Freethought & Rationalism Archive

Jesse · 09-26-2002, 11:19 PM

I like how shifty-eyed they all look.

atrahasis · 09-26-2002, 11:19 PM

Quote:

Originally posted by Doubting Didymus:


Which missing links? What in blazers are you talking about?

Thats for you to figure out

Don't have eyes!!! Cant you see what ohwilleke has??? I know a place where you can have your eyes fixed to a size much more than this

Jamie_L · 09-27-2002, 09:10 AM

Well, lets see, we've covered dinosaur extinction and human civilization. What have we missed?

Missing links? Well, not to humanity. But to birds, yes. It is generally accepted now (as far as I know - no sources to offer) that birds evolved from dinosaurs. Want a feel of whay it might have been like when dinosaurs ruled the earth? Go to an emu farm.

Ancient civilizations? Well, you could conceive of non-human civilizations, but there is absolutely no evidence that I know of to suggest anything of the sort. And there is a fair amount of fossil data from those time periods, so one would expect to be able to recognize something if there were some kind of civilization going on back then.

Lastly, I believe there were all sorts of species extinctions around the time the dinosaurs kicked the bucket. Given the prevailing hypothesis, it's not that surprising.

Jamie

beoba · 09-27-2002, 09:31 AM

Quote:

Originally posted by Black Moses:
Reasearch has shown that the sumerian, the maya and may be also the Aztecs had a highly developed civilisation that came to an abrupt end..The reason to this is a subject to much debate so far...

From what I remember, it was the Spanish Conquistadors there, not much mystery involved.

Ted Hoffman · 09-27-2002, 09:44 AM

Black Moses The Dinosaurs, did they even exist? If yes, what killed them. Is there something we don't know?

There is a lot we don't know. A few (unknowns/challenges) from the links you provided (I have highlighted problems/ areas of weaknesses with what we have today) are below:

a) "The main problem with both hypotheses is the issue of the selectivity of the mass extinction; as you saw before in the background section, some organisms were wiped out, while others were unaffected. Can climate change really explain the differential selectivity of the K-T event?"

b) "Our lack of understanding of the physiology of dinosaurs makes the issue more complex; if they were endothermic, why did they not survive like birds and mammals? If they were ectothermic, why did small dinosaurs not survive like small reptiles?

c) "many studies have focused on the extinction of dinosaurs alone, and have forgotten about the more substantial marine ecosystem collapse. The fossil record suggests that some marine reptiles died out several million years prior to the K-T boundary""

d) it is not easy to prove (test) causation (as noted before), and that most of the ages of the rocks that different evidence comes from are questionable. It is not certain whether there is a gradual decline in the global fossil record, or if there was a sudden catastrophe; some studies in some areas show evidence pointing to different answers.

Black Moses: Can the Dinosaurs story help also connect the missing links in man?

The weakness with this question is it does not state what "missing links" you are referring to. However I think that the extinction theory of dinosaurs might be a model that parallels theories on the catastrophic roots of religion and perharps, mankind and panspermia. But there is such a huge time gap between the K/T boundary and emergence of homo habilis? Neanderthal man? to link the two.

Black Moses Is it only the Dinosaurs that were destroyed? Could there have been also a remote civilisation that was also destroyed in this period?

Again, the time gap is too huge to reasonably link the two.

Black Moses Reasearch has shown that the sumerian, the maya and may be also the Aztecs had a highly developed civilisation that came to an abrupt end..The reason to this is a subject to much debate so far...

Its incorrect to try to conflate the lost civilization and the demise of the dinosaurs precisely for the above reasons.

