Solar System
What is the giant cloud of gas and dust that the solar system formed from called?
Nebula
What is the Sun’s innermost layer called?
About how old is Earth?
4.5 billion years old
What is the most widely accepted theory for the Moon’s formation?
Giant Impact Hypothesis
What is the region called where most asteroids orbit between Mars and Jupiter?
The Asteroid Belt
What theory explains the Solar System forming from a cloud of gas and dust?
Nebular Hypothesis
Which layer gives off the light we see from Earth?
Photosphere
What caused Earth’s first atmosphere to form?
Volcanic outgassing
What body is thought to have collided with Earth to form the Moon?
A Mars-sized body / Theia
What happens to a comet as it gets closer to the Sun?
It heats up and forms a glowing coma and tail.
What two types of planets make up our Solar System?
Terrestrial (rocky) and Jovian (gas giants)
When does a protostar officially become a star?
When nuclear fusion starts in its core, turning hydrogen into helium.
How did Earth’s first oceans form?
As the Earth cooled, water vapor from volcanic activity condensed and fell as rain.
Why is the Moon’s composition similar to Earth’s crust?
It formed from Earth’s outer layers after the collision
What is the difference between a meteoroid, a meteor, and a meteorite?
A meteoroid is in space, a meteor burns in the atmosphere, and a meteorite lands on Earth.
Why are the inner planets rocky while the outer planets are mostly gas and ice?
The Sun’s heat kept gases from staying close, pushing them outward
Explain the purpose of the Radiation zone & Convection zone.
What were the first forms of life to appear on Earth?
Microbial life in the oceans
Name the 4 main theories of the Formation of the Moon.
Capture, Fission, Co-accretion, Giant Impact Hypothesis
Why are comets often described as “dirty snowballs”?
They’re made of ice mixed with dust, rock, and organic materials, like a frozen, dirty snowball.
Describe the steps of the nebular theory for how the solar system formed.
a nebula collapsed under gravity → it spun into a disk → the Sun formed in the center → dust and gas clumped into planetesimals → planets formed from collisions and accretion
What is granulation on the Sun’s surface caused by?
Convection currents of hot gases rising and cooler gases sinking
How did impacts from asteroids and comets change Earth’s chemical composition?
What is they delivered metals, minerals, water, and organic compounds to Earth, enriching its crust and helping create the building blocks for life?
What evidence do scientists use to support the Giant Impact Hypothesis?
Nearly identical isotopic ratios (like oxygen isotopes)
Radiometric dating shows Earth and Moon rocks are both about 4.5 billion years old, consistent with them forming from the same event.
Explain how asteroids, comets, and meteoroids are related to the formation of our solar system.
They are leftover building materials from the early solar system that never formed into planets.