Recent content by Glurth

Arbitrary, it's transparent, and an observer can scuba-dive in it. Please see OP for why we want these features for the thought experiment.

" Just that it must become one." Does this mean there COULD be an opportunity to observe the transition? If we add water at a faster rate than water collapses into the singularity, would our observers be able to see the surface of the water-ball transition into a black hole?

9/8...oh, of course- brain fart. I guess I don't see why the situation of "internal forces cannot be sufficient to resist its collapse" wouldn't automatically turn it into a black hole. What else would that mass collapse down to? (checking out Buchdahl's Theorem now... thank you)

9/8 > 1 I assume you meant 8/9? Hmm, could we see the transition if we added the magic-water "really fast"? (This is a HUGE ball of water (multiple AU), so we could expect it to take some time to all "fall in" anyway.) Edit: Question- if THAT is when we get infinite pressure, isn't that also...

Thought experiment: single use of "magic" Setup: Let's assume we have a giant ball of water in space. Magic: Let's assume the water does not compress its center under its own gravity. (Constant density of 1 g/cm^3) Basic stuff: The mass of this ball of water, (since it does not compress)...

>Russ How big and dense? What happens at various sizes, masses, and temperatures, is what I'd like the sim to show me. Let's assume it is dense enough to be modeled as a gas. >Oudeis P=F*area oops! good catch, thank you, I'll use... F=P*area...

I have a simulation I'm trying out (for fun). A self-gravitating ball of gas, in deep space. (The sim uses a fixed-time-step for each iteration.) I'd like to use Boyles Ideal gas law, the force of gravity, and energy as internal heat. (I don't want to touch enthalpy unless I don't realize...

Update: Issue was combination: power-supply AND pump. Unable to find a resistor, I WAS able to find a twelve volt device that could connect instead. This device failed to turn on when connected to the power supply. (Proving your intuition correct !) I moved my pump input input line to a...

Guess I'll just have to go into town, without a shower, to pickup some resistors. We are living in an RV motor home. The motor is a fairly new seaflo water pump. It is powered by 12v DC, input on a pair of wires. I have no idea what the internal construction is. The power supply is a DC...

oops @Salvador we must have posted at the same time: " I can assure you no laws are broken" hehe sorry for being so sensational in my title. I agree, I'm just missing something, like the power supply stuff you guys mentioned. I think that's where I'll start, just not sure yet how to safely...

Thanks for the feedback Craig! I don't understand how a fault in the windings could cause these odd symptoms of a short (0v) with no current(open circuit). Can you explain? Power supply cutoff: this makes a lot of sense, but I would have expected an over-amperage to blow the fuse. I guess I...

I have a DC powered pump, that has suddenly stopped working. During troubleshooting I came up with the following results, that I just cannot reconcile: Input wires, not connected to pump: 12v Input wires connected to pump: 0v Sounds like a short in the pump right? However, connecting the...

>> Then a homogeneous stated can be imagined as concentric shells from any point. Thus the direct attractive character becomes irrelevant... I love those insights that make you smack your head and say, "well, of COURSE it's that way!" Thank you! >> the dynamical features of the theory...

I guess what's throwing me off is HOW gravity, which locally appears to be an attractive force, at large distances can appear to be repulsive. Is there something else going on other than gravity (like, say... thermodynamic expansion)? Or is gravity, in particular situations, simply warping...

Peter; I must misunderstand, it sounds like you are attributing the expansion entirely to dark energy. >> The assumption of isotropy and homogeneity at cosmic scales leads inexorably to expansion of the congruence. This prediction of GR was extracted before there was observational evidence of...