Jump to content

Raider5678

Senior Members
  • Posts

    2682
  • Joined

  • Last visited

  • Days Won

    2

Posts posted by Raider5678

  1.  

     

    The only people it would, properly, impress are those that fully understood his post; I don’t claim that but I do understand that you don’t.

    I probably don't understand exactly what he said to the depth that he understands it, but I understand enough of it that I can apply it to what I'm thinking. Kind of like drawing a stick figure to represent a human. Not exactly the same, but gives you the basic concept of what we look like. By basic I mean really basic.

     

     

    The hypercube doesn't have to be moving. It's not related to time until you assign that coordinate (a place on a map only needs 3 dimensions to tell you where; time will tell you when something happens at that place). And you don't really "place" something into any dimension. Dimensions aren't places, they're part of the information you need in order to know where and when anything is.

     

    Weird, I know. Here's something to think about. Living in 3 dimensions (even though we only see in 2D), we're able to look at a 2D object and see anything inside it (imagine a square, with 3 circles inside it). So technically, if someone could see in 4D, they could look at us 3Ders and see our insides!

    So the 4th dimension is seeing in 3D, which makes me think of every part of my body put into a pixel "cube" and then all the cubes spread out, allowing the person seeing in 3D to see what is inside me. That's the way I visualise a 4D person would be seeing, although I'm fairly certain nobody does. Additionally, a machine that could see in 3D would be a huge impact for many things. Imagine a medical machine that could see if the heart's pumping or not, where theres internal bleeding, see a collapsed lung. That would be a huge scientific improvement too. :)

  2. In string theory you are forced to consider certain gauge groups and a fixed dimension so that the theory is anomaly free. By anomaly, I mean in the context of quantum field theory. An anomaly is a classical symmetry that does not pass to the quantum theory. These can be phenomenologically helpful, if the symmetries are global, but if they are local then they mess up the whole theory. It is an amazing fact that superstring theory predicts the dimension of space-time and it gets it right to an order of magnitude ;-)

    Phenomenologically. That's a word that would impress people if you casually dropped it into a conversation. But it's about the study of conscious structures from the first person point of view so that might be a little difficult. As for string theory, that is probably the most complicated theory I have ever read about. But it makes sense once you know what it is, but either way if we could find a way to "cut" one of the strings, what do you think would happen? Not that they are a physical thing that could be cut though.

  3. I was reading a wikipedia article (https://en.wikipedia.org/wiki/Gravity_of_Earth) that said that gravity at the equator is weaker then gravity at the poles for a few reasons. First off the poles are flatter than the rest of the planet, meaning you're closer to the center of the earth, hence more gravity. The reason that they are flatter is because the earth is spinning, and the centrifugal force (if your into puzzle boxes: http://www.yot.com/ it involves centrifugal force) is making the equator bulge out. This bulge leads to our next reason the gravity is weaker. SInce you are farther from the center of gravity the gravity is weaker there, and since the planet is spinning the centrifugal force also decreases the gravitational pull on you. Now my question is how fast would the earth have to be spinning to cancel out gravity at the equator, or would it simple turn into a flat disk before the gravity canceled out. And if so, are there any known cases of a planet spinning so fast it's a flat disk without it flying apart?

  4. Dimensions are the number of pieces of information you need to uniquely locate a point. For example, if you want to meet someone, then you will need to specify three spatial dimensions (e.g. latitude, longitude and altitude) plus the time = 4 dimensions.

     

    Dimensions above these (as far as we know) only exist as mathematical abstractions. The mathematics of string theory requires 10 (or more?) dimensions and there are various reasons (excuses :)) why we can't see them: the most common being that they are wound up really small.

    I'm thinking this is the reason your title above your name is Genius. Anyway, thanks for the reply!

     

     

    It's a coordinate system for determining any spot, both physically and temporally (x, y, & z coordinates to pinpoint the spot in space, and t to let you know when to be there).

     

    I had it explained this way. 1D is a line, and if you take every point on that line and move 90 degrees, you have 2D, length and width, in this case in a flat square. Now take every point on that square and move 90 degrees from that, and you'll have a 3D cube. NOW, take every point on that cube and move 90 degrees, and you'll have a 4D hypercube. That's the one that's difficult to grasp. How do you move 90 degrees from every side of a cube?!

     

    The rest (including the 4th spatial dimension) are part of different theories, which is the way all science works. When you say something is theoretical rather than fact, you're misusing the term "theory". Theory is the best you can get in science. Theoretical doesn't mean "unsupported guess". Science doesn't try to "prove facts". It's all about the evidence that supports a concept, and a theory is a model of how we're explaining reality.

