Asteroid hits will destroy ozone layer

[shijing]

I was at my evil neighborhood mega-bookstore today to pick up a book, and while looking at this week's New Scientist I happened to notice the following:

IF A 1-kilometre-wide asteroid lands in the ocean, tsunamis won't be our only worry. A simulation suggests that the vapour and salt thrown up by the impact could damage the ozone layer, leading to record levels of ultraviolet radiation that could threaten human civilisation.

Elisabetta Pierazzo of the Planetary Science Institute in Tucson, Arizona, and colleagues used a global climate model to study the effect of an impact. They found that water vapour and chlorine and bromine from vaporised sea salts would destroy ozone high in Earth's atmosphere at a much faster rate than it is naturally created (Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2010.08.036).

The part about UV radiation made me think about cataclysm-related mutation -- just wanted to make a note.

 

[domi]

I was at my evil neighborhood mega-bookstore today to pick up a book, and while looking at this week's New Scientist I happened to notice the following:

IF A 1-kilometre-wide asteroid lands in the ocean, tsunamis won't be our only worry. A simulation suggests that the vapour and salt thrown up by the impact could damage the ozone layer, leading to record levels of ultraviolet radiation that could threaten human civilisation.

Elisabetta Pierazzo of the Planetary Science Institute in Tucson, Arizona, and colleagues used a global climate model to study the effect of an impact. They found that water vapour and chlorine and bromine from vaporised sea salts would destroy ozone high in Earth's atmosphere at a much faster rate than it is naturally created (Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2010.08.036).

The part about UV radiation made me think about cataclysm-related mutation -- just wanted to make a note.

There's that and the release of e.m. energies coming from overhead cometary explosions that are bound to be high-energy and therefore potentially cell/dna damaging.

 

[Ares]

radiation is also a big problem in the event of a supernova, and comet strike with a supernova will be a double whammy for sure. firestone, in his book says the harmful cosmic rays radiation will travel at light speeds overloading the protective fields of the earth and cause genetic mutations, most of which will be deadly. then comes the debris field (composed of microscopic particles) from the super nova, again travelling at very high speed that can apparently knock a big mammoth off its feet and kill it instantly. very interesting read.

he does speculates though (if i recall correctly) that the radiation encountered in the last great extinction 13,000 BP was the reason human beings suddenly developed art and culture after a period of hunter-gatherer type primitive living.

-pranab

 

[dannybananny]

he does speculates though (if i recall correctly) that the radiation encountered in the last great extinction 13,000 BP was the reason human beings suddenly developed art and culture after a period of hunter-gatherer type primitive living.

C's said that supernova explosions helped humans to activate more DNA scales so it could be that radiation is only negative if ithe supernova is close to some inhabitable planet, maybe if it's further it's more positive.

 

[Human]

radiation is also a big problem in the event of a supernova, and comet strike with a supernova will be a double whammy for sure. firestone, in his book says the harmful cosmic rays radiation will travel at light speeds overloading the protective fields of the earth and cause genetic mutations, most of which will be deadly. then comes the debris field (composed of microscopic particles) from the super nova, again travelling at very high speed that can apparently knock a big mammoth off its feet and kill it instantly. very interesting read.

I don't quite understand what is intended to convey by emphasis on very high speeds.
To my knowledge, almost all of cosmic rays travel with the speed very close to speed of light and it's an approximation used in physics in today models of cosmic rays that they basically do travel with the speed of light. For photons that is off course exactly true, but it is used for all other species of particles, ranging from neutrinos through muons and protons to iron nuclei. Regarding muons in cosmic ray radiation, if they do not travel with the speed very close to speed of light, we would not be able to detect them on Earth surface in such a number like we do (according to special theory of relativity and time dilatation that emerges from it).
I think that the point is, regarding harmful effects, in the intensity/flux. Too many of cosmic rays will, for sure, be very damaging.

he does speculates though (if i recall correctly) that the radiation encountered in the last great extinction 13,000 BP was the reason human beings suddenly developed art and culture after a period of hunter-gatherer type primitive living.

