Gravity: Existence's Rudder And Propeller.
It's Genesis (sic.) was the smiting of an innocuous apple upon the head of eminent scientist, Sir Isaac Newton, as he reclined beneath a tree (validity of story uncertain). Much in the manner of how an apple was the culprit behind Adam and Eve's fall from grace and subsequent expulsion from Eden. It then went on to become the plaything of Einstein, who transformed the entity into a tangible fabric, responsible for manipulating reality to such an extent that space fell in upon itself and wielded the power to annihilate all matter, to the point where light even falls prey to this runaway force. We have recently witnessed this force devour a cloud of gas in the centre of our galaxy and furthermore used as the title for a movie that in the recent week has scooped seven Academy Awards! What is this all-pervasive entity I am referring to? Why, Gravity, of course!
We are all familiar with what it is, throw and catch something in mid air and it's effects are evident, even to the most layman of those versed in physics. However, it contains many properties that even it's original proponent to human consciousness and development - Sir Isaac Newton - never even conceived. Einstein, at the turn of the twentieth century, expanded upon the Newton's Laws of Motion (details of the three salient points of his laws can be found here: http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html and here http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion).
Einstein expounded on the idea with Special and General Relativity. Special Relativity postulates that the laws of physics are invariable and that the speed of light in a vacuum (Speed of Light = 299,792,458 metres per second) is the same for all observers. There are some great tests for Special relativity, one such one is that if a person is to bounce a ball aboard a aeroplane, to that observer, the ball would appear to bounce in an even straight line. However, if it was possible to observe that same bounce from the ground, the bounce of the ball would be angled "relative" to the speed with which the aircraft traveled during the intervening period of when the ball was bounced. Got that? No? Well, not sure that I have either!
General Relativity deals with mass and gravity, a tangible substance the great man dubbed spacetime. The constituent parts of reality comprise of three dimensions of space (up, down, all around) and one of time (time is self-explanatory, tick-tock!) Gravity was postulated by Einstein to act as a force on spacetime, warping it, bending it and twisting it like water spirals around in a whirlpool. The greater the mass of an object (mass and size are not mutually exclusive, a neutron star for example is around the size of London, yet contains masses thousands of times greater than our sun) the more it warps spacetime, to the point when certain conditions permit, to the extent where all matter, light included, cannot escape it's clutches and all known laws of physics break apart, much in a manner that reality collapses past the event horizon of a black hole.
Recent decades of the twentieth have yielded swiftly into the domain of quantum physics, a realm where the three other fundamental forces of existence hold that minute milieu in thrall. The playground of the Strong Nuclear Force: the binder of matter inside atomic nuclei, the Weak Nuclear Force: master of radioactive decay and fusion of particles/atoms and Electromagnetism: the ruler over all interactions, attractive and repellant, between all atoms and fields in the universe (save for gravity, of course). All are smaller in their sphere of influence than gravity, which permeates throughout the cosmos. Despite the fact that gravity works over long distances, it is relatively weak when spanning long distances. It is evident to us in our everyday lives, we appear pinned to the earth's surface, but if we stand, or lift an object nearby, gravity weakens it's grip on us. This hold softens with greater distinction the further we go from our planet, the same rule applies for our sun and for our galaxy, in fact, the entire universe. As the universe keeps expanding, the gravity will force matter so far apart that everything, even on a particle level, will, one day, be too distant to form new stars etc., resulting in this universe becoming a cold, dead wilderness. But never fear, this is so far in the future that the number is crazy. Plus, if you've seen Dancing on Ice, you already are fully aware of what existing in such a universe would be like!
Yet black holes offer a glimpse at how gravity can bend spacetime so far in it's curvature that time itself could theoretically be forced into retreat. Which offers a tantalising possibility, that perhaps gravity can manipulate spacetime in ways that work to our advantage? Some theorise that wormholes through spacetime exist beyond the event horizon of a black hole, spewing out all the energy sucked in through the other side (dubbed as white holes, which some say are quasars spotted in our universe). Wormholes are the mechanism many believe could transport us far distances across the universe (some postulate that particles are entangled via wormholes, but in the words of Marjorie from Little Britain: "but that's not for here.") If this is the case, then gravity has naturally coerced spacetime into spanning vast megaparsecs across the universe, so we could do the same, right?
We have exploited gravity in the past to sate our desires in exploring the Solar System, beginning with the Apollo missions. Gravity was used to slingshot crafts around the moon back to earth, similar was done with the Voyager probes and recently with the Juno probe that is venturing to Jupiter as we speak. Although, what I believe is, that if the universe as a consequence of stellar deaths (massive stars) collapsing in on themselves, create black holes, can we also do the same?
Picture spacetime as a stretchy, super flexible and elastic fabric, able to twist inexorably into black holes as well as being able to expand exponentially at rates exceeding the speed of light at the same time. Such a fabric, the breeding ground of myriad galaxies, stars, planets and subsequently life in a plethora of forms, can be altered in ways to exploit space travel. Perhaps by recreating the force and speed of spin possessed by a black hole and using it to propel ourselves across spacetime? Or to bore through spacetime? Maybe spacetime can be used like an elastic band to force warp drive, the kind of which is common to our vernacular, courtesy of Star Wars and Star Trek? Maybe particles within our body are entangled to others elsewhere in the universe and we merely have to locate their twins in order to travel to and from them? Sounds odd, doesn't it? But remember, so did black holes and quantum entanglement until they were proven to exist!
© Brad James, 2014.