Formation and evolution of the Solar System

NASA's Psyche asteroid mission: a 3.6 billion kilometre 'journey to the centre of the Earth'

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Mercredi, octobre 18, 2023
NASA, Silicon, Solar System, System, Dust, Solar, Planet, Travel, Carbon, Oxygen, Iron, Spacecraft, History, Method, Nature Communications, Nickel, Formation and evolution of the Solar System, Hydrogen, Metal, Metallicity, Palladium, Communications satellite, Sulfur, Psyche, Mars

Psyche was only the 16th “asteroid” ever discovered: inhabitants of the Solar System that were neither the familiar planets nor the occasional visitors known as comets.

Key Points: 
  • Psyche was only the 16th “asteroid” ever discovered: inhabitants of the Solar System that were neither the familiar planets nor the occasional visitors known as comets.
  • With an average diameter of around 226km, the potato-shaped planetoid is the largest “M-type” asteroid, made largely of iron and nickel, much like Earth’s core.
  • Natural laboratories
    M-type asteroids like Psyche are thought to be the remnants of planets destroyed in the early years of the Solar System.
  • In these asteroids, heavier elements (like metals) sank toward the centre and lighter elements floated up to the outer layers.

Sahara space rock 4.5 billion years old upends assumptions about the early Solar System

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Mardi, août 29, 2023
Formation and evolution of the Solar System, Solar System, Sahara, Aluminium-26, Uranium, Lead, Solar, Nature Communications, Fire, Research, 4 Vesta, Erg Chech 002, Planet, Erg Chech, Dust, Isotope, Meteorite, Coal, Uranium mining, Lithium, Copper, Surveying, Holding company, System

On close inspection, the rocks turned out to be from outer space: lumps of rubble billions of years old, left over from the dawn of the Solar System.

Key Points: 
  • On close inspection, the rocks turned out to be from outer space: lumps of rubble billions of years old, left over from the dawn of the Solar System.
  • This is one of the most precise ages ever calculated for an object from space – and our results also cast doubt on some common assumptions about the early Solar System.

The secret life of aluminium

    • Among the many elements in this cloud was aluminium, which came in two forms.
    • Aluminium-26 is very useful stuff for scientists who want to understand how the Solar System formed and developed.
    • Because it decays over time, we can use it to date events – particularly within the first four or five million years of the Solar System’s life.

Uranium, lead and age

    • To figure that out, we will need to calculate the absolute ages of some ancient space rocks more precisely.
    • It’s useful for determining the relative ages of different objects, but not their absolute age in years.
    • There are two important isotopes of uranium (uranium-235 and uranium-238), which decay into different isotopes of lead (lead-207 and lead-206, respectively).

Meteorite groups

    • Achondrites are rocks formed from melted planetesimals, which is what we call solid lumps in the cloud of gas and debris that formed the Solar System.
    • Still other achondrites, including Erg Chech 002, are “ungrouped”: their parent bodies and family relationships are unknown.

A clumpy spread of aluminium

    • Measuring the ratios of all the lead and uranium isotopes was what helped us to estimate the age of the rock with such unprecedented accuracy.
    • We also compared our calculated age with previously published aluminium-26 data for Erg Chech 002, as well as data for various other achondrites.
    • This shows aluminium-26 was indeed distributed quite unevenly throughout the cloud of dust and gas which formed the solar system.