    The hypercube is something I don't understand how moving 90 degrees will get to, it looks more like a 135 degree angle to me. But then its also related to time because its moving, placing it into the 4th dimension. Nice explanation!

    A little more carefully, the quantum theory of a superstring is only consistent in 9+1 dimensions. In other dimensions the superstring has what we call an anomaly, which means that the methods of producing a quantum theory from the classical theory break down.

    Hence a new theory that works like the old one and doesn't break down when you reach the anomaly is wanted. To anyone working on a new theory make sure it tackles this! :)

  5. I have heard alot about the different dimensions, I understand 1D, 2D, 3D, but 4D and 5D are a little confusing to me. Time is supposedly a dimension because you CAN travel through it given the right conditions(I.e gravity anomaly) But the 5th dimension is completely out of my understanding. I have read that there are 10 dimensions (http://www.universetoday.com/48619/a-universe-of-10-dimensions/) but I think that may be just a little bit leaning towards a theory rather then fact. If someone can explain what the dimensions are and how they work that would be nice.

    Thanks!

     

    P.S. I know I am going to take some heat about the gravity anomaly but if I do take heat for it at least I'll learn what the proper reference to it is. :)

  6. The problem with a consistent language, although obscure, is that it's symbology is consistent and a pattern will eventually reveal itself, with scrutiny. A letter or number is assigned a sound or meaning. You have to dissociate this connection between certain values and their equivalent interpretation.into a language someone else can understand. The associations must necessarily be random with each message, so a key has to be produced just for that message. I think that's how encryption works.

    The voynich manuscript nobody can decipher. It's a completely new language that nobody can figure out because it has no known base, making it next to impossible to "decode." If somebody made one that they knew how to read, and taught a few key people to read it, then it would be the world's most effective code for sending messages. Now I know that if people are involved it's bound to fail sooner or later. As time goes on somebody will be bribed and create a key or something, but if you can make one, it's entirely possible to make another. A code like this would be extremely useful, but I don't think anyone could make one. Anybody can come up with random letters forming words, and simple grammar, but making a complex grammar system like english would be extremely complicated in my opinion.

  7. Alright, first thing I'm going to say is that I got this from a book. The book is called Artemis Fowl: The Eternity Code. By Eoin Colfer I thought I should get that out of the way before someone says I got this from a book and it goes off topic. Now, inside the book a kid creates a code based off of no language. In other words, a completely new language that no one could decipher without a key of some kind. My question is if this code is entirely possible or if it's impossible to create. As far as I know if someone tried to make one their subconscious might make it too alike to a certain language, but that's just a guess. This is all speculation, and I'm just wondering if people think such a code is possible.

    Thanks

  8. You did nothing wrong. It is just that the conditions for an object to become a black hole are not fully understood. However, we know that under some general and physically reasonable assumptions that they do form. So the formula you have is okay as a general argument for the length scales involved. That is all I meant.

     

    Ok.

     

    You can look up surface gravity on wikipedia. I am not sure if you will follow the derivation, given your age.

    I read it, and while I didn't understand all of it, I looked up gravity of earth and read that, which made slightly more sense. Then I went back and read that page again and it made much more sense, although I don't fully understand 100% of the formulas

     

    I suspect there should be some factors of the speed of light. But we can pick natural units so that any constants are numerically equal to 1. (I will have to check carefully)

     

    Ok.

     

    The surface gravity of a black hole is basically the acceleration of a test body at the event horizon. In general this is not well defined, but for 'nice' black holes it is. (They need a particular kind of symmetry)

     

    It is like the g ~ 10 m/s^2 at the surface of the Earth.

     

    The Gravity of Earth gave me slightly more understanding of what your talking about. As for a black hole wouldn't its maximum fall speed be the speed of light?

    We are confused by the meaning of 'more gravity'.

     

    Stronger gravitational pull than the previous object is what I meant, but I now understand that it's the distance from the center.

    P.S. How fast would earth have to be rotating to completely counteract the gravity at the equator?

  9. This would be an interesting theory, perhaps the "plug" is gone and that's where all the dark matter is going.... Either way, they are right about thinking outside the box. The only time to do that is in the hypothesis stage, and even then its not always the best idea. Once you pass that you start to look for evidence, and boom. It supports a few things, but it contradicts everything else, and it's clearly a wrong theory. Also, newtons basic laws have been standing for a long time, and no one has ever proved them wrong. I also know that this discussion was finished a while ago but I like reading old topics.

