Expert: Jayendra Upadhye - 12/31/2009

Question
Hello Jayendra: I have a "simple" question about universal expansion and perception of that. First it is more than a theory correct? They've observed and proven universal expansion? But to the question and hopefully I can explain properly what I mean.

This expansion, in regards to how we perceive it: Is it expanding on a spatial level between objects (for example like a car moves in distance away from a point but the particles that make up the car and the point and the fabric between maintain the same proximity to themselves) or is the entire universe, including us and our particles and all space, expanding together? So the second idea would be like a car moving away from a point but the fabric of all points, including the car itself and it's particles and everything, is expanding as well.

If the latter is true, what localized forces might influence the expansion rates and would that affect perception of expansion at various points of space? How does this affect our perception of the expansion? Are we becoming larger (ie. more spacious) along with the expanding universe? What would be the effect of somehow maintaining our spacial integrity (assuming physical theoretical possibility) with the remainder or the universe expanding and what principal(s) would be involved in that?

Well ok, if any of these questions are absurd, please help me understand whatever makes sense. I'm not formally educated, just looking for reading material, wondering, etc. Thanks!

Answer
Hi,
I had these doubts when I was very young.
I dont ofcouser know how old you are.
Actually, all space is expanding, but not the atoms in it.
So it is like you parked two cars close by at night (big bang time) and found they had move a few meters apart by themselves by daybreak (15 billion years later).

The expansion is of the fabric of space and not atoms themselves. Else in the above example, everything having expanded proportionately, you would not have known any difference.

There may or may not be localized rate differentials. Who is to say?
(Like a bubble expanding asymmetrically).
For all we know, we havent been observing the universe for more than 5-6000 years.
So lets not say our knowledge is complete.
You have a questioning mind, and that delights me.
Also you dont seeem cowed down or ashamed by the fact that you are not formally educated.
This is a very good quality.
Humility added to resoluteness in your quest for knowledge.
Mind what I say.If not today, if not in this life, may e some day in another time, another place, your efforts to know will bear fruit.
Keep up that thirst to know.
Very few have it.
Count your blessings.
Regards
Jayen