Supernovae May Explain Mass Extinctions of Marine Animals During Pliocene Era (theregister.co.uk) 76
"The Register has an article on the possibility that a supernova or a series of them could explain a mass die-off of marine animals around 2.6 million years ago," writes Slashdot reader KindMind. From the report: A gigantic supernova explosion may have triggered mass extinctions for creatures living in Earth's prehistoric oceans some 2.6 million years ago, according to new research published in Astrobiology. Marine animals like the megalodon [...] suddenly disappeared during the late Pliocene. Around the same time, scientists [...] noticed a peak in the iron-60 isotope in ancient seabeds. "As far back as the mid-1990s, people said, "Hey, look for iron-60. It's a telltale because there's no other way for it to get to Earth but from a supernova.' Because iron-60 is radioactive, if it was formed with the Earth it would be long gone by now. So, it had to have been rained down on us" explained Adrian Melott, lead author of the paper and a physics and astronomy professor at the University of Kansas.
The team believes that a supernova located 150 light years away set of a chain of supernovae bursts and covered the Earth in a shroud of deadly cosmic ray radiation. This was amplified, Melott said, because the Solar System is right on the edge of an area of the interstellar medium called the Local Bubble. The Local Bubble extends about 300 light years across and contains the two main clouds of dust and gas: Local Interstellar Cloud and the G-Cloud. As the supernovae ejected cosmic rays, these beams of energetic particles would have repeatedly bounced off the clouds to create a "cosmic-ray bath" that could have lasted 10,000 to 100,000 years. Some of that radiation such as cosmic ray muons would have leaked onto Earth, and over time it could have led to genetic mutations and cancers [that would have caused animals like the megalodon to die off prematurely].
The team believes that a supernova located 150 light years away set of a chain of supernovae bursts and covered the Earth in a shroud of deadly cosmic ray radiation. This was amplified, Melott said, because the Solar System is right on the edge of an area of the interstellar medium called the Local Bubble. The Local Bubble extends about 300 light years across and contains the two main clouds of dust and gas: Local Interstellar Cloud and the G-Cloud. As the supernovae ejected cosmic rays, these beams of energetic particles would have repeatedly bounced off the clouds to create a "cosmic-ray bath" that could have lasted 10,000 to 100,000 years. Some of that radiation such as cosmic ray muons would have leaked onto Earth, and over time it could have led to genetic mutations and cancers [that would have caused animals like the megalodon to die off prematurely].
Supernova* May Explains* Mass Extinctions of Briti (Score:1)
Re:It could be. (Score:5, Interesting)
So any evidence of dinosaur cancers, or are we just making shit up now because maybe?
There were no dinosaurs in the Pliocene (5.3 to 2.6 mya). The dinosaurs died out roughly 70 million years ago (except for birds).
The supernova hypothesis is not just conjecture. The Scorpius Centaurus [wikipedia.org] star cluster passed close (150 ly) to earth during the Pliocene, and there are remnants of supernovae from about that timeframe. The iron isotopes are more evidence.
There are other explanations for the extinctions. The Isthmus of Panama formed about that time, which changed ocean currents and may have disrupted migration paths. The climate was cooling and the ice caps formed. As the ice caps freeze and thaw they change salinity (creating cold saline water that sinks to the depths with they freeze, and brackish surface water when they thaw), and more extreme thermal gradients, as cold and saline polar "bottom water" settles into the ocean depths. This changes currents and reduces upwelling.
It could have been any of these factors, or some combination of all of them. The Pliocene extinctions were not sudden like the Permian and Cretaceous-Tertiary extinctions.
Re: (Score:3)
The dinosaurs died out roughly 70 million years ago (except for birds).
I was watching this documentary about feathered dinosaurs. It had an interview with a Chinese Palaeontologist who has done a lot of work on feathered dinosaurs and specifically the feathered raptors that evolved into birds. At the end he terminated the film by excusing himself to the interviewer because his wife had asked him to buy a dinosaur for dinner on his way home. The documentary ended with a shot of him heading home from the market carrying a chicken. It puts a whole new perspective on going to Kent
Re: (Score:2)
I've recently viewed a science video with my kids talking about breeding chickens to be more dinosaur like. If you've seen them run, you'd be impressed at how raptor like they probably are. Obviously the claws have been replaced by wings, but the frame and movement looks like it hasn't changed much in the last 70 million years.
