Curiously, most of the folks I know to whom many folks on this list would
ascribe "magical thinking" to, do, I think, have very little trouble with
the 50 kilofoot level explanation of General Relativity, and might even go
so far as to say, what's the big deal?
Trying to explain Special Relativity to these same folks, on the other
hand, in my humble efforts,
tends to produce various specie of ice cream headache.
Not sure what to make of that. Possibly I'm a crappy explainer.
Carl
On 5/18/12 9:15 PM, Bruce Sherwood wrote:
Yes, that's what I meant in citing Einstein. As for the specifics of
the case, Einstein realized that action at a distance was not
consistent with the Special Theory of Relativity, that nothing could
be communicated at a speed greater than the speed of light. If
something suddenly yanked our Sun far away from us, it would be eight
minutes before the sunlight vanished (the Sun is about 8 light-minutes
away from us), and it would also be eight minutes before our orbit
changed from circular to a straight line. It was these considerations
among others that led Einstein to seek a theory of gravity, which is
now called the General Theory of Relativity.
Bruce
On Fri, May 18, 2012 at 9:10 PM, Grant Holland
<[email protected]> wrote:
Bruce,
Did not Einstein put "action at a distance" wrt gravity to rest with his
general theory? Did he not theorize that gravity is a force that curves
space-time nearby rather than acting on other masses at a distance?
Just askin'
Grant
On 5/18/12 4:13 PM, Bruce Sherwood wrote:
Newton famously said about action at a distance, "I frame no
hypotheses". I take this to mean something like the following:
"I completely agree with you that I haven't explained gravity. Rather
I've shown that observations are consistent with the radical notion
that all matter attracts all other matter, here and in the heavens,
made quantitative by a one-over-r-squared force 'law'. On this basis I
have shown that the orbits of the planets and the behavior of the
tides and the fall of an apple, previously seen as completely
different phenomena, are 'explainable' within one single framework.
I propose that we provisionally abandon the search for an
'explanation' of gravity, which looks fruitless for now, and instead
concentrate on working out the consequences of the new framework.
Let's leave it as a task for future scientists to try to understand at
a deeper level than 'action-at-a-distance' what the real character of
gravity is. There has been altogether too much speculation, such as
maybe angels push the planets around. Let's get on with studying what
we can."
I think Newton doesn't get nearly enough credit for this radical
standpoint, which made it possible to go forward. And of course we
know that eventually Einstein found a deep 'explanation' for gravity
in terms of the effects that matter has on space itself. There are
hints in the current string theory community of even deeper insights
into the nature of gravity.
Bruce
On Fri, May 18, 2012 at 1:38 PM, Russ Abbott<[email protected]>
wrote:
John, I like your gravity question. If this were Google+, I'd click its
+1
button. My wife, who studies these things, says that one of the
fiercest contemporary criticisms of Newton's theories was that they
depended
on a mysterious (magical?) action at a distance.
-- Russ Abbott
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============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
============================================================
FRIAM Applied Complexity Group listserv
Meets Fridays 9a-11:30 at cafe at St. John's College
lectures, archives, unsubscribe, maps at http://www.friam.org
