The Infinite Universe

[kewell_]

I would like to suggest the following proposition for discussion.<br /><br />According to the big bang theory, if we could trace the evolution of the expanding universe backwards in time we would find that at some stage it will have shrunk to half its present size. Likewise at various earlier times it would have been a quarter, then one eighth, then a sixteenth and so on of what it is now until, by continuing the process we would eventually come to the big bang. At that point we should find that the universe was infinitely dense, infinitely hot and infinitesimally small, or so we are told.<br /><br />One important assumption underlying this scenario is that the universe is and always has been finite in size. But no one knows how big the universe really is; whether it is finite or infinite. As far as I know, there is nothing in the laws of physics that precludes the possibility that the universe is infinite.<br /><br />Suppose, for the sake of discussion, that the universe is infinitely big? One would reasonably expect, I think, that the same laws would hold true as they do now and the same evolutionary description as given above would apply but with this difference, that when we trace the history of the expansion backwards in time to when the universe was, say, half its present size the universe would still have been infinitely large. This is because half of infinity is infinity. Likewise, so is a quarter, or an eighth or a sixteenth or any non-zero fraction of infinity, no matter how small.<br /><br />Following this line of logic, if we arbitrarily trace the evolution of an infinitely large universe as far back as we like to any finite time in the past we must find that the universe was then also infinitely large. Even if we continued with the process indefinitely the universe would still be infinite. And so a hypothetical universe that is infinitely large now but finite in age must have been infinitely large at the time of its origin. But if the big bang theory in its pre

 

[weeman]

This topic can venture in so many ways.<br /><br />As Einstein once said, "the universe is finite, but unbounded."<br /><br />It depends on how we define finite and infinite. Many physicists who are in favor of the big bang will say that the universe expands only into itself, because the universe is all that there is. If this universe is truly all that there is, we could essentially say that it is infinite, because it represents everything in existence.<br /><br />Another way to look at an infinite universe is that if you travel in a straight line through space, you can travel forever and never reach an end to the material universe. I think this is how many average people view the universe. <br /><br />The universe can also be infinite if we apply it to the structure of a sphere. Space may be curved so that it curves back in on itself. Lets say that you are traveling on a sphere that had no recognizable surface features. If you kept traveling on that sphere, and there was nothing to help indicate that you were traveling in circles, would you assume that the surface is infinite?<br /><br />More than likely you would <img src="/images/icons/smile.gif" /><br /><br />However, it doesn't exactly mean that the sphere is infinite, it just appears that way. This might be the nature of our universe. It is possible that it had a beginning in time and place. <br /><br />I wouldn't be surprised if we one day found out that the universe is infinite. However, it makes me ask a lot of questions. The way I see it, if the universe is eternal, it has always been here. This would have to mean that time is eternal along with it.<br /><br />So, shouldn't our own existence almost disprove the fact that the universe could be infinite? If time and space had been here for an infinite amount of time before Earth, then it would have taken infinity years for Earth to be created, meaning it should never have happened in the first place.<br /><br />Infinity creates a lot of dilemmas and blunders within our current <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>