- 3890 - SUPERNOVA - shock waves create elements? Some elements arrived on Earth by surfing supernova shock waves. When stars die, they spread the elements they’ve created in their cores out to space. But, other objects and processes in space also create elements. Eventually, that “star stuff” scatters across the galaxy in giant debris clouds.
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3890 - SUPERNOVA
- shock waves create elements?
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- Millions of
years the debris clouds settle onto
planets. How did heavy elements like
manganese, iron, and plutonium show up on Earth? It turns out they’re made in
different processes, often in different parts of the Milky Way. Yet, they’ve
been found layered together on Earth’s seabed. That implies they arrived about
the same time, despite their different origins.
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- These
elements from faraway events are carried by supernova shock fronts just like
surfers catching a wave.
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- First,
there are the Type II supernovae. They occur when a supermassive star dies.
That supernova is one at least eight times the mass of the Sun. These stars fuse
heavier and heavier elements in their cores. When they get to creating iron,
they don’t have enough energy to keep up the production line. The cores collapse
and then everything expands outward very rapidly in a supernova explosion.
That’s enough to send its heavy elements racing through space.
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- Next, there
are Type Ia supernovae. These happen in a binary pair of stars. Material from a
main-sequence star accretes onto its partner, a white dwarf. When too much
material accumulates, there’s an explosion. That results in the
“nucleosynthesis” of heavier elements, including manganese.
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- Another
catastrophic event that likely creates heavy elements is the collision, or
merger, of two neutron stars. As they
spiral in toward each other and eventually smash up, they release a shower of
neutrons. Those, in turn, bombard nearby atoms. This “r-process” event very
quickly produces heavy elements such as plutonium.
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- Somehow,
all this material from different sources ended up on Earth at about the same
time. Scientists found puzzling evidence of that in radioactive isotope
deposits on the seabed in 2021. They weren’t formed normally on Earth or during
the birth of the solar system some 4.5 billion years ago. They had to come from
somewhere else.
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- Getting
elements from there to here. Isotopes
can propagate through large areas of a galaxy via supernova shock waves. These
fronts sweep up collections of elements from various sites. Understanding this delivery process is
particularly crucial as astronomers begin large-scale studies of exoplanets
where life might be possible.
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- It’s a
very important step forward, as it not only shows us how isotopes propagate
through the Galaxy but also how they become abundant on exoplanets beyond our
solar system.
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- Isotopic
abundances are a strong factor in determining whether an exoplanet is able to
hold liquid water, which is key to life. In the future, this might help to
identify regions in our Galaxy where we could find habitable exoplanets.
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February 25, 2023 SUPERNOVA
- shock waves create elements? 3890
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