09 May 2011

Spirit is Matter

From the Mormon Church’s modern scripture, the Doctrine & Covenants Section 131:

7 There is no such thing as immaterial matter. All spirit is matter, but it is more fine or pure, and can only be discerned by purer eyes;
8 We cannot see it; but when our bodies are purified we shall see that it is all matter.

Until a decade or two ago, this statement was confusing to some Mormons and caused some non-believers considerable grief.  However, during the 20th Century, astronomers had noticed, using [Doppler] Red Shifts  and point-mass counts, that galaxies were spinning far faster than could be explained by the visible matter in them.  This wasn’t a small amount of disparity, either: in some cases the galactic spin was an order of magnitude too fast to hold together.  Speculation first turned to invisible gas, or dust, but scans on bands from infra-red to X-Ray showed that these together couldn’t account for what was observed: spiral arms of galaxies were rotating so fast that they should be flinging themselves out into intergalactic space.  The only feasible explanation was that there was additional matter in the galaxies, increasing the pull of gravity sufficiently to hold the galaxies together.  We’re talking 5, 6 times more Dark Matter, as it was dubbed, than visible matter.

In the last decade of the 20th Century, the newer and bigger telescopes coming online were able to reach farther and farther back into deep time: almost back to the time of the Big Bang, calculated from various different means to be about 13.4 billion years ago.  One can use several different kinds of Standard Candle  to figure how far away a given galaxy is.  A problem popped up as they reached farther and farther back in time, however.  Remember that light, though extremely fast, takes a finite amount of time to travel a given distance.  Thus, the greater the Red Shift, the faster the object is moving away, which means it’s a greater distance away, and also that much longer ago that the object separated from our galaxy.   We already knew about visible or baryonic matter, and now we knew that Dark Matter was out there also.  However, two different groups, using two very different approaches, determined that instead of the universe expansion slowing down under the gravitational pull of all that mass... the expansion of the universe was actually accelerating - the universe was expanding faster with time.  It doesn’t take very sophisticated physics (no untestable or unprovable string theory) to actually put a number on this.  Keep in mind that Einstein’s earliest paper in 1905 demonstrated the equivalence of matter and energy (this has been subsequently proven in laboratories and atom bombs) with the famous equation E=MC^2   In other words, matter and energy are interchangeable.  So what kind of energy field would it require to make this expansion accelerate?  It turns out to be about three times more energy than all known visible matter and Dark Matter combined.  This value, now called Dark Energy, checked out repeatedly.  The scientists working on the problem, despite pressure to publish quickly, held off for a long time because they just couldn’t believe these numbers.

So where does the count now stand?
Baryonic (visible) matter that you can put your hands on: a bit over 4% of the universe.
Dark Matter (that no one yet understands, but which astronomers can actually measure distantly): about 25% of the universe.
That leaves about 70% of the universe made up of this newly-discovered but even less-understood Dark Energy.  One recent close calculation of the ratio of baryonic (tangible) matter to all the Dark Matter and Dark Energy for our Milky Way Galaxy is astounding: this ratio is just 0.0003 - a value that catches the breath of any physicist or cosmologist.  There is a lot out there that we know nothing about.

Back to D&C 131: 7-8 – this is a remarkably prescient statement for someone with a 3rd grade education and without a cosmologists’s vocabulary.

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