The early universe consisted only of hydrogen and helium. How were the heavier e
ID: 290746 • Letter: T
Question
The early universe consisted only of hydrogen and helium. How were the heavier elements formed?
Through chemisynthesis; lighter elements reacted to form amino acids.
By plants using photosynthesis to extract energy from light.
These lighter elements coalesced in solar nebula and formed heavier elements through fusion.
Fission of helium atoms in stars creates heavier elements.
The early Earth was a homogeneous molten planet. How did Earth form the different layers of the crust, mantle and core?
Organic chemicals were created through chemisynthesis.
Through nucleosynthesis; the lighter elements were fused together in stars.
By differentiation of elements, separated by density.
By plants using photosynthesis to extract energy from light.
The oldest rocks on Earth are about 3,900,000 (3.9 billion) years old, yet the age of our solar system has been measured as 4.6 billion years old. What might explain what happened to the older Earth rocks?
Intense meteor impact activity early in Earth's history caused melting of the original crustal material.
They are covered up by newer rocks.
They were subducted and reconstituted in the mantle.
All of the above.
Through chemisynthesis; lighter elements reacted to form amino acids.
By plants using photosynthesis to extract energy from light.
These lighter elements coalesced in solar nebula and formed heavier elements through fusion.
Fission of helium atoms in stars creates heavier elements.
Explanation / Answer
1. The heavier elements formed when these lighter elements coalesced in solar nebula and formed heavier elements through fusion.
2. The different layers of the Earth formed by diffentiation of elements separated by density. The iron and nickel components being the heaviest settled into the deepest interior to form the earth's core while the less dense ultramafic rocks made up the mantle and the silicates being the lightest remained on the top forming the crust.
3. All of the above.
Early earth was very much dynamic and was hit by meteor many times. Such meteoritic impacts might have caused melting of the original early crustal material. Sedimentation and the consequent burial of these early rocks might have covered them up by newer rocks and thus they have reached a depth where it is impossible to reach. Subduction at trenches causes melting and subsequent underthrusting of the older rock layers which leads to destruction.
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