Yasel Miguel Rivera Figueroa: Gravity

A couple of weeks back I go to the movie theater to watch the movie Interstellar. This movie is based basically in the end of the world and the efforts of the NASA to save the human race. In the movie NASA is trying to find a planet, in another galaxy, which can sustain the human race and then moved the human population over there using a four dimension wormhole as a shortcut. The main problem in the movie is the time. When traveling from a galaxy to another what is an hour there can be years back on earth. To resolve the movie issue they use the only thing that is constant in both dimensions, gravity. Gravity is a natural phenomenon by which all physical bodies attract each other. This phenomenon, more generally describe by the general theory of relativity exposed by Einstein, is although the weakness of the four fundamental forces but is a crucial factor in every physical body.

Gravity more common affects bodies that possess a defined mass such as objects, persons, animals, etc. Although it is proved that other bodies such as light, which doesn’t have any mass, is affected in a certain way by gravity. This has been proved repeatedly and Einstein even got a parade thrown in his honor for properly predicting it. What it means is that the path of light is affected by things that have a mass, such as the sun. So if a beam of light, say, a far off star passes close enough the sun, the gravity of the sun exerted on the star will make the star bend slightly around it. This will cause that an observer, like us, see the star in a different spot of sky than it’s actually located. Remember this the next time you look up at the stars, it could just be a trick of the gravity.

Another interesting fact about gravity is that isn’t equally even in our planet. Earth isn’t a perfect sphere because mass is distributed unevenly within the planet. The greater a concentration of mass is, the stronger its gravitational pull, creating deformations around the globe. The ice that once cloaked the area during the last ice age has long since melted, but the Earth hasn't entirely snapped back from the burden. Since gravity over an area is proportional to the mass atop that region, and the glacier's imprint pushed aside some of the Earth's mass, gravity is a bit less strong in the ice sheet's imprint. The slight deformation of the crust explains 25 percent to 45 percent of the unusually low gravity; the rest may be explained by a downward drag caused the motion of magma in Earth's mantle.

To conclude this interesting subject I can say that gravity is the reason we are attached to this planet. Most people have idea of what it is but very few know the real reasons why the things for what they work so hard aren’t floating in the air. Gravity is the main cause for an endless number of situations that occur both on Earth and in universe. Also is a factor that should always be kept in mind when working with displacements problems and even construction projects. It’s important that people start studying it; I believe a fallacy to live in such an interesting planet and to not have any idea of how it works.