The+Size+and+Beginning+of+the+Universe

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 * There are countless theories about the beginning of the universe, and thousands of guesses as to the true size of it, but on this page, i will show and explaining the most commonly followed theories and the most realistic guesses.**

-----media type="youtube" key="uabNtlLfYyU" height="251" width="448"- The Big Bang Theory suggests that the entire universe used to be in a VERY hot and unimaginably dense singularity, then exploded and began to expand. a singularity is a point in space where in the equations used to calculate gravity, the variables become infinity. this means that all mass in the entire universe was in a point with virtually 0 volume. then, as it expanded from the explosion, it cooled. they say it happened about 13.7 billion years ago according to recent measurements, but it is not to say that the entire universe was in a dot for a while then randomly exploded, because before the big bang, there was no time. this is inconceivable to us, but before it, time didn't exist, that is, before the big bang, it had been in that state literally forever, because there was no ever before it. even after the big bang, for the next few minutes, it honestly took millions of years, because under extreme gravity, time slows, and with all the matter in the entire universe in a couple of cubic meters, gravity would have been extreme. the evidence people use to support the big bang includes explainable things such as the all objects in space (galaxies, black holes, etc.) seem to be moving away from each other. at first it seemed as though everything was going away from us, leading early astronomers to believe we were the center of the universe, but further observation of distant objects showed that all things seemed to be moving away from each other. because this contradicts the universal law of gravity, this means that something would have to be propelling the universe to expand, and that thing may be the big bang to explain this. it is like. for example, if you put stickers on a balloon, then you blow it up, they all get farther apart, none moving toward another, all moving farther apart.the same might be happening with the unoverse, but instead of something constantly expanding us (like, in the balloon example, the person or thing blowing it up) we rely on the momentum of the big bang to inflate us.
 * __ THE BIG BANG THEORY __**

---media type="youtube" key="9dpqFsIl1dA" height="251" width="448" This may sound odd, but the infinite theory is actually very interesting and realistic, it may be hard to understand, "how could the universe never end? nothing goes on forever, surely.", but, believe it or not, there is actually a good chance that the universe is flat.You are probably thinking "But that's impossible! we live in a 3D world, where am I` looking when i look up or down if we are 3D?" but does that means that we are all 2D?, it means that if there was an infinite line across space, it would never loop back and touch itself in the back, unlike on earth where if you walked in a circle around it you could end up in the same spot. No matter how far you go, unless you turn around you will not end up where you started. If this is the case, then the universe would have to be infinite. Another theory is that, according to calculations, the universe would be an odd saddle/tube like shape. Where it would be infinite in one dimention but curve around in the other, and may or may not be connected at the bottom. Then, there is the most basic and easiest to understand, which is simply that the universe is a big bubble and we're in it while it's getting bigger. While this is really just as likely as any other shape or size. this idea agrees with the big bang above more than any other theory, and most people generally just assume that we live in a bubble, but if we do, what could possibly be outside that bubble? more universes? and how realistic does it seem that if you went far enough in the border of space (obviously won't happen) long enough that you will end up in the same spot? All of the shapes proposed are just as likely as each other, and since there is no real evidence, on account of the size, it is up to you to decide which you will believe.
 * __ SHAPE OF THE UNIVERSE- ALREADY INFINITE, OR STILL EXPANDING? __**

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 * __ AN IDEA OF THE PROPORTIONS OF THE UNIVERSE __**

Many people think of a light year as just "a lot." but i think that some of the things you are about to read will really change your perspective on the importance of petty things in your life. Let's start small. the average person, for example, stands in an area of about 2 square feet vertically. that means that the entire human race, shoulder to shoulder, could fit in Los Angeles alone, at 498 square miles. 498 square miles may seem like a lot, but the earth is a full 196,950,000 square miles, including water. that means that if the earth was covered in a bunch of Los Angeles, wasting no room whatsoever, there would be about 395,482 Los Angeles's. but don't let that fool you, we're only 24,904 miles around at the equator, not as much as you expected, huh? Space travel to the moon may be super amazing and far away, but in truth, its is only 238,855 miles away. that's far though, right? i mean, that's 9.5 times around the earth! Well, if any of you out there are 80, you have already walked half way to the moon! But, it looks like if you want to get to the sun, you'll just have to keep walking, because you still have 92,700,000 more miles to go! so, because the sun is 8.2 light-minuets away, that means that 8 light minuets are about 93 million miles, making 1 light minuet is about 12 million miles. The moon is not even 1 million miles. That sure makes a light year a lot more intimidating, right? well, as it turns out, from the sun to the edges of the solar system, its only about 5 light hours, so that is 12 million miles (1 light minuet) times 300... woah. well, the nearest star is about 4 and a quarter light years away from us. Ever heard of reaching for the stars? well, the nearest one is 2,499,000,000,000,000 miles away... so i guess good luck!  Next, in just diameter, the milky way is around 100000–120000 light years across. It has about 200-400 billion stars in it. The sun is average in size, and it has the mass of 333,000 earths. The milky way is normal in size and star density. Astronomers estimate that there are about 500 billion galaxies, most with at least 200-400 billion starts, equaling about 100,000,000,000,000,000 to 200,000,000,000,000,000 stars in the universe. From earth, they think the edge of the universe is about 46 billion light years away. That would mean that to get to the edge of the universe, you would need to go approximately 5,733,000,000,000,000,000,000,000,000 miles (5.7 octillion). That's 24 zero's after 5,733... and if you stand up, right now, you take up about 2 square feet. About 1/2640 of 1 mile.