Re: (Score:2)
Re: (Score:2)
It puts a whole new perspective on going to Kentucky Fried if you realise that you are munching on a bucket of dinosaur drumsticks.
So it's probably yes, the answer to the age old question; do dinosaurs taste like chicken? Clearly my interpolation from watching flintsones cartoons is wrong here.
Re: (Score:2)
The supernova hypothesis is not just conjecture. The Scorpius Centaurus star cluster passed close (150 ly) to earth during the Pliocene, and there are remnants of supernovae from about that timeframe. The iron isotopes are more evidence.
Supernovae..., perhaps the answer to the Fermi Paradox.
Re: (Score:2)
They're one of the many filters. Many stars pass through areas of high numbers of supernovas such as star forming regions. These regions also have large numbers of blue giants that put out a lot of radiation. There's also areas of dense stars where close enough encounters with other stars are likely to perturb any planets orbit as well as send in more material from comet clouds and such.
Just in a stars travels around the galaxy over billions years, there's a lot of stuff that will screw life developing.
BeauHD sucks as an editor (Score:1)
BeauHD sucks as an editor
BeauHD sucks as an editor
He tells you three times the same thing... and still no inkling as to WHY that would be the case.
This is not how you write summaries, BeauHD. Thus we see that BeauHD sucks as an editor.
"Supernovae" 3 (Score:2)
Re: (Score:2)
That doesn't explain "a chain of supernovae bursts". We write "truck accidents" not "trucks accidents". It should be the same for supernova bursts.
From the way TFS is worded, it could be trying to say that a single supernova can trigger a burst of cosmic radiation from the impact with the particles comprising the "local bubble" clouds it mentioned that bathed the Earth in higher levels of high-energy radiation and particles, and multiple supernovas/sipernovae resulted in a series of bursts from the clouds.
Naturally, this being Slashdot, for all we know it could be talking about Beanie Babies, dinosaurs, or nuclear fusion...or nuclear fusion using Bean
Marine animals? (Score:5, Interesting)
I am curious as to why this would have driven marine animals to extinction without having a similar effect on terrestrial animals. I would want this explained before giving this theory any credence.
Re: (Score:3)
The were mass extinctions of marsupials in South America during the Pliocene. But that was because of an invasion of placental mammals from North America when the Isthmus of Panama formed.
Otherwise, there was no noticeable rise in terrestrial extinctions.
Re: (Score:3)
Re: (Score:3, Interesting)
Yes it is a sort of strange idea that cosmic rays would've driven a large shark of all things, famous for their resistance to cancer, extinct. If the rays did directly kill things they could've messed up the food chain well enough to drive large predators extinct more easily, I'd think.
There definitely are some issues with the hypothesis. The most compelling part is the Iron-60 anomaly. That being said the extinctions seem to be very selective. I'm pretty confident that there were some supernovae, but not so much that it caused the extinctions.
But that's why we have the hypothesis process. Set 'em up, tear 'em down.
Comment removed (Score:5, Interesting)
Re: (Score:2)
Extinguished by a giant bomb gets so many more clicks than shifting ocean currents.
Why only a marine die-off? (Score:4, Interesting)
If the ocean life got a wallop of cosmic rays, wouldn't the land creatures fare even worse?
Neither the article nor paper's abstract went into it, so I instead have to hypothesize that perhaps the ocean surface micro-organisms were especially sensitive to radiation, leading to an ecological collapse... or maybe the supernovae and extinction events are even unrelated.
Occam's razor (Score:2, Funny)
simplest explanation for the extinctions is, Chuck Norris.
Re: (Score:2)
Chunk Norris was born in March 1940. By 1942, all dinosaurs besides birds were extinct[1].
[1] This is probably only because Chuck Norris wasn't able to fly yet at age 2.
