. It could also be blackbody radiation from the localized extreme heat caused by the localized high pressure region.
(I'm guessing. Given the nature of the other questions, this answer may be based on a false assumption about the question.)

TL;DR:
I have an undergrad degree, and I'm guessing that you don't even know what you're asking me in these questions.
E.g. zero-point energy, de Sitter phase, CP violations... come on... I know where to look to find those definitions, but I'm not a PhD, so ... sorry.
I'm happy to take all questions, but if you don't even know what you're asking, then I hardly see the point.
On the other hand, if you do understand these concepts, then please take over the thread for a few posts and educate this monkey.