At a time of 1 microsecond after the big bang, light could have
traveled 299.8 meters since the big bang.

Thus, at the time of 1 microsecond after the big bang, the volume of
the universe was 4/3*pi*(299.8 meters)^3, or about .1 cubic
kilometers.

Would most agree with this statement?

How would the matter or matter-energy density of the universe be
calculated at this point in time in relation to later?

Sam Wormley wrote in message ...
Coreleus Corneleus wrote:

At a time of 1 microsecond after the big bang, light could have
traveled 299.8 meters since the big bang.

Thus, at the time of 1 microsecond after the big bang, the volume of
the universe was 4/3*pi*(299.8 meters)^3, or about .1 cubic
kilometers.


At 1 µs after the Big Bang, the "observable horizon" would have been
.000001 light-seconds for any observer. Assuming the inflationary scenario
is correct, the Universe would be many orders of magnitude larger than
the .000001 light-seconds horizon.

Are you saying that 'the universe' is not 'the observable universe'?

By that criterion, how do we not know that the universe might not be
infinite in distance in every direction?

Coreleus Corneleus wrote:

Sam Wormley wrote in message ...

At 1 µs after the Big Bang, the "observable horizon" would have been
.000001 light-seconds for any observer. Assuming the inflationary scenario
is correct, the Universe would be many orders of magnitude larger than
the .000001 light-seconds horizon.

Are you saying that 'the universe' is not 'the observable universe'?

By that criterion, how do we not know that the universe might not be
infinite in distance in every direction?

It might be infinite... no way to measure... but a universe of finite
age (~13.7 x 10^9 years) is not likely to be infinite even though its
most likely way bigger than our observable horizon.

See: http://www.astro.ucla.edu/~wright/cosmolog.htm#News

At Big Band, the universe was a point [to put it simply]. The distance
between any two particles [let's say points in spacetime, to be clear]
should be arbitrarily close to zero [whatever that might mean!].
After, say, time t, light emitted from point A is at distance t from A
[I hope setting c = 1 is as customary as I think]. Relativity, as I
understand it, says that point B must be closer than that. I think the
OP is asking if it's true.

In calculus, there is the concept referred to as 'limit'.

It means, in general, 'as you approach something'.

Sometimes, if you have several equations that might approach infinity
or zero as a function approaches a specific value, that function can
still be evaluated.

Often it can involve the division of several different functions that
might approach infinity or zero 'on the limit of that function
approaching' a certain value if those functions approaching infinity
or zero can be shown to be equivalent in some way. It would involve
the isolation of all the variables in the equation.

Some of them would probably involve gravity and quantum mechanics.

[I hope these are not platitudes to too great an extent.]