Thursday, August 6, 2009

The edge of the universe

This picture, according to Wikipedia, taken from the Hubble Telescope is the edge of the observable universe.

Beyond that I imagine is the speculated edge of the universe and then the real edge of the universe. It's slightly misleading to label this post "science" because what I'm really interested in here is the universe from it's observable edge onwards. It's really where science, 'the practice of rational observation,' starts to end and philosophy begins to take over. Questions abound: the observable size of the universe compared to the observable age of the universe, how event horizons works, how do we think about observed reality and current reality. (The 8 min sunlight to earth gap!)

So I was wondering (Radagast?) while their may be aliens etc out there in the universe, can we anticipate any surprises between the observable edge of the universe and the real edge of the universe? In otherwords alien life, if we find it, will probably be carbon or silicon based, there may be several more undiscovered periodic elements, star shapes and sizes etc, but can we anticipate any major surprises?

14 comments:

Radagast said...

Interesting question!

It's like photos of the horizon in a desert, such as this.

Occam's Razor suggests that the best prediction of what's past what we can see is more of the same, but in fact, anything is possible.

Luke said...

Great picture.

On a related tangent, what do you think of the "Black swan" theory? That just because we only know of white swans doesn't mean there could black swans out there.

From a Christian world view you'd say there is an edge wouldn't you? So that would imply a few consistent things from here to the edge?

Radagast said...

There might even be pink swans somewhere. As a fantasy and SF nut, I'm fascinated by the world of the speculative.

Science, I think, has to be fairly conservative, though ("all known swans are white") up until the day that new evidence appears -- although it is useful to distinguish between "all known swans are white" and things that are impossible per the known laws of science.

In radical speculation, disciplines other than Science (Mathematics, Philosophy, and Theology) are useful because they can tell us what's impossible ("square circles") as opposed to merely unexpected ("black swans").

To quote Father Brown: “Reason and justice grip the remotest and the loneliest star. Look at those stars. Don’t they look as if they were single diamonds and sapphires? Well, you can imagine any mad botany or geology you please. Think of forests of adamant with leaves of brilliants. Think the moon is a blue moon, a single elephantine sapphire. But don’t fancy that all that frantic astronomy would make the smallest difference to the reason and justice of conduct. On plains of opal, under cliffs cut out of pearl, you would still find a notice-board, ‘Thou shalt not steal.’”

The Borg said...

This isn't answering your question Lukey, but I think if there is alien life, it is going to be completely different to anything on earth. If you take the evolutionary story as the story of life, then life on earth arose out of a series of chance events (random mutations) and within a unique set of circumstances (eg the ongoing right conditions for life and its evolution).

Maybe the universe is big enough? Who knows?

There may be some self replicating life-like thing out there but due to its evolution in unique circumstances (eg a "living thing" made of dust particles "living" in space) it may be totally unrecognizable to us.

What do you think?

Radagast said...

Alien life *could* be radically different to anything on earth. Exobiology has always been a discipline without a (visible) subject matter, and so the fundamental principles by which extraterrestrial life could operate are really not known. Is non-carbon-based life possible, for example?

Nor is there enough evidence to assign a probability to extraterrestrial life -- all people have done is make a few very crude guestimates.

And, as Shyborg suggests, it might be so radically different that we don't even notice it.

Theologically, such life would have the same purpose as life on Earth which we don't notice, or stars which are too far away for us to see.

Luke said...

Thanks Shyborg and Radagast,

1. What if we were to assign a scale to the possible surprises, with 10 being discovery of the edge of the universe and 2 a new periodic element?

2. You need to check your presuppositions Shyborg. Theologically we know the universe can't like God be infinite and cannot be fundamentally chaotic, given the coherent special revelation of God. Therefore there would have to be some sort of theoretical boundary to the universe and what surprises we might expect.

Radagast said...

Father Brown again: The other priest raised his austere face to the spangled sky and said: “Yet who knows if in that infinite universe — ?”

“Only infinite physically,” said [Father Brown], turning sharply in his seat, “not infinite in the sense of escaping from the laws of truth.”


Subject to that proviso, I think Theology could live with a spatially infinite universe (Chesterton appeared to think it was infinite), although Science does suggest that the universe is actually finite.

I agree that the universe cannot be fundamentally chaotic. Hence, assuming that the known laws of physics continue beyond what we can see, we might see:

low surprise: the predicted elements from the island of stability, new kinds of stars, odd things happening to motion at the spatial limits of the universe, etc.

high surprise: new particles, additional physical forces (beyond the 4 we know -- electromagnetic, gravitational, weak, strong), new kinds of life, etc.

The Borg said...

Hey Lukatron, I don't think my argument supposed an infinite universe or chaos... not sure where you got the infinite part from... But as for chaos - when I say life arises by chance I'm not evoking chaos. Instead, it's a unique set of circumstances that allowed for biogensis rather than the sort of event that gives rise to something found commonly in the universe such as stars.

I'm also allowing for the possibility that God chose to create something earthlife-like somewhere else in the universe. Actually (and now I'm rambling) if we did find something earthlife-like we would be forced to choose from the following 3 conclusions:
1. this life form came from earth
2. this life form and earthlife have the common ancestry
OR 3. God exists and he made this life form for his own delight and glory.

The Borg said...

P.S. Why do you think that we can't have an infinite universe, theologically?

The Borg said...

Sorry for the triple posting... those 3 options are not mutually exclusive!!

Luke said...

I don't mind how many times you post cyber sister.

I was just pushing back at you when you said life might arise from "random mutations." You have to say that may appear random or chaotic.

P.S. Why do you think that we can't have an infinite universe, theologically?

Two reasons:
1. God is infinite so that would make two infinite things and raise akward things like which came first and if one did is it still infinite?
2. Genesis 1-2 uses boundaries and edges and patterns to describe the beginning of the universe therefore our worldview and definitions must include or imply them.

Radagast said...

I have to take issue with you on a few things there, Luke, even though you're addressing your sister :)

I think Theology *does* allow the universe to be infinite physically -- hence my Father Brown quote (although Science suggests a spatially finite universe, so it's a hypothetical issue).

When you say "God is infinite so that would make two infinite things," that's equivocating on two different meaning of "infinite." Spatial infinity does not imply "full of infinite potential" or "infinitely difficult to understand" or other things which are true of Divine infinity. Also IMO there's nothing in Genesis 1 that requires the sky to be spatially finite, although I agree that it implies that the sky is *ordered*.

As to "random," that's a tricky word. As a Calvinist, I don't believe anything can be truly "random." Perhaps "contingent" might be a better word, although personally I just use the word "random" to mean "not humanly predictable in advance" (in that sense, rolling dice is "random").

"When I use a word," Humpty Dumpty said, in rather a scornful tone, "it means just what I choose it to mean—neither more nor less."

Luke said...

Radagast,

This comment of yours has been brewing away for a while.

Can you flesh out a little more what you mean by different definitions of "infinite."

Radagast said...

Well, there's spatial infinity. Space could hypothetically be infinite but empty forever.

There's infinity of quantity. I can imagine an infinite flat desert, stretching forever before me, behind me, and to the sides, containing an infinite quantity of sand.

There's "full of infinite potential" -- anything non-contradictory is possible. This is true of God, but not of nature. Those other two infinities do NOT imply this one.

Then there's all the other infinities that apply only to God: omnipotent, omniscient, etc.

Does that make sense?

The problem with "infinite" as a word is that it's use ambiguously.