On May 13, 12:41 am, Bill Pfeifer
hotmail.com> wrote:> DharmaTroll wrote:
>> On May 12, 6:48 pm, Bill Pfeifer
hotmail.com> wrote:>>> Robert Epstein wrote:
>
>>>> now what aboutdarkmatter. any ideas?
>>>> and what is the difference between thestrongforce and theweakforce?
>
>>>> not that I mean to start a physics seminar or anything... :)
>
>
>
>
>> On May 12, 12:35 am, Robert Epstein
verizon.net> wrote:>>> DharmaTroll wrote:
>>>> On May 8, 1:13 pm, Robert Epstein
verizon.net> wrote:>
>>> cool!
>
>>> thanks for the info.
>
>>> now what about dark matter. any ideas?
>>> and what is the difference between thestrongforce and theweakforce?
>
>>> not that I mean to start a physics seminar or anything... :)
>
>>> Robert
>
>>> = = = = = = = =
>
>> Haven't checked out Bill's links, but here's a start, and you can then
>> research further.
>
>> And let me repeat that I'm a renaissance man (a philosopher in the
>> ancient sense) and not a physicist, so I can only give you the
>> intuitive, simple non-mathematical story, cuz datz all I know. But I
>> think that's all you want, so here goes. Ok, we have the 'standard
>> model' of physics, that has to do with sub-atomic particles. Two of
>> theforces, gravity and electromagnetism, act at a distance, and their
>> effect is inversely proportional to the square of the distance, so
>> that if an object is twice as far away there's only a fourth as much
>> of an effect on it and so forth.
>
>> Thestrongandweakforceshave no effect at large distances at all.
>> Thestrongnuclear force is what holds the nucleus of an atom
>> together. As the nucleus contains only protons with positive charges
>> and neutrons with no charge, the electromagnetic force would cause it
>> to fly apart instantly if it weren't for thestrongforce. So it's
>> the 'glue' that holds the protons together which repel each other
>> electromagnetically like two north poles of magnets stuck near each
>> other. However,strongforce is much stronger than the electromagnetic
>> repulsion (hencestrongforce) and so it keeps them glued together.
>> The glue that thestrongforce uses to glue the protons and neutrons
>> together are called gluons. That's how I remember it --strongforce
>> is stronger than the magnetic repulsion, and gluons are how thestrong
>> force glues together the nucleus.
>
>> The weird thing about thestrongforce is that its intensity does not
>> diminish inversely proportional to the distance as do gravity and
>> electromagnetism. Instead, thestrongforce gets stronger as the
>> particles get pulled apart. Now if you just kept pulling them apart
>> further and further, you might think thestrongforce gets stronger
>> and stronger infinitely, but that doesn't happen because as soon as
>> they get far enough apart (and we're talking still the size of the
>> nucleus of an atom), they get destroyed. Or more precisely, there's
>> this cosmic yin-yang effect, where two opposite particles, like a yin-
>> yang pair, pop up out of the void, and one connects to one of the
>> original pair of particles, and it's partner to the other of the
>> original particles, and now you have two separate pairs of particles
>> again with thestrongforce operating between them. No, I'm not
>> making this stuff up. Hence thestrongforce, though it gets stronger
>> as the distance gets greater, has no effect at all for more than a
>> very short distance. That is, pull too hard and you break, which
>> means production of 2 pairs of objects, and then within the pairs, the
>>strongforce again acts and keeps the partners together, but now the
>>strongforce between the separated pairs is zero.
>
>> Intuitively, I think of a coiled spring. Pull on the spring, and the
>> farther you stretch it, the harder it is to stretch further. Stretch
>> far enough and the spring breaks into two springs. Now each of the
>> new springs you can stretch again, but there is no pull between the
>> two springs because they have been completely separated. As for the
>> two yin-yang pair of opposites conjured up out of the void together,
>> think of magnets and how when you cut a magnet in half, separating the
>> south from the north pole, you get two new smaller magnets, each with
>> its own north and south pole, so that a pair of opposite poles was
>> created together, one going with one of the half-magnets and one with
>> the other, so that you now have two complete magnets. Well, that's
>> how thestrongforce works.
>
>> Theweakforce was added last in the standard model to explain
>> radioactive decay of atoms. There are three kinds of decay:alpha,
>>beta,gamma. Physicists could explainalphaandgamma, but notbeta:
>>alphadecay is explained by thestrongforce plus "quantum tunneling";
>>gammadecay is explained by excess energy accompanying the decaying
>> process. Betadecay was a mystery, and theweakforce was added to
>> explain it. Fermi postulated that a neutron decayed into a proton
>> plus and electron, but there was some extra energy missing, so he
>> postulated that it also created this ghost-like particle called an
>> antineutrino, which had this amazing property of being able to fly
>> through almost any amount of matter without hitting a single atom.
