When someone mention ''space was created 13.7 billion years ago and has
been expanding ever since'' which he meant is that the space contained
within this universe has been expanding with the expansion of the
universe. <br>
<br>
Space is the distance between objects within the universe.<br>
Within the universe is everything which exist- matter, energy, galaxy and space. (or so we thought)<br>
<br>
As to what the universe is expanding into, or what lies outside the universe, there are varying views to this:<br>
We see that the universe is expanding as the space between objects
appears to be moving further away from each other at an increasing rate
(Hubble redshift), also supported by the Cosmic Microwave Background.<br>
One may argue that the universe is everything there is and thus it is meaningless to say that it is expanding into 'something'<br>
however, to accommodate this 'moving apart' , there must be an increase
in volume. So how can the universe not increase into any kind of
measurable volume when objects within the universe can move further and
further away apart from each other? <br>
Unless the universe is finite in nature<br>
- now comes another issue- <br>
The universe is not observationally infinite. It has a finite size called the particle horizon which has a radius of 13.5bly.<br>
<br>
My take on this is that many of the assumptions we make do not have solid
empirical evidence thus the truth of this proposition is unknowable and
is subjected to differing perceptions.<br>
<br>
I hope i have not confuse you further.
