Dinosaur extinction: roasted alive at 800 ° C

General scientific debates. Presentations of new technologies (not directly related to renewable energies or biofuels or other themes developed in other sub-sectors) forums).
Christophe
Moderator
Moderator
posts: 79117
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10972




by Christophe » 06/01/11, 17:38

I saw the documentary well but a little too "affirmative" for my taste ... but as it is probably taken from a US thing we understand pkoi, zon always right :D

But the important thing is that it gives the main ideas of evolution!

moby25 wrote:What I always have trouble grasping is how we went from the inert to the living. Why and how bacteria appeared


Well, it is more or less explained: a lot of chance and chances I think.

It started at the bottom of the ocean in the soup of water loaded with carbon and warmed by the volcanic tulips underwater. For the "more complex" life we ​​needed the UV of the sun which made, among other things, H2O2 available after the glaciation of 15 million years ago 635 million years ago.

I did not know that there had been several other mega continents before Pangea, I wonder how we know it is so old !!

I also didn't know that complex life in the oceans (other than bacteria or microalgae) only appeared 500 million years ago. On the 24h scale this corresponds to 21h!

Christophe wrote:And if the Earth was only 24 hours old, modern man (30 years) would only appear in the last 000 seconds. The dinosaurs disappear at around 0.6:23 p.m. (calculations made taking 36 billion years of earth's life)


Then it took 120 million years to create the ozone layer and allow terrestrial life to develop from 380 million years ago.

If we fucked it up, we'll know where to go anyway :D

After there was a big reset (or almost) with the extinction of the permian: https://www.econologie.com/l-extinction- ... s-932.html which allowed the development of dinos ... the rest we know :)

But I learned more in 1 hour 20 minutes than in 10 years of history / geology / biology lessons ... : Cheesy:

(I took notes, I didn't memorize everything but now I know)

ps: the doc also talks about a well-heated atmosphere after the impact of the dino, not 800 ° C but evaluated at 275 ° C (zon found a thermometer?) ... enough to make the big roasted lizard ...
Last edited by Christophe the 06 / 01 / 11, 20: 59, 1 edited once.
0 x
User avatar
Obamot
Econologue expert
Econologue expert
posts: 28725
Registration: 22/08/09, 22:38
Location: regio genevesis
x 5538




by Obamot » 06/01/11, 18:03

What is still zarbi, it is that the eggs of the zoiseaux could be preserved as well as the offspring, while there are few "terrestrial" oviparous which survived. The conditions had to be badly bad to exterminate also some following generations until extinction ...
0 x
Christophe
Moderator
Moderator
posts: 79117
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10972




by Christophe » 12/07/12, 21:37

Were the dinosaurs multi-century old or warm-blooded?

Study dismisses main argument that dinosaurs were cold-blooded animals

By studying the bones of present-day mammals, Spanish researchers from the Institut Català de Paleontologia Miquel Crusafont (ICP) realized that their results challenged the main argument used to demonstrate that dinosaurs were cold-blooded animals. Their work has shown that mammals also possess "stop growth lines", structures thought to be characteristic of cold-blooded animals. The presence of these lines in dinosaur bones served as the main argument to qualify them as cold-blooded animals. The researchers did not prove that dinosaurs were warm-blooded animals, but by dismantling the main argument supporting the opposing theory, they largely reopened the debate.

The growth stopping lines

The growth of cold-blooded animals - so-called ectotherms - depends on external conditions. When these are unfavorable, the ectotherms see their metabolic rate slowed down. Even in favorable periods, their growth potential remains lower than that of warm-blooded animals. These variations in the development of ectotherms leave traces in their bones, the lines of growth stops, highlighted in cross sections. An analogy can be made with the tree rings which highlight the alternation of the seasons. Conversely, warm-blooded animals with continuous growth independent of external conditions would not show these lines.

The presence of these growth arrest lines in cross-sections of fossilized dinosaur bones was a strong case for the theory that they were cold-blooded animals. Theory supported by the fact that today's large reptiles like crocodiles have the same markings and are indeed ectothermic animals. However, this theory also suffered from certain shortcomings. Cold blooded animals are slow growing. As Meike Köler, one of the signatories of the research, points out, "a crocodile would need a century to measure 4 meters because its growth capacity is thirty times less than that of a warm-blooded animal". Knowing the size of certain dinosaurs such as the diplodocus which measured several tens of meters, the hypothesis that it was a cold-blooded animal appears difficult to justify.

An unpremeditated result

Meike Köler's team was not interested in warm-blooded mammals in order to test the hypothesis concerning dinosaurs. Originally, the researchers wanted to study the influence of the ambient environment on current mammals: growth as a function of the outside temperature, water and food resources, etc. By better understanding the impact of these factors on these species, the researchers wanted to shed light on the discussions on the physiology of prehistoric animals.