My take on the dinosaurs is that they were wiped out by a combination of huge volcanism and ejecta that was hitting the earth from an exploded planet under EPH (Exploded Planet Hypothesis). The strengths of this theory (over single asteroid impact hypothesis, sudden climactic change [the nuclear winter thingy]), are explained by Tom Van Flandern as follows:
[Note that it also has greater explanatory power as far as formation of asteroids are concerned, it explains the huge presence of iridium, presence of microtectites and diamonds in the boundary, the discreteness of the global event, absence of K/T boundary in antarctic regions, numerous hot zones of radioactivity in Africa, oceanic and atmospheric compositional changes etc just read on]

Quote:

The geological K/T boundary event at 65 million years ago was global in extent and included the southern hemisphere. [1] Yet a terrestrial impact event, however major, ought logically to confine most of its damage to one hemisphere of the Earth. Global damage requires special circumstances. Dust injected into the atmosphere, for example, would eventually spread around the Earth, but only within a limited range of latitude. Seismic waves transmitted through the Earth might produce major earthquakes at the focus point on the far side, but no plausible model exists to link the giant impact event at Chicxulub in Central America with, for example, the geologically simultaneous Deccan Traps giant volcanism episode in India.

Recently, Kevin Pope showed that the impact of a 10-km sized object on the Earth 65 million years ago could not, as has been widely assumed, trigger a dust-connected “cosmic winter” with global effects. [2-5] His key finding: “The global mass and grain-size distribution of the clastic debris indicate that stratospheric winds spread the debris from North America, over the Pacific Ocean, to Europe, and little debris reached high southern latitudes. These findings indicate that the original K-T impact extinction hypothesis – the shutdown of photosynthesis by sub-micrometer-size dust – is not valid, because it requires more than two orders of magnitude more fine dust than is estimated here.”

Further, since 1991, U.S. geologist Dewey McLean has been suggesting that a K/T boundary impact winter would have been "too transitory, or feeble, to be recorded in the geological record, and not of sufficient magnitude to trigger global biological catastrophe". [6,7] McLean’s and Pope’s papers further the conclusion that the K/T boundary event was not a single impact. Indeed, any overview of the totality of evidence for the nature of the K/T event turns up some evidence inconsistent with all hypotheses but one. Let’s briefly examine that evidence.

Ejecta from an impact is generally limited in range by its maximum speed of about 2.5-3.0 km/s. Anything ejected at higher speeds is vaporized by the shock wave. [8,9] Calculations show that this maximum speed might be sufficient to hurl debris up to 1000 km or so from a terrestrial impact site, but certainly is not enough to spread ejecta globally. For example, Cretaceous stratigraphy is observed to be disturbed only out to a distance of roughly 100-200 km from the Chicxulub crater.

Here is a list of the main features already identified at the K/T boundary [10]:

far more iridium than can be explained by terrestrial processes or slow accretion from space
other siderophile elements, consistent with one or more major impacts
microtectites and diamonds in the boundary clay
a verified global extent and discreteness
shocked quartz well beyond what volcanism can produce
abundant carbon ash
mass extinctions occurring mainly within inches below the boundary layer
“event beds” around the Caribbean Sea
inland seas drained
numerous “hot zones” of radioactivity, especially in Africa
the Deccan Traps, and the onset of an extended period of unparalleled global volcanism
atmospheric and ocean compositional changes
a single global fire
extinction of 70% of species

So we must ask, was all this the result of a single asteroid impact producing the 200 km-diameter crater at Chicxulub in the Yucatan Peninsula? Or was something more involved? The answer is clearly the latter. Consider these points:

A global set of major craters all date (by at least one technique) to the same 65 Mya epoch: Manson (Iowa), Kara (Western Siberia), Kamensk, Gusev, and an unnamed impact in the Pacific Ocean. [11-14] The diameter and abundance of quartz grains are larger in western North America than elsewhere in the world, suggesting that the single largest impact was the Chicxulub event. But the other craters clustered near the same time indicate it was not the only event.
The K/T boundary mostly consists of two distinct claystone layers. The upper (soot, iridium) layer is 3-8 mm thick claystone with multiply shocked quartz. The lower layer is 1-2 cm thick claystone, but lacks shocked grains. Two contiguous, segregated ejecta layers suggest two different geologically-simultaneous causes operating.
Gorceixite (altered tektites, with identical swirl patterns) is segregated within each layer, suggesting that different impact events formed these glassy beads.
A single bolide impact cannot simultaneously explain the pattern of major floral extinctions on land and other extinctions at sea.
A Central American impact is not a likely cause for draining inland seas or producing hot spots in Africa or volcanism in India.
Sediments in Cuba range from 5 to 450 meters thick, probably from a giant wave. The (upper) ejecta layer is 50 cm thick in nearby Haiti, far more than at any other site, suggesting a major impact within 1000 km, which would still be far from the Chicxulub crater in Mexico.
The K/T boundary layer is apparently absent from the Antarctic regions.

Indeed, studies of this K/T mass extinction event contain many suggestions of a cause other than a single impact event. For example, Shoemaker and Izett [15] suggest two or more impacts from a split comet are needed to form the double boundary, especially because there is more than one associated crater. Moreover, plant roots appear in the lower layer (the result of the global fire?), but not in the upper one, indicating that not enough time elapsed between the two events for plants to grow again. That makes coincidental, unrelated impacts very unlikely.

The point about the inland seas may be another telltale clue. Among other indicators of this, apparently an intra-continental sea covered the middle of North America during the Cretaceous period, but disappeared near the K/T boundary. [16] Evaporation of a large, distant body of water would not be an expected consequence of an impact event. Neither is a single global fire. However, both are predicted consequences of heating of the biosphere by a massive, prolonged, heavy bombardment of meteors, as would follow for example the explosive break-up of a planet-sized body elsewhere in the solar system. [17]

The diamond/iridium ratio in the boundary clay layer may constrain the type of impactors. The observed ratio is close to the value found in type C2 chondritic meteorites, one of the most common meteorite types. [18] The diamonds found at the K/T boundary are confirmed to be of extraterrestrial origin, not shock-generated or terrestrial, based on delta C-13 measures. [19] So we are definitely talking about an event of extraterrestrial origin, not a purely terrestrial one. Any such event that might produce the requisite meteors would surely have affected the Moon as well. That implication is apparently confirmed by an analysis of lunar crater formation dates by Schultz, showing three dating peaks, one at 65 million years ago. [20]

Yet another indicator of an exogenous cause for this event is that, although it was nearly global in extent, Earth’s southern polar region was apparently largely excluded. [21] Unfortunately, Earth’s northern polar region lacks a land mass to enable us to determine if it was or was not affected. An exogenous event would generally exclude one polar region because distant bodies near the planetary plane spend up to six months of each year continually below the horizon as seen from each terrestrial polar region. So the observed global pattern seen for the K/T event is consistent with multiple impacts and meteors from an exogenous source taking place over of period of at least one day. The spread in arrival times for multiple fragments from an explosion several astronomical units away is certain to be greater than one day, exposing the entire surface of the Earth except one polar region to meteors and impacts. The following sequence is predicted:

an initial high-energy blast wave consisting of radiation and plasma, requiring days to pass
a break-up debris wave consisting of asteroids and meteors, requiring weeks to pass
a high impact period consisting of asteroids and comets, lasting about 100,000 years
a normal impact period consisting of asteroids and comets, lasting up to 100 million years for asteroids in earth﷓crossing orbits

Here is David Raup’s assessment of Pope's study: “The strong implication is that the impact explanation of the K/T extinction will fall if the dust cloud hypothesis falls.” This may now be seen as referring only to failure of the single impact hypothesis. Instead, we see much to support the already massive body of formally unchallenged evidence for the explosion of at least one, if not several, former planetary bodies in our solar system over its lifetime. [22-33] An excellent match of the exploded planet hypothesis to all the observational evidence in the solar system, not just the K/T-related points discussed here, strongly supports the conclusion that a planetary explosion was the catalyst for the terrestrial K/T boundary mass extinction event, one of the two greatest extinctions since life became abundant on Earth half-a-billion years ago.

