Taku

What event marks the beginning of the universe approximately 13.8 billion years ago?

The Big Bang.

What were the first elements to form after the Big Bang?

Hydrogen and helium.

What does the cosmic microwave background radiation signify?

It provides a snapshot of the universe shortly after the Big Bang, showing residual heat.

How did elements heavier than hydrogen and helium form in the universe?

They were formed in stars through nucleosynthesis and supernova explosions.

What is the solar system formed from approximately 4.6 billion years ago?

A rotating nebula of gas and dust.

What is called when heavier elements sink to Earth’s core and lighter materials rise to form the crust?

Differentiation.

In which process were elements like carbon, oxygen, and nitrogen created?

Nucleosynthesis.

What is the nebular condensation theory?

It explains how a nebula collapses, flattens into a spinning disc, and forms the Sun and planets.

What is differentiation important for in Earth’s formation?

It allowed Earth to separate into layers, concentrating denser materials in the core.

During their main sequence, stars fuse what into what?

Hydrogen into helium.

What process creates heavier elements up to iron in stars?

Fusion.

What can the end stages of a star's life result in?

A white dwarf, neutron star, or black hole.

Why can't stars produce elements heavier than iron during normal fusion processes?

Fusion of iron requires more energy than it releases, halting the process.

How do supernovae enrich the universe with heavy elements?

They scatter heavy elements, enabling the formation of planets and life.

What delivered water and icy compounds to Earth?

Comets and asteroids.

What is another source of water on Earth?

Volcanic outgassing.

What formed as a result of water vapor condensing?

Earth's first oceans.

What is the role of comets/asteroids and volcanic outgassing in the formation of Earth's oceans?

Comets delivered water-rich ice; volcanic outgassing released water vapor.

Why doesn’t the regular water cycle explain the origins of Earth’s water?

The water cycle is a recycling process; it does not create new water.

What were the first life forms on Earth?

Simple unicellular organisms that did not require oxygen.

What essential components did hydrothermal vents provide for early life?

Heat and chemicals.

What did the Miller-Urey experiment demonstrate?

That organic molecules like amino acids could form under prebiotic conditions.

Why are hydrothermal vents considered a potential origin of life?

They provide heat, minerals, and energy for early life forms.

What was the first significant organism to produce oxygen in large amounts?

Cyanobacteria.

What did oxygen react with to cool the Earth?

Methane.

What was the result of the increase in oxygen in Earth's atmosphere?

A mass extinction of anaerobic organisms.

How did the oxygen produced by cyanobacteria impact Earth’s atmosphere and climate?

It reduced greenhouse gases and cooled the planet.

What geological features are formed at divergent boundaries?

Mid-ocean ridges through the process of seafloor spreading.

What feature forms at convergent boundaries?

Ocean trenches where one plate subducts beneath another.

What contributes to the growth of ocean basins at divergent boundaries?

Seafloor spreading pushes older crust outward.

Why is convergent boundary often associated with volcanic activity?

Subduction causes melting and volcanic eruptions.

What is density calculated by?

Mass divided by volume.