SIO 30 - Origin of Earth & oceans

What is the big bang hypothesis/theory?

The idea that the universe began about 13.8 billion years ago from a single, extremely hot and dense point, and has been expanding and cooling ever since

What is nuclear fusion?

When 2 small atomic nuclei join together to form a larger nucleus, releasing a huge amount of energy. The process that powers the Sun and stars

Which is the most abundant element in the universe?

Hydrogen - makes up about 75% of all normal matter in the universe

How are the heaviest elements formed? What is a supernova?

• Are formed during supernova explosions

• A supernova is a powerful explosion of a dying massive star

What is the process that forms planets out of small particles

Accretion: dust and gas particles in space stick together due to gravity and collisions, gradually forming larger clumps that eventually grow into planets

How old is the universe? Solar system? Earth?

• Universe: ~13.8 billion years old

• Solar system: ~4.6 billion years old

• Earth: ~4.5 billion years old

How was the moon formed?

When a Mars-sized object (Theia) collided with the early Earth about 4.5 billion years ago - blasted rock and debris into space, accreted to form the Moon

Define density. How did Earth become density stratified?

• How much mass is packed into a certain volume

• When it was still molten, heavier materials like iron/nickel sank to the center to form the core, while lighter materials like silicates and gases rose to form the mantle, crust, and atmosphere

Where did the Earth’s current atmosphere and oceans come from? Is the Earth’s current atmosphere similar or different from its first atmosphere?

• Came from volcanic gases and comets bringing water

• The first atmosphere had hydrogen and helium, but the current one has nitrogen and oxygen, very different

What is the oxygen revolution?

When cyanobacteria started producing oxygen through photosynthesis, ~2.4 billion years ago, dramatically increased oxygen in Earth's atmosphere

What are the most abundant gasses in the Earth’s current atmosphere?

Nitrogen (78%), Oxygen (21%), Argon (0.9%), Carbon dioxide and others (<1%)