Introduction
Gravity is a ubiquitous force in the universe and is considered a natural phenomena resulting from the interaction of matter wherein an object of sufficient size is able to exert a proportional degree of force to attract objects relative to its inherent mass. This means that an object of sufficient mass is able attract and retain other objects to its surface as a direct result of the gravitational field generated by its sheer size. Used in mathematics it can be written as:
, wherein F means the gravitation force between those two objects, m1 and m2 represent the mass of each objects and r is the distance between those two objects, while G means the Gravitational constant. One way of simplifying the overall concept behind this formula is from the perspective of Isaac Newton wherein in his published work “Theory of Universal Gravitation” he explains that gravity is in a sense a predictable force that acts on all matter relative to its mass and distance. What must be understood though is that as science continues to progress in terms of its ability to examine the universe and the natural world around humanity it has shown that gravity has subtle and inexplicable influences on processes that people would not normally associate with gravity. While it is a well known fact that it is the gravitational interaction between the Earth and the Moon that is responsible for the tides, that it is Earth’s gravity that keeps us from flying off into space and that it is the gravity of the Sun that keeps the Earth in its orbit studies have shown that gravity not only gives objects their weight and helps to adhere them to a surface but can actually influence time itself. Such a phenomenon is evident in the way in which time seems to flow differently based on the inherent application of gravity towards it (i.e. time moving faster in higher elevations as compared to lower elevations). Of particular interest is also the way in which scientists have attempted to utilize the unique properties of gravity and its interaction with background electromagnetic radiation in order to examine the rate of the expansion of the universe and the repercussions such an expansion has on gravity as a constant force. It is this and other details that will be examined in this paper in order to see how gravitation reacts on time, space and technology and how this will impact the way in which people will continue to perceive it in the future. While it may be true that gravity is a constant and ubiquitous force pervading the universe this doesn’t mean that its application on objects, time and light is subject to the same observable constants seen within the local environment on a daily basis.
Gravitation and the Expansion of the Universe
One of the more interesting applications of gravitation is its use in understanding the expansion of the universe by way of the Einstein shift. This particular aspect of astrophysics involves the process by which electromagnetic radiation emitted by a source within a gravitational field is actually reduced in frequency when seen in a region possessing a weaker gravitational field. One way of understanding this particular concept is by understanding that space itself has underlying levels of detectable electromagnetic radiation with stars being one of the primary emitters. As seen in the article of Ellis (2008) since gravitational fields increase in strength due to either the size of an interstellar object or when a combination of such objects work in conjunction with one another it can be assumed that the frequency of electromagnetic radiation would increase in instances where there are significant amounts of gravitation fields working in conjunction with one another and would subsequently weaken when such fields are farther apart (Ellis, 2008). Landsberg (2000) explains that by examining the gravitational red shift inherent in background electromagnetic radiation the expansion of the Universe can actually be measured to a certain degree and it can even be determined when the expansion started to take place (Landsber, 2000). This is particularly interesting to take note of since there have been a variety of theories which have attempted to examine what would happen to the Universe should it reach a particular state of expansion and how this would affect gravity within a localized system. While it is already a proven fact that objects of sufficient mass (i.e. the Earth, Sun, Planets etc.) are capable of developing their own gravitational fields the fact remains that a galaxy in which such objects exist also has its own gravitational pull which in turn is affected by the gravity of other surrounding systems. For example, studies such as those by Goldstein (2009) have seen galaxies converging or one galaxy “eating” another as a direct result of it having a stronger gravitational field yet it is unknown to what extent the collective gravitational fields of all surrounding systems have on gravity itself and how it will be affected as these systems move apart (Goldstein, 2009). Take for example the solar system in which humanity finds itself at the present; while humans are affected by the gravitational field of the Earth all the surrounding planets, planetoids, comets and asteroids are in turn affected by the gravitational influence of the Sun. The same can be said of the solar system itself which is also affected on a much larger scale by the gravitational influence of the Milky Way galaxy. Should anything happen to the gravity of the Sun it goes without saying that this would in turn affect the gravity of the Earth and taking this train of thought onto a much larger scale should anything affect the Milky Way galaxy this would definitely affect the Solar System of humanity. One of the more conservative and thus more well accepted theories regarding the effect of universal expansion on localized gravitation as seen in the study “Local fields forever” (2006) is that localized gravitational fields (i.e. gravity generated by an object of sufficient mass) will be entirely unaffected and that while the expansion of the universe will affect background electromagnetic radiation it is unlikely that the effects will adversely affect individual galaxies (Local fields forever, 2006). From a certain perspective this does make sense since on a localized level the interaction of the solar system with the Milky Way isn’t even felt even more so in the case of the interaction of the galaxy with the entire universe as a whole. It must be noted though that this particular assumption is dependent upon the assumption that the concept of gravity is based upon a force generated by an object of sufficient mass which affects other surrounding objects and is not similar to the concept of time which while affected by gravity isn’t dependent on mass as a means behind its creation.
