On Thursday, October 4, 2018 at 3:55:31 AM UTC-6, Martin Brown wrote:

On 04/10/2018 07:24, Paul Schlyter wrote:

On Tue, 2 Oct 2018 14:09:34 -0700 (PDT), Gary Harnagel
wrote:

Less, but not zero.Â* You have NO idea how much less prevents life
and neither do I, so this is just yammering.

Neither do you have any idea about it.

Actually, I do. The fraction of heavy elements in the human body are in
parts per million, so a star's metallicity of 20% present value is QUITE
sufficient.

So you have no basis whatsoever to claim it is "almost certain" such
civilization will form

So you are dead wrong ... again.

and succeed in interstellar travel.

So you believe that, given a thousand years or so, we won't? How
pessimistic of you!

It is just fantasies and wishful thinking from you.

Nope. It is your pessimism and refusal to really THINK about what we
now know about the universe that clouds your judgment,

The "law of big numbers" doesn't help you here since there are too
many unknown and possibly extremely small numbers involved.

But WE ARE HERE. No Law og Large NUMBERS needed to project our future,
provided one isn't an abject pessimist with zero hope of any future at
all.

Since the biggest stars burn out the fastest I think that locally a few
places may have been favoured with high metallicity very early on and
you only need enough to make a few planets here and there to get going.

Indeed. The question is did they create heavy elements like Type Ia
supernovae do in our era. But finding a galaxy 11 billion years old with
20% the metallicity of our sun is promising. We don't need all that much.

https://en.wikipedia.org/wiki/Compos...ositio n_list

But the early universe was a much more violent place than today and
things closer together so any developing life would be more likely to
get zapped and reset by a close supernova or merging black hole pair.

But they were all gone in less than a billion years. There were big
galaxies with metals 11 billion years ago. Give them 5 billion years
to develop to our level, that means any such civilization would be 6
billion years ahead of ours.

So you believe only scientists can have new ideas?Â* You DO realize
that some SF authors ARE scientists, don't you?

These are by now quite old ideas. Yes, SF ages too as time passes.

Some of it ages quite well. When Kubrick flat imaging tablet devices for
watching TV in 2001 the idea was ridiculous but today they are
everywhere likewise for "communicators" in Star Trek. Partly I think
because the engineers and scientists who grew up watching these programs
thought they were cool ideas and tried to make them in reality.

However, wild hypotheses are definitely "almost certain" to be true.
Dream on, and get back if and when solid evidence for the existence of
these phenomena appears. And note that science fiction is not science
fact.

Nobody but you is trying to bring the topic to actual fact. That is a
straw-man argument, which you regularly try to do.

Clarke's First Law: "When a distinguished but elderly scientist states
that something is possible, he is almost certainly right. When he states
that something is impossible, he is very probably wrong."

However much you wish to make a wormhole it isn't going to happen
without a heck of a lot of energy

Maybe, maybe not. The Alcubierre metric requires humongus energy, but
other metrics (e.g., the Natario metric) require much, much less.

and some very exotic matter.

True. However, there is some hope that "negative energy" can be achieved
in a relative manner, e.g., via the Casimir effect.

And even
if you could make one its stability and unwelcome tendency to spagettify
things near it is an open question.

Having vision is easy, you just fantasize. Making it actually happen is
much much harder.

Again you are trying to foist another straw-man argument on me :-)

Chances are that any civilisation that has been around for so long will
be unrecognisable to us - we could even be living inside one of their
computer simulations of universes.

Computer, end program?

Believing doesn't make it true. It just means that believers will stick
to what they think they know in the face of all evidence to the contrary

That's YOUR definition of believing. Mine is that which is not refuted
by solid evidence.

(even to the extent of being burnt at the stake as a heretic - popular
with the two most prominent brands of Christianity in the middle ages).

Jan Hus, a Catholic priest, was burned at the stake for heresy. A
hundred years later Martin Luther found out about him and said, "We
were all Husians and didn't know it.

