Not quite on the Loo!

It's amazing how a passing thought lunchtime today has been resurrected by
the earlier "Loo" thread this evening.

I think I was reading the SaN article Cosmic Collisions when I realised that
so much in physics and cosmology seems to focus on speed and movement but I
can't remember reading anything on staying still.

There 's plenty of "apparent stillness", e.g. the vase on the mantlepiece,
but that and everything on the the planet is hurtling through space at a
hidden speed as is, we assume, the rest of the one eye verse! Perhaps you
can now see where I'm coming from? (cos I ain't staying still am I ;o) )

It may seem a silly qwezzie, but, is anything out there perfectly still? And
could we place a "perfectly stationary" object in space and know/prove it
wasn't moving?

I've scratched my head enough for now, let's see if the locals up the pub
have the answer!!


Laurence Eddy

51.39.57N
3.14.28W

Well I was there, but I may have moved now..... ;o)

On Tue, 28 Mar 2006 20:07:25 GMT, in uk.sci.astronomy , "Laurence E"
wrote:

It may seem a silly qwezzie, but, is anything out there perfectly still? And
could we place a "perfectly stationary" object in space and know/prove it
wasn't moving?

Define "perfectly stationary", and I'll tell you. :-)

The problem is, everything is measured relative to some frame of
reference. In terms of the one I normally use, only one thing is
perfectly still, and thats me.
Mark McIntyre
--

In article ,
Laurence E To group please!!! wrote:
It may seem a silly qwezzie, but, is anything out there perfectly still? And
could we place a "perfectly stationary" object in space and know/prove it
wasn't moving?

No. According to relativity (which seems to work) there is no way to
distinguish a frame of reference that is at rest.

-- Richard

"Laurence E" wrote in message
...
snip
It may seem a silly qwezzie, but, is anything out there perfectly still?
And
could we place a "perfectly stationary" object in space and know/prove it
wasn't moving?

I don't think that's a silly question, Laurence. It verges on deeply
philosphical in fact. Here are some very amateur musings - corrections,
additions & admonishments welcomed:

Aside from the Einstein view of it all, one can ponder a special case: if
nothing existed in the universe at all (i.e. it were empty) apart from the
object in question, then there would extend an infinite distance in all
directions. Whether the body were stationary or moving at uniform velocity
in any straight line would be immeasurable and a redundant concept.
Whichever way we think it may be moving yields no change in its location -
it's still infinity in all directions. It is only acceleration which gives
rise to measurable forces, whether that acceleration is a changing speed in
a given direction, and/or due to changing direction as in centripetal force.
It is interesting to note that whilst linear speed becomes meaningless in
our void, rotational speed (i.e. angular velocity) can still be measured by
virtue of radial acceleration and 'centrifugal' effect; those being
inertial effects within the body rather than effects linking the body to
other bodies/frames of reference. No, there appears to be no such thing as
absolute standstill, nor such a thing as 100 miles per hour absolute. The
only constant in this universe appears to be the speed of light (which for
the impossible traveller has the effective value of infinity since his clock
stands still regardless the length of his journey - from his viewpoint he
can traverse the entire universe in zero time, whilst we slowcoach observers
see him flash by at about 186,000 miles per second, regardless of how fast
we think we are moving).