Atom Wave: July 2008

Atom Wave

Sunday, July 27, 2008

Time Reversal and Other Curiosities

Believe it or not, I’ve been known to lie; but this is the whole truth. Look out your window tonight and you might see a few thousand stars reaching out into the great expanse. These days, many people consider cosmologists to be in the know about all the stars and galaxies out there. The actual truth is much different.
Remember time? Don’t give me that blank stare. You might remember your birth, but you will never remember your death. This time asymmetry is very irritating to physicists since physical laws don’t really care which way time flows. You might someday see a shuttle launch, but you will never see it land on its launch pad on an imploding cloud of smoke.
Part of the redemption to this mystery lies in entropy. To the uninitiated, entropy is simply the measure of the disorder of a system. That hot cup of coffee next to you is right now in a macrostate, a certain pressure and temperature. Look closer, and the atoms themselves are in their own states of position and velocity; a microstate. Entropy is the number of (actually log) of the number of microstates to a macrostate. Now mix in some cream to the coffee, and you have just raised its microstates and with its entropy.
But the entropy of a closed system will never decrease. Try as you may, the entropy of the cosmos has only been increasing with time. But if its been increasing, it had to be in a low state to begin with.
It may be difficult to comprehend, but empty space contains vast quantities of entropy, a consequence of still not fully understood gravitational microstates. This entropy is part of the quantum space-time fabric of the cosmos itself. Gravity is still awaiting its full understanding when scientists someday build a working theory of Quantum Gravity.
This inevitably brings us to initial conditions, which many cosmologist believe involved inflation; the runaway expansion of the early universe due to ultra dense dark energy. But this creates new problems in itself: as Roger Penrose of Oxford University and others have pointed out. The number of microstates in the universe is a constant, but entropy must always increase to the most stable macrostate. That is the high-entropy vacuum, but this conflicts with initial conditions. But nature has one more trick up its sleeve, quantum fluctuations: the random creation and destruction of particles in a vacuum.
Back in 2004 Jennifer Chen and Sean Carroll of the University of Chicago proposed a curious solution to the unbalanced equation of entropy. Instead of entropy increasing without bound in our universe, let it increase without bound in a multi-universe. In another universe, a quantum fluctuation would pinch off and begin another baby universe in an infinite cascade. As an added curiosity, time could flow backwards in some universes to counter-balance the increasing entropy of this universe and others. It is a brilliant yet still controversial explanation for the entropy problem.

Saturday, July 12, 2008

Space Madness

The inevitable conclusion of the space shuttle program spiraled one parsec closer to satisfaction today with the official announcement by NASA of the schedule for their eight remaining shuttle flights. After that, the shuttle will go into a big sleep and no American astronaut will fly on a Yankee rocket for at least half a decade. By the end of the next decade, people might walk on the Moon again. Once that party is over, it is possible that the United States will depart for Mars.
It is there that insanity lies!
Now I know that humans are a resilient species, but even we have our limits. Using conventional technology, any flight to Mars would take at least six months. Once you arrive, due to orbital mechanics; you can’t leave for another two years. Add on another six months for the return, and we are talking about three plus years of severe isolation. It would be plenty to drive most people mad.

Number 5 from the classic "Ren & Stimpy: Space Madness".

They think I’m crazy!

Saturday, July 05, 2008

The Oil Addict

With the recent sky-high prices of fuel in the United States, many people have complained that the oil companies are raping the economy. While I have no objections to the claim that they are totally taking advantage of us, we Americans have been completely asking for it for years. Ever since the end of the 1970’s Arab Embargo, the US has become a cheap whore, sucking the hydrocarbon tap with ever increasing thirst to get our fix for ever bigger homes and automobiles. With the price now soaring, we are acting like any typical addict and stealing, borrowing, and crying rape; anything to get our next fix!