3 ms·

Dinosaur-killing space rock 'was a comet'

31 points by momchenr 14y ago

swombat 14y ago
But other researchers were more cautious about the results. Well, I'm glad the headline made that clear.
- teeja 14y ago
  Really. This has gotten to be a serious problem with science-reporting lately. Headlines suggest deterministic certainty, article itself says, for example, "probably a speeding comet, US scientists say." (Not even "some US scientists" or "hypothesize".)
Lost_BiomedE 14y ago
"...the team suggests that frequently quoted iridium values are incorrect. Using a comparison with another extraterrestrial element deposited in the impact - osmium - they were able to deduce that the collision deposited less debris than has previously been supposed...The recalculated iridium value suggests a smaller body hit the Earth." I don't know if this instance is the case, but I have noticed a few instances where false knowledge is repeated for years. The ones that I have noticed have been due to researchers being lazy or too rushed to look at the primary source. It always makes me wonder what else we have not yet corrected. The viscosity incident that Feynman mentioned, while different, also freaks me out. See: http://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan.27s_experiment_as_an_example_of_psychological_effects_in_scientific_methodology http://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan.27... Example: A cup of green tea is often said to contain 125-250mg of egcg. While this is true for a gram of sencha or matcha, where the whole leaf is ingested, a hot water brewed tea provides more than an order of magnitude less. Sencha and matcha were measured by ethanol extract, simulating leaf ingestion. But for about a decade now, the original source is not cited but other papers claiming water brew to contain >100mg. If you follow the trail all the way back to the original source, you can see that one person misread the paper and started this false knowledge. It is something I think about a lot when validating my own references.
- pstuart 14y ago
  Don't forget to drink your 8 cups of water each day....
  - pavel_lishin 14y ago
    It's great for washing down spinach.
guard-of-terra 14y ago
As far as I know, while astronomers are fairly sure that it was a giant space rock that killed dinosaurs, biologists/paleontologists are more wary. Some of big dinosaur findings are well after the iridium anomaly - meaning some dinosaurs managed to survive the impact.
- ImprovedSilence 14y ago
  Indeed. I don't have any sources off hand, but I believe the extinction lasted tens of thousands of years. And was only partially set off/caused by the impact. There have also been other mass extinction events, each lasting long periods of time on the "lifetime" scale, but are still just "relatively short periods of time" on a geologic scale. [edit] here's some good reading for you: http://en.wikipedia.org/wiki/Extinction_event http://en.wikipedia.org/wiki/Extinction_event and the event discussed in the article: http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event#Alternative_hypotheses http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_ex...
youngerdryas 14y ago
More likely is it was a binary http://www.newscientist.com/article/dn23126-dinosaurkilling-asteroid-was-a-twin-terror.html http://www.newscientist.com/article/dn23126-dinosaurkilling-... 15% of near earth objects are binaries, a fact that is not widely known. Edit: asteroids --> objects

31 points by momchenr 14y ago

swombat 14y ago

But other researchers were more cautious about the results. Well, I'm glad the headline made that clear.

teeja 14y ago
Really. This has gotten to be a serious problem with science-reporting lately. Headlines suggest deterministic certainty, article itself says, for example, "probably a speeding comet, US scientists say." (Not even "some US scientists" or "hypothesize".)

Lost_BiomedE 14y ago

"...the team suggests that frequently quoted iridium values are incorrect. Using a comparison with another extraterrestrial element deposited in the impact - osmium - they were able to deduce that the collision deposited less debris than has previously been supposed...The recalculated iridium value suggests a smaller body hit the Earth." I don't know if this instance is the case, but I have noticed a few instances where false knowledge is repeated for years. The ones that I have noticed have been due to researchers being lazy or too rushed to look at the primary source. It always makes me wonder what else we have not yet corrected. The viscosity incident that Feynman mentioned, while different, also freaks me out. See: http://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan.27s_experiment_as_an_example_of_psychological_effects_in_scientific_methodology http://en.wikipedia.org/wiki/Oil_drop_experiment#Millikan.27... Example: A cup of green tea is often said to contain 125-250mg of egcg. While this is true for a gram of sencha or matcha, where the whole leaf is ingested, a hot water brewed tea provides more than an order of magnitude less. Sencha and matcha were measured by ethanol extract, simulating leaf ingestion. But for about a decade now, the original source is not cited but other papers claiming water brew to contain >100mg. If you follow the trail all the way back to the original source, you can see that one person misread the paper and started this false knowledge. It is something I think about a lot when validating my own references.

pstuart 14y ago
Don't forget to drink your 8 cups of water each day....
- pavel_lishin 14y ago
  It's great for washing down spinach.

guard-of-terra 14y ago

As far as I know, while astronomers are fairly sure that it was a giant space rock that killed dinosaurs, biologists/paleontologists are more wary. Some of big dinosaur findings are well after the iridium anomaly - meaning some dinosaurs managed to survive the impact.

ImprovedSilence 14y ago
Indeed. I don't have any sources off hand, but I believe the extinction lasted tens of thousands of years. And was only partially set off/caused by the impact. There have also been other mass extinction events, each lasting long periods of time on the "lifetime" scale, but are still just "relatively short periods of time" on a geologic scale. [edit] here's some good reading for you: http://en.wikipedia.org/wiki/Extinction_event http://en.wikipedia.org/wiki/Extinction_event and the event discussed in the article: http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event#Alternative_hypotheses http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_ex...

youngerdryas 14y ago

More likely is it was a binary http://www.newscientist.com/article/dn23126-dinosaurkilling-asteroid-was-a-twin-terror.html http://www.newscientist.com/article/dn23126-dinosaurkilling-... 15% of near earth objects are binaries, a fact that is not widely known. Edit: asteroids --> objects