By studying these species of ruminant mammals living in different ecosystems, the researchers demonstrated that the bones of these mammals also carried lines of stop growth. The latter are then more the marks of an adaptation of the metabolism of the animals to changes in environmental conditions than directly associated with a different type of metabolism (hot / cold blood). This is how the researchers realized that their work challenged the commonly accepted hypothesis on dinosaurs. As Köler says, "no one had thoroughly studied mammalian bones, there was no consistent and comprehensive study on this topic."

This work highlights two essential points of the researchers' work. On the one hand, the results of a research project and its implications are difficult to predict exhaustively when the research project is defined. On the other hand, there are commonly accepted hypotheses, sometimes lacking solid foundations, which constitute as many new possibilities for future research projects.


http://www.bulletins-electroniques.com/ ... /70589.htm
0 x
User avatar
Flytox
Moderator
Moderator
posts: 14138
Registration: 13/02/07, 22:38
Location: Bayonne
x 839




by Flytox » 12/07/12, 23:18

It will be time to reestablish some truth about the extinction of the Dinosaurs even if it clashes with the convictions of some ( Obamot for example:

Image

Image

: Mrgreen:
0 x
Reason is the madness of the strongest. The reason for the less strong it is madness.
[Eugène Ionesco]
http://www.editions-harmattan.fr/index. ... te&no=4132
User avatar
Obamot
Econologue expert
Econologue expert
posts: 28725
Registration: 22/08/09, 22:38
Location: regio genevesis
x 5538




by Obamot » 12/07/12, 23:51

I close the eyes for this time : Lol: : Cheesy:
0 x
Christophe
Moderator
Moderator
posts: 79117
Registration: 10/02/03, 14:06
Location: Greenhouse planet
x 10972




by Christophe » 25/03/13, 19:08

Rebound: dinosaurs reportedly killed by comet

According to a new theory, it was a comet, not an asteroid, that would have damaged the dinosaurs. Only this explanation would justify the quantity, overestimated in the past, of iridium found in sediments dating from the Cretaceous-Tertiary crisis. Some experts are skeptical.

The news came a few weeks ago: a celestial body sealed the fate of dinosaurs 66,038 million years ago very precisely. It fell on the Yucatán peninsula (Mexico), where it gave birth to an astroblem 180 km in diameter called Chicxulub. The meteoritic origin of this site has been confirmed for many years, since large quantities of iridium were found in the sediments of the time. However, no natural terrestrial source can explain the values ​​detected. It is therefore more than likely that this iridium arrived from space.

By looking at this element, Jason Moore of Dartmouth College (United States) recently realized, with several collaborators, that the quantities mentioned were overestimated. To do this, he made comparisons with the concentration of osmium of extraterrestrial origin, which can also be found in sediments dating from the Cretaceous-Tertiary crisis. The spatial origin of the Yucatán crater is however not questioned. However, doubts were expressed about the size of the impactor.

It is commonly accepted that dinosaurs owe their disappearance to an asteroid approximately 10 km in diameter. A 2007 study even thought it had identified him with precision (the culprit was then called 298 Baptistina), but observations made by the Wise telescope finally exonerated the accused in 2011. According to Jason Moore, the celestial body having brought the iridium would be much smaller than we think. Besides, it wouldn't be an asteroid ...

A long-lived comet involved

This result, presented during the 44th Conference of Lunar and Planetary Sciences (LPSC) held from March 18 to 22 at The Woodlands (United States), raises questions. In fact, how could a celestial body less than 10 km in diameter have been able to create a crater 180 km in diameter? The answer is simple: he had a lot more energy (and therefore speed) than we think on impact.

Thus, the Chicxulub astroblem was created by a small object moving at a very high speed. According to the researchers, it can only be a long-lived comet, that is to say a celestial body made of dust, rock and ice whose period is more than 200 years. The trajectories of these structures are very eccentric relative to the Sun. Thus, they accelerate a lot when approaching our star, which explains why they arrive in the vicinity of our planet faster than an asteroid.

This information already suffers from several criticisms. Geochemistry makes it possible to determine the mass of iridium which spread over Earth during the collision, but not that of the impactor. Likewise, it is not possible to say with precision what percentage of it has spread over our planet or, on the contrary, has returned to space following the shock. According to researchers at Dartmouth College, 75% of the mass of the comet has been spread on Earth. But for other experts, an asteroid 10 km in diameter could explain everything if only 20% of its mass remained on our planet after impact. The famous saga "But who killed the dinosaurs?" Is therefore not yet complete. Strongly the next episode.


http://www.futura-sciences.com/fr/news/ ... mate_45442
0 x

Back to "Science and Technology"

Who is online ?

Users browsing this forum : Ahmed and 180 guests