An Exploding Star 65 Light-Years Away From Earth May Have Triggered a Mass Extinction:
Life was trying, but it wasn't working out. As the Late Devonian period dragged on, more and more living things died out, culminating in one of the greatest mass extinction events our planet has ever witnessed, approximately 359 million years ago.
The culprit responsible for so much death may not have been local, scientists say. In fact, it might not have even come from our Solar System.
[...] In their new work, Fields and his team explore the possibility that the dramatic decline in ozone levels coinciding with the Late Devonian extinction might not have been a result of volcanism or an episode of global warming.
Instead, they suggest it's possible the biodiversity crisis exposed in the geological record could have been caused by astrophysical sources, speculating that the radiation effects from a supernova (or multiple) approximately 65 light-years from Earth may have been what depleted our planet's ozone to such disastrous effect.
Journal Reference:
Brian D. Fields, Adrian L. Melott, John Ellis, et al. Supernova triggers for end-Devonian extinctions [open], Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.2013774117)
(Score: 0) by Anonymous Coward on Monday April 05 2021, @05:21PM
It was an Illudium Q34 Space Modulator. The Q36 was newer tech., but too unreliable and subject to EM interference.
(Score: 1, Interesting) by Anonymous Coward on Monday April 05 2021, @05:51PM
it's a fun video:
https://kurzgesagt.org/portfolio/death-from-space/ [kurzgesagt.org]
(Score: -1, Troll) by Anonymous Coward on Monday April 05 2021, @05:56PM (1 child)
The Late Devonian extinction was caused by anthropogenic global warming.
(Score: 2) by Anti-aristarchus on Monday April 05 2021, @11:12PM
Obviously you are confusing the Late Devonian extinction with the Early Denisovan extinction.
(Score: -1, Flamebait) by Anonymous Coward on Monday April 05 2021, @06:01PM (1 child)
Could this mean our current global warming is also caused by exploding stars? In which case we shouldn't feel bad about driving SUVs... in fact they provide the best shelter from radiation effects. The research seems credible since the author list doesn't appear to have any diversity hires.
(Score: 2) by Tork on Monday April 05 2021, @06:45PM
🏳️🌈 Proud Ally 🏳️🌈
(Score: 2) by Beryllium Sphere (r) on Monday April 05 2021, @09:25PM (3 children)
So naturally we think of that as normal, but diurnal land animals are a small minority of species.
Unless there's some way excess UV could harm nocturnal and ocean creatures, how can it cause a mass extinction as opposed to massacring a small minority?
(Score: 4, Informative) by PartTimeZombie on Monday April 05 2021, @10:04PM (2 children)
This might help explain how it all works. [wikipedia.org]
TL:DR The sun provides the energy for all life on Earth. If UV get too high plants die, and everything else does too. (Or, in the case of the late Devonian 50% of all genera).
(Score: 2) by Beryllium Sphere (r) on Tuesday April 06 2021, @01:00AM (1 child)
Makes sense. I thought about plankton after I'd clicked Submit. Definitely a mechanism for hurting ocean life.
(Score: 2) by PartTimeZombie on Tuesday April 06 2021, @01:55AM
I wasn't even thinking about plankton, but I should have as life had only just begun to move onto land during the Devonian. But yes, to much UV would have been terrible for plankton presumably.
(Score: 2, Informative) by khallow on Tuesday April 06 2021, @01:33AM (2 children)
Then there's the matter of what went extinction. Marine organisms, particularly the coral types of the day, were hard hit with a lot of extinctions. Terrestrial organisms apparently weren't. So how does an increase in UV hurt only sea-based creatures and plants? The lethal symptom each extinction phase/event appears to be ocean anoxia with large deposits of oxygen poor sediments from those periods. Plenty of stuff can cause that.
As to finding the culprit supernova(s)? Give it up unless the supernova(s) were part of a cluster that's still visible to us. In ~360 million years, the Solar System would have traveled around the galaxy more than one full orbit (it takes crudely about 250 million years to do at the Sun's distance from the galactic center). It presently travels a little faster than 1 light-year every 2000 years or about 180k light-years. Unless the supernova remnant(s) was following almost an identical trajectory, it's no longer anywhere near the Sun. And that's third of a billion years is plenty of time for the supernova remnant (neutron star, strange matter star, or black hole) to achieve extremely cold temperatures. You're unlikely to see it, even if it is nearby except through gravitational lensing or something running into it and generating fusion.
So you're stuck looking for neighboring stars that might have a similar elemental composition. That's going to be hard since the supernova radically change the composition of a star, and yet again because of that age, most radioactive products will have decayed to undetectability by now.
(Score: 2) by PartTimeZombie on Tuesday April 06 2021, @02:01AM (1 child)
The Wikipedia article makes the point a couple of times that it is difficult to be definite about things that happened more than 360 million years ago, and as you point out, there seem to have been several pulses of extinctions.
I noticed this bit:
so it's possible it wasn't really an extinction event as such at all.
(Score: 1) by kvutza on Tuesday April 06 2021, @12:21PM
Well, it still looks like *something* did happen, and that it was on a larger time scale. The WP article [wikipedia.org] suggests that at least a part of it was due to *new* weathering due to onset and spread of vascular plants, leading to eutrophication and benthic decimation.
Since it was probably about more events, some of them could had been based on those supernovae, especially when it did hit terrestrial life (contrary to the benthic extinctions, as UV would get absorbed by water and mud before *only* affecting benthic organisms).
(Score: 2) by PiMuNu on Tuesday April 06 2021, @06:46AM (1 child)
Not sure which locales are allowed to get BBC podcasts, but I listened to a great "In Our Time" from Radio 4 about the Late Devonian extinctions a couple of weeks ago (the format is that they get 3 or 4 academics to talk through a particular subject, helped by the host to keep time/etc).
https://www.bbc.co.uk/programmes/m000sz7x [bbc.co.uk]
(Score: 2) by PiMuNu on Tuesday April 06 2021, @06:47AM
ps: they have a reading list on the page, with links to books and also journal articles.
(Score: 0) by Anonymous Coward on Tuesday April 06 2021, @12:35PM
It's the same with nuclear war. Even if you are not affected, it would blow away the ozone layer and then we would have fun. So even if you dodge the nukes, you would be screwed.
https://www.nti.org/gsn/article/limited-nuclear-war-could-deplete-ozone-layer-increasing-radiation/ [nti.org]