| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
17 Oct 2006 04:29:40 AM |
| Object: |
Radio-active decay question |
I am not a physicist. I enjoy asking occassional questions to this
group.
I think the following is correct:
The total radio active material of element X could have been double its
current mass a half-life before.
If so, around the big bang, a large section of our universe should've
been heavy, radio active elements.
Just what percent of the universe is heavy radio active material now
and how much was there at/near the big bang?
TIA,
-Bhushit
.
|
|
| User: "Greg Neill gneill rem @ ove netcom.ca" |
|
| Title: Re: Radio-active decay question |
17 Oct 2006 07:14:51 AM |
|
|
<joshipura@gmail.com> wrote in message
news:1161077380.270296.128950@f16g2000cwb.googlegroups.com...
I am not a physicist. I enjoy asking occassional questions to this
group.
I think the following is correct:
The total radio active material of element X could have been double its
current mass a half-life before.
If no new materials were being made then yes, that
could be true. But lighter radioactive atoms are
being made all the time through the decay of
heavier ones so their numbers tend to be replenished,
and supernovas are cooking up new batches of
radioactive atoms all over the universe.
If so, around the big bang, a large section of our universe should've
been heavy, radio active elements.
No, it was mostly hydrogen with a pinch of helium
and a dash of lithium. The heavier atoms mostly
get cooked up in supernova explosions.
Just what percent of the universe is heavy radio active material now
and how much was there at/near the big bang?
Google: cosmic element abundance
.
|
|
|
|
| User: "Sam Wormley" |
|
| Title: Re: Radio-active decay question |
17 Oct 2006 02:16:02 PM |
|
|
wrote:
... around the big bang, a large section of our universe should've
been heavy, radio active elements.
The temperature and expansion rate of the early universe (first three
minutes or so) resulted in *only* hydrogen and helium with traces of
deuterium, lithium and beryllium.
http://www.mhhe.com/physsci/astronomy/fix/student/chapter26/26f15.html
When looking at the Universe about us:
o We find mostly hydrogen and helium. Why--we have compelling
evidence drawn from many corners of astronomy and physics that
the universe evolved from a hotter dense state. When one models
the hotter denser state of about the first few hundred seconds,
particle physics predicts that roughly 75% hydrogen and 24%
helium will be formed from the primordial soup. Observation
confirms these abundance's.
o We have a good understanding of nucleosynthesis of elements
through the iron group, including carbon, nitrogen and oxygen.
I refer you to to Lang (1999), "Astronomical Formulae Vol. I",
Sec 4.4, "Nucleosynthesis of the Elements", pp 402-432.
o We have some understanding of creation of elements with atomic
number greater than the iron group. The computing power and
detail during the relativistic collapse of stellar structures
is a tough problem for details... no hint whatsoever that these
processes are incorrect for the nucleosynthesis of the observed
heavier elements.
Ref: "Astronomical Formulae" Lang 1998 pg 103
"We now realize that elements heavier than iron cannot be
produced in successive static burning stages within stars.
This is because any nuclear reaction involving the iron
group of nuclei, with atomic weight A ~ 56, cannot provide
fuel for the thermonuclear fires that support a star and make
it shine. Instead, the iron-group elements act like seeds for
the synthesis of heavier elements by neutron capture. Such
processes were first suggested by George Gamow for nonequilibrium
nucleosynthesis during the early stages of the expansion of
the Universe (Gamow, 1948; Alpher, Bethe and Gamow, 1948), and
applied to the later stages of stellar evolution by Burbidge,
Burbidge, Fowler and Hoyle (1957), often called B²FH, and
independently by Cameron (1957)".
"Double-peaked features in the abundance curves Relative Abundance
vs Atomic Weight] (Fig. 5.27) indicate that two neutron capture
processes, called the r-process and the s-process, must synthesize
elements with atomic weights A greater than 60. The rapid (r- process)
neutron capture occurs on time scales of about 100 seconds, which
is rapid (r) compared to electron beta decay in the synthesis
networks, while the s-process is much slower (s), occurring over
scales of 10² to 10^5 years. All naturally occurring radioactive
elements with A > 209, including the long-lived uranium, U, and
thorium, Th, parents, 238U, 235U and 232Th, require the r-process,
which builds beyond mass 238 to nuclei that decay back to these
radioactive parents. The r-process probably occurs during stellar
explosions, called supernovae, that rapidly provide a large neutron
flux with a short duration".
