Mass Extinctions - A Threat from Outer Space or Our Own Planet's Detox?

[Mr. McD]

University scientists suggest extraterrestrial theories are flawed and that more down to earth factors could have accounted for past mass extinctions.

Earth history has been punctuated by several mass extinctions rapidly wiping out nearly all life forms on our planet. What causes these catastrophic events? Are they really due to meteorite impacts? Current research suggests that the cause may come from within our own planet – the eruption of vast amounts of lava that brings a cocktail of gases from deep inside the Earth and vents them into the atmosphere.

http://www2.le.ac.uk/ebulletin/news/press-releases/2000-2009/2006/03/nparticle-cjk-whw-tkd

[opihimoimoi]

1. Its Both.....

[Warpy]

2. There's also a branch of science that states life is an artifact

of planets and may exist in forms we haven't conceived of on planets where anything remotely terrestrial is impossible.

Since "primordial ooze" experiments have found all the precursors, including complex proteins, to be created rather quickly (in hours, not eons), this may be the closest we can come to the truth of the matter.

Planetary based and controlled mass extinctions make perfect sense according to this paradigm, planets simply resetting themselves whenever one type of life has run its course.

[central scrutinizer]

4. but if they find life on other planets,

will it taste like chicken?

[sutz12]

3. This is kind of old news.

It's been on the Science and Discovery channels. The Yucatan meteor is the consensus end of the dinosaurs, and the Siberian super volcano covers one of the other mas extinctions.

[Odin2005]

5. The K/T extinction is the only one with proof of an extraterrestrial cause

Ever since the K/T impact basin in Mexico confirned that an impact played a role in the K/T extinction there has been a fad of blaming impactors for every mass extinction. It's about fucking time that stupid fad started losing popularity. Not all mas extinctions are caused by giant impacts and not all giant impacts cause mass extinction. The enviroment needs to be under stress for a giant impactor to cause a mass extinction. The impactor associated with the impact basin under Cheasapeake Bay had no apperent long term affects. Just before the K/T impactor hit, the enviroment had been stressed by lots of volcanism in India and the Rockies, and a rapid drop in sea level at the very end of the Cretaceous destabilized ecosystems by the formation of land bridges and a huge decrease in available shallow sea area.

The Permian extinction is beleived to be caused by volcanism and release of marine methane deposits causing a rapid increase of global temperature by 10 degrees C, and a rapid drop in oxygen levels casing when a rapid drop in sea level exposed anoxic marine mud, sucking the oxygen out of the air.

[General Paranoia]

6. Err... not so much - maybe evidence is showing up for most

Gosh, I didn't know that it was a fad to take into account that the earth gets Lucifer's Hammered every so often. Until all mass extinctions have overwhelming evidence as to their cause, we don't know what caused "ALL" of them. As soon as I heard they found the Chicxulub crater I ran to checkout where the Deccan Flats (in India) was at the time (you get my drift?). I was puzzled that it took a couple of years before someone put forward a paper on what happens when the energy from a sizable impact reaches the other side of the earth. If you need a simple picture, look at Saturn's Moon Mimas. There are fracture lines all over the side opposite the crater. India wasn't exactly right next door to Mexico at the time but they had some whopping eruptions right about that time.
:wow:

I suppose the environment was under stress when the Moon was created because if there was an ecosystem here at the time, there were a considerable number of mass extinctions. Many Scientists whose field of expertise is the Earth seem to think the biggest bangs must come from Volcano's. I wonder if they think a volcano gave birth to the Moon. I know we have had some big volcanoes but could you point to one that put LOTS of (or any) magma into orbit? Pretty standard for an sizable space rock with a typical velocity and an unfortunate orbit. Not to pile on but, do we have any examples of a volcano able to create tsunami's 300 meters or so high?
:evilgrin:

Actually the Permian extinction is "believed" to be caused by an RBSR (REALLY BIG Space Rock) somewhere in the Great Barrier Reef and I suspect the Siberian Flats volcanism is a minor side effect. :eyes:

http://www.sciencenews.org/articles/20010224/fob1.asp

There are also various hints of a long term periodicity to impacts and extinctions.

I know there are various dating problems related to extinctions, craters (that have been found so far), major volcanic eruptions and oxygen level drops. In the end I expect those dates to move around quite a bit. I will be a lot more than astonished it they try tell us everything has been figured out and all impacts played either a minor or no role at all in mass extinctions.