[Rockhounds] A Crater in Arizona Is Proof of the Universe's Wicked Curveball

[Kreigh Tomaszewski]

Earth isn’t nearly as pock-marked as the Moon or Mars
<https://www.popularmechanics.com/space/moon-mars/a45899515/nasa-suspension-solar-conjunction/>—thanks
to the Earth’s mesosphere, which protects the planet from large
meteoroids—but that doesn’t mean impacts aren’t possible. Just ask the
dinosaurs.

A “modern” example of this impact exception is the Barringer Crater
<https://science.nasa.gov/resource/meteor-crater-arizona-usa/>, located 37
miles east of Flagstaff in the desert of northern Arizona. Although it
formed around 50,000 years ago, the impact site
<https://www.popularmechanics.com/science/environment/a45139880/scientists-find-worlds-only-mountaintop-impact-crater/>
is
remarkably well-preserved, thanks to its arid surroundings.

Analyzing this impact crater by creating various computer simulations,
scientists from Brazil’s University of Campinas determined that the
iron/nickel-rich meteor was likely spinning fast when it struck the Earth
during the late Pleistocene. It was also probably composed of clumps of
smaller rocks loosely held together by gravity
<https://www.popularmechanics.com/science/energy/a40241329/gravity-energy/>.
The results of the study were published last month in the journal *Physical
Review E*
<https://journals.aps.org/pre/abstract/10.1103/PhysRevE.108.054904>.

“We carried out discrete element method computations of spinning granular
projectiles impacting onto cohesionless grains for different bonding
stresses, initial spins, and initial heights,” the paper reads. “Our
results shed light on the dispersion of the projectile’s material and the
different shapes of craters
<https://www.popularmechanics.com/space/moon-mars/a24291/curiousity-boron-findings/>
found
on Earth and other planetary environments.”

Impact craters are not a one-size-fits-all geological
<https://www.popularmechanics.com/science/a32669465/snowball-earth-great-unconformity-geologic-record-missing/>
feature.
Some are deep and narrow (with various formations within the crater itself)
while others, such as Barringer Crater
<https://barringercrater.com/the-crater>, are wide and shallow—basically
your mind’s-eye definition of an impact site.

To determine how meteors form these disparate-shaped holes (apart from
simple velocity), the researchers created simulations with virtual
projectiles that were clusters of 2,000 tiny spheres. This digital space
detritus was then “dropped” on a grainy layer that stood in for Earth’s
surface. What the researchers discovered in doing this is that rapidly
rotating asteroids
<https://www.popularmechanics.com/space/deep-space/a26875604/two-asteroids-same-origin/>
created
wide and shallow sites, just like the one at Barringer Crater. That means,
to borrow baseball parlance, the meteorite—called Canyon Diablo—was more of
a wicked curveball than some kind of spin-less fastball.

https://www.yahoo.com/lifestyle/crater-arizona-proof-universes-wicked-140000014.html