Life Cycle of Stars and Fusion

The video explains the transformation of a planetary nebula into a white dwarf. It begins with an introduction to planetary nebulae, describing how stars like the sun undergo fusion processes, turning hydrogen into helium and then into carbon. As the star exhausts its hydrogen, it becomes a red giant, eventually forming a carbon core surrounded by layers of fusing helium and hydrogen. The instability of helium fusion leads to the ejection of the star's atmosphere, creating a planetary nebula with a carbon core and a diffused gas cloud. The exposed core, now a white dwarf, is the remnant of the star, appearing white due to trapped heat, despite the absence of fusion.

What is a planetary nebula?

• A type of planet

• A cloud of gas surrounding a star's core

• A black hole

• A type of galaxy

What elements are involved in the fusion process in stars like the Sun?

• Hydrogen and Oxygen

• Helium and Carbon

• Hydrogen and Helium

• Carbon and Nitrogen

What happens when a star becomes a red giant?

• It starts fusing hydrogen into helium

• It turns into a black hole

• It starts fusing helium into carbon

• It explodes into a supernova

What is the core of a star composed of when it forms a planetary nebula?

• Carbon

• Silicon

• Oxygen

• Iron

What causes the atmosphere of a star to be ejected into space?

• Unstable hydrogen fusion

• Stable hydrogen fusion

• Unstable helium fusion

• Stable helium fusion

What is a white dwarf?

• A type of galaxy

• A black hole

• The exposed core of a star

• A type of planet

Why does a white dwarf appear white?

• It is very cold

• It is still undergoing fusion

• It is made of ice

• It has a lot of heat trapped in the core

What surrounds a white dwarf?

• A field of ice

• A ring of asteroids

• A shell of diffused gas

• A cloud of dust

What is the main characteristic of a star considered 'dead'?

• It no longer emits light

• It no longer has an atmosphere

• It no longer has a core

• It no longer undergoes fusion

What remains at the center of a planetary nebula?

• A black hole

• A neutron star

• A white dwarf

• A red giant