5,334 reputation
1530
bio website keith-s-thompson.github.com
location San Diego, CA
age 55
visits member for 3 years, 1 month
seen yesterday

I'm a programmer and all-around nerd living in San Diego, California.
I work at JetHead Development Inc.

E-mail: Keith.S.Thompson@gmail.com


2d
revised Andromeda/Milky Way collision: How, and how accurately, can a galaxy's lateral velocity be measured?
deleted 107 characters in body
2d
accepted Andromeda/Milky Way collision: How, and how accurately, can a galaxy's lateral velocity be measured?
2d
comment Andromeda/Milky Way collision: How, and how accurately, can a galaxy's lateral velocity be measured?
@ChrisWhite: Ok, you've convinced me -- and the account of the person who posted the other answer seems to have been closed.
Nov
8
revised A mirror flips left and right, but not up and down
T2
Oct
12
awarded  Yearling
Sep
30
awarded  Explainer
Sep
23
awarded  Good Answer
Aug
25
comment How does gravity work underground?
The ancient Greeks knew about Newtonian gravity?
Jun
4
awarded  Necromancer
Jun
4
awarded  Nice Question
Apr
28
awarded  Enlightened
Apr
28
awarded  Nice Answer
Mar
12
comment Why would a pendulum experiment give $g > 9.8\ \mathrm{m/s^2}$?
@Kvothe: Yes, but wouldn't applying the formula for larger angles (where the pendulum will take longer to swing back and forth than the simple formula implies) yields a smaller value for the gravitational acceleration -- assuming accurate measurements?
Mar
8
comment How can I destroy earth with physics?
Last December, I received a text message from the USGS which said there had been an earthquake near Polson, Montana with a magnitude of 22.0. My first thought was that the Solar System would have a new asteroid belt, but my calculations indicated that there probably wouldn't be enough left to form one; the energy released would be about 250,000 times Earth's gravitational binding energy, more than enough to vaporize the planet. Unfortunately for your evil schemes, a followup message revised the magnitude to 2.2.
Feb
14
comment Why gravity decreases as we go down into the earth?
The pull of gravity is zero at the center, since the entire planet pulls on you from all directions. It falls off from 1g to 0g (more or less smoothly, but not uniformly) as you go from the surface to the center. But due to the greater density of the core, it actually increases until you reach the bottom of the mantle. See also this question.
Jan
24
comment How physical objects (e.g. Earth and Apple) are aware and do computation about each other?
@MikeDunlavey: I'd say that both Newton's and Einstein's theories (as distinct from what they personally might have said about their theories) are observations about how things behave. Neither addresses the question of "why".
Jan
24
comment How physical objects (e.g. Earth and Apple) are aware and do computation about each other?
Nobody does. We observe how objects behave, and we refer to certain aspects of that behavior as "gravity". That doesn't mean we ultimately understand what, if anything, "causes" gravity. But I see no reason at all to assume that the underlying causes, if any, involve computation or awareness.
Jan
24
comment How physical objects (e.g. Earth and Apple) are aware and do computation about each other?
Why do you assume physical processes (which we may or may not entirely understand) require awareness and computation?
Jan
19
awarded  Nice Answer
Dec
21
comment Didn't Newton's Corpuscular theory fail to explain reflection?
@VINAY: As I said, the idea is that the corpuscles interact with ordinary matter but not (significantly) with each other. For example, there might be one chance in a thousand of a corpuscle colliding with an atom of ordinary matter, but only one chance in a million of two corpuscles colliding. But we know that the corpuscular theory is wrong, so you can only go go so far in making it consistent with reality.