  10. I would suggest typing out most of the words, and making computerized tables. They could hold all the information and it would be clearer and easier to understand. As for the computer I don't understand it, except your running off calculations off of irrational numbers that never end nor repeat, resulting in a computer. Good luck!

  11. Ok I get it, the closer you are to the center of the mass the higher the gravity is, since the density of black holes is as dense as it can get, the object is really small, allowing things to get way closer to the center of the gravity. The event horizon is the distance from the center that the gravity is so high, any light that hits the event horizon enters a gravitational pull way too powerful to escape, hence the black hole is the distance from the center that light can't escape from, therefore making it black. Ok, this coupled with the other posts completely work together and answer my question. Thanks!

  12.  

    It doesn't. So, for example, if the Sun suddenly turned into a black hole nothing would change; we would continue to orbit it in the same way. (Well, it would get very dark and cold ...)

     

    The difference is that you can get much closer to a black hole than you can an "ordinary" object of the same mass.

    Ok, that makes sense. But why does light get caught in a black hole?

  13.  

     

    No. Gravity depends on the mass (in Newtonian physics; in GR it's more generalized to energy) and how far away you are from the mass. So if you increase the density but reduce the volume to keep the mass the same, and your distance from the center of that mass is the same, the gravitational pull on you would be the same.

     

    You can write the mass as density*volume, so you can have an equation that has density in it, but the important dependence is on the product density*volume

    Ok thanks, that helps a lot.

     

    The formula you give is okay, it is based on the event horizon of a spherically symmetric non-rotating black hole. So, as a hand-waving argument this is perfectly okay.

     

    Your question about Newton's constant, the m there is meters.

     

    Your statement about a black hole having a huge amount of gravity is very slack. The usual thing one could mean by this is the surface gravity, which for a non-rotating black hole is 1/4M where M is the mass (in appropriate units).

    Right, hand waving argument. Not quite sure what it is but I'm guessing I did something wrong here. Either way the statement I made earlier was pretty slack, but the 1/4M equation I can't figure out. A black Holes mass, divided by 4, is a black hole's gravity if it's a non-rotating black hole. The mass would be measured in the appropriate units such as kilograms and grams? So a 1000 kilogram black hole, would have 250 gravity. I'm not sure what the appropriate unit for the 250 gravity would be, but if you could explain the equation a little better that would help. Thanks for the meters part though!

     

     

    Yes, this formula is correct. It is called the Schwarzschild radius: https://en.wikipedia.org/wiki/Schwarzschild_radius

     

     

    m3 is metres cubed (i.e. volume)

    kg is kilograms (and kg-1 means 1/kg or "per kilogram")

    s is seconds, so s-2 means 1/s2 (or "per second squared")

    Thanks, the universal gravitational constant is a lot easier if you know what the variables are.

    For galactic center sized black holes ( million or billion solar mass ) the density needed for collapse can be less than that of water.

    While for a star a couple of times bigger than our sun, even the density of neutronium will not allow for collapse.

    So the bigger something is, the less density is required to collapse in on itself if I am understanding this correctly. Is that correct?

     

    Ok now, why does a black hole have more gravity than its previous counter part that collapsed in on itself?

  14. Ok, while reading about the curvature about space time, black holes, and gravity, I came across a formula that tells you how small something has to be to become a black hole. Since a black hole has a huge amount of gravity at the event horizon, I came to the conclusion that perhaps gravity changes as density increases. The formula is as follows:

    R=(2GM)/(c^2)

    This means that you can calculate how small something has to be to become a black hole by "doubling the object's mass, multiplying it by the universal gravitational constant, and dividing the entire thing by the speed of light squared"

    This is a quote from the website http://io9.gizmodo.com/5974372/at-what-point-would-the-earth-become-a-black-hole

    I don't know how reliable this website is but the formula seems pretty sound and other people go with it so I trust it enough. Unless it's not a trustworthy site. This formula may also seem pretty easy to figure out, but the universal gravitational constant is this:

    6.67408 × 10-11 m3 kg-1 s-2

    10 to the -11 power is a really tiny number, negative 1 trillion if I did my math correct. But then again I might not have because I'm only in 7th grade. Either way m3 I have no idea what it stands for, nor kg, or s. Mass, kilograms, and something else is my best guess. If someone could please explain if density does modify gravity, and if you could explain the formula that would be great!

    Thanks.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.