19
votes
Accepted
Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?
Mark's answer is correct, but in my opinion is not clear enough. Let's make it a bit simpler:
Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?
NO, DEFINITELY ...
- 23.1k
13
votes
Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?
It's a commonly-proposed theory that geomagnetic reversals cause extinction events, but there's no evidence for it. There aren't enough mass extinction events for any sort of statistical analysis, ...
- 1,209
11
votes
Variations in Gravity over Time
Is there any consensus about the conjecture that gravitational force on Earth may have changed significantly over geological time;
No, Earth's gravity did not change significantly over time. Yes, ...
- 23.1k
10
votes
Accepted
Unwarranted claim of higher degree of accuracy in zircon geochronology
I can't be entirely sure but I'll make an informed guess:
That value doesn't come for a single measurement. Therefore, if the error in the age of a single sample is $\pm125$ kyr, you just need to ...
- 17.6k
8
votes
Accepted
What if we detonated the entire worlds nuclear supply in the center of the earth?
I'll ignore the complete impossibility of getting the world's nuclear arsenal to the center of the Earth and the impossibility of exploding them all at once. The total number of nuclear weapons, ...
- 23.2k
6
votes
Why are pole reversals not more detrimental to life?
There are several factors to consider. The main one is the atmosphere (especially if you want to compare Mars with the Earth's during magnetic reversals). Earth's atmosphere is a formidable shield ...
- 17.6k
5
votes
Accepted
Safest spots when an asteroid hits?
Being in a submarine in the ocean is not a good idea because if a large asteroid hits the ocean the shock wave created, and its energy, would be very large. If the submarine survives intact its ...
- 24.6k
4
votes
Accepted
Could the current climate change events cause long-term problems in the viability of Earth to sustain life?
There is one scenario in which climate change could render the Earth inhospitable to life in general, which would be a runaway greenhouse effect. In a runaway greenhouse effect, the Earth would get ...
- 11.6k
3
votes
How long does earth take to recover from mass extinctions? What is "normal"?
Mass extinctions are selective: not all living organisms will be affected by it to the same extent. Meaning also that various groups will recover from it at various speed: a group from which half of ...
- 5,338
3
votes
Accepted
Why haven't weeds overtaken the entire planet?
A weed is just a plant where you do not want it. Totally a matter of context. Tumbleweeds are non-native, introduced centuries ago. I assume you mean the invasive species of plants that have been ...
- 1,207
3
votes
Accepted
gamma ray burst, extinction-level event
As bon noted in the comments, that it the time it would take the gamma rays to reach Earth. Gamme rays travel at the same speed as all other forms of electromagnetic radiation, including visible light,...
- 23.1k
3
votes
How is geological time divided into units?
The divisions in the geologic time scale have evolved over time.
Its origins can be traced back to Nicolaus Steno in 1669 described two basic geologic principles.
The first stated that sedimentary ...
- 5,959
3
votes
Unwarranted claim of higher degree of accuracy in zircon geochronology
The uncertainty on the decay constant / half life is systematic. This means that, if the "used" value would be off the "true" value by 0.05%, then it would affect all the ages in ...
- 851
3
votes
What if we detonated the entire worlds nuclear supply in the center of the earth?
To add to David Hammen's answer. Earth is big. I hate to use the words "really really big" cause there are things much bigger, like the sun, but Earth is quite large.
Imagine what would happen if ...
- 5,847
2
votes
Where can I see/photograph the KT boundary on South Table Mountain?
According to Cretaceous-Paleogene Boundary the coordinates are: 39.7488 deg N, -105.1633 deg E
The linked page has some photographs with this descriptive text:
The Cretaceous-Paleogene (K-Pg) ...
2
votes
Accepted
Has Earth's geological activity calmed down in the past 250 million years?
The large-scale volcanic eruptions you mention are called Large Igneous Provinces (LIPs) and are probably linked to mantle plumes. They have been investigated for quite some time now. Ernst & ...
- 7,729
2
votes
Accepted
Signatures of acid rain at KT boundary
Estimated sulfur release 325 gigatonnes = 325,000 teragrams. The numbers in this diagram are in teragrams
Sulfur Cycle
so the release is $\approx 1000\times $ today's annual sulfur cycle.
I think ...
- 2,369
2
votes
Could the current climate change events cause long-term problems in the viability of Earth to sustain life?
100 years is not very long-term at all. The added CO2 will not miraculously disappear after a century, but will go on warming the planet. (And that's just assuming that humans stop burning fossil ...
- 1,748
2
votes
Could the current climate change events cause long-term problems in the viability of Earth to sustain life?
Depends on the further actions humanity takes. If we keep on pumping green house gases into the atmosphere, survival will become significantly harder. Sure, we most likely wont be able to create a ...
- 726
2
votes
Why are pole reversals not more detrimental to life?
National Geographic published an article about this in January 2018 - No, We're Not All Doomed by Earth's Magnetic Field Flip.
Yes, the flipping of the magnetic poles does take a long time - ...
- 24.6k
2
votes
Percentage of Oxgen left after burning all the available biomass
Estimates of earth's total biomass vary widely, from 0.5 to 4 trillion tons C, so instead of citing a source, I'll just go with an assumption of $1\times10^{15} \text{kg C}$. Measuring biomass in ...
- 3,366
2
votes
Are there any metal anomalies other than iridium in the K-Pg boundary?
Another good historical perspective from this blog:
http://lablemminglounge.blogspot.com/2006/09/iridium-anomaly-as-historical-artifact.html
Iridium anomaly as historical artifact
Everybody knows ...
- 23.1k
1
vote
Accepted
Permian-Triassic mass extinction. Consequences on Earth's system
Wow, I just finished watching this it seems we know, or can guess, quite a bit about the level of Carbon, particularly Methane that were released at the end of the Permian and what they did to the ...
- 4,260
1
vote
Recovery From the Great Dying
Let me propose that if an anoxia event were a cause of the P-T marine extinction; then it wouldn't be Pangaea that would slow recovery, but Panthalassa; the global ocean counterpart to Pangaea.
Here ...
- 3,366
Only top scored, non community-wiki answers of a minimum length are eligible