Time and Gravitation: An Examination of the Unique Interaction between Time and Gravity
Many individuals view the concept of time as an inexorable approach towards the inevitable; unceasing, uncaring and above all unaffected by forces within the natural world yet what must be understood is that time itself is affected by gravitational forces which results in a unique and in fact observable and thus measurable effect. For example, in the experiment “Optical Clocks and Relativity” conducted by Chou, Hume, Rosenban and WinelanD two atomic clocks were utilized wherein both were placed on separate and identical tables yet one clock was raised 33 centimeters above the other and a length of optic fiber (75 meters in total) was used to connect both clocks to measure whether there would be any measurable difference in time when one clock was raised a bit higher in relation to the gravitational effect of the Earth on it. The result of the experiment showed that the atomic clock that was raised higher experienced a degree of time dilation wherein it ran faster than the lower one at exactly 90-billionth of a second within an estimated period of 79 years. Based on this and other experiments which have attempted to examine time dilation (i.e. two people carrying the same watch and measuring the difference in time between the watch that is stationary and the one that is moving over a period of 1 year) it can be stated that gravity warps time in such a way that the closer you are to the source of gravity (i.e. the Earth) the slower time actually moves whereas the farther you are away from it (i.e. on a mountain top or in space) the weakened force of gravity actually causes time to speed up (Ferreira 2009). Before readers of this paper start packing their bags in order to live on the nearest mountain top it must be noted though that this particular aspect of time dilation has a relatively insignificant bearing on the human lifespan. Even if an individual were to move to a relatively higher location in order to experience the full effects of time dilation the result would probably equate to nothing more than a total life extension of under half a second thus making the notion of living on mountaintops in order to live longer through time dilation rather ridiculous. One aspect of time dilation thought process that should be taken into consideration is its impact on modern day GPS satellite systems due to their relative distance from the Earth. As mentioned earlier, gravity affects time less the farther away a point is from the source of gravity as such objects in orbit around the Earth are of course not as affected as compared to objects that are on the ground. What must be understood is that GPS satellites have internal atomic clocks that operate faster by 38 microseconds as compared to other atomic clocks on Earth. The reason behind this is quite simple, in order to compensate for the time dilation caused by the waning effects of gravity these satellites need to adjust their internal mechanisms in order to take account of the difference in time between the surface and space. If this wasn’t done the internal mechanisms of the satellite would progressively give inaccurate readings in terms of its position in space relative to the ground and the time it took to get there which would result in an ineffective GPS system. Another interesting aspect of gravity is that it can actually “stop” time itself; black holes, which are the result of a star’s mass, collapsing in on itself, have a point of infinite gravity at the center which is aptly named a gravitational singularity. Gravitational singularities are primarily responsible for the effect black holes are known for which is to suck nearly everything (i.e. planets, small stars, asteroids, meteors, even light) towards its center. Since it has already been established that gravity can affect time it must be questioned what would be the effect of a gravitational singularity, which can suck even light itself, on time? Theoretical studies such as those seen in the article by Shiga (2011) hypothesize that due to the sheer force of gravity at the center of a black hole time would quite literally stop from the perspective of an outside observer (Shiga, 2011). For example, if a person were to fall into the event horizon of a black hole and not be crushed in the process from his perspective time would pass normally while for those observing him it would appear that he would quite literally be stuck in space and isn’t even falling at all. While there as of yet no actual applications of this particular gravitational theory on society at the present it does present itself as a rather interesting perspective regarding the interaction between time and gravity and how it seems gravity is the superior force due to its ability to affect not only light but time itself.
