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age 54
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BEE 1992, MEE 2001, PhD in progress

Starting building Heathkits in early 70s. Consumer electronics tech through 80s. EE since then. Sold company in 00s. Teach EE classes on occasion now.


7h
revised Length contraction and simultaneous length measurements
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9h
revised Length contraction and simultaneous length measurements
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9h
comment Moon's orbit period as seen from a spaceship traveling at 0.8c
I recommend that you consider the distinction between observer in relativity and 'looking out the window'. They're not the same concept: en.wikipedia.org/wiki/Observer_%28special_relativity%29 This isn't a trivial consideration - what one sees looking out the window is much different from what one observes according to an inertial reference frame.
9h
answered Length contraction and simultaneous length measurements
17h
revised If two events both have a spacetime interval of zero, can they both be said to be happening “now”?
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1d
answered If two events both have a spacetime interval of zero, can they both be said to be happening “now”?
1d
comment Why is it that the cathodic battery symbol in an equivalent battery circuit doesn't point in reverse for an open circuit case?
it's modeled as two capacitors using an equivalent circuit diagram: those capacitor like symbols are not, in fact, capacitor symbols. Batteries aren't modelled as capacitors since, for a capacitor, there is zero current through for constant voltage across.
2d
answered How much could one slow down aging using existing spacecraft?
2d
answered Do massless particles follow the curved spacetime or not?
Jul
20
comment Gravitational atraction of fast object
The asteroid and you gravitate, yes. I'm not sure what you mean by 'feeling' an attraction, in free-fall, one 'feels' inertial.
Jul
20
revised Basics of Current Electricity
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Jul
20
answered Basics of Current Electricity
Jul
20
answered Why does the current increase in an LC circuit while the capacitor is being discharged?
Jul
20
comment Gravitational atraction of fast object
In relativity, gravity is not a force. The fact is simply this: the Newtonian gravitational force formula is fine in the low-speed, low mass-energy limit of general relativity. However, you're stipulating that the system is ultra-relativistic while, at the same time, using the Newtonian concept of gravitational force and the special relativistic (outdated) concept of relativistic mass. But that's simply not a valid way to think about this problem.
Jul
19
awarded  Nice Answer
Jul
19
comment Could Jupiter be a star like in “2010: the year we made contact”?
The answer is that yes, Jupiter could be turned into a star by an arbitrarily advanced civilization (should we, I wonder, have an "arbitrarily advanced civilization" tag?) but, please, don't ask me how. I've got that movie on DVD - I just may watch it again this weekend to see how it's aged.
Jul
18
comment Gravitational atraction of fast object
This is related to the question of whether or not an object can "move so fast" that it becomes a black hole. So I'm voting to close as a duplicate of physics.stackexchange.com/q/3436/9887
Jul
18
comment Gravitational atraction of fast object
"(I know it's impossible)". Why? Motion is relative. In the reference frame of a proton with a speed of $0.999... c$, relative to the asteroid (not impossible) it is the asteroid that has this speed.
Jul
18
comment The Hole Argument
@JLA, of the 10 independent metric components, 6 describe the geometry in a coordinate independent way leaving 4 coordinate degrees of freedom so one can use these coordinate degrees of freedom to choose coordinates in which the line element is in its simplest possible form. Solving the field equations in these coordinates determines the functional form of the metric components in this coordinate system. One can perform a coordinate transformation from $r$ to $r'$ such that the 2nd line element is in the same form as the first showing that the coordinate independent geometry is identical.
Jul
18
revised The Hole Argument
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