To paraphrase Rocky and Bullwinkle, whatsa(dark)matta'u. I need help in getting a handle on this dark matter/energy thing. Just a very interested lay person here, so be gentle. It's my first time.
Simply speaking, space that falls into a black hole reaches superluminal velocities past the even horizon, right? Thus rendering light unable to escape.
I thought it was because of gravity. That the gravity was so strong that nothing could escape once it was past the event horizon. Right or wrong? And what of naked singularities? Read an article in Scientific American a few months ago about them. They don't have an event horizon according to the article. Of course, they exist for the briefest of moments before they evaporate.
Tony - yes, the gravity actually causes space itself to fall into the singularity, and since nothing can travel through space faster than c, but space itself travels at >c, no photons can escape - the sum of the velocity vectors always end up pointing into the singularity.
Thanks Mick. Which brings me to Hawking radiation. Funny how we got away from dark matter/energy. But that's how these things go. Trying to bring it back around. Virtual pair, before anihilation, one falls into black hole, the other doesn't. Since it has enough velocity to escape, it becomes real, and the higher energy state makes sure it is positive, so net sum addition of matter in the universe? Would this possibly be dark matter? Sorry if this seems a naive question, just trying to put some stuff together that I have read. And what about the higher energy state? Would that dissipate? Since this is now a real particle, and information must be equal, what is this energy? Is this particle possibly a boson? I really know this is kinda weird questions, but trying to learn here. Thanks,man.
Tony - I think (and I'm totally a layman, btw) that as the virtual particle pair is split, the positive particle escapes into the universe (IIRC referred to as a "hairy black hole"), but the negative (I believe antimatter) particle robs the black hole of an infinitesimally small amount of energy (=mass), if I understand the process correctly, thus keeping the energy balance. This is why black holes eventually do "evaporate" and disappear - but it does take a very VERY long time. The time scale for this I think it referred to as cosmological decades. I did hear somewhere that there were speculations that the dark matter is mainly made up of neutrinos (which are leptons/fermions), but I'm not sure if this is still the case.
Thanks. Gives me something to search for on the science sites. Really appreciate all the input. Some of this stuff that I read I think might be ideas, not even hypothesis. Just have to try and read more critically. Again, thank you.
I do hope I haven't lead you down the provberbial primrose path with my laymanness, but this is the way I understand things. And, you hit it right on the head - critical reading, not just accepting what someone else says for gospel (pun intended). :)
Anything I have seen recently about Dark Matter seems to take it as a given that it has been established that it can't be regular matter, but I must have missed when that was established. I always thought that it might be rogue planets or Brown Dwarfs (not by those names of course, they were coined decades later), and when both were recently discovered to exist, I figured that bolstered my idea, but apparently best estimates of their numbers fall far short. Neutrinos were recently proven to have a rest mass so they contribute, but every article still seems to assume Dark Matter is something even less interactive than them.
I'm not up on the most recent discoveries, but I can offer a bit of history on dark matter, if you're interested.
Vera Rubin coined the term when she discovered that stars move at the same speed regardless of their distance from the center of a galaxy, which was counter to what they knew about the movement of celestial objects in a galaxy. When mapping the speeds of stars, the speed measured should "drop off" as you enter the outer rims of a galaxy, but it didn't. She said that in order to explain that, there would have to be a lot more stuff in the galaxy than what we see. Since we can't see it, they called it dark matter. Since then, they've been looking for the "dark matter".
My favorite theory, though it didn't pan out, was the MACHO theory. Massive Compact Halo Objects were suspected to be the dark matter everyone was looking for. My understanding of them is that they are stars that basically fizzled out and didn't possess the right properties to explode or turn into black holes. The most apt description I heard was "star corpses". The MACHOs were detected, but found to have a minimal mass and could not account for the large amount of "stuff we couldn't see".
Last I heard on the neutrino front was that someone had successfully captured one, but was unable to determine whether it had any mass or not. I just did a quick search and the most recent article I could find on the subject says that's still the case. It seems that it's become the theory that they probably do have mass, but it's negligible, which means it's probably not what they're looking for. Wonder what's next on their list.
Thanks. I can tell it fascinates you, as well. One question I have always pondered is it takes mass to measure anything, right? So if you can measure it, then that excludes that. But if you can't measure it, then what? I know I sure don't know. So (tongue firmly in cheek) I suggest radishes. Could be the answer, huh (lol)? And thanks for the history. Sometimes the search is more revealing than the answers. Thanks, and be well.
Not only are the stars in the outer areas of galaxies rotating "too fast", but the dark matter also produces gravitational lensing - a feature/effect that indicates that dark matter indeed has mass (since gravity does influence photons, themselves virtually massless).
Okay, Einstiens general theory of relativity. Got that. But are you suggesting galaxies of dark matter? Because all forms of EM radiation are lensed, not just photons, i.e., x-rays, gamma rays etc. Could it be Stromen (sp) spheres, which can be mistaken for the lensing effect. Do the hydrogen lines coincide?