It comes down to how much vision you have vs. how big a pessimist
you are.

And in what way could VISION alone give us knowledge?

It gives us possibilities, and statistics gives us probabilities.

Show me a hyper advanced space faring civilisation or a signal from one
and I will be the first to agree that they exist. Until that time they
are at best a figment of your imagination. I am inclined to think that
the energetics and timescales for interstellar travel are so great that
very few if any civilisations ever expand beyond the confines of their
own solar system. Space is big - really really big. HHGG

http://www.quotationspage.com/quote/33085.html

All we need is an Infinite Improbability Drive :-)

Without any solid base, you are. It is easy to get caught up in wishful
thinking. But even a visionary must distinguish what we know from what
we merely believe, or else his visions will at some stage fall flat to
the ground.

No they can persist in the face of all the evidence to the contrary.

I'll be the first to recant if you present solid evidence that no
advanced civilization exists or that travel from one place to another
faster than light can get there is impossible.

Why not?Â* Dreamers make reality happen.Â* Pessimists just sit around
moping.

Nope. Realists are those who make reality happen. Dreamers just dream,
and when one dream fails they switch to another dream. To make things
happen you must be careful about distinguish speculation from knowledge..

Dreamers and creative people can think of things but it takes engineers
and scientists to make something that will actually work.

As YOU pointed out above, those who believed the dreamers made cell phones
happen. Of course, railroads don't happen until it's time to railroad.

But regarding extraterrestrial civilizations we humans cannot make that
happen. It either has happened or has not happened and we cannot do
anything about that. Your dreams can never create extraterrestrial
civilizations billions of years into the past.

If there was one they would probably be so abstract by now that we
wouldn't recognise them anyway. They would almost certainly have made
the transition to being a self improving AI singularity.

Would they? With billions of years of self-improvement, wouldn't that
include a highly-developed sense of responsibility to less developed
civilizations? Particularly, if developing civilizations have a tendency
toward self-destruction as some here have asserted.

Clarke's Third Law: "Any sufficiently advanced technology is
indistinguishable from magic."

When you talk about extraterrestrial life, don't you mean real
life in the real universe and not just your fantasies and wishes?

I believe in ET.Â* Why wouldn't you?

I consider it possible that they exist.
But I'm not expecting to see LGMs shopping in Tesco's any time soon.

Neither am I.

No, I'm a realist.

No, you're a mope-around.Â* And you cannot possibly be a "realist"
since you admit that we don't know.

The reality **is** that we don't know...

I think the evidence is tilting towards the idea that simple life might
be more common than we thought but unless and until we find an
independent occurrence on Mars, Enceledus or Europa there is no evidence
one way or the other. It is all about belief in the absence of evidence.

Yes, but it is MUCH more desirable to be an optimist rather than a
pessimist.

So you admit that calling yourself a realist is just as nonsensical
as my calling myself a visionary :-))

Calling yourself a visionary is clarifying, since it says you are
talking about your visions, not about reality. And, no, your visions
will never be able to create extraterrestrial civilizations billions of
years into the past.

I never said anything about creating ET. You're blathering straw-man
nonsense again.

Chances are they died with their star anyway. Interstellar travel for
life forms is in the seriously too difficult category. Interplanetary
travel for humans is still very very tough with only the moon having
ever been visited (and that was done 50 years ago).

Says a pessimist.

Indeed.Â* As a human being, however, I want to have a "world view.."
It's important to me.Â* I have developed mine over many years and
I'll hold it until and if the evidence refutes it.

That's fine, however you should admit that it's just a vision. Reality
itself can be very different.

Could be. Probably is. Even with 99% probability, that 1% can bite.

But, if you remember, I began this, um, treatise to demonstrate the
abject failure of atheism. I maintain that anyone who calls himself
an atheist is either ignorant of cosmology, incapable of critical
reasoning (i.e., stupid) or dishonest. One cannot rule out the
existence of a godlike race of beings.

I find it interesting how many fight against this very simple idea.