Monday, November 21, 2005
Art & Science

You wouldn’t think, looking at my previous blogs, that I would consider myself a very artistic person. Yet I do, very much so.

Back when I was in college, and afterwards when I was actually working in radio astronomy, I did a lot of painting and sketching, took art classes and hung out with an artistic crowd at the same time I was working at the radio telescope, and I received very different impressions from the two groups.

Many of the physicists and other scientists I hung out with rather looked down their noses at art as something essentially meaningless because it had no practical purpose, and did not add to the body of empirical knowledge.

At the same time, many of the artists with whom I associated had plenty of contempt for the scientific crowd, thinking of them as nothing more than techie geeks tossing around dangerous devices and substances with total, amoral disregard for the well-being of the planet and their fellow human beings. Scientists, they felt, had no concern at all for the human soul.

Both groups were wrong about the other, of course, although I doubt the two will ever reconcile.

I started oil painting during my final year in college. I had to take a Fine Arts elective to round out my degree requirements and decided to give oil painting a try (mostly because that was the only Fine Arts class offered that summer, and I wanted to finish my degree by the fall.) I walked into the classroom and the instructor, a seventy-six year old lady with big pop-bottle eyeglasses, pointed one lacquered fingernail at me and said, “You! What’s your major?”

“Physics,” I replied.

“Well, you need some art in your life,” she said. “Take a seat.”

I did, and stayed in that class the rest of that year, and the year after, long after my Fine Arts requirement had been filled. I was lucky to get her as an instructor, because she could work wonders with her students. She believed everyone had a latent artistic talent within them, and all they needed was the right environment to bring it out. She kept the atmosphere in her class light and easy, encouraged her students to browse each other’s works and offer critiques. Over the course of the semester everyone got to know each other really well. We learned a lot about her life too, and she had one of the most amazing lives of anyone I have ever met.

She had been married six times, had traveled to Alaska and South Africa and just about everywhere in between. She had visited every continent except Antarctica. She served in the Marines as a truck driver during World War II, and received her Master’s in Fine Arts from Berkeley. She was not just an artist, but also a model, a photographer, and an ordained minister. Mention just about any part of the world and she could tell you a story of a time she visited it, and told many such stories over a bottle of beer with her students after class. She often said one of the great regrets of her life was that she never got to see the Apollo Moon landing in 1969. She was living in South Africa at the time, and television was outlawed under apartheid, out of fear it would teach the native Africans to read.

“They harmed themselves,” she said, “just to keep the black Africans down. 20 million South Africans never saw the Moon landing just because the whites were afraid the blacks would become educated and throw off their rule.”

Later, when I decided physics wasn’t really what I wanted to do, it was the respect I gained for art in her class that convinced me to get into writing. If physics taught me about the Universe, then art and writing has taught me about life, and made me into a well-rounded person, and I have her to thank for it.

Posted by Robert Williams 2005-11-21 20:11:27

Wednesday, November 16, 2005
The Big Deal with Little Things

Continuing on my last blog entry, some people may wonder just what Stephen Hawking (the aforementioned “wheelchair guy”) did to deserve his iconic status in physics. To answer that, you need to address two major branches of physics: general relativity and quantum mechanics.

For most of the time since their discovery these twosubjects seemed to have almost nothing to do with each other. General relativity is for the most part the physics of gravity, space, and very large objects like galaxies and black holes. Quantum mechanics is the physics of tiny particles like protons, neutrons, and electrons, and of the even tinier particles that make them up. Early attempts to quantize gravitational fields, that is divide them up into little “gravity particles,” failed miserably, and most of the time quantum mechanics ignores the effects of gravity. However, near a black hole, you can’t ignore the effect of gravity on small particles.

You see, even in a perfect vacuum, empty space is filled with energy. Hawking was able to show that extremely tiny particles are constantly being created and destroyed from out of this energy. They’re always made in pairs, a particle of ordinary matter and a counterpart particle of antimatter with it. Almost as soon as they appear, they annihilate each other and go back into the energy field of empty space. They’re so tiny and exist for such a brief period of time that they aren’t even categorized as conventionally “real.” Instead, they’re called “virtual” particles. Most of the time, it isn’t possible to detect these so-called virtual particles.

But that is where a black hole comes in.

When these particles are madenear the event horizon of a black hole, sometimes the black hole sucks in one and the other one flies off into space, free to exist “for real.” This newly emancipated particle also steals a little kinetic energy from the black hole’s gravitational field. Since this energy is just another form of matter (E=mc² anyone?), that means that little virtual particle just made the black hole a little lighter. This is how black holes radiate, and since Stephen Hawking came up with the idea, it is called Hawking radiation.

