Just a different, much more ubiquitous kind
From the Church of Jesus Christ of Latter-day Saints’ (the preferred name; it’s commonly called the Mormon Church) 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 few decades ago, this statement was confusing to some Church members and drew ridicule from some non-members. However, during the latter part of the 20th century astronomers had noticed, using red shifts (moving-away form of Doppler shifts of starlight) 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 for the galaxy 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 anywhere near 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 to 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: to see light emitted almost back to the time of the Big Bang, calculated from various different means to be about 13.8 billion years ago. One can use several different kinds of “Standard Candle” (cosmic distance-measuring methods) 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 means it was that much longer ago that the object separated from what became 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 of experimental physicists, using slightly different approaches, determined that instead of the universe expansion slowing down under the gravitational pull of all that mass, the expansion of the universe is actually accelerating. In other words, the universe is expanding faster with time (Perlmutter, et al., 1997; Riess et al., 1998). This won the Nobel Prize for Physics in 2011.
It doesn’t take very sophisticated physics to actually put a number on this. Keep in mind that one of Einstein’s earliest papers (Einstein, 1905) demonstrated the equivalence of matter and energy (this has been subsequently proven in laboratories, solar physics, and atom bombs) with the famous equation e=mc2. 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,” has 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 – the stuff that you can lay your hands on or see: a bit over 4 percent of the universe.
Dark matter (which no one yet understands, but which astronomers can actually measure remotely): about 25 percent of the universe.
That leaves about 71 percent of the universe made up of this newly discovered but still not 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 astonishing: this ratio is just 0.0003 – in other words, almost all of the Milky Way is NOT “regular” matter. This is a value that catches the breath of any physicist or cosmologist. It means there is a lot out there that we know close to nothing about. As in, at least 96 percent of the universe. (See the later section “Dark Energy – Something Even Bigger” for more on this subject.)
Back to D&C 131: 7-8 – this is a remarkably prescient statement for someone with a 3rd grade education and without a cosmologist’s vocabulary. This statement seems to be saying that there is matter out there that cannot be seen by our eyes, and Joseph equates that invisible matter, which physicists have recently concluded forms the vast bulk of the universe, with what he called “spirit.” The implication here is not that the latest research in astrophysics proves Joseph Smith to be correct. (Few atheists would be persuaded of this anyway, especially since Joseph equated this non-visible matter with that particular word, spirit.) Rather, the take-away here is that one religion taught back in the 1830s that there was far more to our universe than could be seen. This is now borne out by new cosmological data about the universe. It is one of the things that make it possible for us to be believing scientists, because there is clearly abundant room in LDS Church theology for scientific thinking.
And vice versa.