Neutron Stars and Pulsars
● The existence of neutron stars was predicted just two years after James
Chadwick discovered the neutron itself. Bell-Burnell and Hewish's pulsar was the
first such object to be found.
PAGE 22
● Pre-first discovery observations of neutron stars and pulsars came to light after
Shklovsky, Bell-Burnell and Hewish's work, and we now know that neutron stars
have similar diameters and masses, but can have densities up to 1018 kg m 3.
● A typical grain of table salt weighs 300 g on the Earth, but a fragment of typical
neutron star material would weigh well over 1015 tonnes on the surface of a
neutron star.
PAGE 23
● Trying to put numbers like these into a human perspective is difficult, but a
neutron star mountain with a height of 1/500 of the width of a human hair would
require as much effort to climb as Everest on Earth.
PAGE 24
● Neutron stars are black holes with magnetic fields up to 1015 times that of the
Earth. They spin at rates ranging from 100s of times per second to once every
ten seconds or so, and the slowest known pulsar is currently PSR J0250+5854,
1,600 pc away in Cassiopeia.
PAGE 25
● When a neutron star emits radiation, it forms two cones in space, and when we
observe a neutron star from Earth, we see a rapid flash or pulse of radiation from
the neutron star.
PAGE 26
● Neutron stars come in only one variety, but there are three types of pulsars,
depending on the energy source of the emissions. The Crab nebula pulsar, for
example, started emitting radio waves in 1970 and had slowed down to 33.7 ms
(1780 rpm) by 2012.
● The existence of neutron stars was predicted just two years after James
Chadwick discovered the neutron itself. Bell-Burnell and Hewish's pulsar was the
first such object to be found.
PAGE 22
● Pre-first discovery observations of neutron stars and pulsars came to light after
Shklovsky, Bell-Burnell and Hewish's work, and we now know that neutron stars
have similar diameters and masses, but can have densities up to 1018 kg m 3.
● A typical grain of table salt weighs 300 g on the Earth, but a fragment of typical
neutron star material would weigh well over 1015 tonnes on the surface of a
neutron star.
PAGE 23
● Trying to put numbers like these into a human perspective is difficult, but a
neutron star mountain with a height of 1/500 of the width of a human hair would
require as much effort to climb as Everest on Earth.
PAGE 24
● Neutron stars are black holes with magnetic fields up to 1015 times that of the
Earth. They spin at rates ranging from 100s of times per second to once every
ten seconds or so, and the slowest known pulsar is currently PSR J0250+5854,
1,600 pc away in Cassiopeia.
PAGE 25
● When a neutron star emits radiation, it forms two cones in space, and when we
observe a neutron star from Earth, we see a rapid flash or pulse of radiation from
the neutron star.
PAGE 26
● Neutron stars come in only one variety, but there are three types of pulsars,
depending on the energy source of the emissions. The Crab nebula pulsar, for
example, started emitting radio waves in 1970 and had slowed down to 33.7 ms
(1780 rpm) by 2012.
