Simple Answers to Eternal Questions

Simple Answers to Eternal Questions

What happens when an irresistable force meets an immoveable object?
The object moves.
In the real world, all forces are irresistable, and there is no such thing as an immoveable object. Any force -- even a small, weak force -- applied to any object causes some motion of the object, even if it is only a very small motion.
If you imagine a universe in which there is such a thing as an immoveable object, then any or all of the laws of physics which apply to the real Universe might be irrelevant. You'd have to invent a whole new physics to determine what would happen when a force meets this immoveable object. Such an imaginary universe would have no connection to reality, though.

Which came first, the chicken or the egg?
The egg.
Eggs were around for hundreds of millions of years before the first chicken. Fish, insects, worms, molluscs, and all kinds of critters that have since become extinct have reproduced by making eggs, starting all the way back in the Cambrian Period of the Paleozoic Era.
If you restrict the question to "Which came first, the chicken or the chicken egg?", the answer is still "The egg."
The first chicken grew from an egg. That egg was a chicken egg. Its parents were not chickens. Whatever made that first chicken distinctly a chicken made it distinctly different from its parents.
Actually, it is not so easy to say that an individual is the first member of a new species or breed. Evolution works on populations. At one point in time, a population of birds something like chickens existed. The population evolved, and by several generations later, they had changed enough to be chickens. There is no boundary between the two.
Consider the colors in this rectangle. The rectangle represents a population of birds. At the left is an early time, before the first chicken. At the right is a later time, after chickens had evolved. Green represents the precursor of the chicken. Orange represents the chicken.

At what point do pre-chickens become chickens?

What is "Life As We Know It"?
In an episode of the original Star Trek, a silicon creature burrowed through solid rock at high speed. In the movie The Andromeda Strain, examination by electron microscope of a mysterious life form from Space showed it to have a five-sided crystalline structure. These are examples from science fiction of life not as we know it.
Some might say that only life originating on Earth could be "as we know it". But life elsewhere could be very different from Earthly life, yet share some basic characteristics which would make it not quite so totally alien.
I think that all life as we know it shares three qualities:

1: Carbon
Life on Earth is constructed largely of carbon compounds, many of which form incredibly long chains. Alien life based on carbon would almost certainly include proteins, made of linked amino acids. Amino acids are fairly simple compounds of carbon, nitrogen, hydrogen, oxygen, and a few other elements. Carbon atoms form the backbone of an amino acid. All the other atoms are attached to the carbons. There is no reason to limit life as we know it to life built only on the amino acids present in life on Earth. These include most of the simplest amino acids, though, so I would expect these simple forms to be common to all life as we know it.
Other carbon compounds would probably include carbohydrates (sugars, dextrins, starches, glycogens, cellulose, and the like), alcohols, phenols, hydrocarbons, fats, waxes, and nucleic acids. The last are particularly important to us, of course, because they contain the genetic code which holds all the information about how we are made. Other life, as we know it or not, could use some type of nucleic acid for this purpose, or it might use some entirely different mechanism.
2: Water
Life as we know it depends on liquid water. Without water, life on Earth just wouldn't work. Life elsewhere might substitute alcohols, methane, ammonia, or some other liquid, but I don't feel that it would be life as we know it. This implies that such life must be found in a place where the temperature and pressure allow liquid water to exist.
In our solar system, at the present time, the only place we KNOW liquid water can exist is on Earth. Mars clearly had large amounts of water in the distant past, but conditions are now very marginal for its retention. Mars's atmosphere would need to be much denser to keep water in its liquid state. Some of the moons of Jupiter may have oceans of water hidden beneath surface ice which is many kilometers thick. A probe may be sent to orbit Jupiter's moon Europa in a few years to study the ice and learn how water below it could be sampled for signs of life.
3: Cells
Life as we know it is built of, in, and around cells. Life without cells should be entirely possible -- that's undoubtedly how it began here on Earth -- but again, it wouldn't be life as we know it. Cells allow the organization of living matter into tissues, organs, and structures that are enormously complex, and complexity is what life and intelligence are all about.
Cells are basically little bags or boxes made mostly of proteins (in animals) or cellulose (in plants) filled with water and all sorts of other proteins and chemicals. The cell wall is very complex, letting material pass in and out under the precise control of biochemical mechanisms that science is only now beginning to unravel. Some cells have independant existence, such as protista and red blood cells. Others are firmly connected to their neighbors. A single nerve cell in a human being can be more than a meter long, extending from a toe to the spinal cord. The cell walls of trees are what wood is, and animal cells excrete the materials which form bones, teeth, and seashells.

On a page of its own...

The Tomato Question

Click the link above to learn the awful truth, the answer to that most perplexing of classic conundrums, The Tomato Question.

Zeno's Paradox: Can Achilles ever catch the tortoise?

Zeno asked: If Achilles and the tortoise run a race, and the tortoise is given a head start, then Achilles must run for some time before he reaches the point where the tortoise was when they started. By then, the tortoise has moved ahead some distance. Achilles must then run for an additional time to reach that point. Again the tortoise will have moved further ahead. And so on, without end. How can Achilles ever catch up to the tortoise?
No problem.
Every increment is a smaller distance and shorter length of time than the one before. The endless number of ever-smaller distances add up to the distance from Achilles' starting point to the point where he passes the tortoise. The endless number of ever-shorter time periods add up to the time it takes Achilles to catch up to the tortoise. Zeno's analysis simply looks at smaller and smaller pieces of the interval remaining just before Achilles passes the tortoise, and avoids ever looking at that point or beyond.
The process of dividing something into more and more pieces which become ever smaller is the basis of calculus, invented by Isaac Newton and Gottfried von Leibniz more than 2000 years after Zeno's time. Calculus is needed to accurately describe changes in a thing when the rate of change is itself changing. Although Zeno's paradox seems rather silly, it introduced a very powerful mathematical idea essential to the development of modern technology.

Could Saturn really float on water?

The fact that Saturn is the least dense planet in the Solar System is often illustrated by the remark that it could float on water, if a big enough body of water were available. Later I hear people ask, "Is that true? Could Saturn really float on water?"
Of course not.
At least, not all of it.
A body of water large enough to dunk Saturn into will itself be a planet-- a planet consisting entirely of water. The gravitational force of all that water on itself will pull it into the shape of a sphere.
But it isn't possible to have a body of liquid water as large as Saturn. The weight of the water near the surface of the sphere, pressing down on the interior, will compress the water in the interior into a form of ice. That will happen even if the interior is kept very hot. Under high enough pressure, water becomes ice no matter what temperature it is. The majority of the interior of a water planet as big as Saturn will be solid ice.
The water planet and Saturn will also attract each other gravitationally. That means they accelerate toward each other as they get closer together. Instead of Saturn gently dropping into the water planet, the two will collide at high speed. The sudden compression of matter in both planets will heat the matter to high temperatures-- up to several thousand degrees-- hot enough to break the water molecules apart into separate hydrogen and oxygen atoms, and hot enough to make them glow brilliant white for a few minutes.
Only a small fraction of the two planets will be vaporized, and Saturn is already mostly vapor (although cold vapor), but it will still make quite a mess.
Even before the planets collide, the difference in gravitational force between the near part of each planet and the far part of each planet (tidal force) will rip the planets apart.
(Explain how different materials stratify in the new planet)
So the lightest materials in Saturn -- hydrogen, helium, and other light gases -- will indeed "float" on the outside of the new planet, but the heaviest materials -- rock and metal -- will sink to the center.

To my Space and Science home page
Jeff Root
February 10, 2006