Skip to main content

Posts

Showing posts from August, 2010

12) Dark Matter: Mass/Energy Equivalence

We should remember that in every scenario where a substance or object succumbs to stress in a way that changes its nature (as discussed in the previous post), the principles of mass/energy equivalence remain in play, as do those of mass/energy conservation. For instance, the sun’s nuclear furnace works by compressing hydrogen atoms into helium (although, not quite so directly), resulting in a loss of mass in the form of energy. But, using the handy equation,  E = mc 2 , we can account for the mass of the original hydrogen atoms even after this fusion takes place. It is important to understand something else about mass/energy equivalence too, which is that it does not imply that mass and energy can be converted between states in some trivial way; it says that the  mass of a body is a measure of its energy content . One way of thinking about this is to consider unit of measure conversions: one gallon of liquid is equal to 3.785 liters. Although this analogy is far from perfect (it does

11) Dark Matter: Galaxy Formation and Spacetime Stress

In the previous post, I discussed some of the oddities revealed in the Hubble Ultra Deep Field Image. Specifically, the strange occurrence of what appear to be galaxies of vastly different ages occupying the same regions of space, within what is believed to be a snapshot of the early Universe itself (or, at least part of it). At the end of that post, I concluded that the most straightforward solution to this mystery lies in the likelihood that these galaxies formed in place (at their relative positions) as a result of something other than the Big Bang. The next question is, if the matter from which these galaxies were formed did not originate from the Big Bang, then where did it come from? And, what triggered their formation? Let us think about the rigidity of space and Universal expansion again. As we discussed in a prior post, spacetime is incredibly rigid, but it expands nonetheless. And, despite this unrelenting and ever-accelerating expansion, the matter within it condenses into

10) Dark Matter: Odd Galactic Neighborhoods

If there isn't enough observable matter within a given galaxy to account for the fact that it does not simply fall apart, then what explanation (other than Dark Matter) is there for its formation? Is it possible that the galaxies formed in place, at their relative positions within the Universe, rather than being part of the debris field of some enormous explosion (the Big Bang)? It seems worth considering. Of course, if we do consider it, we must then ask where all the matter  did  come from. Indeed we do. For some, this question is enough in itself to dismiss any argument against the Big Bang altogether. Yet, I must hold out that to the open-minded, considering this question is no less sensible than believing that all the matter in the Universe originated from a singularity. Speculation like this leads to many valid questions, not the least of which being, "What about all the other supporting evidence for the Big Bang?" A fair question to be sure, but that's wh

9) Dark Matter: Distribution of Matter

In actuality, speculation about the origins of the Universe is very often speculation about the origins of matter. The Big Bang tracks everything back to a  singularity  – a single theoretical point where everything that  is  today, at one time existed in a condensed, ethereal state, which eventually exploded and evolved into the Universe as it is now. Given our observations and reflections on the Universe, this theory seems almost, but not quite reasonable. First, the Big Bang is essentially targeted at two fundamental and hereto unexplained features of the Universe; 1) that it is expanding and 2) that there seems to be no other reasonable explanation of its origins. Beyond these two conditions, which the Big Bang seems particularly well suited to explain, are other observations that it doesn’t address quite so elegantly. One of the biggest problems with the Big Bang is the distribution of matter. Deep space astronomy has revealed that there is a remarkably even distribution of ga