Neutron Stars When stars about five times the mass of the sun run out of fuel, their own weight compresses the material unbelievably. The protons and electrons making up the matter are forced together forming neutrons.

Shrinking Stars Spin When a figure skater is spinning slowly, and then pulls in their arms, what happens?

Pulsar In 1967 Jocelyn Bell and Anthony Hewish discovered a type of neutron star called a Pulsar with a radio telescope If the initial mass is between about 1.4 and 8 solar masses, everything happens more quickly. When the stage of heavy element formation is reached, the core temperature rises to around 3,000,000,000K. The core is now made of iron, which will not react. As the reactions cease, the core implodes; this is followed by a rebound explosion: a Supernova. Most of the material is hurled into space, leaving a cloud of expanding gas at the centre of which is a small (a few km in diameter), super-dense (about 1,000,000,000,000,000 tonnes per cm3) object made of neutrons. This neutron star spins very rapidly, often many times a second. It has a very powerful magnetic field which gives direction to the radio pulses emitted by the star, rather like a lighthouse. The first pulsar (pulsating radio source) was discovered in 1967 by Jocelyn Bell. The pulsar in the Crab Nebula, M1, in Taurus is the remnant of the supernova of AD1054 which, for a while, was so bright as to be visible in the daytime sky. Pulsars gradually slow down and become cold and dead.

Pulsar A pulsar is a rotating neutron star spinning many times a second

“Sounds” of Pulsars When signals from a pulsar are received by a radio telescope and amplified you can listen to them.

Pulsar in the Crab Nebula Chinese astronomers noted a super-bright star that shown for a few weeks in the year 1054 AD. In the position they noted we now see this object. And this is what we hear

Pulsar in the Vela Supernova Remnant The pulsar that remains from the star that created this nebula pulses at a slower rate, about 11 times per second…

Discover a Pulsar Activity Three of the stars in the star field are pulsing. Which ones? We’ll build something called a stroboscope to help us.

Discover a Pulsar Activity As the disk turns it first shows, then hides the viewed object many times a second. This has the effect of slowing any pulsing of the object, making it easier to see.

Hear a Pulsar Scientists can convert the blinking of a pulsar into sound waves. Each click you hear is one flash of the pulsar.