Leading Horses to Water


Ancient Greeks began the way of thinking originally known as natural philosophy but which we now call science.  Science emerged as we know it during the Renaissance, in an age dominated by fear, superstition, injustice, and brutality.  In other words, pretty much like the present.  These musings are aimed at explaining how science works, and how science can serve even nonscientists in their efforts to make sense of the world.  I can try to explain things but it’s up to you to decide whether or not you wish to drink from these waters.

#21 - Mars Rovers

American Heathen:  aired: 22 September 2012

The recent successful landing of another Mars rover, Curiosity, in August of this year has been a source of national pride for an embattled national space exploration program here in the USA.  The challenges associated with just getting the rover onto Mars, to say nothing of what may be encountered during its multi-year missions, are daunting. 

In the times before missions to Mars began to provide empirical data by which scientific speculation could be validated, various ideas existed about what Mars would be like.  Many of those ideas proved to be grotesquely, even laughably wrong.  When the human mind is unfettered by the need to be consistent with evidence, it can go anywhere it chooses.  There are many logical possibilities, and even more possibilities that are illogical, but it’s not possible to choose among those ideas without evidence.  Without evidence, all we have is logic if we are to make a rational choice, but what is logically plausible may still be far from reality.

As an example of this, in the era before spacecraft were sent to Mars, it was suggested by some planetary scientists that the air pressure on the surface of Mars was about 50 mb.  By way of comparison, the air pressure on the surface of the Earth is about 1000 mb.  A pressure of 50 mb corresponds to the pressure at a height of about 22 km (more than 12 miles up!) above the Earth’s surface.  I remember seeing a scientific paper that proposed this value of about 50 mb, based on some evidence obtained not directly from Mars but by measurements done here on Earth.  The analysis of the data included a statistical test of the validity of the calculation, and it offered a relatively high probability that the value of about 50 mb was in the ballpark, so to speak. 

Some years later, the first measurements directly from Mars showed that the actual surface pressure was much less than 50 mb - more like 5 mb.  That pressure value corresponds to a height of about 35 km above the Earth (more than 20 miles).  How could those scientists have been so wrong?  Well, this sort of thing happens all the time when we have no data by which to test our ideas.  Science is all about the data – logic is necessarily involved but it plays a lesser role.

Not only is the atmosphere of Mars very thin compared to that here on Earth, but the gases that make up that atmosphere are mostly carbon dioxide, with only a very tiny amount of oxygen.  Even if the pressure could be increased, the Mars atmosphere wouldn’t sustain human life.  Like all the rest of the planets in our Solar System except Earth, Mars is pretty hostile to humans, although it’s probably the least hostile of them.  Nevertheless, an exciting motivation for the exploration of Mars is the possibility of finding evidence of life on Mars.  If not actual life, there may be evidence of the existence of life from a time when the surface of Mars was not so hostile to Earth-like life.  The issue is a very important one for us humans – are we the only planet with life in the vast volumes of the Universe?  If, as science now reveals, planets are abundant in the universe, the chances of life forming elsewhere may be relatively high.  The existence of extraterrestrial life is an important question for humans, not just because of the scientific interest, but also for our ability to understand our place in the universe.

We once thought that we were the center of the universe.  Science has shown the planets we can see easily don’t revolve around us, as it was once thought, but revolve around the sun, as does the Earth.  And our sun is a more or less ordinary star in one of the arms of a vast galaxy of billions of stars (the Milky Way).  And the Milky Way Galaxy is but one of billions of galaxies we can see in our advanced telescopes.   Our physical position in the universe is comparable to a mote of bluish dust floating in the atmosphere of the Earth.  Could it truly be that the incomprehensible vastness of the Universe is devoid of life, but for us?  Do we still qualify as something absolutely unique in the Universe, or are we but one among many living creatures in a Universe teeming and pulsating with life?

These are indeed important questions to us humans.  Science has shown us that many of the myths conjured up in the scriptures of religion simply are not true.  But scientific predictions of the nature of the Universe are not settled by consulting some authoritative ancient book.  They’re tested against empirical observations – evidence that can be used to evaluate how good our ideas are, and how they may need modification to fit the evidence.  We don’t change the evidence to fit the idea – we change the idea to fit the evidence!  When new evidence comes in, it’s likely that our ideas will change again and again.  Every time we explore a planet for the first time, scientists are surprised by the new data!

Just imagine – we now have machines rolling about on the surface of Mars, designed to provide us with new evidence about Mars and its history.  On the surface of Mars!!  To our naked eyes, Mars is but a tiny pale orange dot in our night sky.  It takes many months to get there on what seems to us to be a fairly speedy spacecraft.  It takes a speed of about 11 km/s (or about 25,000 mph) just to escape the Earth’s gravity!  Distances in space are nearly incomprehensibly large!  It takes about 8 minutes for light to travel from Mars to the Earth! And now our far-away machines will be giving us new insights by which our concepts of Mars once again will be changing. 

The cost of sending the Mars Science Laboratory (aka the Curiosity rover) to Mars was about $2.5 billion.  According to one Website, the Catholic Church had an estimated annual income of more than $400 billion in the year 2000.  If we consider that the Catholic Church has been an impediment to science over most of its long history, with its doctrines about our place in the Universe mired in stagnation for nearly 2 thousand years, it seems to me that we’re getting a huge return in terms of knowledge and insight from the relatively modest cost of the Mars Science Laboratory, especially when compared to what it takes to operate the single largest christian denomination for one year.  What new insights has the church given us?  Another comparison – a Nimitz-class aircraft carrier costs about $4.5 billion, somewhat less than twice the cost of the MSL.  The National Football league generates annual revenues of about $9.5 billion – almost four times the cost of the MSL.

Our newest Mars rover is a tribute to that very human spirit of seeking knowledge and understanding, rather than accepting mythology as sacred truth, and scriptures as evidence.  The rover is a shining symbol of human aspirations to learn our true place in the Universe, without prejudice or fear of what the answer might be.  We are made of star debris, and our ancestry therefore goes back a long way, but only relatively recently have we begun to seek fearlessly and resolutely some credible answers to our questions.

Science is not a religion but rather a tool for those who wish to think for themselves about the natural world.  Its primary characteristic is its willingness to entertain questions from those who wish to obtain believable answers.