Aug 9, 2025 04:01 AM
https://www.eurekalert.org/news-releases/1094161
EXCERPTS: Touchdown airbursts — a type of cosmic impact that may be more common than the crater-forming, dinosaur-killing kind — remain somewhat less understood. UC Santa Barbara Earth Science Emeritus Professor James Kennett and collaborators continue to make the case that these high-energy events deserve closer attention.
“Touchdown events can cause extreme damage through very high temperatures and pressures,” Kennett said. “And yet they don’t necessarily form a crater, or they form ephemeral surface disturbances, but they’re not the classic major craters that come from direct impacts.”
In four recently published papers, Kennett and co-authors presented evidence for several cosmic airbursts of different ages — events in which the impactor, such as a comet, explodes above ground, sending heat and shockwaves to the Earth’s surface. From the North Atlantic deep-sea floor to a site of an ancient desert civilization, these papers present a bevy of new evidence in support of the extremely high temperatures and pressures associated with these events. The so-called impact proxies include rare elements and minerals derived from the comet itself, molten glass and spherules formed from terrestrial materials at high temperatures, and shocked quartz, which displays patterns of cracks in this very hard material.
[...] Taken together, these papers point to the idea that cosmic impacts, and in particular touchdown airbursts, may occur more often than previously thought.
“They’re far more common, but also possess much more destructive potential than the more localized, classic crater-forming asteroidal impacts.” said Kennett. “The destruction from touchdown events can be much more widespread. And yet they haven’t been very well studied, so these should be of interest to humanity.” (MORE - missing details, no ads)
EXCERPTS: Touchdown airbursts — a type of cosmic impact that may be more common than the crater-forming, dinosaur-killing kind — remain somewhat less understood. UC Santa Barbara Earth Science Emeritus Professor James Kennett and collaborators continue to make the case that these high-energy events deserve closer attention.
“Touchdown events can cause extreme damage through very high temperatures and pressures,” Kennett said. “And yet they don’t necessarily form a crater, or they form ephemeral surface disturbances, but they’re not the classic major craters that come from direct impacts.”
In four recently published papers, Kennett and co-authors presented evidence for several cosmic airbursts of different ages — events in which the impactor, such as a comet, explodes above ground, sending heat and shockwaves to the Earth’s surface. From the North Atlantic deep-sea floor to a site of an ancient desert civilization, these papers present a bevy of new evidence in support of the extremely high temperatures and pressures associated with these events. The so-called impact proxies include rare elements and minerals derived from the comet itself, molten glass and spherules formed from terrestrial materials at high temperatures, and shocked quartz, which displays patterns of cracks in this very hard material.
[...] Taken together, these papers point to the idea that cosmic impacts, and in particular touchdown airbursts, may occur more often than previously thought.
“They’re far more common, but also possess much more destructive potential than the more localized, classic crater-forming asteroidal impacts.” said Kennett. “The destruction from touchdown events can be much more widespread. And yet they haven’t been very well studied, so these should be of interest to humanity.” (MORE - missing details, no ads)