Stellar Evolution
All stars form in nebulae, huge clouds of gas and dust.
Though they shine for thousands of years, stars do not last forever. The changes that occur in a star over time and the final stage of its life depends on a star's size.
Eventually, the hydrogen that powers a star's nuclear reactions begins to run out. The star then enters the final phases of its lifetime. All stars will expand, cool and change colour to become a red giant or red supergiant.
What happens next depends on how massive the star is.
Stars
Stars are massive, glowing balls of extremely hot gas (called plasma) in space. The Sun is our closest star.
All the energy in a star is made in its centre (its core), by a process called nuclear fusion. The star releases the energy as heat and light. This is what makes a star shine. The outward force generated by the fusion process is balanced by the inward pull of the star's gravity. It is the balance between the two which stops the star from collapsing or expanding.
Claudius Ptolemy
Occupation
Mathematician, Astronomer, Geographer
Year born
100 AD
Research Areas
Movements of planets and stars, Cartography
- Early Life
Claudius was born in Alexandria, Egypt, which was part of the Roman Empire at the time.
Very little is known about his life. The information we do have has been taken from the books he wrote.
Cecilia Payne Gaposchkin
Occupation
Astronomer
Year born
1900
Research Areas
Stars, Spectroscopy
- Early Life
Cecilia was born in Wendover, England. Her mother was interested in lots of different topics like nature, music and theatre. Cecilia spent lots of time reading in her home's library.
At the age of 19, she won a scholarship to Cambridge University to study science. During that time, Cecilia went to a talk given by Arthur Eddington. Arthur talked about his recent trip to Africa to observe the stars near a solar eclipse. This sparked Cecilia's interest in astronomy.
Classify a Star
What is a star?
We can see thousands of stars in the night sky - small points of light in the vastness of space. But what are stars? How do they make light? Why are they different colours? Watch this video to find out some more information about stars!
Make a 3D Constellation
Ricardo Schiavon
Occupation: Astrophysicist
Research Areas: Galaxy formation, Observational astronomy
"I consider myself extremely lucky to be where I am, do what I do, and to be surrounded by so many amazing people here in Liverpool."