.
|
|
|
|
| User: "Igor" |
|
| Title: Re: Radio-active decay question |
17 Oct 2006 10:55:53 AM |
|
|
wrote:
I am not a physicist. I enjoy asking occassional questions to this
group.
I think the following is correct:
The total radio active material of element X could have been double its
current mass a half-life before.
If so, around the big bang, a large section of our universe should've
been heavy, radio active elements.
No, those elements weren't even formed at the big bang. The lighter
elements up to, and including Iron were formed by stellar fusion much
later. But that was only after sufficient hydrogen, which was created
immediately after the big bang, had time to coalesce into stars and
start the fusion process. And the heavier elements were only formed
even later in supernova type explosions which are the fate of only
certain types of stars.
Just what percent of the universe is heavy radio active material now
and how much was there at/near the big bang?
No matter how you look at it, heavy or even light elements make up an
extremely tiny proportion of the universe. The dominant elements
remain hydrogen and helium.
.
|
|
|
| User: "Ben Newsam" |
|
| Title: Re: Radio-active decay question |
20 Oct 2006 10:59:27 AM |
|
|
On 17 Oct 2006 08:55:53 -0700, "Igor" <thoovler@excite.com> wrote:
No matter how you look at it, heavy or even light elements make up an
extremely tiny proportion of the universe. The dominant elements
remain hydrogen and helium.
Or dark matter, whatever that is.
.
|
|
|
|
|
| User: "John Bailey" |
|
| Title: Re: Radio-active decay question |
18 Oct 2006 07:35:48 AM |
|
|
On 17 Oct 2006 02:29:40 -0700, wrote:
I am not a physicist. I enjoy asking occassional questions to this
group.
I think the following is correct:
The total radio active material of element X could have been double its
current mass a half-life before.
If so, around the big bang, a large section of our universe should've
been heavy, radio active elements.
Just what percent of the universe is heavy radio active material now
and how much was there at/near the big bang?
I think your question is an excellent one. It's only partially
answered by the responses so far. After looking around, the best
suprise was this item from wikipedia:
(quote)
Carbon-14 has a half-life of 5730 years and would have long ago
vanished from Earth were it not for the unremitting cosmic ray impacts
on nitrogen in the Earth's atmosphere, which forms more of the
isotope. When cosmic rays enter the atmosphere, they undergo various
transformations, including the production of neutrons. The resulting
neutrons participate in the following reaction on one of the N atoms
being knocked out of a Nitrogen (N2) molecule in the atmosphere:
(formula too complex to copy and paste) (end quote)
http://en.wikipedia.org/wiki/Radiocarbon_dating
I suspect an inventory of all the ways radioactive elements can be
added to the mix in current processes, when combined with a good
estimate of the current mix and then regressed for 13.7 billion years
to check the starting mix for reasonableness--would turn up the fact
that we are missing some factors. Just a guess. Along with the
mystery of why there is little or no negative matter (positrons and
anti-protons etc) and what is dark matter/energy; just one more
question I plan to ask God--given the opportunity.
.
|
|
|
| User: "Autymn D. C." |
|
| Title: Re: Radio-active decay question |
20 Oct 2006 08:18:07 AM |
|
|
John Bailey wrote:
mystery of why there is little or no negative matter (positrons and
anti-protons etc) and what is dark matter/energy; just one more
question I plan to ask God--given the opportunity.
I'm here, the real version at least. Those aren't "negatiive" matter;
those are negative or conjugate charges.
#18240:
<http://egroups.com/group/free_energy/msearch?query=Autymn+antimatter>
Some dark matter are ashy compounds of many fortial motes; the else is
negative matter. Look up "New Model" on this group.
-Aut, your God
.
|
|
|
|
|
|
Related Articles |
|
|
