Posted on 01/15/2002 7:02:17 AM PST by PatrickHenry
Once upon a time -- a bit more than 100 years ago -- many scientists believed that seemingly empty space wasn't empty at all, but was filled with a substance called luminous ether. This mysterious stuff, never seen in any laboratory on Earth, was thought to explain how gravity from one celestial body could affect another.
By the end of the 19th century, though, luminous ether had gone the way of countless other scientific misconceptions. Today, another mysterious substance beguiles astronomers, and this one isn't going away. In fact, it's been at the forefront of cosmological theories for decades. It's called dark matter, and it is now widely accepted by astronomers as the stuff most of the universe is made of.
"We've known that it exists for more than 25 years," says astronomer Virginia Trimble of the University of California Irvine. "But we don't know what the hell it is."
How can astronomers be so certain of something they have never seen? The answer comes from observations of how stars and galaxies move, studies that have been going on for more than 50 years. Within spiral galaxies, individual stars and clouds of gas are orbiting faster than they should if they were only being affected by the gravity of the galaxy's visible matter. The same is true for clusters of galaxies: The motions of individual galaxies can't be explained by the gravity of what astronomers can see.
To explain these observations, astronomers have deduced that galaxies are surrounded by vast halos of a different, unseen kind of matter.
This so-called dark matter is invisible to us because it does not radiate energy. But it does have mass, and that means it can supply the extra gravity necessary to hold galaxies, and clusters of galaxies, together. Even in the bizarre world of cosmology, it's a strange proposition.
But is dark matter the only explanation?
Perhaps scientists don't entirely understand the way gravity works; perhaps Isaac Newton's famous law of gravitation needs some revising. But that idea, says the University of Arizona's Chris Impey, is not very popular.
"Definitely most astronomers are extremely unwilling to give up Newton's law," he says. "So it's essentially a choice of two evils: You either hypothesize that Newton's law is wrong, and that our knowledge of the gravity theory is incomplete. Or, you hypothesize a fundamental microscopic particle that has never been detected in any physics lab, whose properties are only constrained by these astronomical observations. Which is a pretty uncomfortable position for physicists to be in."
Still, as Trimble explains, dark matter is the lesser of the two evils, simply because it requires fewer departures from accepted physics.
To explain the observations by revising the theory of gravity, astronomers would have to identify a few different effects, each of which would operate at a different distance scale. But with dark matter as the explanation, Trimble says, "You only need one Tooth Fairy."
[The rest is omitted, but you can visit the source and read it all.]
The heavenly orbs circle around the earth because they are pushed by the gentle breath of the angels.
The aether, like MacArthur, shall return. It probably won't be quite the same concept as the old aether, but eventually someone will find it very useful in a new formulation of the continuum. Just wait. Some grad student somewhere is probably working out the math right now, and maybe his faculty advisor is enough of a firebrand to give it a try. :)
The amount we know, compared to the amount we propbably do NOT know, makes it likely that the difference between the knowledge of, say, a real thinker like yourself, compared to the knowledge of a child, is for all pratical purposes non-existant.
Not to mention that this new data makes it possible that half of what we THINK we know is FALSE.
Is it possible that humans are "intrinsically" unable to fathom the true secrets of the universe? For instance, is it possible that time is somehow the fourth dimension, and that we are as blind as flatlanders attemptingto understand that which we can never comprehend?
This possibility will be aggressively dismissed, as it leaves those without faith with nothing...
How do you know?
First, no theory about dark matter proposes a supernatural nature (in other words, no one suggests that dark matter is outside of and unaffected by the laws of nature). The only statements about dark matter are that it is mass which is difficult to detect. Second, no one suggests that we should worship dark matter.
Very clever.
Given that we do not understand all that there is to understand about "nature", now apparently to include THEORIES which have existed for centuries like the Theory of Gravity, isn't it possible that that which we consider "supernatural" is in fact natural, yet unfathomable? In fact, wouldn't flatlanders consider objects with depth to be "supernatural?"
Many natural phenomena which we now understand -- because of science -- were previously believed by various religions to be supernatural: Lightning, storms, tides, disease, gravity, the motions of the planets, etc. This is true also of evolution.
