This is a picture from the COBE satellite which shows, roughly, the temperatures of the existing universe shortly after the so called "Big Bang" (which was neither big nor a bang; the term was coined as an insult to the theory). What we're looking at are very, very, very slight temperature differences in the "space-time" of the early universe. The working theory is that these differences provided the framework that galaxies emerged from later -- the existing "mist" of galaxies (don't forget - there are hundreds of billions of galaxies) is arranged along the patterns represented above.
Which is all fine and well. I get it. What I am struggling with lately (and believe it or not, I'm spending a good deal of time these days thinking about these types of things), is the difference between the expansion of "space-time", and the speed of light.
To explain: Consider a quasar. A quasar is not really a "thing", but rather a description of a certain stage of a black hole's existence. To wit, a quasar condition indicates the black hole is actively feeding on matter directly at hand, and usually happens at the early stages of the black hole - later in it's life, it does not have as much matter at hand, so cannot feed as much, thus does not produce much energy as a by product (quasars are defined by this release/"creation" of energy by the black hole).
Still with me? That was the easy part. Anyways, we only see quasars far, far away in the universe. Since space is so big, distance = time. When we look at any star in the sky, we are looking at light that is old - sometimes years old, sometimes hundreds of years old, thousands, millions, and up to billions of years old. We estimate the age of our universe to approximately 14 billion years old. We see quasars in the range of 3 billion years ago and older. That is, we are seeing them as they were a long time ago, since it takes time for light to travel.
What I don't get is this: All energy in our universe was created in the "big bang". This energy expanded at that moment, and continues to expand - this is our current reality. My dilemma is: Since all energy was created at the same time, how can we see something in the past? Should we not all be on the same level of "space-time" expansion? Or, is the speed of this expansion faster than the speed of light (the only explanation I can come up with)?
If you picture the universe as an expanding balloon on which we reside on the surface, you can visualize the expanding universe. How, in this analogy, could you look back into the "center" of the "balloon" and see the past, unless it simply took the light much, much longer to catch up with the expansion of actual space.
Any help?
2 comments:
Very good question. And thanks for the explanations, I needed them. I will check back to see if anyone can answer.
Also consider: Our solar system is at least second generation star, probably third or even fourth. Every generation prior we would see "in the past". Yet the very material that makes us up was involved in those older generations. So, again, it's as if the speed of expansion, of space, is much faster than the speed of light.
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