Understanding the Difference between the Newtonian and Einsteinian Notions of Gravitation and its Application Towards
From the perspective of Einstein, all things with sufficient mass (i.e. the planets, Sun, etc) actually cause space-time to curve and that it is this subsequent curvature that causes an alteration in the very geometry of space-time the direction of which points towards the center of a nearby mass that is the largest within the immediate area. As such the closer an object is to a particular mass the larger its curvature is in the local space-time. Going even further Einstein stipulates that if there are no external forces that are acting upon a particular object/mass then it will simply follow a geodesic path in relation to the altered geometry of the local space-time regardless of the degree of curvature that is apparent. One way of seeing this particular example is in the way in which Einstein interprets the way in which the planets move around the Sun wherein they are merely following their geodesic paths with no force between them and the Sun itself. This is in direct contrast to the Newtonian way of interpreting gravitation wherein it is stated that the planets are held in place by the opposing forces of the Sun pulling on the planets while the planets are pulling on the Sun. What must be understood is that if we were to take the theory of Einstein into consideration then the expansion of the Universe can thus be stated as each galaxy following its own geodesic path due to the absence of a sufficient enough force to counteract their subsequent drift. Another way of looking at the theory of Einstein is from the perspective of many astrophysicists that there is indeed a giant black hole at the center of every galaxy. If this is true then the reason why numerous stars, planets and systems or even the entire galaxy itself hasn’t been pulled into it is because of the curvature of space time around the black hole which causes all the systems within the galaxy to curve around it into a roughly disk shaped pattern. This may also explain why a majority of galaxies observed today have all consisted of being somewhat disk shaped in size.
Conclusion
Based on the various facts that have been presented so far it can be seen that the gravity has yet to be fully understood due to the thousands of possible permutations, interpretations and aspects that humanity has yet to fully understand in regards to how it actually functions, whether there is a way to artificially control it or better yet utilize its natural forces in such a way that it could benefit humanity as a direct result. While this paper has detailed the means in which gravitational forces and their effect on electromagnetic radiation can be utilized as a means of detecting the continued expansion of the universe it must be questioned whether there really won’t be an adverse effect of this continued expansion on localized gravity. As mentioned earlier there is still much that is not fully understood on how gravity works and it based on this that the theory presented in “Local fields forever” (2006) regarding nothing truly happening on a localized level is still just that “a theory” it cannot be stated with absolute certainty that nothing will happen. On the other end of the spectrum the section of this paper detailing the effect of gravity on time actually reflects the theory of relativity detailed by Einstein and serves to prove his assumptions. It must be questioned though why time itself is affect, while Einstein has detailed the effects of the curvature of space time and how gravity influences it there have been no conclusive studies which explain why such a phenomena occurs. As such this bears the need for further investigation into the nature of gravity in order to determine what aspects of it is able to influence time to such a degree. Lastly, the perspectives of Newton and Einstein have been shown in this paper in regards to their interpretation of how gravity affects the way in which the planets circle around the Sun. While neither can be described as being 100% right it cannot be said that they are wrong either. Newton’s views regarding gravitational forces and Einstein’s theory regarding gravity inducing a curvature in space time have merits in explaining the orbits of the planets in relation to the Sun but as of yet it cannot really be stated that either theory can be made into what can be interpreted as a universal constant. Everything that has been presented so far can be considered a form of supplemental information regarding gravitation and as such should be considered a guide for future study in regards to this truly interesting aspect of science.
Reference List
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Ferreira, P. D. (2009). Einstein’s Theory of Gravity and the Problem of Missing Mass. Science, 326(5954): 812.
Goldstein, A. (2009). Watch as galaxies collide. Astronomy, 37(11): 56.
Landsberg, P. (2000). Seeking Ultimates : An Intuitive Guide to Physics. Institute of Physics Pub.
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Shiga, D. (2011). ‘Gravity lines’ trace warped space-time. New Scientist, 210(2809): 14.