In the Beginning .... Cosmologists are beginning to converge on what they call a "standard model" of the universe that is towering in its ambition. By Dennis Overbye. [New York Times: Science]
The universe...is 13.89 billion years old, plus or minus half a billion years. Only 4.8 percent of it is made of ordinary matter. Matter of all types, known and unknown, luminous and dark, accounts for just 27.5 percent. The rest of creation, 72.5 percent, is the mysterious dark energy...
THat's a lot of mystery! What's the mysterious dark energy? Love? Ignorance? The Force? Dance Fever? Jeez, this is great reading:
"The big news in the last decade is that even half a universe ago the universe looked pretty different," said Dr. Alan Dressler of the Carnegie Observatories in Pasadena. Galaxies before then were small and irregular, with no sign of the majestic spiral spider webs that decorate the sky today.
We would barely recognize our own Milky Way galaxy, if we could see it five billion years ago when the Sun formed, he said.
"By eight billion years back, it would be unrecognizable," said Dr. Dressler.
How many science fiction novels are in those three paragraphs?
Physicists recognize four forces at work in the world today — gravity, electromagnetism, and the strong and weak nuclear forces. But they suspect, based on data from particle accelerators and high-powered theory, that those are simply different manifestations of a single unified force that ruled the universe in its earliest, hottest moments.
As the universe cooled, according to this theory, there was a fall from grace, and the laws of physics evolved, with one force after another "freezing out," or splitting away.
Some loaded language there!
In 1998, two competing teams of astronomers startled the scientific world with the news that the expansion of the universe seemed to be speeding up under the influence of a mysterious antigravity that seems embedded in space itself and that is hauntingly reminiscent of Einstein's old, presumably discredited, cosmological constant.
"Dark energy," the phenomenon was quickly named.
If dark energy is real and the acceleration continues, the galaxies will eventually speed away from one another so quickly that they couldn't see one another. The universe would become cold and empty as the continued acceleration sucked away the energy needed for life and thought.
There are even more science fiction novels in those paragraphs. Depressing, somehow, to think of this, even though this heat death will happen billions and billions of years after the sun and everything we can see is gone. Still, we may be living in a simulation at that end time!
A flat universe is the most mathematically appealing solution of Einstein's equations, cosmologists agree. But they are puzzled by the specific recipe, large helpings of dark matter and dark energy, that nature has chosen. Dr. Turner called it "a preposterous universe."
But Dr. Martin Rees, a Cambridge University cosmologist, said that the discovery of a deeper principle governing the universe and, perhaps, life, may alter our view of what is fundamental. Some features of the universe that are now considered fundamental — like the exact mixture of dark matter, dark energy and regular stuff in the cosmos — may turn out to be mere accidents of evolution in one out of the many, many universes allowed by eternal inflation.
This is a heavy article; contained within it is a universe of questions, tons more articles. The next couple decades of cosmological resaearch are going to be very exciting.
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