Chuck Norris is a demigod: https://www.youtube.com/watch?... [youtube.com]
Re: (Score:1)
Chunk Norris was born in March 1940. By 1942, all dinosaurs besides birds were extinct
Little known fact, in 1942 a toddler Chuck Norris visited the natural history museum and accidentally stumbled on a Megladon jaw on display. In doing so he impacted it so hard that the force reverberated back through time causing the extinction of the entire species.
Re: (Score:2)
Re: (Score:3)
Thank you! I am now reassured. I was terrified by the prospect of the Great Tribulation but I now know that this won't happen before the next nearby supernova. We know that IK Pegasi - the closest supernova candidate - is too far away to cause us any harm so I can now assume that the Great Tribulation is not due before we approach another candidate so in several millions years. Thanks again! I can go back sinning.
Re: (Score:1)
None of those ideas will work. A nearby supernova and/or a gamma ray burst will probably occur during the Great Tribulation. It's very reasonable to interpret John's prophecy in the book of Revelation to include such an event.
Negative! any serious inspection of the truths contained in God's book make it very obvious that the Tribulation is started by a cosmic beatdown between Chic-Fil-A and Taco Bell.
Re: (Score:2)
"Develop interstellar travel" Stop watching TV, it is bad for you. The closest star to Earth is Alpha Centuri and it is 4.22 light years from Earth. Just a guess, but you won't be going there on your imagined interstellar space ship at the speed of light. If you are lucky, you might get to half that speed. Then there is the speed up and slow down phases. So you might get there in 10 years.
You'll be wanting to bring along a lot of food...you cannot build a space ship that big. So you'll be wanting to grow it
circular reasoning? (Score:2)
Because iron-60 is radioactive, if it was formed with the Earth it would be long gone by now. So, it had to have been rained down on us
Joe: We know for sure how old the Earth is, because of radiometric dating.
Bob: Hey cool. BTW, what's that stuff there?
Joe: Iron-60.
Bob: Cool. Wait a minute, how could that still be there?
Joe: Well, it must have fallen on us.
Bob: Cool, how do you know that?
Joe: Er, well ... if it was formed with the Earth it would be long gone by now. So, it had to have been rained down on us.
Bob: Oh ... OK. That's logical ... I guess.
{...}
Bob: Er, so that other stuff over there ... how do you know that didn't rain
Re: (Score:3)
Re: (Score:2, Informative)
Bob: Er, so that other stuff over there ... how do you know that didn't rain down on us?.
Joe: I hate you.
Seriously?
Location in strata, total amount, distrbution with other elements.
But your Iron-60....
Okay, a layer of a specific element is found in a thin layer of sediment that isn't found elsewhere. You can then try to figure where it might have come from. Iron is a good candidate for a supernova, because Iron creation is the end of the fusion process right before a star goes supernova.
Re: (Score:2)
Re: (Score:2)
The Laschamp event was a short reversal of the Earth's magnetic field. It occurred 41,400 (±2,000) years ago during the last ice age and was first recognised in the late 1960s as a geomagnetic reversal recorded in the Laschamp lava flows in the Clermont-Ferrand district of France. The magnetic excursion has since been demonstrated in geological archives from many parts of the world. The period of reversed magnetic field was approximately 440 years, with the transition from the normal field lasting approximately 250 years. The reversed field was 75% weaker, whereas the strength dropped to only 5% of the current strength during the transition. This reduction in geomagnetic field strength resulted in more cosmic rays reaching the Earth, causing greater production of the cosmogenic isotopes beryllium 10 and carbon 14. The Laschamp event was the first known geomagnetic excursion and remains the most thoroughly studied among the known geomagnetic excursions.
Re: (Score:2)
Radiocarbon dating, and C14 production in particular, is usually calibrated with some other source. Counting tree rings is the most popular. C14 production is certainly not regarded as constant.
Since you can clearly use Wikipedia, perhaps you should have read the radiocarbon dating entry?
Wondered about the barber shop mirrors.... (Score:2)
Later when we were taught absorption, reflection, scattering and transmission it dawned on me that even if the mirrors were nearly 99.9999% reflective, even that 1.0e-06 or 1.0e-12 scattering would degrade the images and eventually the later images will be less bright and eventually fade to black.
Reflectio
Gene Drive Extinction? (Score:2)
"A gigantic supernova explosion" (Score:2)
How about just "supernova"?