STARS“Balls of burning gas billions of miles away”

STAR INFORMATION The core of a star is like a giant

thermonuclear reactor They are mostly made up of hydrogen (and

dust) Scientists can observe stars and make

hypothesis about them based on understanding light, wavelengths and electromagnetic radiation

THE BIRTH OF A STAR Clumps of gas and dust floating around in a

nebula get draw together by their own gravity

This clump of material attracts more and more bits until the pressure causes the centre to collapse in on itself (now it is a protostar)

With enough dust and pressure, the centre will eventually reach 10 000 000 °C, and all the atoms there will fuse into larger atoms (hydrogen becoming helium)

This is called fusion

STAR LIFE CYCLE (FIGURE 11.3 PG 371) All stars start in a nebula, but from there one of

three things can happen 1: low mass stars

These spend most of their lives as cool red dwarfs, then hotter small dim white dwarfs, then they burn out

2: intermediate mass stars These burn faster than low mass stars, they become

a red giant, then a white dwarf and finally a black dwarf (our sun is one of these)

3: High mass stars Consume fuel very quickly, become a supergiant,

which later explodes in a supernova. This can either collapse into a black hole or a small neutron star

BLACK HOLES The centre has such intense gravity that

nothing can escape it, even light!!! Because we can’t see them we can only find

them by measuring how they affect objects around them