C's said that supernova explosions helped humans to activate more DNA scales so it could be that radiation is only negative if ithe supernova is close to some inhabitable planet, maybe if it's further it's more positive.

There are claims that slightly increased level of radiation is in fact beneficial for living beings and not harmful at all (something about that can be found on _http://en.wikipedia.org/wiki/Radiation_hormesis). Of course when talking about possible benefits of radiation, one has to be careful what kind of radiation it is spoken about (e.g. alpha particles are highly toxic but an ordinary sheet of paper can stop them and exactly because of that they are very bad for our skin or if ingested and on the other hand muons from cosmic ray radiation normally just go through us with no interaction at all).

For example, it is said that flora and fauna in area around Chernobyl basically flourished some time after the disaster (when levels of radiation dropped a little bit compared to initial one). Well, I suspect that it's not only due to increase of radiation but also because since then there hasn't been almost any human influence in that area whatsoever.

Also, during airplane flights one gets much higher doses of radiation (due to cosmic rays) than on ground, and cosmic rays are more abundant on mountain tops than at ground level. And also there are some natural places on our planet where radiation levels are "through the roof".
_http://en.wikipedia.org/wiki/Orders_of_magnitude_%28radiation%29

So, I think there is much more than meets the eye when radiation is in question, especially cosmic rays.

 

[Ares]

he does speculates though (if i recall correctly) that the radiation encountered in the last great extinction 13,000 BP was the reason human beings suddenly developed art and culture after a period of hunter-gatherer type primitive living.

C's said that supernova explosions helped humans to activate more DNA scales so it could be that radiation is only negative if ithe supernova is close to some inhabitable planet, maybe if it's further it's more positive.

How the DNA mutation affects a person may also have a lot to do with their inner development i think (as would be the case with the wave, as per Cs), which would be the key once it reaches earth and what happens to the remaining society and human progress a whole. and if we have the wave, the comets and the supernova happening at roughly the same time, it could make the process complex due to possible inter-reaction between the 3

 

[Ares]

I don't quite understand what is intended to convey by emphasis on very high speeds.
To my knowledge, almost all of cosmic rays travel with the speed very close to speed of light and it's an approximation used in physics in today models of cosmic rays that they basically do travel with the speed of light. For photons that is off course exactly true, but it is used for all other species of particles, ranging from neutrinos through muons and protons to iron nuclei. Regarding muons in cosmic ray radiation, if they do not travel with the speed very close to speed of light, we would not be able to detect them on Earth surface in such a number like we do (according to special theory of relativity and time dilatation that emerges from it).
I think that the point is, regarding harmful effects, in the intensity/flux. Too many of cosmic rays will, for sure, be very damaging.

sorry if i was not clear Sasha, let me try again :)

according to the author, when a supernova explodes it releases 2 major outbursts:
one is the initial explosion that releases all sorts of radiation, including cosmic rays, gamma, UV etc. that are assumed to be travelling at light speeds. These rays are what kills of most of the plants, and the depending fauna either die of starvation, or due to genetic mutation that kills them over time and makes reproduction difficult. think of the survivors of the hiroshima blast.

the other blast happens when the remaining physical matter is ejected as the whole star explodes (except the core i think which either becomes a white dwarf, a neutron star, or a black hole depending on how massive it was). this matter does not travel at light speed because it is not radiation, but fast enough for it to take about 500 odd years if its within a couple hundred light years from earth. now this matter for the most part is supposed to be so pulverized that it is actually microscopic spherules (most are metallic and hollow, if i may recall), and when it reaches the earth it accelerates further and hits any remaining living animals like a super fast blast of tiny comets that have enough force to instantly pierce through and kill anything that is in the way.

i'm speculating that if the supernova is far enough, the radiation would still reach us since its travelling at light speeds, but the star debris may have lost enough velocity by the time it enters the solar system to not be major threat. however, it only has to reach the edges of the solar system for it nudge the comets in the oort cloud into sun and/or earth crossing orbits to cause another round of extinctions!