Expansion, not Explosion

According to this article, it states that the early universe exploded matter and energy. Well, according to modern astronomy and cosmology, the “explosion” is more of an expansion. An explosion paints an inaccurate picture. But I am going to be lenient, and say the article is prone to inaccuracy, simply because it is not made by Cecil Adams. :smiley:

Perhaps there is a definition of explosion which suits the circumstances.

TheFreeDictionary

How can time have a temporal quality (speed of change in distance between particles)?
How can space have a spatial quality (direction / size of universe changing)?

None of this paints anything close to a realistic picture.

I hate that whole metaphor because it is senseless. Unless spacetime exists on another fabric of spacetime (e.g. in a larger universe) by which we are measuring its expansion, it doesn’t make sense to talk about expansion or the speed at which that is happening.

But if you think about this in terms of string theory (haven’t even tried the math, not convinced, but just for argument’s sake), it makes even less sense because the other dimensions are qualitatively different than space and time.

I read somewhere (can’t offer any more precision, appropriately) that we have a poverty of language. Perhaps it was Dawkins: he says we are unaccustomed to dealing with great orders of magnitude: very large and very small discrepancies in scale. Likewise, the structure of our language and the majority of its content refers to objects both in time and space. For example, it may be absurd to speak of “before the big bang”, both temporally and spatially (and which other “befores” are we honestly familiar with?

It’s not a metaphor; space is literally expanding. And it can be measured because space isn’t empty. Nor is it the same as objects simply moving through space; for example, space can expand faster than light, while objects can’t move that fast.

Since Ian, who wrote that staff report, no longer participates on the SDMBs, I can’t ask him whether he’d like to change the wording. I think, however, that he was writing metaphorically rather than precisely. He does, after all, lead in with comments about ponds and balloons as analogies…

You should read the many, many threads in GQ we’ve had on this.

Your remarks indicate that you don’t understand how physicists describe space or spacetime and certainly don’t understand the extra dimensions of string theory. Without that understanding anything you say will inevitably wind up being as wrong as this.

We have many working physicists who patiently explain what relativity and quantum mechanics and efforts to combine them really mean, sometimes even in language that non-physicists can comprehend. There are a couple of threads active right now from people who start off saying that current theory is not “realistic” for whatever their false understanding of realistic is and lots of good explanations and metaphors and corrections are to be found there.

Yes, a metaphorical usage of the term “explosion” would be a plausible answer. However, one must consider that there is a popular misconception about the “Big Bang”, and that is that the Big Bang is really an explosion. I am not sure whether Ian is using the popular misconception of the term, or truly expressing this term metaphorically. Because there is this confusion, the plausible answer that you suggest now becomes implausible. He (I assume “Ian” is a masculine name, because I once knew a fellow classmate that went by the same name) uses the phrase “The Big Bang banged”. The word “bang” connotes a loud sound, which would give a further false impression, as sound is the perception of waves. If there is no observer, then there is no sound, just waves. The last thing I would like to point out is that he says, “They lie close to the event horizon, the frontier of our expanding universe.” When he uses the pronoun “they”, I think he is referring to “the first moments”. I think the “first moments” he is trying to imply is the Cosmic Microwave Background, because it is the CMB that gives us clues about our once dense, hot, and opaque universe. Unusually, he calls the frontier of our expanding universe “the event horizon”. I am not saying that he is wrong; I’m just saying his usage is atypical. I would think that the event horizon is most commonly used in describing the part where we can’t see in black holes, not at the frontier of the Cosmic Microwave Background.

If anyone has any thoughts on this, please tell me! I want to make sure I have this right!

Then again, Ian may be right on the “bang” part. The early universe after the Big Bang Nucleosynthesis, which occurred when the universe was 3 minutes old, gave rise to an initial radiation-dominating universe, where everywhere was hot, dense, and opaque. Electromagnetic waves are a kind of waves, though they are not really sound waves, as the term “bang” that Ian used seem to imply. Then, the universe became matter-dominated before cooling down even further to become dark energy dominated, and the supposed fate of the universe is that it would eventually expand into a Big Chill, but that will depend on new theories of physics and how fast the universe is actually expanding/accelerating. Too bad we still are unsure about the nature and properties of dark energy and dark matter. :frowning:

Space can’t expand because expansion is a spatial property and space doesn’t have spatial properties.

I have asked this to three theoretical physicists and they all ended with the same answer:

“You’re right–all we know is that it takes longer for light to get from one point to another, but saying that there is more space between objects, and thus, we say space is expanding. But true, we can’t measure space itself because only objects in space can be measured that way.”

You will be fascinated to know that this message board is not the home of all physics discussions on the Internet.

I’m not saying it’s not “realistic”. (What does that even mean???)

I’m saying, the use of the language when translating the math is so poor that the difference between “explosion” and “expansion” really doesn’t make a big difference.

I have gone through the math and the non-physicist language does not describe it.

I believe using the wrong metaphors to describe things can lead people to think about things in the wrong way.

For example, if you make the speed of light a variable (I realize IT IS NOT A VARIABLE but I am saying IF, and I know nobody will do this…) then you can end up with space not “expanding”.

My point is about the language used to describe mathematical observations, not the observations themselves, which are clear. There are a lot of metaphorical interpretations, though, and none of them will match perfectly the data that we have.

True. The Straight Dope only provides general know-how and the straight dope on various topics. We can’t expect every answer (on the Straight Dope) to be agreeable among scientists (and even among scientists themselves, they tend to disagree). In addition, the language that we use, English, is rather limited in terms of its vocabulary. There was one time I had a Biology lecturer who had to put the definition of evolutionary theory in lots of quotations to show that it means not what it literally says, because one asshole can come in and use the EXACT same wording and “disprove” evolutionary theory, claiming that it is only and merely a theory. Also, note that some people may not have received an education past high school or college, so educating people in simple language can be very difficult. For example, being an editor on the Simple Wikipedia, sometimes it’s not easy trying to manipulate complicated concepts into simple words that everybody (children and foreigners) can understand. However, since mathematics is an universal language, perhaps that can assist our communication.

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I believe using the wrong metaphors to describe things can lead people to think about things in the wrong way.
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You do have some backup. The Sapir-Whorf Hypothesis says something similar to what you have mentioned: that the language that we use can shape our thinking.

Procrastinating, he was quoting you when you said:

There was an opposing hypothesis, that the universe had a stable (finite or infinite) limit and that the matter inside it was shrinking, but it was not borne out by observation or modelling as far as I’m aware. Besides, it doesn’t change the physical properties of the universe, merely the analogies we draw to physical things, which will be flawed for the above reason. We simply can’t know what is above and beyond observable reality (again, relations within reality, so making flawed assumptions) and those that claim to know with absolute certainty are usually trying to get money off of people.

Edit: wikipedia uses the term “intrinsic expansion”: as in, using the best measures available, things appear to be moving apart from each other within the universe. To reverse the direction of an analogy, we could likewise say that the light travelling from a car towards us was increasing in speed rather than that the car was increasing in speed, but that doesn’t change the fact that we really ought to move out of the way.

I see all too often lately people getting overly pedantic about non-technical English words. If you want to fuss over light-year, that’s good. But “vegetable”, “nut”, or “explosion” for that matter, give it up.