On Friday, October 5, 2018 at 3:40:17 AM UTC-6, Martin Brown wrote:

On 04/10/2018 17:39, Gary Harnagel wrote:

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

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.

It isn't very useful to a corporate being as a stellar plasma though.
You need at least enough material out to iron and a little bit beyond to
build a planet big enough to hold onto liquid water and an atmosphere
which is almost certainly a prerequisite to life evolving on any planet.

Sure. The existence of galaxies 11 billion years ago allows plenty of
time for all of that.

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

We might get to the other planets in that sort of timescale. I don't
expect the first attempt to visit Mars to work very well. Too many dodgy
optimists involved and not enough hard engineering.

Indeed. And the atmosphere (and low magnetic field) doesn't do a very
good job of absorbing/deflecting nastiness such as solar wind, etc.

We are here but that says nothing about how many more Earth like planets
there are in the rest of the universe.

The number is not important. All that's needed is ONE in hundreds of
trillions FEW BILLION YEARS AGO.

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

The human body doesn't last well inside a stellar interior.

If metals accounted for some of the stars 11 billion years ago, then there
was a previous generation of stars with less but still sufficient. And
when those 11-billion-year-old stars supernova, there will be even more.

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.

Or dead when their star expired.

Or moved to newer star systems.

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."

Let us know when you have invented perpetual motion or FTL travel then.

Straw-man baloney.

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.

You are in a world of science fiction fantasy divorced from reality.

It was scientists that suggested that, not any SF authors.

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?

I doubt they would be that cruel.

How cruel are we to ants and spiders?

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.

So you will believe anything at all then uncritically if there is no
solid evidence to refute it.

Straw-man assertion.

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.

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

All we need is an Infinite Improbability Drive :-)

If you believe in that then you really are very lost.

You REALLY don't have a sense of humor, do you. Methinks you do protest
too much :-)

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.

I can't prove it but it seems highly likely that FTL travel is impossible
- at least in the sense of moving faster than light in a vacuum.

If Alcubierre-type metrics are possible then FTL may indeed be possible.
But they may be based on something allowed by general relativity that is
not compatible with the real universe. For now, they must be considered
a possibility.

Shortcuts might exist if we can find a way to use them.

Given a few million years we might do so.

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.

Sometimes devices get invented before the technology that will enable
them to actually work satisfactorily. Babbages later difference engines
for example were just beyond Victorian manufacturing capability.

And Leonardo's inventions, too. It just wasn't time to railroad.

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.

They would also be evolving for all that time too so would be nothing
like their original form.

Maybe we just don't recognize what an ideal form would be.

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

It is a cute quotation and may well hold if you encounter a civilisation
with technologies more than a hundred years ahead of yours.

Maybe, maybe not. A MILLION years, certainly,

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.

You sound far too credulous.

What? You are disputing yourself?

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.

Why? Being over optimistic about going to Mars will probably cost the
crew that goes there their lives.

It's THEIR lives. I'm not THAT much of an optimist.

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.

I have a pretty good idea about the energetics for interstellar travel,
it isn't going to be easy and it may be impossible except in a few
special places where stars are very close together.

Impossible? That's a VERY pessimistic word :-)

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.

However the probability is more like 99.9999999999999999999999%

You don't know that and it's irrelevant anyway.

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.

You can't rule them out but neither can you rule them in.
Their existence or not is completely unknown.

But the probability is not zero, hence a critical thinker cannot claim
nonexistence without putting himself in a bad light.

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

Just because you believe something does not make it true.

--
Regards,
Martin Brown

And I didn't say I believed this. I only point out that aggressive
atheists are dishonest, ignorant or stupid.