Friday, June 30, 2006

Where Do Colors Come From?

In the world there is electromagnetic energy that varies in frequency and intensity but it is not “colored” frequency and intensity. Electromagnetic energy is colorless. When humans absorb vibrations in the range of 350 to 750 nanometers, we experience colors from blue to green to red. But that’s about us, not the world. There is no color in the world. There is no color in the brain. So where does the color come from?

Monday, June 26, 2006

What is Life?

Usually life is defined as a certain a set of activities or processes, such as reproduction, metabolism, irritability. But it is not too difficult to come up with examples that meet each criterion and yet which are not alive, according to common sense. Crystals grow, for example. Fire “metabolizes” fuel, grows, and reproduces itself. Rivers are irritable, in that they try to get around rocks, dams, and other obstacles placed in their path.

Just having DNA is not good enough, since I don’t want to say that a test tube full of DNA is alive. Is a virus alive? Scientists aren’t sure. If it is alive, does it stay alive when you take it apart, or is there something special about the system of parts that confers aliveness. Are gametes alive (e.g., sperm and egg cells)? Spermatazoa certainly look alive, but they do not have full complement of DNA, and can’t reproduce.

At some point, one is forced into a corner, defining life simply as those things that are alive, and the definition is totally circular. That's no good.

I don’t think there is a special “life force,” but I think the question of life must be wrongly formulated somehow.

Image from:

Monday, June 19, 2006

How Tall Can A Tree Get?

There are some very tall, old-growth fir trees near my house. Some of these trees are at least 4 feet (1.5 m) in diameter at their base and must be at least a hundred and fifty years old. Some of them tower 100 to 150 feet high (30-45 m), I would guess. How tall could they get, assuming they did not eventually succumb to disease or lightning? Is there any practical limit? One limiting factor is the difficulty of getting water up to the top to supply growth. Water is heavy. What does it take to lift water 150 feet or more in the air?

Water gets up the tree partly by capillary action, but also because it is sucked up by a sort of hydraulic vacuum. The needles transpire, giving off water, creating a negative pressure in the capillaries, which are completely closed pipes all the way down to the roots. The negative pressure at the needles literally sucks water out of the ground, right up to the top. That may not be exactly right, but that’s what I believe.

Still, even given that the water transport system is a water-tight vacuum pump, there must be some limit to how much vacuum fir needles can create at the top before they implode from negative pressure. Also, why wouldn’t all the lower down needles sap off the water and reduce the pressure long before the water ever got to the top?

There’s also a structural problem. Wood can only withstand so much compression before it splinters and splits. At some point the weight of the tree would simply crush the wood near the ground and the tree would collapse from its own weight. Why haven’t I ever heard of that happening?

So I just don’t know how tall a tree can get.

Saturday, June 10, 2006

What is the Purpose of the Retinal Image?

In some ways, the eye works like a camera obscura, as Kepler described in 1604. The lens of the eye forms an upside-down and backward, two-dimensional image of whatever you are looking at, on the concave inner back wall of the eye. A doctor can see your retinal image when she looks into your eye. But you can’t see your own retinal image, so what is the point of having it? And even if the retinal images were copied to the brain (which they are not), you still couldn’t see them. What are they for?

Friday, June 02, 2006

Where Do We Go at Night?

Once a day, I lie still in a specially darkened and quieted room, and wait to be taken away. I have covered myself in blankets to assist in thermoregulation in the hours ahead, just as an astronaut dons a space suit prior to an extra-vehicular adventure. And in twenty minutes, I am gone. Where, I do not know. Seven or eight hours later, I have returned, with only a few uninterpretable dream snapshots of where I have been. This happens every single day of my life. Why do I accept that as perfectly ordinary? It’s incredible! One third of my life is spent in some other world I know nothing about!