patcl@tektronix.UUCP (Pat Clancy) (10/04/83)
In an article in the Oct. Scientific American ("The
Large-Scale Structure of the Universe"), the authors make
the statement that "In the early stages of expansion
the galaxies recede from each other at an apparent velocity
that exceeds the speed of light" (p. 75).
This brings up a problem which I have wondered about
occasionally, concerning the execution of the big bang:
if we start with a "singular point of infinite density"
(same article), which expands as both matter and radiation,
then the radiation should "outrun" the matter, so that
at any time after time 0, any observer should see radiation
originating at any point within the radius of the expansion.
That is, if particles A and B started at the same spatial
location at time 0, then at time t > 0, A and B will be
separated by a distance d, which must be less than the
distance light can travel in time t. Therefore, the "event
horizon" at any point should include all other matter
originating in the big bang.
Now, I realize there must be an error in this logic, so
where is it? I suspect it has something to do with the
curvature of space, perhaps in making the transition from
a state of "infinite" to finite curvature (ie., the
transition out of time 0).
In the same vein, the SA article states that "a massive
neutrino cannot continue indefinitely moving at the
speed of light" (p. 80). How can a particle with mass move
at the speed of light for any length of time? Is it possible
to move at light speed and have some mass other than zero
or infinite?
Pat Clancy
Tektronixpatcl@tektronix.UUCP (Pat Clancy) (10/04/83)
[Sorry if this appeared twice to anyone]
In an article in the Oct. Scientific American ("The
Large-Scale Structure of the Universe"), the authors make
the statement that "In the early stages of expansion
the galaxies recede from each other at an apparent velocity
that exceeds the speed of light" (p. 75).
This brings up a problem which I have wondered about
occasionally, concerning the dynamics of the big bang:
if we start with a "singular point of infinite density"
(same article), which expands as both matter and radiation,
then the radiation should "outrun" the matter, so that
at any time after time 0, any observer should see radiation
originating at any point within the radius of the expansion.
That is, if particles A and B started at the same spatial
location at time 0, then at time t > 0, A and B will be
separated by a distance d, which must be less than the
distance light can travel in time t. Therefore, the "event
horizon" at any point should include all other matter
originating in the big bang.
Now, I realize there must be an error in this logic, so
where is it? I suspect it has something to do with the
curvature of space, perhaps in making the transition from
a state of "infinite" to finite curvature (ie., the
transition out of time 0).
In the same vein, the SA article states that "a massive
neutrino cannot continue indefinitely moving at the
speed of light" (p. 80). How can a particle with mass move
at the speed of light for any length of time? Is it possible
to move at light speed and have some mass other than zero
or infinite?
Pat Clancy
Tektronixkevin@ecsvax.UUCP (10/05/83)
Pat Clancy stated in a recent article in net.physics (tektroni.1428) that "the 'event horizon' at any [point in time] should include all other matter originating in the big bang." (his reasoning can be seen in his article). I quite agree. In fact, there are many scientist who hypothesis that if the mass of the universe is sightly greater than the current estimations, we are living in a closed universe. (i.e. the mass of the universe will slow the acceleration of all matter until it halts and then colapses back into the point in "space" where it all began). A comment on my use of "space" above. The term space is used loosly to describe the spacial cordinates outside the "event horizon" described above. A Recent article in NATIONAL GEOGRAPHIC talked briefly on the posiblity of hidden mass in Black Holes, black patches in space, and general presence of matter, hydrogen, between planets, stars, galaxies, etc. If the above does turn out to be true then we do know what it is like to be inside a black hole. (Our black hole, the universe, being several billion light years across, at least in our measurements ....).
patcl.tektronix@Rand-Relay@sri-unix.UUCP (10/21/83)
From: Pat Clancy <patcl.tektronix@Rand-Relay> Thanks for your reply. I would be interested in finding out what your disatisfactions with the big bang model are; perhaps you could post them to the net sometime? I have never been clear on the precise meanings of the basic terms used in the theory. For example, the initial "bang" is sometimes described as taking place "everywhere" simultaneously, which seems to account nicely for the (presumed) fact that there are areas of the universe which are not yet within our event horizon; however, this seems on the surface to be incompatible with the idea of a "point" which expands. Ie., does "space" expand, or does matter expand within space? I presume that if I understood the theory mathematically, I would not be confused over these questions. Any references you would care to recommend, either pro- or anti-bang? Pat Clancy Tektronix