As I begin my preliminary reading and research for a distinctly possible book about Gravity for popular reading, I revisit a couple of posts I had written about in 2013. It is just as well that eight years later, I am on the cusp of a book about this most defining of the four forces of nature.
September 2, 2013
I think I have reached a stage in life where there is no difference between comprehension and incomprehension. Most concepts in physics, which I thought I comprehended in my younger years, are now safely beyond my comprehension. Gravitation is one such idea. I have always been fascinated by it but with advancing years it makes progressively less sense to me. I think I just don’t get it any more.
To be sure, my not getting it is not at the level of a fourth grader not getting it but not getting it in all its philosophical dimensions. Albert Einstein’s idea of curvature in spacetime caused by massive objects is exquisitely picturesque to me but I can no longer comprehend it. As I have often said the words strung together as part of sentences to explain his theory do make sense to me both individually and collectively but then at the end of it the final conclusive meaning eludes me.
My incomprehension about gravitation as a scientific concept does not prevent me from occasionally interpreting its philosophical and physical manifestations. For instance, I wrote the following as recently as May this year:
Gravitation as a natural phenomenon has been on my mind for as long as I can remember. In particular, I keep revisiting how gravity is at the heart of everything we are and the universe is.
Strangely, it is for the third time in as many years that I am thinking of gravity roughly around this time of year. It was in March, 2011, after the Japanese earthquake and tsunami, and again in April, 2012 that I wrote about gravity. This time it was triggered yesterday while watching my daughter Hayaa’s weekly soccer game; especially when I saw this assistant referee against the backdrop of the overcast sky above and the fresh green grass below. I was sitting in my partially broken deck chair on the sideline.
The entire activity of children running and kicking the ball, the ball moving, rising and falling, self in somewhat wobbly chair and the assistant referee with his feet firmly planted on the ground, everything was one of the millions of manifestations of gravitation.
Everything on Earth has evolved in response to the particular intensity of her gravity. On Mars, for instance, we would have to evolve in response to a gravitational force 62 percent lower than here. Presuming for the sake of illustrating the point that life could have still evolved and thrived on Mars, it would be so very different. Martians might still have played football (as in European football played with feet) but it would have been 62 percent slower than on Earth. Of course, the Martians would not have felt the slowness of their football because for them that would be the natural speed and their only reference point. Our understanding and experience of things are necessarily situational.
A vast majority of us, who would never get to enjoy interplanetary travel, cannot possibly know how it would feel to be on a planet which has 38 percent of our gravity. Even the expression “The gravity of the situation…” would have meant something different. An earthling visiting Mars would perhaps say, “The 38 percent gravity of the situation…..” As always, I digress but then an earthling would digress on Mars because of its lower gravity.
Am I glad that gravitation exists? Mostly yes, but I am equally curious about what if there were a sudden, albeit a slight variation in our terrestrial gravity. What if gravity could leak like a liquid?
The National Space Biomedical Research Institute (NSBRI), established by NASA, makes some fascinating points about the effects on human body of varying gravity. It talks about the effects of changing gravity on bones, muscles, spine, cardiovascular systems, inner ear and balance and sleep.
One was taught a long time ago that it is our inner ear that is particularly sensitive to gravity and helps us keep our orientation. Here is how the NSBRI explains: “On Earth, a complex, integrated set of neural circuits allows humans to maintain balance, stabilize vision and understand body orientation in terms of location and direction. The brain receives and interprets information from numerous sense organs, particularly in the eyes, inner ear vestibular organs and the deep senses from muscles and joints. In space, this pattern of information is changed. The inner ear, which is sensitive to gravity, no longer functions as designed. Early in the mission, astronauts can experience disorientation, space motion sickness and a loss of sense of direction. Upon return to Earth, they must readjust to Earth’s gravity and can experience problems standing up, stabilizing their gaze, walking and turning. These disturbances are more profound as the length of microgravity exposure increases. The changes can impact operational activities including approach and landing, docking, remote manipulation, extravehicular activity and post-landing normal and emergency egress.”
So as I sat on the sideline yesterday, somewhat disinterestedly watching the game but thinking more about gravity, it was entirely unique to my being on this particular planet. My predilections, predispositions, perspectives and perceptions would have been radically different even on our nearest celestial body, the dusty desolation we call Moon. That’s because my brain would have formed differently in keeping with the gravity there. By the way, the lunar gravity is a mere 16.7 percent of Earth’s. My point again is our certitudes become invalid even on our nearest neighbor. So next time you clear your throat and adjust your collar to hand down what you believe to be a grand universal pronouncement, take a pause and preferably give up the idea.
