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The evidence for the YDIH is quite strong. But as usual science only makes progress one obituary at a time. Science is not an exercise in accepting a scientis

The evidence for the YDIH is quite strong. But as usual science only makes progress one obituary at a time. Science is not an exercise in accepting a scientist's say-so, dammit. It's an exercise in producing and testing hypothesis. For sciences that study the past it's harder to test because you can't build a test, but you can still check that a hypothesis is consistent with all the data available so far and any future new finds about the past. In particular I find very compelling the theory that the YDIH hit the laurentide ice sheet over Michigan, sending huge ice boulders out that created the Carolina bays and essentially did great damage, but with water ice, thus leaving very little direct physical evidence -- no craters (apart from the Carolina bays), no rocks out of place, no layer of material from the impactor (because it was a comet rather than an asteroid). Before sonar evidence showed that the continents must move, geologists would say that the tectonics theory was debunked (using whatever the appropriate term was then). Well here we are now saying the exact opposite. The only thing we can say with certainty right now is that we don't have consensus as to the cause of the Younger Dryas at this time. To say that the YDIH is debunked is not true and not helpful.

jschveibinz 2y ago
"Science is not an exercise in accepting a scientist's say-so, dammit." May your words echo in the hallways of this forum!
- cryptonector 2y ago
  Don't hold your breath. HN is full of people with credentials, and people with credentials tend to push credentialism, and that means deferring to the experts on other fields so that others will defer to one in one's field of expertise. Mike Shapiro at Sun was fond of telling us that "we're not specialists -- we're generalists who can specialize as needed". I think that is a good attitude in general. It doesn't mean we get to weigh in on things we know nothing about, but it does mean we get to do critical thinking and that we can self-educate in order to form opinions when necessary.
  - wkearney99 2y ago
    And sensibility to recognize when having (let alone voicing) an opinion isn't necessary.
YeGoblynQueenne 2y ago
>> In particular I find very compelling the theory that the YDIH hit the laurentide ice sheet over Michigan, sending huge ice boulders out that created the Carolina bays and essentially did great damage, but with water ice, thus leaving very little direct physical evidence -- no craters (apart from the Carolina bays), no rocks out of place, no layer of material from the impactor (because it was a comet rather than an asteroid). In that case, how do can we tell that's what happened?
- cryptonector 2y ago
  Antonio Zamora is a scientist studying this who writes papers and posts videos on YouTube at https://www.youtube.com/@Antonio_Zamora https://www.youtube.com/@Antonio_Zamora and he does a good job of showing how the Carolina bays point towards the impact location, and what not. I'm not going to summarize it all here, but the point is that there is some, and perhaps enough evidence to go on.
throwaway290 2y ago
OK good to know. This is caused by comet remains through which Earth goes twice a year, right? If astronomy data supports "Earth totally could get hit by a chunk from it" that's also a step. Are future threats from these comet chunks trackable by NASA?
maxbond 2y ago
What do you find disatisfactory about the conventional explanation that the Carolina bays are thermokarsts? On a smell test level, here's a picture of a thermokarsts: https://upload.wikimedia.org/wikipedia/commons/7/73/Permafrost_thaw_ponds_in_Hudson_Bay_Canada_near_Greenland.jpg https://upload.wikimedia.org/wikipedia/commons/7/73/Permafro... And here's some pictures of the Carolina bays: https://lh3.googleusercontent.com/-RzXM7ywZkS8/WKW0zLlhU4I/AAAAAAABRyQ/Wrg9F4KqXJ4/carolina-bays-52.jpg?imgmax=1600 https://lh3.googleusercontent.com/-RzXM7ywZkS8/WKW0zLlhU4I/A... https://en.m.wikipedia.org/wiki/Carolina_bays#/media/File%3ARobeso2.jpg https://en.m.wikipedia.org/wiki/Carolina_bays#/media/File%3A... Things aren't identical just because they look alike, but again on a smell test level, it doesn't immediately strike me as implausible. I'm certainly no expert on impact craters but that doesn't really look like a field of impact craters to me. I've never seen a photo of a field of oblate impact craters. In the LIDAR you can see many of them overlap. That would suggest to me that what formed these ovals happened many times, rather than all at once. If you think about it, the way you get an oblate crater is to hit at an extreme angle, right? But if was an airburst, then the debris would be going down. So it should make circular craters. Maybe it's an airburst just off the ground, a few hundred feet up or something. That way it's close enough to spray the ground at an extreme angle. But then the Carolina bays would be very close to the epicenter. So we should see some rotation among the "craters". But they're parallel. Which would mean, if they were craters, that the blast was very far away. (In which case, they would have had time to come down in parabolic arcs, and we're back to circular craters.) If it wasn't an airburst, then it was a direct hit a mere 13k years ago. That's young enough that we should be able to find the crater. I've seen supervolcano caldera much older than that, I wouldn't imagine a crater would erode any faster. > To say that the YDIH is debunked is not true and not helpful. I dunno. This isn't a scientific observation, but there's something fishy with this hypothesis. It's being popularized by conspiracy theorists, and the Comet Research Group, some of it's proponents, were busted for faking evidence. The theory posits something really attention grabbing and dramatic, but it's also very speculative and didn't originate in physical evidence. Meanwhile the alternative explanation that the AMOC was choked out by freshwater melting off the glaciers is very tidy, there's ample physical evidence for it, and it doesn't need to bring in an unlikely and external element like a comet. This explanation amounts to, "what we know was happening at the time kept happening until that forced the environment to change, through a well established mechanism we can continue to make physical observations of today." Contrast that with, "we're going to look at a time the environment changed, and back out an explanation of why that might have happened." This just feels too convenient for me. This seems to be at least as much a vehicle for people like Hancock to claim their hypothesis - which just so happens to be a very cool and engaging story - isn't getting it's due from the scientific establishment, as it is a serious scientific endeavor to understand what happened in the Younger Dryas.

