This is the first in a series of posts exploring the effects of modern cosmological knowledge on the validity of the Bible. It is an ongoing discussion between me and two other people (BAA & WP) at the ex-Christian.net forums. BAA is an amateur astronomer, and he has done his best to simplify a very complex subject. Some of the technical details in this discussion have necessarily been glossed over. BAA started the discussion off by asking us to consider this question:
Two sailors, Bob and Jim, are on their yachts – one in the Atlantic and one in the Pacific.
They are hundreds and hundreds of miles from the nearest land or island. All they can see is the sky above them and water, extending to their respective horizons. Now, please consider these questions:
1. Is Bob’s horizon literally the edge of his world, which he could sail right off or is it just a visual effect of the curvature of the Earth, with the Atlantic carrying on beyond the limits he can see?
2. Same question, but applied to Jim, in the Pacific.
3. Allowing for time zone differences and the weather, if Bob and Jim could instantly swap places, would they notice anything significantly different in their ‘new’ locations?
BAA then followed up by giving us these links, which discuss the Copernican and Cosmological principles, for consideration:
My answer to BAA after reading the information at the above links was this:
Thanks, but that is some really deep stuff. I like science and cosmology but have a hard time comprehending it all. I do better with liberal arts subjects. lol… I will read over it a few more times.
BAA’s answer to me was as follows:
Don’t fret Jeff!
I’ve cited this technical stuff so that you can see that what I’m planning to explain here is kosher, supported by by hard science and reliable… that’s all! I never got as far as college and I don’t get the math behind it all, either. Anyway, let’s start off with Bob and Jim.
The answer to question #1 is obviously, No.
Bob’s horizon is just a visual limit to how far he can see. There’s no actual edge or end of the world for him to sail his boat off. Ditto for #2 and Jim. They both have their own horizon’s and neither of these is where their world comes to and abrupt edge or end. So, the obvious answer to #3 is that they’d notice no real difference, if they swapped places instantly.
Now, this is more or less the same kind of answers we get if we apply the Copernican and Cosmological Principles, when we look out into space. Just as Bob and Jim see themselves as the center of their reality, so we on Earth see something similar. Let’s ask ourselves another question. If we could instantly teleport ourselves a trillion light-years in any direction to another Earth-like planet, what would we see when we looked up at the sky?
Pretty much the same as we see from Earth.
That’s because the universe looks generally the same wherever you go and whatever direction you look in. The big words scientists use are homogeneity and isotropy, but in a nutshell, these mean that everything is more or less the same, everywhere. There’s no definable center to the universe. It just looks as if we’re at the center.
But don’t be fooled by appearances!
We know that Bob and Jim see themselves as being at the center of everything, when of course, they aren’t. It just looks that way to them. This is a visual effect of their fixed p.o.v. from onboard their yachts. Even if they swap places they still see themselves as being in the center of their reality. Wherever they go, they’ll always see things that way. And this explains why, if we instantly jumped a trillion light-years to another planet, this new p.o.v. would still seem to us to be the center of everything.
Another way of visualizing this is to think of yourself in a vast forest.
Wherever you look there’s nothing but trees to be seen. Walk ten miles in any direction and you see the same thing. Take a right-angle turn and go another ten miles… same result. Double back or choose a random direction. Go ten miles or a thousand, it makes no difference. Same result. If this forest isn’t just vast, but covers the e-n-t-i-r-e surface of the Earth (no seas’ lakes or rivers) all you will ever see is the same thing, no matter where you go and no matter what your viewpoint is. There will be no end and you can walk forever around the world, always seeing nothing but trees, trees and more trees.
This is, roughly speaking, what we see in space.
Anywhere you go, it looks generally the same. The universe has no definable center. What we see as the edge of the universe isn’t a physical edge – just as Bob and Jim’s horizons aren’t physical edges. The edge of the observable universe is just the limit of how far we can see. In their case, it was the curvature of the Earth that limited how far they could see. In our case, what’s limiting us is the finite speed of light.
I’m (just) old enough to remember Nixon’s call to Aldrin and Armstrong on the Moon, back in ’69.
The was a 1.25 second delay between them that made their conversation weirdly drawn out. Why? Because radio signals, like light, take a finite time to go anywhere. We see the Moon as it was 1.25 seconds ago – not as it is right NOW! We see the Sun as it was about 8 minutes ago. The signals from our Mars rovers can take up to 20 minutes to reach us. Voyager’s transmissions take hours to get here. The nearest bright star, Alpha Centauri, appears to us as it was in the middle of 2009. Why? Because it’s light takes 4.3 years to reach us – that’s why.
The Andromeda galaxy? It’s 2.5 million light-years away and so we see it as it was …2.5 million years ago.
Looking out into space means looking back in time. There’s no way round this. Because light, radio, X-rays and every other type of radiation travels at a fixed and limited speed, we’ll always see the universe as it was – never as it is, right NOW! Therefore, since the universe is 13.8 billion years old, we can’t see any further than that. This is the limit of our observable universe. It’s our visual horizon, the cosmic equivalent of Bob and Jim’s resepctive horizons on Earth.
So, the edge of our universe is a purely visual edge, nothing more.
The universe doesn’t just stop existing beyond that point any more than the Atlantic or Pacific oceans stop existing beyond the limits of Bob and Jim’s vision.
The main point to understand today is this.
There’s no scientific basis for assuming that we live in the center of the universe. It just looks as if we do. But once we understand that the universe looks the same from anywhere and everywhere, we can appreciate that the Earth isn’t central and isn’t special. Once we see that viewpoints can be instantly swapped without moving us any nearer to or further from the center (because there is no center), we have to conclude that our position in the universe isn’t privileged or important at all.
Part 2 is coming soon! Glory!