References[1] Science 294, 1613 & 1700-1702 (2001).
[2] CCNet 14/2002.
[3] GSA Release #02-04, 2002/01/23.
[4] Geology 30#2, 99-102 (2002).
[5] <a href="http://www.gsajournals.org/gsaonline/?request=get-abstract&issn=0091-7613&volume=030" target="_blank">http://www.gsajournals.org/gsaonline/?request=get-abstract&issn=0091-7613&volume=030</a> &issue=02&page=0099>.
[6] D.M. McLean, Global biomass burning: atmospheric, climatic, and biospheric implications, Levine, J. S., ed., MIT Press, Cambridge, 493-503 (1991).
[7] <a href="http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/impwintr" target="_blank">http://filebox.vt.edu/artsci/geology/mclean/Dinosaur_Volcano_Extinction/pages/impwintr</a> .html
[8] Science 271, 1387-1392 (1996).
[9] CCNet Special, 10 July 2001.
[10] Thanks to S. Krueger for some items on this list.
[11] Lunar & Planetary Science XXII, abstracts, 961-962 (1991).
[12] Nature 363, 670-671 (1993).
[13] Nature 363, 615-617 (1993).
[14] Nature 288, 651-656 (1980).
[15] Science 255, 160-161 (1992).
[16] Science News 141, 72-75 (1992).
[17] E. �pik, Irish Astron. J. 13, 22-39 (1977). In a 1978 colloquium and subsequent discussions at the U.S. Naval Observatory in Washington, DC, �pik acknowledged that evidence for an exploded planet survived his own falsification test, and agreed that the “nuclear winter” effect of smoke from the meteors would keep the biosphere cool enough to prevent all life from perishing.
[18] Nature 352, 708-709 (1991).
[19] Nature 357, 119-120 (1992).
[20] P.H. Schultz and S. Posin, Global Catastrophes in Earth History, LPI Contrib. No. 673, 168-169 (1988).
[21] Nature 366, 511-512 (1993).
[22] T. Van Flandern, Dark Matter, Missing Planets and New Comets, North Atlantic Books, Berkeley, chapter 11, (1993; 2nd edition 1999) – synthesis of exploded planet hypothesis (EPH) evidence.
[23] Icarus 36, 51-74 (1978) – technical justification for the EPH.
[24] <a href="http://metaresearch.org." target="_blank">http://metaresearch.org.</a> “Solar System” tab, “EPH” sub-tab – recent updating and distilling of the most telling EPH evidence, and how its predictions have fared; to be published in 2002.
[25] Mercury 11, 189-193 (1982) – the EPH as an alternative to the Oort cloud for the origin of comets.
[26] Icarus 47, 480-486 (1981) – the EPH’s “satellite model” for comets as an alternative to the “dirty snowball” model.
[27] Science 203, 903-905 (1979) – asteroid satellite evidence, confirming an EPH prediction.
[28] Science 211, 297-298 (1981) – technical comment on previous paper.
[29] Asteroids, T. Gehrels, ed., U. of Ariz. Press, Tucson, 443-465 (1979) – theory and observations of asteroid satellites.
[30] Dynamics of the Solar System, R.L. Duncombe, ed., Reidel, Dordrecht, 257-262 (1979) – short summary of selected EPH evidence.
[31] Dynamics of Planets and Satellites and Theories of their Motion, V. Szebehely, ed., Reidel, Dordrecht, 89-99 (1978) -- short summary of selected EPH evidence.
[32] Comets, Asteroids, Meteorites, A.H. Delsemme, ed., U. of Toledo, 475-481 (1977) – short summary of EPH evidence with technical critiques and author responses.
[33] Science Digest 90, 78-82 + 94-95 (1982) – popular exposition of the EPH and its implications

For a clearer understanding of EPH, check <a href="http://iidb.org/ubb/ultimatebb.php?ubb=get_topic&f=57&t=000444&p=4" target="_blank">This thread</a> where a meteorite scientist (beausoleil) is locked in debate with Tom Van Flandern (expert in celestial mechanics) over EPH.