jschveibinz 2y ago

"Science is not an exercise in accepting a scientist's say-so, dammit." May your words echo in the hallways of this forum!

cryptonector 2y ago
Don't hold your breath. HN is full of people with credentials, and people with credentials tend to push credentialism, and that means deferring to the experts on other fields so that others will defer to one in one's field of expertise. Mike Shapiro at Sun was fond of telling us that "we're not specialists -- we're generalists who can specialize as needed". I think that is a good attitude in general. It doesn't mean we get to weigh in on things we know nothing about, but it does mean we get to do critical thinking and that we can self-educate in order to form opinions when necessary.
- wkearney99 2y ago
  And sensibility to recognize when having (let alone voicing) an opinion isn't necessary.

YeGoblynQueenne 2y ago

>> In particular I find very compelling the theory that the YDIH hit the laurentide ice sheet over Michigan, sending huge ice boulders out that created the Carolina bays and essentially did great damage, but with water ice, thus leaving very little direct physical evidence -- no craters (apart from the Carolina bays), no rocks out of place, no layer of material from the impactor (because it was a comet rather than an asteroid). In that case, how do can we tell that's what happened?

cryptonector 2y ago
Antonio Zamora is a scientist studying this who writes papers and posts videos on YouTube at https://www.youtube.com/@Antonio_Zamora https://www.youtube.com/@Antonio_Zamora and he does a good job of showing how the Carolina bays point towards the impact location, and what not. I'm not going to summarize it all here, but the point is that there is some, and perhaps enough evidence to go on.

throwaway290 2y ago

OK good to know. This is caused by comet remains through which Earth goes twice a year, right? If astronomy data supports "Earth totally could get hit by a chunk from it" that's also a step. Are future threats from these comet chunks trackable by NASA?

maxbond 2y ago

What do you find disatisfactory about the conventional explanation that the Carolina bays are thermokarsts? On a smell test level, here's a picture of a thermokarsts: https://upload.wikimedia.org/wikipedia/commons/7/73/Permafrost_thaw_ponds_in_Hudson_Bay_Canada_near_Greenland.jpg https://upload.wikimedia.org/wikipedia/commons/7/73/Permafro... And here's some pictures of the Carolina bays: https://lh3.googleusercontent.com/-RzXM7ywZkS8/WKW0zLlhU4I/AAAAAAABRyQ/Wrg9F4KqXJ4/carolina-bays-52.jpg?imgmax=1600 https://lh3.googleusercontent.com/-RzXM7ywZkS8/WKW0zLlhU4I/A... https://en.m.wikipedia.org/wiki/Carolina_bays#/media/File%3ARobeso2.jpg https://en.m.wikipedia.org/wiki/Carolina_bays#/media/File%3A... Things aren't identical just because they look alike, but again on a smell test level, it doesn't immediately strike me as implausible. I'm certainly no expert on impact craters but that doesn't really look like a field of impact craters to me. I've never seen a photo of a field of oblate impact craters. In the LIDAR you can see many of them overlap. That would suggest to me that what formed these ovals happened many times, rather than all at once. If you think about it, the way you get an oblate crater is to hit at an extreme angle, right? But if was an airburst, then the debris would be going down. So it should make circular craters. Maybe it's an airburst just off the ground, a few hundred feet up or something. That way it's close enough to spray the ground at an extreme angle. But then the Carolina bays would be very close to the epicenter. So we should see some rotation among the "craters". But they're parallel. Which would mean, if they were craters, that the blast was very far away. (In which case, they would have had time to come down in parabolic arcs, and we're back to circular craters.) If it wasn't an airburst, then it was a direct hit a mere 13k years ago. That's young enough that we should be able to find the crater. I've seen supervolcano caldera much older than that, I wouldn't imagine a crater would erode any faster. > To say that the YDIH is debunked is not true and not helpful. I dunno. This isn't a scientific observation, but there's something fishy with this hypothesis. It's being popularized by conspiracy theorists, and the Comet Research Group, some of it's proponents, were busted for faking evidence. The theory posits something really attention grabbing and dramatic, but it's also very speculative and didn't originate in physical evidence. Meanwhile the alternative explanation that the AMOC was choked out by freshwater melting off the glaciers is very tidy, there's ample physical evidence for it, and it doesn't need to bring in an unlikely and external element like a comet. This explanation amounts to, "what we know was happening at the time kept happening until that forced the environment to change, through a well established mechanism we can continue to make physical observations of today." Contrast that with, "we're going to look at a time the environment changed, and back out an explanation of why that might have happened." This just feels too convenient for me. This seems to be at least as much a vehicle for people like Hancock to claim their hypothesis - which just so happens to be a very cool and engaging story - isn't getting it's due from the scientific establishment, as it is a serious scientific endeavor to understand what happened in the Younger Dryas.