>> Theweakforce was created to explain this.
>
>> In physics lingo, theweakforce changes an up quark to a down quark
>> or down quark to an up quark, which is an action that can't be
>> explained by thestrongforce (or the other two macro-levelforces).
>> When you change an up quark to a down quark or a down quark to an up
>> quark, you get another one of these yin-yang pair creations out of the
>> void (seriously, I'm not making this up). In this case you create the
>> electron and an antineutrino (or a positron and a neutrino), which are
>> hurled out of the atom when a neutron decays into a proton: this is is
>> what we call radioactive decay of atoms, specificallybetaradiation.
>> Electrons and neutrinos (and other leptons) are not affected by the
>>strongforce, so this fought force was needed to explain what caused
>> this radiative decay, the hurling of an electron and antineurino out
>> into the world, to take place. Theweakforce is also short-range
>> only and vanishes completely on any distance larger than the size of a
>> nucleus of an atom. Just as thestrongforce uses 'gluons' to do it's
>> work, theweakforce uses 'bosons' to do its work, which are huge
>> masses, like a hundred times the mass of a proton.
>
>> As for dark matter, well, that's at the other end of the spectrum --
>> the outer space world. We all wondered whether or not after the Big
>> Bang, the expanding universe would fizzle out like fireworks in the
>> sky and have a slow cold death, or whether the expansion would stop
>> altogether, and then the stars would pull back together into a 'big
>> crunch' only to explode again into a new Big Bang. Bhante Punnadhammo
>> and I both intuitively liked the latter possibility, because it had an
>> organic feel to it, like a cosmic heartbeat. Well, it turns out both
>> were wrong because we recently found out that the expanding universe
>> isn't slowing down -- so there isn't the question anymore as to
>> whether it will slow down enough to stop and come back together.
>> Instead, it's speeding up, and we are actually accelerating away from
>> all the other galaxies! It's crazy and it doesn't make sense. So --
>> we invented dark matter to explain it. Dark matter also explains the
>> unusual ways that galaxies spin, which doesn't fit the normal models.
>> Dark matter can't be seen, but there is much more of it than ordinary
>> matter. Furthermore, and even more mysteriously, there is dark
>> energy, which gets really bizarre. I think that's a good place to
>> stop (especially because that's all I know about it without looking it
>> up).
>
> Thanks for the explanation. Much better for a dabbler like me than the
> links I pulled out of google.
Yeah, it's hard to find nice, clear intuitive explanations for some of
this stuff on the net. I just figured I'd take the time and try to
flesh out my own basic understanding, as I like reading pop-sci books
to get a grasp of the basic ideas.
There's a great book I read on dark matter and the new cool mysteries
of inflation and so forth that I'd recommend highly. The first half
is a nice summary, in simple layman's terms of astrophysics up to the
present, and then the rest of the book goes into the latest paradoxes
and mysteries, with all the dark matter and dark energy talk. You can
get this book used for a buck (plus 4 more for shipping) at amazon, if
you can't find it in the library. Btw, the author also has a
wonderful book on the history of the number zero that I couldn't put
down. After reading books like these, I can get the basic concepts
and articulate them fairly easily, as well as refute the
disinformation-meisters like Keynes, so I thought I'd share this one
with you if you want a nice read both on the history and present
speculation about that spooky dark matter and energy.
--DharmaTroll
"Alpha and Omega: The Search for the Beginning and End of the
Universe"
by Charles Seife 2003 ISBN-13: 978-0670031795
Review From Publishers Weekly:
Did the universe really begin with a bang, and will it end with a
whimper? Well-known science journalist Seife gives a comprehensive
survey of "theories of everything" from the ancients to the latest
discoveries. He explains why some scientists now theorize that the
universe may have begun-and may end-with a "big splat," and explains
the "ekpyrotic scenario," which says a parallel universe, like a giant
membrane, may be floating toward our universe. The recent, highly
publicized discovery that the universe is expanding at an ever faster
rate seems to support this idea. Another theory of everything that is
sure to be encountered more and more frequently in magazines and
newspapers is "M-theory," which combines the weird worlds of
supersymmetry and string theory. According to supersymmetry, every
particle has a twin superpartner endowed with very different
properties than familiar subatomic particles. This helps solve the
question of where the missing matter in the universe is, since the
baryonic particles that we are able to detect make up only 5%% of the
total. String theory postulates the existence of membranes
unimaginably minuscule and curled up in multiple dimensions. Seife
also explains how large-scale projects in Louisiana and other sites
are aimed at detecting gravity waves, one of the holy grails in
science. In an appendix, he lays odds on which scientists look
destined to win a Nobel Prize for their discoveries and the areas of
research that we will probably see in tomorrow's headlines. In short,
Seife provides lucid explanations of very complicated topics for the
science buff or well-rounded general reader.