Hope this sheds more light.

[ September 27, 2002: Message edited by: Intensity ]

atrahasis · 09-27-2002, 11:12 PM

Intensity has done a good job <img src="graemlins/notworthy.gif" border="0" alt="[Not Worthy]" /> <img src="graemlins/notworthy.gif" border="0" alt="[Not Worthy]" /> though i have a cup of question for him..

(a)Was man around at the K-T event..(O.K i know even he was he still at the hunter and gatherer stage) If he was how did manage survive such a catastrophic event..

(b)Though the K-T event and the sumerian event are separated by a big gap of time, could an almost similar event have caused the sudden 'death' of most ancient cities...
----Alan alford suggests the passage of Niburu near the earth to be cause of its wobble

Hope this sheds more light.

Yap it did,.. thanks

Jeremy Pallant · 09-27-2002, 11:24 PM

Quote:

Originally posted by Black Moses:
Was man around at the K-T event.

No. Mammals, yes, homo sapiens, no.

atrahasis · 09-28-2002, 12:35 AM

Quote:

Originally posted by Jeremy Pallant:


No. Mammals, yes, homo sapiens, no.

Not only homo sapiens, even homo habilis

[ September 28, 2002: Message edited by: Black Moses ]

Jesse · 09-28-2002, 02:47 AM

Black Moses:
Not only homo sapiens, even homo habilis

Nah, not even close--check out the <a href="http://www.wsu.edu:8001/vwsu/gened/learn-modules/top_longfor/timeline/timeline.html" target="_blank">hominid species timeline</a>:

As you can see, australopithecus to homo sapiens all lived within the last 5 million years or so. The "hominoids", the group which includes both "apes" and hominids like us, probably only diverged from monkeys in the early part of the Miocene epoch, which lasted from 24 million years ago to 5 million years ago (you can see a timeline of all the geological periods, along with major evolutionary changes associated with each one, <a href="http://www.sdnhm.org/fieldguide/fossils/timeline.html" target="_blank">here</a>, while a more detailed timeline with separate pages for each period can be found <a href="http://www.palaeos.com/Timescale/default.htm" target="_blank">here</a>).

In contrast, the dinosaur extinction happened 65 million years ago, when there were no hominids, no apes, and no monkeys. It's possible some of the earliest <a href="http://helios.bto.ed.ac.uk/icapb/collection/museum/beth97/prosim.htm" target="_blank">prosimians</a> (which today are represented by forms like lemurs and bushbabies) had evolved by the time of the dinosaur extinction, but that's it.

Incidentally, you should take Intensity's post with a large grain of salt--virtually no one in the scientific community takes the "exploded planet hypothesis" seriously (see the <a href="http://iidb.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=57&t=000444" target="_blank">When the gods came down</a> thread if you're interested).

[ September 28, 2002: Message edited by: Jesse ]

Ted Hoffman · 09-28-2002, 03:57 AM

Ohwilleke said :For that matter the oldest evidence of humankind (or pre-human hominids) is about 1,000,000-5,000,000 years ago which is still long after the dinosaurs expired. Morever, there are multiple lines of corroborating evidence (gentic diversity, archeology, location of fossil finds, linguistic patterns) that suggest the humanity orginated in Africa, so the likelihood of finding human fossils older than the oldest pre-human fossil finds made in Africa is remote.