I now struggle with even the difference between the Newtonian idea and Einsteinian idea about the direction of forces that act on us as we feel grounded to the Earth like the referee is in the picture above. The Newtonian idea was that just as we are being pulled toward the Earth, the Earth is also being pulled by us. The Einsteinian idea says we are being pushed up even as we are pushing back on the Earth.
While I am at it I might as well mention the fallacy of straight lines. Since we all lived in curved space there are no real straight lines except that given the massive scale of the spacetime curve we may treat relative short lines between any two points as straight for all practical purposes. (Just about now I can see you scratching your head and saying “What is this man talking about?”) That incomprehension is precisely my point.
In my case comprehension and incomprehension about everything constantly cancel each other out in the final result, although at specific points in time one may be greater than the other.
April 6, 2012
The universe is forever balancing competing gravities.
It could be competing gravities between celestial bodies such as stars and planets or between sentient beings like you and I. When that balance goes out of control, things crash into each other.
Fortunes fall as do reputations in a way that is not so different from objects falling to the ground. In cultural terms, falling is regarded as a bad thing as in falling from grace. In physics, falling is merely a fact of the universe resulting from gravity that is shorn of any emotion or moral judgment. Come to think of it, the thud of a fall from grace is inaudible unlike that of a rock hitting the ground. In the physical world when you fall, you know instantly you have fallen. In the moral world, when you fall it takes a lifetime to experience that.
Being a universal force, gravity is really at the heart of everything. It holds everything together with the possible exceptions of fire and human mind. Fire can go in any direction as can human mind. The worship of fire in many cultures has also something to do with the fact that it seems to defy gravity. In reality, only a transient form of that appears to be rising. The soot eventually does fall.
I have been meaning to ramble on about gravity for a long time because it is a force I do not quite comprehend and yet can never escape. Everything we are on this planet of ours can be attributed to the earthly gravity and the kind of force it exerts. It is conceivable that even a slight change in the value of ‘g’ (as in terrestrial gravity) would radically alter everything and everyone. We forget that all of us are so completely a product of a vast variety of random happenstances. So next time when you feel like strutting and bragging, remember there is nothing special about anyone of us.
In the aftermath of the Japanese earthquake and tsunami last March I wrote the following. It bears repeating because while ground is a decisive part of who we are, gravity is infinitely more consequential in a universal sense.
The earthquake-tsunami-radiation triumvirate in Japan demonstrates just how profoundly we as a civilization are shaped by a stable terra firma. Everything that has happened on this planet, particularly in the past 250,000 years since the rise of homo sapiens-- speech, language, culture, religion, conflicts, triumphs, revolutions, genocides , politics, economy, cinema, technology, bigotry, altruism, compassion, orgasm, Internet, blogs, Muammar Qaddafi and iPad2—has happened because the terra firma has generally remained stable.
We forget that we exist the way we do precisely because the ground beneath us has not slipped too much and too often. For over three decades I have thought about this theme. Some day I would like to write in detail about how the fact that we live on solid ground has so overwhelmingly created and defined the human race. What if we were a strictly water-based civilization? I am quite sure our brains would have been wired very differently and we then would have created a radically different civilization. Can you imagine territorially defined nation-states if the whole planet was just water? And how do you define boundaries in a medium that is never steady?
For some strange reason we treat our incidental geological reality as our natural right and build a whole lot of mythologies around it. It is true that as a species humans are extraordinarily adaptable and flexible. One can say with a fair degree of certainty that we would have created a civilization in response to our geological conditions, however different they might have been.
The problem is that we have come so far as a solid ground-based species that we would find it practically impossible to survive if the earth were to fundamentally reshape its contours suddenly. Of course, in terms of its overall planetary impact the Japanese quake-tsunami cannot be considered even significant, but it is big enough to make us all wonder what if the earth’s crustal plates were to suddenly go into a global subduction mode.
It would help us all to remember that the ground beneath us is also a consequence of gravity and the way things have coalesced across the universe because of it. In my younger days, I used to feel utterly frenzied by the thought of the sheer randomness of it all. With age one becomes resigned to it, more grounded as it were. Incidentally, feeling grounded too has everything to do with gravity.
P.S.: This is what I mean by how fire and human mind defy gravity. My mind does indeed go in any direction it wants to.