What the dinosaurs discovered
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…despite being annihilated, no less — from "A meteor from another solar system may have hit Earth, and the implications are fascinating", CNN 4/17/2019:
[h/t Bob Shackleton]
April 20, 2019 @ 6:54 am · Filed by Mark Liberman under Crash blossoms
« previous post | next post »
…despite being annihilated, no less — from "A meteor from another solar system may have hit Earth, and the implications are fascinating", CNN 4/17/2019:
[h/t Bob Shackleton]
April 20, 2019 @ 6:54 am · Filed by Mark Liberman under Crash blossoms
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Trogluddite said,
April 20, 2019 @ 8:29 am
A good giggle for the holiday weekend! However, the picture caption seems barely less of a wreck than the body of the article. For example…
"Loeb and his co-author Amir Siraj studied the velocity of objects entering the Earth's atmosphere, which can be used to predict whether the object was traveling in relation to our sun's orbit."
Is this is a new definition of "predict" that I haven't come across before, or have these scientists also mastered time travel? The "sun's orbit" around what? The galactic centre, I can only suppose, but that's of little relevance to what is or is not orbiting the sun.
"But the second-fastest, Loeb says, bore all the hallmarks of being literally out of this solar system."
Having *originated* from beyond the solar system maybe, but not "being" (literally, no less) outside it at the time of writing, I should have thought (or have the scientists also mastered building a lab on the other side of a worm-hole in space-time, too!)
Gregory Kusnick said,
April 20, 2019 @ 10:49 am
If Loeb and Siraj are using an object's currently known trajectory to calculate where it should be visible in historical images of the sky, that's a legitimate usage of "predict" in my opinion. But I grant that CNN's phrasing of it is a mess.
Andrew Usher said,
April 20, 2019 @ 11:17 am
No (although I agree), 'whether', not 'where', was actually meant. That was the author's way of rendering 'whether the object was interstellar'.
This is lousy even by the usual standards of science journalism. The article has not been edited at all, given the obvious typos.
k_over_hbarc at yahoo.com
Ellen K. said,
April 20, 2019 @ 11:29 am
It actually took me awhile to get the wrong reading, the one that fits with the LL headline. Perhaps because I read it as a headline, not a caption.
AntC said,
April 20, 2019 @ 7:07 pm
Whether or not what's getting exposed in North Dakota is the aftermath of the Chicxulub meteor, that doesn't establish the meteor wiped out the dinosaurs. The timing is wrong: the dinosaurs were already in serious decline before then; a meteor might have upset earth's climate for a few years, but not for long enough to wipe out life forms to that extent. Perhaps the meteor was the straw that broke the camel's back.
So sorry to all the glib science journalists trying to tell a racy story. Dinosaur extinction caused by meteor is a nice meme. The explanation is more likely to be due to long-term vulcanism of the Deccan Traps, over tens of thousands of years. (Still the blink of an eye in geological terms.) Not least because vulcanism is what caused every previous mass extinction.
Andrew Usher said,
April 21, 2019 @ 12:25 am
Wrong.
The establishment of the impact as the cause of the mass extinction is one of the triumphs of modern geological science, and can't be tarnished by some uninformed speculation on a blog post. I am not going to give any scientific explanation (though I well could), because the kind of people that believe that nonsense won't (or can't) listen to any.
KeithB said,
April 22, 2019 @ 8:37 am
Andrew:
If you are referring to AntC's post, I am not sure what your beef is since what he said was the current thinking about the dinosaurs.
Peter Erwin said,
April 23, 2019 @ 1:15 am
@ AntC
The timing is wrong: the dinosaurs were already in serious decline before then
That's like saying that if someone in their 60s was shot in the head, the bullet didn't kill them, because they were "already in serious decline". In other words, no, that's a silly argument.
(And the K-Pg extinction wiped out much more than just the non-avian dinosaurs — three-quarters of plant and animal species vanished, including over 90% of mammals.)
a meteor might have upset earth's climate for a few years, but not for long enough to wipe out life forms to that extent.
Well, I'm glad you understand this better than all the scientists who have actually studied what 10 to 20-km asteroid impacts might do.
Peter Erwin said,
April 23, 2019 @ 1:36 am
@ Trogluddite
The "sun's orbit" around what? The galactic centre, I can only suppose, but that's of little relevance to what is or is not orbiting the sun.
Yes, the Sun's orbit about the galactic center. This is relevant if you want to have a guess at where, in a very general sense, the meteor might have come from originally. For example, if its velocity was mostly perpendicular to the Sun's orbit, then it might have from a star in the galactic halo rather than the disk.
KeithB said,
April 23, 2019 @ 8:42 am
Hmm…
Maybe I am a bit behind in the science first two ghits:
Dinosaurs 'already in decline' before asteroid apocalypse – ScienceDaily
https://www.sciencedaily.com/releases/2016/04/160418160957.htm
Dinosaurs were thriving before asteroid strike that wiped them out …
https://www.sciencedaily.com/releases/2019/03/190306081711.htm
Andrew Usher said,
April 25, 2019 @ 7:14 pm
In other words, there's no consensus on what would have happened to the dinosaurs absent the great impact.
But there's no scientific doubt that an asteroid strike is really a profound event, and as such we need to do everything in our power to prevent one, because it's one of the few things (and probably the most likely) to wipe out mankind as we know it.
R. Fenwick said,
April 26, 2019 @ 5:19 am
@AntC:
Dinosaur extinction caused by meteor is a nice meme. The explanation is more likely to be due to long-term vulcanism of the Deccan Traps, over tens of thousands of years.
The idea that the K-Pg extinction was not at least in large part the result of the Chicxulub impact is a minority view at best, even within the professional palaeontological community. Sure, one could make a case that the Chicxulub impactor finished off the job that the Deccan Traps started (and honestly, as scientists we should be well past the singular-cause mindset by now, I'd have thought), but the close correspondence between the dates of the Chicxulub impact and the K-Pg boundary on the one hand, and the problematic fact that the Deccan Traps eruption took place over nearly a million years with something like 75% of the eruption volume appearing to have taken place after the K-Pg boundary (see Sprain et al. 2019) on the other, means that promoting the Deccan Traps to primary causal agent is very difficult indeed.
Not least because vulcanism is what caused every previous mass extinction.
That's not even close to proven and stating it so baldly without any additional information borders on dishonesty. The best candidate for a volcanic mass extinction is the Permian-Triassic extinction event, corresponding very well to the eruptions of the Siberian Traps (and what's more, the Siberian Traps have been well-associated with an unusually high degree of pyroclasticity, which makes it an even better candidate for the major climatic disruptor necessary for the scale of the Permian-Triassic event). The Devonian-Carboniferous extinction event, by contrast, appears to be the summing of what appears to be as many as ten distinct extinction pulses perhaps spread out over as much as 25 million years, and the largest of these pulses (the Kellwasser event) impacted predominantly marine taxa, inconsistent with what one would expect from a volcanic winter. There's a good argument to be made that the evolution of vascular systems in land plants towards the late Devonian allowed the much-increased colonisation of terrestrial environments, a massive increase in organic contribution to soil, subsequent nutrient runoff and algal blooms, and then widespread marine anoxia consistent with the essentially marine focus of the extinction. And all that's ignoring the first true mass extinction, the Great Oxygenation Event, which was almost certainly not volcanically triggered.