Page 13 - COSMOS & H -Health - Science

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I I It was necessary for the high-speed encounter between
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It was necessary for the high-speed encounter between
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E E a r t t h a n d a n o t h e r b o d y t o b e h e a d - o n d u e t t o t t h e
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necessary mixing. Based on earlier estimations, the
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n n e c e s s a r y m i i x i i n g . . B a s e d o n e a r l l i i e r e s t t i i m a t t i i o n s , , t t h e
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necessary mixing. Based on earlier estimations, the
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M M o o n w a s n o t f f o r m e d b y a d i i r e c t h i i t r a t t h e r t t h a n b y a
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Moon was not formed by a direct hit rather than by a
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Moon was not formed by a direct hit rather than by a
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g g l l a n c i i n g b l l o w a t a h i i g h a n g l l e t t h a t t t i i l l t t e d t t h e s i i d e o f f t t h e
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glancing blow at a high angle that tilted the side of the
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glancing blow at a high angle that tilted the side of the
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Earth.
E E a r t t h . .
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Earth.
Research that came out in January 2016 suggests that
Research that came out in January 2016 suggests that
Theia's remains reside on Earth and the Moon indicating
Theia's remains reside on Earth and the Moon indicating
that the impact was, in fact, a head-on collision. The study
that the impact was, in fact, a head-on collision. The study
demonstrated that the oxygen isotopes in rocks from Earth
demonstrated that the oxygen isotopes in rocks from Earth
and the Moon have the same structure. This led to the belief
and the Moon have the same structure. This led to the belief
that both are from a similar source and from well-mixed
that both are from a similar source and from well-mixed
material. If Theia had merely glanced at the Earth, you
material. If Theia had merely glanced at the Earth, you
would expect the Moon and Earth to have different isotopic
would expect the Moon and Earth to have different isotopic
signatures.
signatures.
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Two continent-sized anomalies with low seismic velocities in
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Two continent-sized anomalies with low seismic velocities in
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the lowermost mantle have been identified via seismic
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the lowermost mantle have been identified via seismic

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imaging of Earth's interior. These anomalies are known as
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t t h e l l a r g e l l o w - v e l l o c i i t t y p r o v i i n c e s ( ( L L V P s ) ) . . A c o m m o n
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the large low-velocity provinces (LLVPs). A common
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the large low-velocity provinces (LLVPs). A common
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i i interpretation of the LLVPs is that they are compositionally
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interpretation of the LLVPs is that they are compositionally
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d d i i f f f f e r e n t f f r o m t t h e s u r r o u n d i i n g m a n t l l e a n d a r e f f u n d a m e n t t a l l l l y
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different from the surrounding mantle and are fundamentally
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different from the surrounding mantle and are fundamentally
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dense heterogeneities. Based on canonical giant-impact
d d e n s e h e t t e r o g e n e i i t t i i e s . . B a s e d o n c a n o n i i c a l l g i i a n t t - i i m p a c t t
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dense heterogeneities. Based on canonical giant-impact
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calculations, part of Theia's mantle may have been carried to
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c c a l l c u l l a t i i o n s , , p a r t o f f T h e i i a ' ' s m a n t t l l e m a y h a v e b e e n c a r r i i e d t t o
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calculations, part of Theia's mantle may have been carried to
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t t h e s o l l i i d l l o w e r m a n t t l l e o f f p r o t t o - E a r t t h . .
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the solid lower mantle of proto-Earth.
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the solid lower mantle of proto-Earth.
We find that Theia Mantle Material (TMM) is intrinsically
We find that Theia Mantle Material (TMM) is intrinsically
2.0–3.5% denser than proto-Earth’s mantle based on
2.0–3.5% denser than proto-Earth’s mantle based on
models of Theia’s mantle and the observed higher FeO
models of Theia’s mantle and the observed higher FeO
content of the Moon.
content of the Moon.
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In 2023, computer simulations reinforced that hypothesis.
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In 2023, computer simulations reinforced that hypothesis. .
-Krishna Rajeev
- XII-C