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visits member for 4 years, 8 months
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Author of Beta's Rule: "Never add to code that doesn't work."


Jun
8
awarded  Yearling
Apr
28
comment What is the theoretical lower mass limit for a gravitationally stable neutron star?
@RobJeffries: I... hadn't thought of that. I have not done the math. My intuition tells me that it will, but that proves nothing. It depends on the model, and if I'm wrong there must be a critical mass threshold that rises with time. Well, now I know what I won't be getting any work done for a while because of.
Apr
28
comment What is the theoretical lower mass limit for a gravitationally stable neutron star?
@RobJeffries: As I understand the state of Cosmology, there are several competing theories on the long-term fate of the universe, but the serious contenders agree that with time, the intensity of background radiation approaches zero. No black hole can have become small yet, but every black hole will become small some day.
Apr
23
comment Why don't things get destroyed by gas molecules flying around?
There are solid materials that can be quickly destroyed by the impact of air molecules at ordinary temperatures. And around here, they have been.
Feb
1
awarded  Popular Question
Nov
21
comment Melting diamond and cool down as diamond
Note that at standard temperature and pressure ("ordinary" conditions), diamond is unstable. Diamonds are somewhat rare because they form slowly in the Earth's mantle, then they must be carried up to the surface relatively quickly so that they don't have time to "relax" into graphite.
Oct
27
comment What is the theoretical lower mass limit for a gravitationally stable neutron star?
Theoretically, large black holes eventually turn into small black holes as they evaporate. It just takes a long time.
Sep
24
awarded  Autobiographer
Sep
7
comment How can interstellar space have a temperature of 2-3K?
If you think of temperature as being about the motion of molecules, then it's about the average of their kinetic energy, not the sum. A pot of boiling water (at sea level, in normal weather) is at 100C, no matter how big it is.
Sep
7
comment How do you find the average speed and average velocity?
Which of these do you understand: "speed", "velocity", "average"?
Sep
6
comment Can resistance be directional?
Imagine a thick bundle of insulated copper wires, all running in the same direction.
Jun
30
comment Why does the speed of the propellant limit the speed of a space ship in open space?
@this: The same can be said of a rocket employing baking soda and vinegar, if the fuel tanks are big enough.
Jun
30
awarded  Supporter
Jun
17
comment Hydrostatic pressure - doesn't density vary with depth?
It's interesting to note that if the Pacific were ten times deeper, there might be ice at the bottom...
Jun
17
comment Do black holes cause gravitational redshift?
The edited question is clearer, but you still seem to be confusing two different questions, 1) will the ray escape? (No, it won't), and 2) will it be red-shifted? (Yes, for some observers.)
Jun
17
comment Do black holes cause gravitational redshift?
Is the source inside the event horizon, or outside? (There is now some doubt about whether event horizons actually exist, but bear with me.)
Jun
11
comment Moon's pull causes tides on far side of Earth: why?
When I take a little boy by the hands, pick him up and twirls around, his arms are pulled horizontal; that is understandable, since I am pulling them. But his legs are pulled horizontal too, even though no one is pulling them. Likewise, he pulls my arms outward from my body, but somehow my coattails are also pulled outward from my back.
Jun
9
comment Why is electric current dangerous to humans?
Few cells can survive the trip up to the boiling point, never mind the effect of the boiling.
May
12
answered Electric Field due to a disk of charge. (Problem in derivation)
Apr
10
comment Why isn't jumping from a high altitude fatal?
@Luaan: No, I would not call hitting a stone wall "friction", and I don't see how you got there. I think that "friction" is a useful term for solid-solid interaction, but it should not be extended to solid-gas interaction unless we remember that we are talking about an entirely different mechanism. I hear it used to refer to the entire process of heat generation in reentry, so the division of heat generation into "compression" and "friction" seems misleading at best.