Alien visits, Cesium Clocks & Such
Michael McNeil
In article <6...@tekigm2.UUCP> timo...@tekigm2.UUCP (Timothy D Margeson)
writes:
>In article <13...@mmintl.UUCP> fra...@mmintl.UUCP (Frank Adams) writes:
>>In article <6...@tekigm2.UUCP> timo...@tekigm2.UUCP (Timothy D Margeson)
>>writes:
>>>
>>>What if carbon has not decayed at the same rate for all these years?
>>>Seriously, how do we know that the universe is stable enough for the
>>>assumption that carbon isotopes have and always will decay at the same rate?
>>> Timothy Margeson
>>
>>Estimates of the age of the Earth and of life on Earth do not depend on
>>a single factor like carbon dating. Sources for estimates include the
>>dating of rocks in which fossils are found. These estimates are based
>>mostly on various radioactive decay rates, which all give consistent
>>
>>Another independent check is the analysis of minor mutations, which happen
>>at a fairly constant rate as far back as we have been able to measure.
>>
>>It is asking too much of coincidence for the laws of the universe to change
>>in such a way that the rate of radioactive decay and everything else we
>>have been able to measure has changed in proportion. (It is possible that
>>they have changed as regard to things like the gravitational constant.
>> Frank Adams
>
> Einstein once pointed out that within a given frame, one cannot tell if the
>frame is moving or not. It seems to me that our dependence on the decay rate
>of radioactive compounds for age detection (although it's the best way we
>know to do) leaves something to be desired.
> Timothy Margeson
These two sentences have very little to do with each other.
> Cesium clocks and such do work for time envelopes as what we humans
>are used to dealing with, but over billions of years? We can't answer that
>question, so we make gross assumptions (best guesses, if you will) about the
>world around us. This sort of decision process has led the world into many
>dark ages. The world is flat, otherwise we'd fall off the other side is a
>good example of the masses leading the way of science. [...]
>
>I'm not a good soapbox spokesman, but when I see that something as simple as
>deviation in atomic decay rates is possible (prove me wrong if you can, or
>rather, prove to me that the decays have been constant forever),
I assume that you are a layperson who doesn't follow the details of
scientific progress (this seems obvious to me from your writing, but
please correct me if I'm wrong). It is easy to lean back and imagine,
"hey, maybe the rate of radioactive decay changes with time!" Your
conclusion is then deceptively easy: "why, those turkey scientists
must be just throwing sheer guesswork at us, calling it fact!"
No offense intended, but do you really think you can sit back in your
easy chair and out-think the thousands of very smart men and women who
have devoted their lives to investigating these questions? Scientists
do not close their eyes to obvious show-stoppers! (Any scientist who
does gets quickly and publicly taken to task by younger Ph.D.s at the
competing university down the road.) Not only are questions such as
whether physical laws vary with distance or duration scientifically
respectable, but they've been thoroughly investigated time and again!
And, unlike you, scientists don't just speculate in a vacuum. It's
possible to *see* if physical laws vary with distance -- just open
your eyes and look out across the universe. The orbits of stars and
galaxies, the spectra of everything in sight, betray the operation of
fundamental physical laws. (Among which, in case you weren't aware,
are the laws governing the radioactive decay of elements.) When we
see the same laws, unaltered by so much as a small factor, operating
half a universe away, a certain confidence is induced in those laws.
Also, many people in discussions of the past talk as if the past were
inaccessible and unknowable, therefore one can speculate with no risk
of rebuttal. In fact, we have a direct window on the past, a time
portal if you will, and this is our viewpoint on the universe itself.
Time in this cosmos of ours is a function of distance, and looking far
away in distance automatically means looking deep into the distant
past. When we see physical laws operating quite unchanged over those
enormous distances, we are also seeing -- here and now, eyeball to the
telescope -- those laws operating unchanged in the utterly remote past.
>I tend to react rather violently. People who take the stance that this
>IS THE TRUTH can be easily compared to several 'lion food' types.
I'll risk your getting violent at being contradicted. (You don't
*have* any lions, do you?) By the way, you certainly seem to be
taking a dogmatic stance in your article that you have "THE TRUTH."
And you lack what the scientists you criticize possess in abundance --
*evidence*. Your case would be stronger if some facts were with you.
>Science, having no better way of accounting for certain things that do not
>fit into prescribe models, tends to say that these things are flukes, or
>anomalies, and that the model is good anyway. I ask, how many theories
>have come and gone in the past fifty years, giving way to better theories?
There's one thing you're missing. Yes, theories do come and go. But
each theory must explain the world at least as well as its predecessors
did -- and no theory can contradict the evidence. On the other hand,
anyone who's ever taken a scientific measurement knows that flukes and
anomalies *do* occur in the data -- both random and systematic in type.
Random errors, basically just noise and fluctuations in the data, are
dealt with by well-understood techniques for estimating the accuracy
of measurements and computing standard error deviations for derived
results. However, when only one method is available, for dating, say,
it is possible for unknown *systematic* errors to reside in the method.
Systematic errors result from a flaw in our understanding of how a
physical process (used as a measurement tool) works, thus allowing
substantial errors to accompany it, beyond what has been estimated.
