Re: Shielding spacecraft against cosmic radiation

On 16/03/2024 6:15 am, Jeroen Belleman wrote:

On 3/15/24 16:11, John Larkin wrote:

On Fri, 15 Mar 2024 13:11:29 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
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On 3/15/24 10:35, John Larkin wrote:

On Fri, 15 Mar 2024 07:28:39 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
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On a sunny day (Thu, 14 Mar 2024 10:38:47 -0700) it happened john larkin
<jl@650pot.com> wrote in <s3d6vi95gfrbs6omoula55soaktalpggru@4ax.com>:
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On Thu, 14 Mar 2024 16:46:07 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
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On a sunny day (Thu, 14 Mar 2024 08:13:31 -0700) it happened John Larkin
<jl@997PotHill.com> wrote in <in46vipa7a3eb6q7au6alobve5vfmv5jso@4ax.com>:
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On Thu, 14 Mar 2024 06:13:43 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
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On a sunny day (Wed, 13 Mar 2024 03:54:24 -0700) it happened John Larkin
<jl@997PotHill.com> wrote in <ae13viptr1sskaqq1h2ru1j9i85sdecfrd@4ax.com>:
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On Wed, 13 Mar 2024 07:09:47 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
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On a sunny day (Tue, 12 Mar 2024 14:18:18 -0700) it happened john larkin
<jl@650pot.com> wrote in <34h1vihp32geb2olkcscfksbr8k0bdgdmu@4ax.com>:
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On Tue, 12 Mar 2024 06:22:55 GMT, Jan Panteltje <alien@comet.invalid>
wrote:
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Shields up: New ideas might make active shielding viable
Active shielding was first proposed in the '60s. We’re finally close to making it work.
https://arstechnica.com/science/2024/03/shields-up-new-ideas-might-make-active-shielding-viable/
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bit of static oelectricity, 1 MV ?

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That's all absurd, cramming a crew into a tiny dark cylinder, deep
inside tons of magnets, to reduce their radiation exposure a little.

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Yes that may be more dangerus, tha tI why I like the elctrostatic solution.
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Space is not people-friendly. Earth is.
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Traveling to or living on Mars woud be lethal. Living on the moon
would be bad too.

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Maybe we could convert some comet, live inside it,
use its material for power water and  shelter
and put an engine on it and start interstellar travel:
https://en.wikipedia.org/wiki/%CA%BBOumuamua

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You go first.

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Oh I would not mind flying the comet thing, would want to have a say in the design and food chosen though.
but it will take generations to reach any target destination.
So you have to bring whole families ,
or as things go now, just some skin and have a computah hatch you
and teach you when growing up near the destination.
Makes you wonder if the first life on earth was brought here in a similar way
(circular reasoning).

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Earth is too good to be an accident, and our life form is too complex
to have evolved from inorganics. Other civiizations in the universe
have probably advanced for billions of years. So it's likely that
Earth and DNA-based life were designed, maybe as a high school science
project. I give it a B-.

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Well I won't attack your religious beliefs

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I expressed no religious beliefs, and it's good that you wouldn't
attack any.
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RNA World is a religious belief. Concensus and faith without evidence.
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Just watched some news story where a sort of computer robot was teaching kids...
Again, an other science program today on TV about planets: all sort of basic chemistry was found
on some moons and asteroids.

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Sure. Chemicals are not life, as a junk box full of parts is not a
working electronic instrument.
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They did a testing in the lab and made RNA from just basic chemicals added some heat cycling and dry soak cycle
like you will find on planets (sun, tides):
https://phys.org/news/2022-03-insight-life.html
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we are just a chemical reaction really.
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We are an astoundingly complex structure that uses chemicals and
quantum mechanics. At least I am.

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from elementary particles to atoms to molecules to self-replicating

RNA (check)

from RNA to DNA and ever more complex forms like us (check)
Readup on Darwin
:-)

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Read up on the ways our cells operate and reproduce. It's astounding.
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Darwin was very smart, but he had no idea how cells work. I think that
if he had, he'd have been skeptical of random evolution and selection
as our origin.
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And we are skeptical of your intelligent design stance. For that
matter, there are quite a few blunders in living beings that an
intelligent designer wouldn't have made.

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What you call my "stance" is one conjecture. I have others that you'd
approve of even less.
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Our cells are extraordinary, so their creation might have been an
extraordinary process. Refuse to think about possibilities if that's
your style.
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There are youtube videos about cell replication that are mind
boggling. It doesn't work until a zillion fiendshly complex things all
work, and the cell defines them for itself.
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Thinking about possibilities helps electronic design too.

 There are lots of chemists and biologists who think that self-
replicating RNA is a credible step on the path towards evolving
life. There is no need for the seeds of life to have come from
elsewhere than earth, although that possibility is not excluded.
 It's remarkable that the reproduction of RNA and DNA still today
can be made to work simply by cycling the temperature of the right
mixture of chemicals, much like day and night cycles, as may well
have happened on a young earth.
 To our current knowledge, actual intelligent designers are even
less probable than random mutations producing a working cell. How
did the intelligent designers come to be? They would have been
subject to the same kind of constraints as life on earth, the
right conditions and enough time.
 In fact, as long as we haven't found evidence of life elsewhere
in the universe, we can't have any real idea of how common or rare
it is. However, we *can* be pretty confident that *intelligent*
life is at least a few million times less likely than just any
life. On those grounds, I have less trouble believing in evolution
than in intelligent design.
 Darwin's evolution provides a plausible path to the complex life
we see today, without requiring intelligent or divine intervention.
That's its strength. Postulating such intervention is superstition
unless direct convincing evidence is found.
 As for the possible existence of alien civilisations with billions
of years advance on us, I'm skeptical. Based on what we see on earth,
I tend to think that technically advanced civilisations are unstable.
I think they'll blow themselves up rather quickly, on cosmic time
scales.

That assumes that everybody is as silly as we are.
There people who look at human social organisations over the past few thousand years and see evidence of the evolution of better modes of government. I grew up in Australia where the constitution was ratified in 1901. It works better than the US constitution, which was ratified in 1776, and the UK's arrangements which got extensively reworked from 1832.
I spent 19 years in the Netherlands where the constitution got dramatically reworked  "In 1917, like in 1848 influenced by the tense international situation, universal manhood suffrage was introduced combined with a system of proportional representation to elect the House of Representatives, the States-Provincial and the municipality councils. The Senate continued to be elected by the States-Provincial, but now also employing a system of proportional representation, no longer by majorities per province."
Proportional representation seems to be a key advance leading to multi-party democracy and coalition governments which seem to work better than their Australian, UK and US equivalents.
We'll probably learn to do even better in future if the more primitive arrangements in places like the US and Russia don't produce a catastrophic failure before they get cleaned up.
--
Bill Sloman, Sydney