Touchdown airbursts — a type of cosmic impact that may be more common than the crater-forming, dinosaur-killing kind — remain somewhat less understood.
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.
Read More: University of California - Santa Barbara