Actually, the earlist human ancestor, based on the ProCon Skull (Proconsul man?) is supposed to have lived 22mya. The proConSkull is below:

09-28-2002, 02:47 AM	#19
Jesse Moderator - Science Discussions Join Date: Feb 2001 Location: Providence, RI, USA Posts: 9,908	Black Moses: Not only homo sapiens, even homo habilis Nah, not even close--check out the <a href="http://www.wsu.edu:8001/vwsu/gened/learn-modules/top_longfor/timeline/timeline.html" target="_blank">hominid species timeline</a>: As you can see, australopithecus to homo sapiens all lived within the last 5 million years or so. The "hominoids", the group which includes both "apes" and hominids like us, probably only diverged from monkeys in the early part of the Miocene epoch, which lasted from 24 million years ago to 5 million years ago (you can see a timeline of all the geological periods, along with major evolutionary changes associated with each one, <a href="http://www.sdnhm.org/fieldguide/fossils/timeline.html" target="_blank">here</a>, while a more detailed timeline with separate pages for each period can be found <a href="http://www.palaeos.com/Timescale/default.htm" target="_blank">here</a>). In contrast, the dinosaur extinction happened 65 million years ago, when there were no hominids, no apes, and no monkeys. It's possible some of the earliest <a href="http://helios.bto.ed.ac.uk/icapb/collection/museum/beth97/prosim.htm" target="_blank">prosimians</a> (which today are represented by forms like lemurs and bushbabies) had evolved by the time of the dinosaur extinction, but that's it. Incidentally, you should take Intensity's post with a large grain of salt--virtually no one in the scientific community takes the "exploded planet hypothesis" seriously (see the <a href="http://iidb.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=57&t=000444" target="_blank">When the gods came down</a> thread if you're interested). [ September 28, 2002: Message edited by: Jesse ]</p>

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09-26-2002, 11:19 PM	#11
Jesse Moderator - Science Discussions Join Date: Feb 2001 Location: Providence, RI, USA Posts: 9,908	I like how shifty-eyed they all look.

09-27-2002, 09:10 AM	#13
Jamie_L Veteran Member Join Date: Oct 2001 Location: U.S. Posts: 2,565	Well, lets see, we've covered dinosaur extinction and human civilization. What have we missed? Missing links? Well, not to humanity. But to birds, yes. It is generally accepted now (as far as I know - no sources to offer) that birds evolved from dinosaurs. Want a feel of whay it might have been like when dinosaurs ruled the earth? Go to an emu farm. Ancient civilizations? Well, you could conceive of non-human civilizations, but there is absolutely no evidence that I know of to suggest anything of the sort. And there is a fair amount of fossil data from those time periods, so one would expect to be able to recognize something if there were some kind of civilization going on back then. Lastly, I believe there were all sorts of species extinctions around the time the dinosaurs kicked the bucket. Given the prevailing hypothesis, it's not that surprising. Jamie

09-27-2002, 11:12 PM	#16
atrahasis Regular Member Join Date: Mar 2002 Location: South of Sahara Posts: 216	Intensity has done a good job <img src="graemlins/notworthy.gif" border="0" alt="[Not Worthy]" /> <img src="graemlins/notworthy.gif" border="0" alt="[Not Worthy]" /> though i have a cup of question for him.. (a)Was man around at the K-T event..(O.K i know even he was he still at the hunter and gatherer stage) If he was how did manage survive such a catastrophic event.. (b)Though the K-T event and the sumerian event are separated by a big gap of time, could an almost similar event have caused the sudden 'death' of most ancient cities... ----Alan alford suggests the passage of Niburu near the earth to be cause of its wobble Hope this sheds more light. Yap it did,.. thanks

09-28-2002, 03:57 AM	#20
Ted Hoffman Veteran Member Join Date: Feb 2001 Location: "" Posts: 3,863	Ohwilleke said :For that matter the oldest evidence of humankind (or pre-human hominids) is about 1,000,000-5,000,000 years ago which is still long after the dinosaurs expired. Morever, there are multiple lines of corroborating evidence (gentic diversity, archeology, location of fossil finds, linguistic patterns) that suggest the humanity orginated in Africa, so the likelihood of finding human fossils older than the oldest pre-human fossil finds made in Africa is remote. Actually, the earlist human ancestor, based on the ProCon Skull (Proconsul man?) is supposed to have lived 22mya. The proConSkull is below:

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