Nowanything that radiates energy (in the form of little virtual particles or otherwise) must have a temperature, and in this black holes are no different. For a black hole about the same mass as the sun its temperaturewould be about 0.0000025 K. Pretty darn cold, but still a temperature.

Remember how I said the virtual particles made the black hole a little lighter? Now physicists are wondering what would happen to a black hole when all its mass radiates away. You see, as the black hole gets smaller, its temperature increases. So it radiates faster, and starts losing mass at a faster rate, getting smaller and hotter until… what? Some think it would just disappear, or it might explode in a big burst of gamma rays. Others think it might just keep on losing mass indefinitely, even after its mass becomes less than zero, or negative-mass. Still others think that once its mass got down to a value called the Planck mass, its gravitational field would become so small that it could no longer be described classically, but by (drumroll, please) quantum mechanics. Boom, you’ve just unified two very different fields, and made a big advance into the theory of quantum gravity. So you see, it was a very big deal, involving very little things.

Posted by Robert Williams 2005-11-16 20:17:19

Wednesday, November 9, 2005
Homer's Oddity

There's so much I don't understand about astrophysics. I wish I read that book by that wheelchair guy.

-Homer Simpson

Ah Homer, where would we be without your wisdom? I'm sure when a lot of people hear in the news about astronomers finding exciting new evidence of a black hole at the center of the galaxy, they feel the same way.

The aforementioned exciting news is that astronomers using the Very Long Baseline Array, or VLBA, have imaged an enormous fountain-like jet of energy coming out of the center of the galaxy, and narrowed its size there down to about half an astronomical unit long, which is about half the distance between the Earth and the Sun. The energy jet is thought to be produced by a massive black hole, sucking in matter around it so quickly that jets of charged particles shoot out from each side of it, rather like a bar of soap slipping through a wet hand.

Having worked at the Very Large Array Radio Telescope, which often collaborates with the VLBA network, I took many observations for astronomers using the VLBA. Also, having written my senior thesis paper on supernova explosions and researched black holes for my first novel, The Remembrance, this is also exciting for me.

First,I thinkthe VLBA needs some explanation. Its basic principle is this: the bigger a radio telescope is, the more it can see. Makes sense, right? Now, the neat thing about radio telescopes is that if you link two of them together, you can double their resolution.Then you can make the resolutioneven betterif you move them further apart. The further apart your linked telescopes are, the further into space you can see. The distance between the telescopesis called the baseline, (hence Very Long Baseline Array). Now if you have a lot of radio telescopes scattered across, say, North America, and they are all linked together, they can function like single big radio telescope the size of the North American continent. The VLBA has radio telescopes scattered across the Northern Hemisphere, so it is like a big telescope 5000 miles wide. Pretty cool, huh?

There is a lot of tantalizing evidence for black holes, but nothing concrete.Radiotelescopeshavesuch a hard time imaging black holes because the gravity of the black hole is so powerful that not even light (and radio waves are just another form of light) can escape it. Soastronomers have to look for indirect evidence, like the energy jet produced by the infalling matter, and hope they can learn something about the black hole by the radio waves coming off the jet.

I suppose the most impressive thing is that even an instrument as large and complex the VLBA, a telescope that takes up a good chunk of the Earth's surface, is stretched to its limits trying to penetrate the secrets at the center of the galaxy. It's enough to make you want to read that book by that wheelchair guy.

Posted by Robert Williams 2005-11-09 23:06:47

Sunday, October 30, 2005
Unintelligent Design

For some time in Kansas there has been some debate about whether or not to include "intelligent design theory" in classrooms, which basically states the Universe was created by an intelligent being. Proponents of the idea say they want it included in curricula in theinterest of free discussion of ideas, although many of these same proponents are the ones who voted to remove all mention of the word "evolution" from classrooms a few years back. Apparentlythey were not so concerned about free discussion back then.

I make a point to steer clear of politics for the most part,but I did want to say a few things about the evolution/intelligent design debate, which has unfortunately become political. Much of the basis of intelligent design is that if any of the physical laws of the Universe were different, then we could not possibly exist. Well, this is true, although it does make it sound like the whole point of the Universe is for humans to exist, a very arrogant proposition.

As an example, I'll use an argument put forth by Lee Strobel in his book, The Case for a Creator. Strobel states that the mass liberated in the form of energy in the thermonuclear conversion of hydrogen to helium must be exactly 0.007 of the available hydrogen for the Universe to exist as is does. Vary this amount only slightly in either direction and life as we know it would not exist.

First let me say that this a much more intelligent argument than many have put forward so far in these debates, which why I bring it up. So I praise Strobel for researching his arguments better than most on both sides of this issue.

However, the argument is specious. If the Universe were different, then whatever beings that did exist could marvel that it was made just right for them. Strobel places a qualifier in his sentence in which he says “life as we know it.” This is not the same as saying life is impossible in an alternate Universe where the mass defect ratio is different. He is only saying that there wouldn’t be people and dogs and cats and trees and all the other lifeformswith whichwe are familiar.

