Hmmmmm...I wanna see their model for this.
RA, you'd have a better grasp of the physics behind this...what do you think? Locally, yes, I can accept this hypothesis, but globally? Musta been one h*lluva bolide, and I'm not convinced that smaller biota would have survived even in well-protected niches...availability of free atmospheric oxygen being a major factor.
Permian, maybe...K/T? Call me very skeptical.
Just watched a show on Science Channel this past weekend.
The Planets were all formed by a disk of dust that kept getting bigger. Then the big parts kept getting bigger, then gravity of the big ones made them bigger.
According to the Scientists on the subject Pluto and Venus Proved this theory.
Yet when it comes to Uranas and Neptune the quote is:
"No matter how many times we tired we could get no computer model to create these two planets. It just didn't work. We put in all the data and still came to nothing. I think the science is not yet perfect."
And as to the big extinction, there is one "respected archeologist, he looks like a hippie wears a hat all the time, (name escapes me) He said that there is a little tree frog in S. America and if you change his surrounding temp by a degree it DIES. He does not believe in the Asteroid but says what killed the Dinos was the little critters, Disease.
Land bridges afforded at time migration and some had immmunities others did not. ???
If Science was always right then scienctist would always agree. Either evidence says planets were formed one way or another. But then 2 PLanets do not fit into the mix at all.
As Stephen Hawking said, "The big bang happened, but can we say that a supreme being did not use that method to "create" the universe?" It is something that must not be left out.
Have you seen the Caloris Basin on Mercury? It is a crater the size of Texas and it fills about one-fourth of an entire hemisphere on Mercury.
4 billion years ago, a 100 kilometer-wide asteroid struck Mercury creating an impact crater that is 1300 kilometers wide. The Caloris Basin, as the crater is called, could hold the entire state of Texas!
The Caloris Basin on Mercury
Not seeing the thermodynamic models, it is hard to speculate. However, after talking with some of my colleagues yesterday, the jury is still out with me on this one. If there was this world wide thermal event, there should be evidence in the KT layer suggesting such. Is the carbon ratio in the KT layer synonymous with this type of thermal event? I just don't know. However, there is at least some recent data (albeit scaled down by a very large factor) from the Tunguska event of 1908. The best evidence to date is that a meteor exploded during entry into the Earth’s atmosphere. Trees were flattened as far away as 30 kilometers due to this explosion prior to surface impact. And interesting side note: There is an increase of Iridium in the local area, not unlike the Iridium found in the KT layer.
Why did the meteor “explode” prior to impact? It has been proposed that the aerodynamic pressure build up of the atmosphere was greater that the ability of the meteor to remain in one piece. This caused it to explode roughly 10 kilometers above the Earth’s surface with an estimated energy release similar to a 15 Megaton thermonuclear device. This in effect turned the kinetic energy into heat energy. The forest directly under this fireball was immediately ignited.
The 64-dollar question is would it be possible for a meteor with the mass required for the KT event also create enough of a pressure wave to have a similar breakup? Since there is evidence of a crater (Tunguska has none), this suggests the meteor did not succumb to a total atmospheric breakup (kinetic energy to heat energy). With this in mind, would there be enough ejecta during the reentry releasing kinetic energy to heat coupled with the actual impact to create this worldwide heat pulse?
