Neutron Stars & Black Holes
- In the final evolutionary stages of a massive star's life cycle, the remnant left after a supernova explosion will either be:
- A neutron star
- A black hole
Characteristics of a Neutron Star
- Neutron stars are objects formed in stars with cores which have masses greater than the Chandrasekhar limit
- Neutron stars are:
- Extremely dense
- Very small
- To put into perspective how dense and small a neutron star is:
- The density of a neutron star is 4 × 1017 kg m−3
- The density of the Earth is 5 × 103 kg m−3
- The density of a white dwarf is 1 × 109 kg m−3
- A neutron star with the mass of the Sun would be only 30 km in diameter
- Some neutron stars rotate rapidly (up to 600 times per second) emitting bursts of highly directional electromagnetic radiation
- These stars are called pulsars
Characteristics of Black Holes
- The core collapses into an infinitely dense point called a singularity
- A singularity is defined as:
A theoretical point at which matter is compressed to an infinitely small point and the laws of physics, as they are currently understood, break down
- The gravitational field is so strong that nothing, not even light, can escape it
- This region is known as a black hole
- The boundary at which light and matter cannot escape the gravitation pull of the black hole is called the event horizon
- The escape velocity beyond the event horizon is greater than the speed of light, hence photons cannot escape from a black hole
Characteristics of a Black Hole