Also, the Universe is not perfectly made for life. Most of it is a vacuum, or very radioactive. And the mass defect ratio, which influences how the stars shine and synthesize elements and form planets and life and so on, is only one small part of literally millions of other factors involved in the development of life.Given that it is so complex, it does seem unlikely that it would emerge in the first place, but given the size of the Universe, the number of stars and planets, and the same physical laws everywhere, by the law of averages it has to happen occasionally. Lots of people at SETI are busy trying to figure out if it can happen more than once. Also, life can adapt to its environment. Organisms that can deal with hardships survive and those that can’t quickly die off, so you can get beings perfectly suited to their surroundings very quickly, and develop diversity over long periods of time. So eventually critters emerge that can look around in awe that things seem so perfectly suited to them.

Let me also say that none of the above arguments really say anything about the existence or non-existence of God. Do we say that if we could somehow prove that life could exist in a Universe with a different mass defect ratio, then God would not exist? I don’t think so. We can't say that any more than we can say the theory of evolution means God does not exist, when it does not mean that either.

Carl Sagan used to say that when people asked him if he believed in God he usually responded, “What is God?” Lots of different people have very different conceptions of Him.Proponents of intelligent designoften (though not always)try to prove the existence of the God of the Bible, and putting only that in schools is the state favoring a single religion over others, a violation of the First Amendment.

Personally, I think a general discussion various world religions would be a good thing inpublic schools, as long as no single religion is put forward as right and it is kept outof the sciencecourses.After all, what other concept has had such an enormous impact on human history than religious ones? Also, it could help instill some harmony between people with different spiritual beliefs, whose relationships can sometimes be contentious. And a little harmony would be a good thing in the world today.

Posted by Robert Williams 2005-10-30 23:35:29

Monday, October 24, 2005
The Ways and Means of Time Travel

I want to talk about real time travel, okay? Stuff that can really happen, stuff that really does happen somewhere in the Universe.

First you should know about special relativity.

Here’s special relativity in a nutshell: When something moves, its length gets shorter, its mass increases, and the rate at which it moves forward in time slows down.

All of these effects are so small that they only get really noticeable when you move close to the speed of light. This is why it is impossible for anything with mass to travel as fast as light: if you did, you would have no length, infinite mass, and you wouldn’t go forward in time at all. And I’m afraid you can’t do that.

Anyway, time would still go forward at its usual rate for anything outside the moving object. So if you went out on a space trip to some distant star on a ship traveling at close to light speed, a few years might pass for you while on Earth decades, or even centuries, may have passed. In a way, you have traveled into the future.

Now here’s a kicker from General Relativity: Gravity can also affect time. Stephen Hawking and Roger Penrose famously showed that time comes to a halt inside a black hole. The black hole’s gravity is so intense that it warps spacetime around it to a point, and time can’t move forward. You’re going to see some slowing of time as you get closer to it as well, so that passing very close to a massive object like a black hole or a cosmic string (see my previous blog post below) could also slow down your own personal time, so that more time would pass for the rest of the Universe than would pass for you. Just don’t get too close, or you’ll never get back out again.

In fact, if you fell inside a black hole, the last thing someone watching you fall in would simply see you approach the edge of it, suddenly become motionless, and then disappear. That’s because a certain distance away from a black hole, light can’t escape its gravitational pull. This distance is called the Schwarzschild radius, and this what physicist talk about when they refer to a black hole’s “size.” Since all the actual matter in a black hole is compressed down to a single point, it doesn’t have a conventional 3-D size. So physicists use the Schwarzchild radius, the distance beyond which light can’t escape the black hole, as a measure of its size. The Schwarzschild radius also gets bigger as the black hole gets bigger, so it is a measure of the black hole’s mass as well.

Now, it may also be possible that at the center of black holes, the gravity is sometimes so intense that it punches right through the fabric of spacetime and makes an Einstein-Rosen bridge, better known as a wormhole. This hole in space and time could potentially take you anywhere in the Universe, and at any time, past or future.

Another place you’ll find wormholes is all around you. According to modern quantum physics, empty space is full of them. They’re just very, very small, a tiny fraction of the diameter of a proton. At that size, the structure of space gets very porous, for lack of a better word. The tiny wormholes flicker in and out of existence, and in theory, it might be possible to isolate one and expand it, until it gets big enough for an object with mass to pass through. The catch is, making one big enough to pass a spaceship through might take more energy than exists in the Universe, so don’t start packing your bags for that next interstellar wormhole trip into the year 10,000 B.C. just yet.

Those are the ways and means of time travel.

Posted by Robert Williams 2005-10-24 21:27:00