• When worlds collide: Studying impact cra

    From ScienceDaily@1:317/3 to All on Wed Mar 30 22:30:46 2022
    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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