When worlds collide: Studying impact craters to uncover the secrets of
the solar system
Date:
March 30, 2022
Source:
Purdue University
Summary:
While for humans the constants might be death and taxes, for
planets the constants are gravity and collisions. Astronomers are
using information about impacts to understand the history and the
composition of planets, moons, asteroids and meteorites throughout
the solar system.
FULL STORY ========================================================================== While for humans the constants might be death and taxes, for planets
the constants are gravity and collisions.
========================================================================== Brandon Johnson studies the latter, using information about impacts to understand the history and the composition of planets, moons, asteroids
and meteorites throughout the solar system.
"Impact cratering is the most ubiquitous surface process shaping
planetary bodies," Johnson said. "Craters are found on almost every
solid body we've ever seen. They are a major driver of change in
planetary bodies. They drive the evolution of planetary crusts. All
the planets and asteroids were built from a series of impacts. Studying
impacts can help us determine the composition and structure of planets."
As an associate professor in the Department of Earth, Atmospheric, and Planetary Sciences in Purdue University's College of Science, Johnson
has studied almost every major planetary body in the solar system. And
the time scale of his research ranges from relatively recent impacts to
nearly the beginning of the solar system itself.
Collecting clues about collisions helps Johnson reconstruct the
environment in which the collisions took place, offering deep insights
into how and when bodies formed. His research is helping humans explore
the planetary bodies in the solar system with only physics, math and
a computer. Space missions and laboratory analyses provide a constant
supply of new data and questions to work on.
"Most meteorites contain chondrules -- small, previously molten,
particles," Johnson said. "Essentially, by studying the formation of
chondrules by impacts, we can better understand what was going on in
the nascent solar system. For example, based on one impact, we were
able to determine that Jupiter had already formed right around 5 million
years after the first solar system solids, changing the timeline of our understanding of the solar system." Johnson and his lab staff incorporate known factors about the composition and physics of planetary bodies into complex computer models, running the models through a range of conditions
and comparing the results with observed phenomena. Analyzing movements
and collisions can offer insights into the composition of asteroids and meteorites, helping scientists understand how elements like water and
metal are distributed through a solar system. By studying impact craters
and basins on places like Pluto, Venus and icy moons, and the mechanics
of other processes occurring on Europa and asteroids like Psyche, his team
can understand more about their interiors; whether they have molten cores
and plate tectonics, for example, or whether they have liquid oceans.
His work doesn't just span the solar system. He studies impacts closer
to home, too, including on Earth's own moon and terrestrial impacts that
may have affected the way Earth's crust, atmosphere and biosphere evolved.
An online impact calculator tool developed by the late Jay Melosh,
Johnson's mentor and former Distinguished Professor of Earth, Atmospheric
and Planetary Sciences, allows anyone to study the impacts of various
rocks into the Earth.
Johnson and his team are rebuilding the tool for a new generation of
planetary students.
========================================================================== Story Source: Materials provided by Purdue_University. Note: Content
may be edited for style and length.
========================================================================== Journal Reference:
1. J.R. Elliott, H.J. Melosh, B.C. Johnson. The role of target
strength on
the ejection of martian meteorites. Icarus, 2022; 375: 114869 DOI:
10.1016/j.icarus.2021.114869 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/03/220330121354.htm
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