pecker says:

# 24 bobbo “interesting definition of dark. Are you sure you are not anthropomorphizing the universe just a little bit?”

I’m not sure where I might be accused of anthropomorphizing. The only thing I can imagine is where I said ‘there is real darkness out there’. I wasn’t consciously hinting at any human darkness – just trying to say something like ‘there are patches of sky from which absolutely no light is coming’.

““Dark” as defined by what humans can see or including what moths can “see” in the infra red?”

If a photon or a radio wave is just the transfer of energy between two particles, the same definition of ‘dark’ could apply to infrared light or any other wavelength that we can’t see directly with our eyes.
A patch of sky that looks dark to us would also appear dark to a moth because there are no particles there.

“I do like the notion of every direction ending on a star.”

If that was the case, every bit of the night sky would appear bright white as you would be looking directly at the surface of a star.

“I don’t think that would define an infinite number.”

I was just trying to make the case for there being darkness and that there must be a finite number of stars. But you are right, if you wanted a white-hot night sky you could have either:
– a finite number of stars packed tightly into a finite universe,
– a finite lump of stars floating in an infinite universe, or
– an infinite number of stars in either a finite or infinite universe.

“But, if the universe isn’t infinite, whats on the other side?”

Personally I favor the idea that the universe is finite and, on large scales, space is looped around – if you travel in one direction for long enough you end up back where you started. Similar to not falling off the edge of what looks like a flat world because it is actually spherical, when seen at larger scales.
From that perspective there is no way of getting to an edge; no edge or ‘other side’ exists.

bb says:

#31
Consider the infinity of all positive integers compared to the infinity of both positive and negative integers. Then, compare that with the infinity of all rational numbers between 0 and 1 … or the even ‘bigger’ infinity of all irrational numbers between 0 and 1.

Mathematically, all these infinities are the *same*! There is no such thing as a bigger infinity compared to another infinity.

But I have a terrible time trying to wrap my mind around that – the same thing happens when I study quantum physics. God *does* play dice with the universe!

pecker says:

# 35 bobbo,
“Ok, so when the universe is said to “be expanding” what is it expanding into?”

Hmm, that’s a tough one. I haven’t thought about that for some time. If I was to put money on it, I’d say the universe was expanding into something unknowable.

It is possible that there are limits to what is discoverable about the universe. In fact, the universe may even be setup so it’s impossible for us to even prove that there are limits on what we can know about it’s underlying workings. If that is the case, from our perspective within it, there would be no physical way of finding out what is ‘outside’ of the universe.

Our brains, the dimesions we see and even physical relationships like ‘inside’ and ‘outside’ are properties of the universe we are within. Even if there weren’t limits on what we could find out about this universe, how could we infer anything about another ‘adjacent’ universe if our concepts like ‘adjacent’ and ‘next-to’ can only be applied to this universe.

I guess you could say this is defeatist, but I tell myself it’s practical and simplifies things – allows me to sleep easy beleiving it’s not my fault I don’t know what’s going on.

As for the infinite number of stars thing. I read the argument in a book discussing big-bang vs steady-state theories years ago. I will see if I can find exactly how it went…

pecker says:

bobbo, I found it, it’s called Olbers Paradox

deowll says:

The role played by humans, in fact our entire galaxy, in the Universe would seem to be to trivial for mere words to express.

Improbus says:

What is beyond the observable universe? /dev/null,

JimR says:

Energizer knows how big the universe is.

Glenn E. says:

Ya know, they can make these incredible powerful telescopes and spy satellites. And I see very little reason for needing to send humans out into space, to try and make the very same measurements, and pictures, that these unmanned devices can do. It’s simply not worth the risks, to justify man’s presence, at taxpayers’ expense. In order to fulfill a bunch of defense contractors’ dream budgets. That’s all the US Space program is really about. Keeping these leeches in the black ink, between wars. As soon as any serious spending reform threatens the program, saving Lockheed’s or Boeing’s bottom line, becomes the final argument. SCREW THEM. They’re existence isn’t guaranteed in the Constitution. I wish everyone in California, and in the Tv and film industry, would stop acting as if the world will come to an end without their precious Space program. They’re often in league with the NASA contractors, ya know.

Or at least reign in NASA’s spending, and stop training and preparing for a manned “Mars Mission” that’s never going to happen. Trust me, it won’t. Astronauts talk a good “flight”. But I’ll bet none of them have signed up, FOR REAL, to go to Mars. And NASA treats anyone who does ask to go, as possibly insane! So they’re not even taking their own goals seriously. Go ahead and volunteer, and see if they don’t lock you away.

Let’s stick to risking unmanned probes, to do the rock sampling. We don’t need to risk human bodies in space, to do 99% of this work that a machine can do. Just because it’s more glamorous that an American astronaut hero is doing it. And gets more appropriations from Congress, than probes do.