Skip to comments.Four Keys to Cosmology
Posted on 08/31/2005 8:19:37 AM PDT by PatrickHenry
In what is widely regarded as the most important scientific discovery of 1998, researchers turned their telescopes to measure the rate at which cosmic expansion was decelerating and instead saw that it was accelerating. They have been gripping the steering wheel very tightly ever since.
As deeply mysterious as acceleration is, if you just accept it without trying to fathom its cause, it solves all kinds of problems. Before 1998, cosmologists had been troubled by discrepancies in the age, density and clumpiness of the universe. Acceleration made everything click together. It is one of the conceptual keys, along with other high-precision observations and innovative theories, that have unlocked the next level of the big bang theory.
The big bang is often described as an event that occurred long ago, a great explosion that created the universe. In actuality, the theory says nothing about the moment of creation, which is a job for quantum physics (or metaphysics). It simply states that as far back as we can extrapolate, the cosmos has been expanding, thinning out and cooling down. The big bang is best thought of not as a singular event but as an ongoing process, a gradual molding of order out of chaos. The recent observations have given this picture a coherence it never had before.
From the perspective of life on Earth, cosmic history started with inflation -- a celestial reboot that wiped out whatever came before and left the cosmos a featureless place. The universe was without form, and void. Inflation then filled it with an almost completely uniform brew of radiation. The radiation varied from place to place in an utterly random way; mathematically, it was as random as random could be.
Gradually the universe imposed order on itself. The familiar particles of matter, such as electrons and protons, condensed out of the radiation like water droplets in a cloud of steam. Sound waves coursed through the amorphous mix, giving it shape. Matter steadily wrested control of the cosmos away from radiation. Several hundred thousand years after inflation, matter declared final victory and cut itself loose from radiation. This era and its dramatic coda have now been probed by high-precision observations of the fossil radiation [see "The Cosmic Symphony"].
Over the ensuing eons, matter organized itself into bodies of increasingly large size: subgalactic scraps, majestic galaxies, galactic clusters, great walls of galaxies. The universe we know -- a set of distinct bodies separated by vast expanses of essentially empty space -- is a fairly recent development, cosmologically speaking. This arrangement has now been systematically mapped [see " Reading the Blueprints of Creation"]. Starting several billion years ago, matter has been losing control to cosmic acceleration. Evidently the big bang has gotten a second wind, which is good for it but will be bad for us. The ever faster expansion has already arrested the formation of large structures and, if it continues, could rip apart galaxies and even our planet [see "From Slowdown to Speedup"].
In developing a cohesive and experimentally successful account of cosmic history, cosmologists have settled the disputes that once animated their field, such as the old debates between the big bang theory and the steady state theory and between inflation and its alternatives. Nothing in science is absolutely certain, but researchers now feel that their time is best spent on deeper questions, beginning with the cause of the cosmic acceleration.
Although the discovery of acceleration was revolutionary, cosmologists' initial response was fairly conservative. They dusted off an idea of Einstein's, the so-called cosmological constant, which represents a new type of energy -- an example of what is more generally known as dark energy. But many physicists are thinking that a revolutionary discovery calls for a revolutionary response. Maybe the law of gravity works differently on gigantic scales than it does on humble, everyday ones [see "Out of the Darkness"].
Just as a nuclear missile cannot be fired unless two keys are turned simultaneously, the explosive progress in cosmology has depended on multiple observational and theoretical keys being turned at once. Will the rush of new ideas lead to chaos? Will order reemerge? Must the cosmos be "preposterous," as one of the authors of this special report once put it? Or will it start to make sense again?
I remember that when I took an introductory astronomy class in college 25 years ago, my professor explained the Big Bang, etc., told us that the scientists had everything figured out all the way down to a tiny fraction after the Big Bang, and that the only thing they could not explain was that millionth of a second after the Big Bang and the Big Bang itself. Now, they are backtracking. They knew less than they thought.
Wow-- I had no idea that matter was so smart. ;)
Thanks for the ping!
That's OK. Life will get boring once we know everything. ;^)
Correction: they knew less than you thought your professor was telling you.
The radiation varied from place to place in an utterly random way; mathematically, it was as random as random could be.
Order out of chaos, or chaos out of chaos?
It's probably just me, but these sort of conflicting statements make it hard for me to keep from laughing.
Are you made out of matter?
Not really, they can still describe everything right up to the tiny fraction after the big bang. As for their theories on expansion, they remained open-minded and insisted on observation to verify their theories and once observation proved the theories wrong, they abandoned them.
The scientific method is a wonderful thing.
How about a extra-super grand unified theory so we don't leave God on the dock? Does anybody else get sense there are too many words devoted to shrinking the universe?
That would have to be Chaos with initial cap. Chaos is smart matter.
This is just my opinion, but physical theories seem to explain what is know today, but fail eventually at the edges of knowledge. It could be that existence is infinitely deep, turtles all the way down.
It seems to me I have heard words very much like this before. I just can't seem to recall where it was. Can anyone help me?
"Inflation then filled it with an almost completely uniform brew of radiation."
I no cosmologist, but isn't this sentence a tautology? I mean, isn't "inflation" the process of filling something almost completely? So, couldn't this sentence be re-stated as follows:
Something inflated it with an almost completely uniform brew of radiation.
Something tells me that the predicate "filled it" needs a subject, and that it begs the question to say that "inflation" filled anything.
I like to think I'm animate and intelligent. But my wife may have a different opinion.