I don't know what you mean by "natural, yet unfathomable". It is true that there are many things not yet understood (and the list in the prior paragraph has many things not yet fully understood); but that doesn't mean that such things are incomprehensible. If someone were to claim that a natural phenomenon is, by its very nature, incomprehensible, he would be obliged to prove this.
Which, of course, could not be done, as it would be unfathomable.
I must fall back on the "Flatland" example. Because a three dimensional object would not be observable to a flatlander, he could never prove its' existence, although it is natural.
Consequently, were there another dimension beyond the three that WE can observe, we would be unable to observe it, and the true nature of the universe would then be forever hidden from our five mortal senses.
In fact, this would go a long way toward explaining such perplexing problems as the true nature of photons, and how they travel at the speed of light.
Pity is, we will never know whether all that we think we learn is real or a "theory."
I certainly agree with the above. Let us not forget that many natural phenomena have been grossly misunderstood because of bad science. ---Phlogiston, spontaneous generation, even a geocentric universe, blood letting, infinite universe just to name a few. In fact the foolishness of much science can be compared to the foolishness of superstitions. I imagine 100 years from now scientists will scoff at our science as ridiculous theories attempting "to save the phenomenom"
Not if they talked to a competent topologist. Working with high-dimensional things is part and parcel of linear algebra, too.
Have you seen any of the Heavy Metal bands lately? ;-)
I believe so, yes.
I view several of the participants on this thread as something like a new species of man, schizophrenicus dawkinicus, if you will. They are split in two --- on the one hand they delight in reminding man of his lowly origins in the primeval slime and his random, useless, purposeless progress down through the ages, and, on the other, they stand astride the universe, boldly proclaiming that the few pounds of pink meat inside their skulls is capable "knowing" everything "worth considering."
I find it bizarre, frankly. It is a syndrome that has become quite prevalent among intelligent people, especially the scientifically inclined, and all of those I refer to are surely that. But although lining up endless specs of matter in a row, the obsession of the hardcore materialist, tells us lots of useful things --- the modern world is built upon them --- it doesn't tell us anything at all about the interesting questions of existence, and it never will.
Indeed.
To the extent that a higher dimensional object is disjoint from the "flatland" space, it is the equivalent of not existing at all (to the flatlander, that is, since he can only perceive that which is part of his flat space). On the other hand, to the extent that a higher dimensional object DOES interact with the "flatland" space, it is perceived BY THE FLATLANDERS as the projection of the higher dimensional object onto the lower dimensional "flatland" space, i.e., it is percieved as a flat object, like any other in "flatland."
To illustrate the point consider a cone suspended above a flat plane ("flatland"). If the cone does not intersect the plane, the "flatlanders" have no idea there is such a thing, as it can't intereact with their "Universe" as long as it not "in" their "Universe," which is equivalent to and indistinguishable from it not exiting at all, from their point of view.
If, however, we thrust the cone thru the plane such that the cone's axis is orthogonal to the plane, a circle of expanding diameter is formed on the plane, coincident with the cone being "sliced" by the plane. If we incline the axis intersection of the cone slightly, an expanding ellipse is formed in the plane, instead of a circle. Increasing the angle of intersection even more such that the plane never cuts completely across the cone, a parabola will be formed in the plane, and if the cone intersects the plane with its axis parallel to the plane, one branch of an hyperbola will be created by the intersection.
Note that in every case where the cone interacts with the plane of "flatland," the object formed by this projection of the cone onto the plane is an ordinary "flatland" object (point, circle, ellipse, parabola, hyperbola). [Note: they are perceived as the foregoing geometric shapes ONLY if we view the flat space form a point external to the space. To the "flatlander," all "flatland" objects appear as points or lines that "block" various paths within "flatland".]
There is NOTHING "magical" or "mysterious" or "supernatural" about what they would see when a higher dimensional object interacts with their lower dimensional space. The "flatlanders" would just see more points and lines, just as they always do (as "flatlanders" can't "look down" on their own space.)
Not that anyone asked.....
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