Stars

Which nuclear reaction occurs in stable stars?

May/June 2023

Four of the stages in the life cycle of a star, up to the point when it becomes a red giant, are shown. W The inward pull of gravitational attraction is exactly matched by an outward force from its centre. X Gravitational collapse inside the star causes the temperature to rise. Y The star increases in size. Z Most of the hydrogen has changed into helium. What is the correct sequence of these stages, beginning with the earliest?

May/June 2023

Astronomers use light-years to measure vast distances in space.

May/June 2023

Fig. 8.1 shows a nebula that was produced by a supernova.

May/June 2024

A star’s life cycle starts when a huge cloud of dust and gas collapses.

May/June 2025

Nuclear fusion is a process that happens in the Sun and in other stars.

Oct/Nov 2020

What is the initial stage in the life cycle of stars?

Oct/Nov 2023

What is never produced by the explosion of a red supergiant?

Oct/Nov 2024

A star that is stable in a faraway galaxy has a mass greater than 15 times the mass of the Sun.

Oct/Nov 2024