Thursday, November 11, 2010

We Must Always Question Science

I am currently taking my Physics students through a quick synopsis of modern physics.  I have to catch myself on occasion from stating any relatively recent science developments as though they are factual.  The stories behind modern scientific discoveries are factual, but we must not be too quick to dub any finding a scientific law.

What in the scientific realm can we say we are completely certain of?  A scientific law is a rule that, in the eyes of the scientific community, has not yet been broken.  In science, we begin with a hypothesis or an observation, and devise an experiment that will test it.  Eventually, a theory becomes a law if it appears to stand the test of time.  It is easy to disprove a law; it just takes one example.  It is nearly impossible to prove a law to be true.  Mathematics is a relatively pure and exact discipline, and is borrowed by the science community on a regular basis.  Science is not a pure discipline in the sense that there is always human error associated with it.  By error, I do not mean calculation error, although there are plenty of those too. 

Fundamental scientific errors are made when the experiments are devised as a means of proving something.  This process is very difficult, as it requires a particular setup, and, inevitably, certain assumptions must be made.  Essentially, all experiments require that the scope of what is being tested be narrowed.  Although tempting, it is dangerous to expand the experiment’s results as applicable to other test setups.  A scientist’s greatest desire is to generalize a concept, but it is a leap that must be based on further experimentation, not a hunch.

There exist countless examples in the history of science where scientists were forced to retrace their steps; they needed to “un-generalize” their finding.  A fun example of this is Newtonian Mechanics.  In the late seventeenth century, Isaac Newton wrote the book on Mechanics.  For more than two centuries, Newton’s Laws stood unchallenged by the scientific community.  In 1905, the most important year thus far in modern science (the year it was born), Albert Einstein showed that Newton’s Laws, which assumed that time was absolute, were limited in scope.  Newtonian Mechanics only works for bodies moving much slower than the speed of light.  Time and space themselves are relative – they depend upon how fast the timer is moving through space.  The reason Newton’s Laws took so long to be adjusted, is because in our typical life experience, nothing moves nearly as fast as light (300,000 km/s).  Einstein’s theory of relativity should serve as a lesson to all scientists: we can only trust the laws of science so much, as they are devised by man, and are thus prone to error.
Solving the scientific puzzle that governs the universe is like solving a series of interconnected mysteries.  Today, millions of “science detectives” examine old and new data trying to unravel the mysteries of science.  Old findings are compared to new findings, old laws are upgraded, and new laws are developed, only to be challenged again in the future.
The most compelling argument for always questioning our findings was stated in recent years by cosmologist Lawrence Krauss and physicist Robert Scherrer.  Their study notes that the same experiment can yield different results if it is conducted at a different period in time.  The reason for this is that our Universe appears to be expanding.  Things we can see today with our most advanced telescopes will not be visible in a very long time, say one hundred billion years from now.  At that time, if a cosmologist (human or otherwise) were to look up at the Earth’s sky, using today’s technology, they would see only darkness beyond our galaxy.  The light arriving from far off galaxies would have a wavelength that spans a greater distance than our 100,000-light-year galaxy, and would be imperceptible to today’s best telescopes. 

The chilling corollary of this is that without the intergalactic information than humanity has been able to acquire, these future cosmologists would not be able to deduce that a “Big Bang” had ever occurred.  The same tests would yield different information, and would lead to a completely different picture of our Universe, and what its origins were.
An even scarier prospect that we should take very seriously, is that our current technology is unable to obtain accurate information about our Universe.  Has incomplete data already led us to false conclusions?  What if we missed an opportunity to acquire some critical information in the past?  What if the answers to our questions are racing away from us at the speed of light?  We would never catch them, and the true nature of the Universe would remain a secret to us indefinitely!  To quote a recent documentary about Quantum Physics, “What the Bleep do we Know?”
This train of thought may all seem very paranoid.  After all, our day to day life, while governed by the laws of the Universe, would go on, as it has for thousands of years, without a definite unified law of physics.  However, what if we prove, at some point in the future, that the quest for this law is an impossible one, as the information can never be obtained?  I suppose we could then question whether this fact in itself can be proven.  Still, scientists would be justified to despair.  Imagine writing an exam for which all the answers are not known to you, but what is worse, could never be known to you, or any other living human.  I suppose that is what it is like to write a philosophy test. 
As it turns out, when one studies Physics to a certain depth, one will often find oneself in philosophical territory.  In fact, a hundred years ago, the subject of Philosophy made up a fair portion of the University-level Physics curriculum.  Philosophy is where Albert Einstein began when he asked, “What would I see if I sat on a beam of light as it traveled along?”  The answer to this question led him to his most famous discovery of 1905, and perhaps his career, that E = mc2.  This finding eventually gave rise to nuclear physics.
The engineer in me says that questioning long-standing scientific laws is a waste of time until we have a problem.  The scientist in me wants to scrutinize any given law in order to disprove it.  For scientists, it is important to keep an open mind.  Einstein’s open mind allowed him to explore the possibility that time is not an absolute, linear reference frame - the consequences of which led to many technological breakthroughs in the twentieth century.  We must remain humble, with our egos in check; we did not write the laws of the Universe, but life offers us the opportunity to discover them.  It is shocking to find out that under some circumstances, life may also deny us that opportunity.

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