How many astronomers does it take to change a light bulb? 10^[(10)^100], because they love really big numbers.
As mentioned, as the universe slows (or accelerates) in its expansion, relative time increases (or decreases). Without an outside reference point this is not perceivable because everything is affected equally, except maybe on a subconscious level that I called "accelerated time syndrome" where it seems every year gets shorter. But what if the universe is expanding not only in the sense that everything is getting farther away from everything else, but expanding in size as well? Every particle making up every atom actually getting LARGER all the time. And what if this enlargement is happening so fast that the mysterious and undefinable force we call GRAVITY is actually just INERTIA, where everything is pressing against everything else as objects at rest tend to stay at rest? And how big does everything have to get before the universe doesn't fit anymore?
OK dumb idea......never mind. Let's stick with some cold hard mathmatical facts for a while before I sprain my prefrontal cortex.
I recently had a discussion with the ever-elusive "Dr. Betts" as to the immensity of the known Universe and came to the conclusion (again) that it simply is not conceivable by the human mind. The most tangible description I’ve seen is probably the intro to the Avatar papers, from which I will be stealing a few references. However, just for grins and lack of anything else better to write about, I will attempt to describe this immensity in a way that makes sense and thereby put our own existence into some perspective.
One giant leap for astronomers over the last century was the development of methodologies for determining the speed and distance of objects in space. The Doppler Effect is when a moving object emits sound, light or any other wave, the length of that wave is stretched as the object moves away from the emission or compressed as the object moves toward or tries to "follow" the emission. In sound this is manifested in pitch, the way a train whistle drops in tone as it passes. In light it is measured by spectral shift, and this shift can be used to calculate the velocity of an object. As we know, what we call the Sun is actually our closest star, one of thousands we see in the night sky and one of millions in our little corner of the galaxy. If we had a spacecraft capable of moving at 10,000 miles per hour it would take about a year to get to the Sun from here. That it would be such an overwhelming object in our sky at such a distance says something of it’s size and brightness to be sure. In this same craft at 10,000 mph the travel time to our next closest star would be 297,000 years. In this same craft from that point it would take an additional 11 million years to reach our closest neighboring gaseous star cluster, and 133 billion years to reach the closest sister spiral galaxy. From this point, galaxies and nebulae are similarly spaced out within this particular galaxy cluster. After 9 trillion years you would leave this so-called “island universe”, and from there in this same craft at 10,000 miles per hour, the next closest island universe would take an additional 7000 trillion years to travel to. This is a single straight line 300,000,000,000,000,000,000,000,000 miles long (I have no idea how to pronounce this number). Keep in mind that we are still in an isolated corner of the “known” universe, and more importantly, that this straight-line distance actually extends out in every direction. To create a number in square miles would be an exercise in futility since the number would be meaningless. It would seem real space travel is not possible, and suffice it to say there’s lots of empty space left over even with galaxy clusters containing a few dozen to a few hundred galaxies, each galaxy containing a few billion to a half trillion stars each quite similar to our own slightly smaller than average Sun. I had always wondered why they gave galaxies number designations instead of names, but with the telescopes we have today new ones are discovered every day and we’ve already identified more of them than there are words to apply to them. To keep from being too overwhelmed let’s just stay in our own galaxy for a moment. The Milky Way galaxy is a spiral galaxy of at least two hundred billion stars. Our Sun is buried deep within the Orion Arm about 26,000 light years from the center. If we were to pessimistically assume that only 1 per cent of all these stars have planetary systems that leaves 2 billion solar systems that are similar if not identical to our own. If we assume that out of all these systems only 1 per cent contain a planet capable of sustaining life that leaves 20 million planets similar if not identical to our Earth. If we assume that out of all these planets only 1 per cent have evolved life to our level or beyond that leaves 200,000 worlds with species similar if not identical to the human race. This is a yield of 1 ten-thousandth of 1 per cent of the stars in just our galaxy alone. Now assume that out of these 200,000 worlds that 1 per cent evolved races capable of space travel, either via wormhole, warp drive or some other violation of Einsteinian Law. That leaves 2000 alien races roaming the galaxy in search of intelligent life. Now are any of these races visiting Earth? Well, if they are searching for intelligent life then we are probably not that interesting to them. And, as demonstrated by this statistical numbers exercise, the odds of them even finding us are astronomical (no pun intended). But we can always imagine, and take cold comfort in knowing that however isolated, we are not alone in the Universe.