Commenting On Comments

Prolific commenter truth=freedom writes about my favorite oatmeal recipe:

I thought the recipe would be much akin to the one I make (which I read in the Daily Camera *many* years ago, and which Helen Dohrman told me about *many* years before that).

Quite different.

“Mine” is much less energy intensive.

But somehow fails to provide a link, or even a vague description, of this manna from oats.  I’ve never eaten any oatmeal-like product that approaches the Good Eats overnight version, but I’m curious to hear more.   As for energy-intensivity, I don’t think running a crockpot for 8 hours really takes that much energy, all things considered.  Probably less than driving to and from the grocery store for most folks…

While Mike S follows up to report that he’s actually seen the SMORPAK in a store: “A bag of   Marshmallows, A box of   Graham Crackers,   Milk Chocolate and four of our famous Smorstix Marshmallow Roasting Stix are all here and ready to use. Smorpak, Everything but the Campfire®.”

Getting past that Everything but the Campfire bit – isn’t that like saying the Romans, with their chariots, pretty much had automobiles, Everything but the Internal Combustion Engine! – this actually makes sense to me.  When you want to buy stuff for S’Mores, you are stuck buying a whole box of graham crackers and a whole bag of marshmallows, which really turns out to be more graham crackers and, especially, more marshmallows than any one person, or even family, could possibly use.  As a single guy, I have never gotten more than 1/3 of the way through a bag of marshmallows before they went completely stale and I had to throw them out.  As such, I appreciate the possibility to buy a pack with the correct proportion of ingredients, prebundled for my convenience!  I still can’t get over the fact that they’re selling branches, though.  That’s ridiculous.

Finally, on a slightly more serious note (although, really – what’s more serious than S’Mores?) alanogilvy writes

Your opening phrase (“one of my favorite-ever descriptions in science”) has me thinking about what mine might be. What are some of your others?

That’s a good question, and not one I have an obvious answer for off the top of my head.  One that occurs to me comes from Brian Greene’s Fabric of the Cosmos.  He’s trying to explain the idea of expanding space, and what that means.  We know that space is expanding because, according to our telescopes, any direction we look in the universe, every galaxy is racing away from us in a completely symmetric fashion.  If you thought of the Big Bang as an explosion, which took place in a particular point in space, the only place from which everything would appear symmetric was from exactly at the center.

Thus, we can either conclude that the Big Bang happened in our cosmological neighborhood, a proposition of such dizzyingly unlikely odds that it would be akin to accepting Ptolemy’s geocentric cosmology, or we can conclude that space is expanding.

Since we are only three-dimensional beings, the best we can do to really picture this is to move down a dimension.  Imagine that we knew of some two-dimensional beings, living on the surface of a massive spherical balloon.  Of course, they wouldn’t know they were on a sphere, since they are two-dimensional.  So far as they could tell, space was infinite and flat (the curvature of the sphere would be so slight that they couldn’t notice it with our senses, just like you and I cannot notice the earth’s curvature while standing on its surface.)  Imagine that their galaxy was like a penny glued to the surface of the balloon.  There were many other pennies, galaxies, studded all over the balloon’s surface.  Our hypothetical race’s two-dimensional astronomers can see these galaxies, because in their 2-D universe, light is trapped on the surface of the balloon, so it bends with the surface’s curvature.

Then, someone with a really big pump starts inflating the balloon.  To our hypothetical astronomers, it would appear that, all of a sudden, every galaxy in the known universe were moving away from them.  Furthermore, although this takes a little math to prove, the further away from them a galaxy was, the faster it would appear to be receding.

This is, in essence, what we are seeing.  Anywhere we look in the universe, we see galaxies moving away from us, and the further they are from us, the faster they are receding.  If you try and imagine some 4-dimensional beings trying to explain a Big Bang in their universe, they would tell a similar story, only, for them, the idea of an hollow 4-dimensional space (remember that, although our 2-D beings lived on a sphere, they only lived on the surface, so their existence was 2-dimensional) would be sensible, and they would be telling their students about how light was “trapped” in only those 3 dimensions (oh, those poor 3-dimensional fools!), etc. etc. etc.

It’s a long explanation, but is, to my mind, the best I’ve ever read about how space itself can expand, and how we know that this is, indeed, what is happening.

Anyone else have any favorite scientific metaphors to share?

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