The Universe 2026 S1

What is a star?

A luminous ball of gas

What causes a star to give off light?

Nuclear fission

Can stars be different colours, if so, what’s the cause?

Yes, the hotter the star, the more blue in colour

What is nuclear fusion?

Where two light atomic nuclei combine to become a single heavier nucleus

What is a solar system?

A gravitationally bound system, consisting of a star and the objects the orbit it

What are nebulae?

A stellar nursury of immense clouds of dust and ionised gases for to-be stars, or remnants of dying stars

What’s a galaxy?

A massive gravity-bound system of stars, gas, dust, and dark matter

What are the three main types of galaxies?

Spiral, elliptical, irregular

What is the observable universe?

A spherical region centered on Earth, containing all matter and energy that can be theoretically observed

How are the structures observed?

Nebula > Star > Solar system > Galaxy > Universe

Where does star birth occur?

In nebulas

How does star birth begin?

When hydrogen gas is pulled into a dense ball by gravity

What is the early stage of the formation of the star called?

Protostar

Three key things needed for star formation.

Hydrogen, gravity, time

Why do stars get hotter as they compress?

Stars get hotter as they compress due to the gravitational contraction, which converts gravitational potential energy into heat

A star forms in a giant cloud of gas and dust, called a ____

nebula

Some of the gas and dust is pulled into a giant, swirling vortex by _____

gravity

As the matter is compressed into smaller spaces, the temperature _______

increases

Over hundreds of years, the cloud gets thicker and forms a giant spinning ____

disc

At the centre of the disc, gravity crushes the gas into a super-____, super-hot ball

dense

Huge jets of ___ bursts out from the centre

gas

Over the next half-million years, the young star gets ____, _____, and hotter

smaller, brighter

What state of matter is the sun?

Plasma state