Originally Posted by Teddy Tortorici
Eddie, there is no center of the universe as far as anyone competent can tell. In physics, you can call anything you want the "center of the universe," and often we solve problems assuming the Earth is the center of the universe. And by "solving problems," I mean: determining what the outcome will be before it happens.
Long range snipers solve a physics problem every time they make a shot, and the bullet lands where they want it to land, not just because of their shooting skill, but their ability to take into account the variables necessary to put a bullet where you want it. You should ask Tim Kennedy (or any other trained sniper) what he needs to take into account when making the longest shots he's capable of, and see if he thinks the Earth is flat and the center of the universe.
Throughout human history, astronomers have looked at the night sky and wrote down what they saw. Everyone who has ever done this saw basically the same thing: a backdrop of tiny lights that seem randomly distributed throughout the sky with one long streak where the lights are more concentrated (we now know this to be the milky way galaxy that we are a part of). Anyone who has looked at the night sky for long stretches of time, will also sometimes see brighter lights that move around the night sky in a very different way from the background (we now know these lights to be other planets; on the right nights you can see Mars or Venus very easily without a telescope). When you try to describe (mathematically) the motion of the other planets with the view that the Earth is the center of the universe, it is an incredibly difficult problem to solve because from our perspective, the planets are flying around in crazy looping patterns, but if we approach the problem as the sun being the center of the universe, it is very easily shown how to predict the motion of the other planets.
Galilean relativity is a tool people can use to change what you consider the center of the universe to be. However, Einstein showed there is more you need to take into account when considering really fast things. General Relativity allows you ultimate power in choosing a center of the universe and being able to predict an outcome. Galilean relativity still works, but it starts to deviate from reality when speeds approach the speed of light.
Part of what someone has to do when they solve physics problems is to choose a center of the universe which makes the problem easy to solve. However, when you choose a "reference frame" (as it's called) where the Earth is flat, the force of gravity is down, and it is the center of the universe, you can solve many simple high school level physics problems, like predicting where a marble will land on the floor if you roll it off a small ramp fashioned onto a table. However, since planets are spherical, spin on an axis, and are being hurled around the sun, when predicting the motion of a bullet being shot over long distances, it is crucial to take into account the fact that the earth is a sphere spinning and flying through space.
You can always take these details into account, even when solving simple problems like marbles rolling down ramps, but when things are moving relatively slow, the effects of the Earth being a planet, which goes around a star, are so minuscule you can't discern the difference without extremely advanced precision when measuring the actual outcomes.
Physics has a long rich history of developing theories and models to predict outcomes and people going out and doing experiments to see whether or not the models really predict outcomes before they happen. Most physicists are contrarians who are trying to find things wrong with our current understanding of physics. What we have today in 2017 has been refined over hundreds of years, so we've got a pretty solid lock on understanding a lot of things. Physics isn't a complete body of knowledge yet, and we don't know everything, but we know some things!
Next time you're on a mountain at night, just look up.
Long range snipers solve a physics problem every time they make a shot, and the bullet lands where they want it to land, not just because of their shooting skill, but their ability to take into account the variables necessary to put a bullet where you want it. You should ask Tim Kennedy (or any other trained sniper) what he needs to take into account when making the longest shots he's capable of, and see if he thinks the Earth is flat and the center of the universe.
Throughout human history, astronomers have looked at the night sky and wrote down what they saw. Everyone who has ever done this saw basically the same thing: a backdrop of tiny lights that seem randomly distributed throughout the sky with one long streak where the lights are more concentrated (we now know this to be the milky way galaxy that we are a part of). Anyone who has looked at the night sky for long stretches of time, will also sometimes see brighter lights that move around the night sky in a very different way from the background (we now know these lights to be other planets; on the right nights you can see Mars or Venus very easily without a telescope). When you try to describe (mathematically) the motion of the other planets with the view that the Earth is the center of the universe, it is an incredibly difficult problem to solve because from our perspective, the planets are flying around in crazy looping patterns, but if we approach the problem as the sun being the center of the universe, it is very easily shown how to predict the motion of the other planets.
Galilean relativity is a tool people can use to change what you consider the center of the universe to be. However, Einstein showed there is more you need to take into account when considering really fast things. General Relativity allows you ultimate power in choosing a center of the universe and being able to predict an outcome. Galilean relativity still works, but it starts to deviate from reality when speeds approach the speed of light.
Part of what someone has to do when they solve physics problems is to choose a center of the universe which makes the problem easy to solve. However, when you choose a "reference frame" (as it's called) where the Earth is flat, the force of gravity is down, and it is the center of the universe, you can solve many simple high school level physics problems, like predicting where a marble will land on the floor if you roll it off a small ramp fashioned onto a table. However, since planets are spherical, spin on an axis, and are being hurled around the sun, when predicting the motion of a bullet being shot over long distances, it is crucial to take into account the fact that the earth is a sphere spinning and flying through space.
You can always take these details into account, even when solving simple problems like marbles rolling down ramps, but when things are moving relatively slow, the effects of the Earth being a planet, which goes around a star, are so minuscule you can't discern the difference without extremely advanced precision when measuring the actual outcomes.
Physics has a long rich history of developing theories and models to predict outcomes and people going out and doing experiments to see whether or not the models really predict outcomes before they happen. Most physicists are contrarians who are trying to find things wrong with our current understanding of physics. What we have today in 2017 has been refined over hundreds of years, so we've got a pretty solid lock on understanding a lot of things. Physics isn't a complete body of knowledge yet, and we don't know everything, but we know some things!
Next time you're on a mountain at night, just look up.
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