universe

What did the ancient geocentric model claim?

That Earth was at the centre and everything orbited around it.

What key observation did Galileo make that disproved the geocentric model?

Moons orbiting Jupiter and phases of Venus.

What does the heliocentric model state?

The Sun is at the centre and planets orbit the Sun.

What is a planet?

A large round object that orbits a star and doesn’t produce its own light.

What is a star?

A huge ball of hot gas that produces its own light and heat.

What is our solar system made of?

The Sun, 8 planets, moons, asteroids, comets, and dwarf planets.

What is cosmic microwave background radiation (CMB)?

Faint leftover radiation from the early universe after the Big Bang.

Why does the abundance of hydrogen and helium support the Big Bang?

Big Bang models predicted lots of light elements, and observations match.

What does redshift tell us about the universe?

That galaxies are moving away and the universe is expanding.

What does the Big Bang theory describe?

The universe beginning as a tiny, hot point and expanding over time.