Question Asked, Question Answered

I never really thought about the word "ponder" much, which is strange, because I spend most of my time pondering things. I pretty much wake up every morning with questions in my head and now that I think about it, I go to sleep every night with questions in my head. I'm glad I'm not a cat or I surely would be long dead from curiosity.
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I love astronomy and I end my day every day by looking at the APOD - the Astronomy Picture of the Day. I've woken up half dead on the couch in the wee hours of the morning and dragged myself in here to look at the APOD. When I go on vacation, the first thing I do when I get home is look at all the APODs I missed. I love my APOD.
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The other day, I was pondering the whole "universe is expanding" concept and thought about all the gallaxy collision photos I have seen - like the one above. My brain could not reconcile expansion and collision. I thought: If everything is moving outward, how can things run into each other? My next thought was: I wish I could ask an astrophysicist. On a whim, I typed "ask an astrophysicist" into google. Guess what?
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Yes! There is a website for that! I sent this question: If the universe is expanding, why do galaxies collide? If everything is moving outward like a perfect spiderweb or pond ripple, how can things run into each other? It seems to be counter intuitive. And I got an answer!
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A NASA astrophysicist, James Ira Thorpe, sent me this response:

Excellent question! When we speak about the expansion of the universe, we are referring to the largest length scales of the universe.
On those scales, it is true that all objects are moving away from one another. However on smaller scales (where small can include galaxy clusters that are tens of thousands of times larger than our galaxy) the strength of gravity can still overcome this universal expansion and lead to galactic collisions. However, the recent discovery that the expansion of the universe is accelerating means that the scale over which gravity wins over expansion is shrinking. Eventually galaxy clusters, galaxies, solar systems, stars, planets, people, and all matter will be driven apart! Fortunately we have a long way to go before that happens, if ever.
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I think it's really cool that I can ponder something and get an answer on the internet. I think it would be really awesome if every single question we had could be answered just by typing it into the internet. Maybe it will happen. That's something to ponder.