For example, thirty or so years ago inconsistencies began to be noticed
in the carbon-14 dating technique, when its results were compared with
known historical artifacts. The development of the technique of tree-
ring dating eventually provided enough reliable data points so that the
carbon-14 scale could be precisely calibrated -- accounting for the
variations in the rate of formation (not radioactive decay) of carbon-
14 in the upper atmosphere -- with the result that carbon-14 dating is
now as accurate in practice as it was formerly thought to be in theory.
The problem with carbon-14 dating only occurred because we had a time
scale for which there was (until the advent of tree-ring dating) only
*one* good dating method available -- carbon-14 dating. As a result,
lacking a "check," carbon-14 dating was vulnerable to a systematic
error -- which turned out to exist. (Cosmic rays, which create
carbon-14 in Earth's upper atmosphere, vary in density over time.)
However, since scientists are aware of the possibility of systematic
error, they attempt to eliminate the problem by finding methodologies
which are independent -- that is, which depend on somewhat different
physical principles for their operation. If several such independent
lines of evidence can be found, and the results generally agree with
each other, and those results aren't contradicted by other apparently
valid evidence, then and only then do scientists conclude they have a
result which is reliably known -- in this case, the age of the Earth.
Earth's age wasn't determined by any *single* dating method -- and thus
is not subject to systematic errors. The various dating methods used,
although they have varying degrees of accuracy, provide checks on each
other and establish upper and lower limits on the overall time frame.
Consistent corroboration via multiple independent lines of evidence --
that is the goal, and in dating Earth it has been more than achieved.
>Okay, what am I saying? When talking about time, especially when the values
>discussed are greater than 10,000 years, we really don't know what we are
>talking about. We are making gross assumptions that really don't bear any
>relationship with reality as we know it.
Why don't you just say *you* don't really know what *you* are
talking about! I repeat, science has considered this matter very
carefully, and has good reasons for the conclusions it has reached.
>If I'm wrong, then take your Cesium clock, orbit it around the moon a few
>times, compare it to an identical clock left on earth. If the two times are
>the same, I'll believe you that radioactive decay is constant. Otherwise,
>explain to me which clock has the correct time. Simple? Good. BTW, I believe
>just a test was done by NASA a few years ago, the clocks proved one of the
>relativity claims by Einstein, something about time dialation. The clocks were
>different when they returned, so I ask, whivh one IS the correct time? And
>which one do we use as a standard for figuring how old we are?
Why, the clock we have kept *with us* has the correct time *for us*!
Clocks that have gone *elsewhere* will record the correct time for the
path they have followed. All clocks are equally correct (if they keep
good time), but if they differ in their pathway through space and time,
they may show different results. This is to be expected; none of the
clocks are incorrect. Einstein taught us to comprehend this process.
And if you think Einstein is your ally in this discussion, forget it.
According to Einstein's theory of relativity, one could, for example,
take some radium-226, say (half-life of 1,622 years), and send it on
a spaceship on a trip around the universe, traveling near the speed
of light. Billions of Earth years later, the ship returns. When the
(original!) crew emerges, they don't *appear* to be billions of years
old. The container holding the radium is examined... and voila! The
radium hasn't decayed away! Are we then to conclude that you have
proved your case, and radioactive decay *does* occur at varying rates?
Not at all! This phenomenon (relativistic time dilation) is *already
factored into the theory*. Once again using Einsteinian relativity,
it is possible to compute the effect that an arbitrary pathway through
space and time -- such as that of our spaceship -- would have on the
actual time interval experienced, thus allowing us to correct for the
effects of the ship's movements. When this computation is performed,
we discover that only a few decades of ship-time have elapsed -- not
coincidentally, precisely matching what the various timepieces aboard,
whether cesium, electromechanical, or human, have registered. Thus,
we see that the radium has decayed at exactly its expected *constant*
rate. It is in this sense, and this sense alone, that scientists say
that the rate of radioactive decay is constant over distance and time.
>Thanks for listening, any comments will be read, and appreciated.
> Tim Margeson
Sorry if my reply seems strong (but your talk of violence and general
tone of I-know-you're-wrong is strong, too). All I ask is that you
allow in your imagination for the fact that others have imaginations
too, and unlike you, some have followed through and investigated the
matter -- in all its multitudinous ramifications -- *most* carefully.
If you want to discuss in detail the various lines of evidence which
are used in dating the Earth, or just why it is that scientists think
that the rate of radioactive decay is constant, I'll be happy to so.
(I'm directing follow-ups to net.origins, unless specified otherwise
by the responder, as that's where I believe this discussion belongs.)
--
Michael McNeil
3Com Corporation "All disclaimers including this one apply"
(408) 970-1835
{hplabs|fortune|idi|ihnp4|tolerant|allegra|glacier|olhqma}
!oliveb!3comvax!michaelm
The present investigation [using Cepheid variables for the
first time as an indicator of distances beyond the Magellanic
clouds] identifies NGC 6822 as an isolated system of stars
and nebulae of the same type as the Magellanic clouds,
although somewhat smaller and much more distant. A
consistent structure is thus reared on the foundation of
the Cepheid criterion, in which the dimensions, luminosities,
and densities, both of the system [NGC 6822] as a whole and
its separate members, are of orders of magnitude which are
thoroughly familiar. The distance is the only quantity of
a new order. The principle of the uniformity of nature thus
seems to rule undisturbed in this remote region of space.
Edwin P. Hubble, "NGC 6822, a remote stellar system,"
*Astrophys. J. 62*, 409-433.